Dépouillements

A detailed and reduced reaction mechanism of biomass-based syngas fuels / Marina Braun-Unkhoff in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Titre : A detailed and reduced reaction mechanism of biomass-based syngas fuels Type de document : texte imprimé Auteurs : Marina Braun-Unkhoff, Auteur ; Nadezhda A. Slavinskaya, Auteur ; Aigner, Manfred, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Biofuel  Combustion  Flames  Gas  mixtures  Gas  turbines  Laminar  flow  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : n the present work, the elaboration of a reduced kinetic reaction mechanism is described, which predicts reliably fundamental characteristic combustion properties of two biogenic gas mixtures consisting mainly of hydrogen, methane, and carbon monoxide, with small amounts of higher hydrocarbons (ethane and propane) in different proportions. From the in-house detailed chemical kinetic reaction mechanism with about 55 species and 460 reactions, a reduced kinetic reaction mechanism was constructed consisting of 27 species and 130 reactions. Their predictive capability concerning laminar flame speed (measured at T0=323 K, 373 K, and 453 K, at p=1 bar, 3 bars, and 6 bars for equivalence ratios [cursive phi] between 0.6 and 2.2) and auto ignition data (measured in a shock tube between 1035 K and 1365 K at pressures around 16 bars for [cursive phi]=0.5 and 1.0) are discussed in detail. Good agreement was found between experimental and calculated values within the investigated parameter range. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] A detailed and reduced reaction mechanism of biomass-based syngas fuels [texte imprimé] / Marina Braun-Unkhoff, Auteur ; Nadezhda A. Slavinskaya, Auteur ; Aigner, Manfred, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Mots-clés : Biofuel  Combustion  Flames  Gas  mixtures  Gas  turbines  Laminar  flow  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : n the present work, the elaboration of a reduced kinetic reaction mechanism is described, which predicts reliably fundamental characteristic combustion properties of two biogenic gas mixtures consisting mainly of hydrogen, methane, and carbon monoxide, with small amounts of higher hydrocarbons (ethane and propane) in different proportions. From the in-house detailed chemical kinetic reaction mechanism with about 55 species and 460 reactions, a reduced kinetic reaction mechanism was constructed consisting of 27 species and 130 reactions. Their predictive capability concerning laminar flame speed (measured at T0=323 K, 373 K, and 453 K, at p=1 bar, 3 bars, and 6 bars for equivalence ratios [cursive phi] between 0.6 and 2.2) and auto ignition data (measured in a shock tube between 1035 K and 1365 K at pressures around 16 bars for [cursive phi]=0.5 and 1.0) are discussed in detail. Good agreement was found between experimental and calculated values within the investigated parameter range. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Rotordynamic stability predictions for centrifugal compressors using a bulk-flow model to predict impeller shroud force and moment coefficients / Manoj K. Gupta in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 14 p. Titre : Rotordynamic stability predictions for centrifugal compressors using a bulk-flow model to predict impeller shroud force and moment coefficients Type de document : texte imprimé Auteurs : Manoj K. Gupta, Auteur ; Childs, Dara W., Auteur Année de publication : 2011 Article en page(s) : 14 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Rotors  Flow  instability  Compressors  Impellers  Mach  number  Pistons  Compressible  flow  Swirling  flow  Flow  simulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : An analysis is developed for a compressible bulk-flow model of the leakage path between a centrifugal-compressor impeller's shroud and its housing along the impeller's front and back sides. This development is an extension of analyses performed first by Childs (1989, ASME J. Vib. Acoust., Stress, Reliab. Des., 111, pp. 216–225) for pump impellers. The bulk-flow model is used to predict reaction force and moment coefficients for the impeller shroud. A labyrinth seal code developed by Childs and Scharrer ( 1986, ASME Trans. J. Eng. Gas Turbines Power, 108, pp. 325–331) is used to calculate the rotordynamic coefficients developed by the labyrinth seals in the compressor stage and also provides a boundary condition for the shroud calculations. Comparisons between the measured shroud moment coefficients by Yoshida et al. (1996, Proceedings of the 6th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, 2, pp. 151–160) and model predictions show reasonable agreements for the clearance flow and reaction moments. For the conditions considered, low Mach number flow existed in the shroud clearance areas and compressible-flow and incompressible-flow models produced similar predictions. Childs' model predictions for the direct damping and cross-coupled stiffness coefficients of a pump impeller produced reasonable agreement; hence the present model was validated to the extent possible. A rotor model consisting of an overhung impeller stage supported by a nominally cantilevered rotor was analyzed for stability using the present bulk-flow model and an API standard Wachel–von Nimitz formula model (1981, J. Petrol. Technol., pp. 2252–2260). The bulk-flow model predicted significantly higher onset speeds of instability. Given that some compressors have been predicted to be comfortably stable using API standard Wachel–von Nimitz formula but have been unstable on the test stand, these results suggest that unidentified destabilizing forces and or moments are present in compressors. Seal rub conditions that arise from surge events and increase the seal clearances are simulated, showing that enlarged clearances increase the preswirl at the seals, thus increasing these seal's destabilizing forces and reducing stability margins. These results are consistent with field experience. Predictions concerning the back shroud indicate that shunt-hole injection mainly acts to enhance stability by changing the flow field of the division wall or balance piston seals, not by influencing the back-shroud's forces or moments. Effective swirl brakes at these seals also serve this purpose. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Rotordynamic stability predictions for centrifugal compressors using a bulk-flow model to predict impeller shroud force and moment coefficients [texte imprimé] / Manoj K. Gupta, Auteur ; Childs, Dara W., Auteur . - 2011 . - 14 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 14 p. Mots-clés : Rotors  Flow  instability  Compressors  Impellers  Mach  number  Pistons  Compressible  flow  Swirling  flow  Flow  simulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : An analysis is developed for a compressible bulk-flow model of the leakage path between a centrifugal-compressor impeller's shroud and its housing along the impeller's front and back sides. This development is an extension of analyses performed first by Childs (1989, ASME J. Vib. Acoust., Stress, Reliab. Des., 111, pp. 216–225) for pump impellers. The bulk-flow model is used to predict reaction force and moment coefficients for the impeller shroud. A labyrinth seal code developed by Childs and Scharrer ( 1986, ASME Trans. J. Eng. Gas Turbines Power, 108, pp. 325–331) is used to calculate the rotordynamic coefficients developed by the labyrinth seals in the compressor stage and also provides a boundary condition for the shroud calculations. Comparisons between the measured shroud moment coefficients by Yoshida et al. (1996, Proceedings of the 6th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery, 2, pp. 151–160) and model predictions show reasonable agreements for the clearance flow and reaction moments. For the conditions considered, low Mach number flow existed in the shroud clearance areas and compressible-flow and incompressible-flow models produced similar predictions. Childs' model predictions for the direct damping and cross-coupled stiffness coefficients of a pump impeller produced reasonable agreement; hence the present model was validated to the extent possible. A rotor model consisting of an overhung impeller stage supported by a nominally cantilevered rotor was analyzed for stability using the present bulk-flow model and an API standard Wachel–von Nimitz formula model (1981, J. Petrol. Technol., pp. 2252–2260). The bulk-flow model predicted significantly higher onset speeds of instability. Given that some compressors have been predicted to be comfortably stable using API standard Wachel–von Nimitz formula but have been unstable on the test stand, these results suggest that unidentified destabilizing forces and or moments are present in compressors. Seal rub conditions that arise from surge events and increase the seal clearances are simulated, showing that enlarged clearances increase the preswirl at the seals, thus increasing these seal's destabilizing forces and reducing stability margins. These results are consistent with field experience. Predictions concerning the back shroud indicate that shunt-hole injection mainly acts to enhance stability by changing the flow field of the division wall or balance piston seals, not by influencing the back-shroud's forces or moments. Effective swirl brakes at these seals also serve this purpose. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Effects of pilot fuel and liner cooling on the flame structure in a full scale swirl-stabilized combustion setup / Jens Färber in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Titre : Effects of pilot fuel and liner cooling on the flame structure in a full scale swirl-stabilized combustion setup Type de document : texte imprimé Auteurs : Jens Färber, Auteur ; Rainer Koch, Auteur ; Hans-Jörg Bauer, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Combustion  equipment  Cooling  Doppler  measurement  Fuel  systems  Gas  turbines  Laser  velocimetry  Swirling  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The flame structure and the limits of operation of a lean premixed swirl flame were experimentally investigated under piloted and nonpiloted conditions. Flame stabilization and blow out limits are discussed with respect to pilot fuel injection and combustor liner cooling for lean operating conditions. Two distinctly different flow patterns are found to develop depending on piloting and liner cooling parameters. These flow patterns are characterized with respect to flame stability, blow out limits, combustion noise, and emissions. The combustion system explored consists of a single burner similar to the burners used in Siemens annular combustion systems. The burner feeds a distinctively nonadiabatic combustion chamber operated with natural gas under atmospheric pressure. Liner cooling is mimicked by purely convective cooling and an additional flow of “leakage air” injected into the combustion chamber. Both additional air flow and the pilot fuel ratio were found to have a strong influence on the flow structure and stability of the flame close to the lean blow off (LBO) limit. It is shown by laser Doppler velocimetry that the angle of the swirl cone is strongly affected by pilot fuel injection. Two distinct types of flow patterns are observed close to LBO in this large scale setup: While nonpiloted flames exhibit tight cone angles and small inner recirculation zones (IRZs), sufficient piloting results in a wide cone angle and a large IRZ. Only in the latter case, the main flow becomes attached to the combustor liner. Flame structures deduced from flow fields and CH-chemiluminescence images depend on both the pilot fuel injection and liner cooling. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Effects of pilot fuel and liner cooling on the flame structure in a full scale swirl-stabilized combustion setup [texte imprimé] / Jens Färber, Auteur ; Rainer Koch, Auteur ; Hans-Jörg Bauer, Auteur . - 2011 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Mots-clés : Combustion  Combustion  equipment  Cooling  Doppler  measurement  Fuel  systems  Gas  turbines  Laser  velocimetry  Swirling  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The flame structure and the limits of operation of a lean premixed swirl flame were experimentally investigated under piloted and nonpiloted conditions. Flame stabilization and blow out limits are discussed with respect to pilot fuel injection and combustor liner cooling for lean operating conditions. Two distinctly different flow patterns are found to develop depending on piloting and liner cooling parameters. These flow patterns are characterized with respect to flame stability, blow out limits, combustion noise, and emissions. The combustion system explored consists of a single burner similar to the burners used in Siemens annular combustion systems. The burner feeds a distinctively nonadiabatic combustion chamber operated with natural gas under atmospheric pressure. Liner cooling is mimicked by purely convective cooling and an additional flow of “leakage air” injected into the combustion chamber. Both additional air flow and the pilot fuel ratio were found to have a strong influence on the flow structure and stability of the flame close to the lean blow off (LBO) limit. It is shown by laser Doppler velocimetry that the angle of the swirl cone is strongly affected by pilot fuel injection. Two distinct types of flow patterns are observed close to LBO in this large scale setup: While nonpiloted flames exhibit tight cone angles and small inner recirculation zones (IRZs), sufficient piloting results in a wide cone angle and a large IRZ. Only in the latter case, the main flow becomes attached to the combustor liner. Flame structures deduced from flow fields and CH-chemiluminescence images depend on both the pilot fuel injection and liner cooling. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Autoignition delay time measurements of methane, ethane, and propane pure fuels and methane-based fuel blends / M. M. Holton in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Titre : Autoignition delay time measurements of methane, ethane, and propane pure fuels and methane-based fuel blends Type de document : texte imprimé Auteurs : M. M. Holton, Auteur ; P. Gokulakrishnan, Auteur ; M. S. Klassen, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Fuel  Ignition  Natural  gas  technology  Organic  compounds  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Autoignition delay experiments in air have been performed in an atmospheric flow reactor using typical natural gas components, namely, methane, ethane, and propane. Autoignition delay measurements were also made for binary fuel mixtures of methane/ethane and methane/propane, and ternary mixtures of methane/ethane/propane. The effect of CO2 addition to the methane-based fuel blends on autoignition delay times was also investigated. Equivalence ratios for the experiments ranged between 0.5 and 1.25, and temperatures ranged from 930 K to 1140 K. Consistent with past studies, increasing equivalence ratio and increasing inlet temperatures over these ranges decreased autoignition delay times. Furthermore, addition of 5–10% ethane or propane decreased autoignition delay time of the binary methane-based fuel by 30–50%. Further addition of either ethane or propane showed less significant reduction of autoignition delays. Addition of 5–10% CO2 slightly decreased the autoignition delay times of methane fuel mixtures. Arrhenius correlations were used to derive activation energies for the ignition of the pure fuels and their mixtures. Results show a reduction in activation energies at the higher temperatures studied, which suggests a change in ignition chemistry at very high temperatures. Measurements show relatively good agreement with predictions from a detailed kinetics mechanism, specifically developed to model ignition chemistry of C1-C3 alkanes. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Autoignition delay time measurements of methane, ethane, and propane pure fuels and methane-based fuel blends [texte imprimé] / M. M. Holton, Auteur ; P. Gokulakrishnan, Auteur ; M. S. Klassen, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Mots-clés : Combustion  Fuel  Ignition  Natural  gas  technology  Organic  compounds  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Autoignition delay experiments in air have been performed in an atmospheric flow reactor using typical natural gas components, namely, methane, ethane, and propane. Autoignition delay measurements were also made for binary fuel mixtures of methane/ethane and methane/propane, and ternary mixtures of methane/ethane/propane. The effect of CO2 addition to the methane-based fuel blends on autoignition delay times was also investigated. Equivalence ratios for the experiments ranged between 0.5 and 1.25, and temperatures ranged from 930 K to 1140 K. Consistent with past studies, increasing equivalence ratio and increasing inlet temperatures over these ranges decreased autoignition delay times. Furthermore, addition of 5–10% ethane or propane decreased autoignition delay time of the binary methane-based fuel by 30–50%. Further addition of either ethane or propane showed less significant reduction of autoignition delays. Addition of 5–10% CO2 slightly decreased the autoignition delay times of methane fuel mixtures. Arrhenius correlations were used to derive activation energies for the ignition of the pure fuels and their mixtures. Results show a reduction in activation energies at the higher temperatures studied, which suggests a change in ignition chemistry at very high temperatures. Measurements show relatively good agreement with predictions from a detailed kinetics mechanism, specifically developed to model ignition chemistry of C1-C3 alkanes. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Tuning of the acoustic boundary conditions of combustion test rigs with active control / Mirko R. Bothien in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Titre : Tuning of the acoustic boundary conditions of combustion test rigs with active control : extension to actuators with nonlinear response Type de document : texte imprimé Auteurs : Mirko R. Bothien, Auteur ; Christian Oliver Paschereit, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Combustion  equipment  Gas  turbines  Nonlinear  control  systems  Thermoacoustics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the design process, new burners are generally tested in combustion test rigs. With these experiments, as well as with computational fluid dynamics, finite element calculations, and low-order network models, the burner's performance in the full-scale engine is sought to be predicted. Especially, information about the thermoacoustic behavior and the emissions is very important. As the thermoacoustics strongly depend on the acoustic boundary conditions of the system, it is obvious that test rig conditions should match or be close to those of the full-scale engine. This is, however, generally not the case. Hence, if the combustion process in the test rig is stable at certain operating conditions, it may show unfavorable dynamics at the same conditions in the engine. In previous works, the authors introduced an active control scheme, which is able to mimic almost arbitrary acoustic boundary conditions. Thus, the test rig properties can be tuned to correspond to those of the full-scale engine. The acoustic boundary conditions were manipulated using woofers. In the present study, an actuator with higher control authority is investigated, which could be used to apply the control scheme in industrial test rigs. The actuator modulates an air mass flow to generate an acoustic excitation. However, in contrast to the woofers, it exhibits a strong nonlinear response regarding amplitude and frequency. Thus, the control scheme is further developed to account for these nonlinear transfer characteristics. This modified control scheme is then applied to change the acoustic boundary conditions of an atmospheric swirl-stabilized combustion test rig. Excellent results were obtained in terms of changing the reflection coefficient to different levels. By manipulating its phase, different resonance frequencies could be imposed without any hardware changes. The nonlinear control approach is not restricted to the actuator used in this study and might therefore be of use for other actuators as well. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Tuning of the acoustic boundary conditions of combustion test rigs with active control : extension to actuators with nonlinear response [texte imprimé] / Mirko R. Bothien, Auteur ; Christian Oliver Paschereit, Auteur . - 2011 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Mots-clés : Combustion  Combustion  equipment  Gas  turbines  Nonlinear  control  systems  Thermoacoustics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the design process, new burners are generally tested in combustion test rigs. With these experiments, as well as with computational fluid dynamics, finite element calculations, and low-order network models, the burner's performance in the full-scale engine is sought to be predicted. Especially, information about the thermoacoustic behavior and the emissions is very important. As the thermoacoustics strongly depend on the acoustic boundary conditions of the system, it is obvious that test rig conditions should match or be close to those of the full-scale engine. This is, however, generally not the case. Hence, if the combustion process in the test rig is stable at certain operating conditions, it may show unfavorable dynamics at the same conditions in the engine. In previous works, the authors introduced an active control scheme, which is able to mimic almost arbitrary acoustic boundary conditions. Thus, the test rig properties can be tuned to correspond to those of the full-scale engine. The acoustic boundary conditions were manipulated using woofers. In the present study, an actuator with higher control authority is investigated, which could be used to apply the control scheme in industrial test rigs. The actuator modulates an air mass flow to generate an acoustic excitation. However, in contrast to the woofers, it exhibits a strong nonlinear response regarding amplitude and frequency. Thus, the control scheme is further developed to account for these nonlinear transfer characteristics. This modified control scheme is then applied to change the acoustic boundary conditions of an atmospheric swirl-stabilized combustion test rig. Excellent results were obtained in terms of changing the reflection coefficient to different levels. By manipulating its phase, different resonance frequencies could be imposed without any hardware changes. The nonlinear control approach is not restricted to the actuator used in this study and might therefore be of use for other actuators as well. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Ethanol-hydrocarbon blend vapor prediction / Romain Privat in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 08 p. Titre : Ethanol-hydrocarbon blend vapor prediction Type de document : texte imprimé Auteurs : Romain Privat, Auteur ; Jaubert, Jean-Noël, Auteur ; Freddy Garcia, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Gas  turbine  power  stations  Ignition  Safety  systems  Vaporisation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the volatile fuel price environment of today, the quest for alternative fuels has become a heavy and long term trend in power generation worldwide. Incorporating alternative fuels in gas turbine installations raises multiple engineering questions relating to combustion, emissions, on-base and auxiliary hardware capability, safety, etc. In 2008, GE carried out a field test aimed at characterizing the combustion of ethanol in a naphtha fuelled gas turbine plant. The testing strategy has been to locally prepare and burn ethanol-naphtha blends with a fraction of ethanol increasing from 0% to nearly 100%. During the engineering phase prior to this field test, it appeared necessary to develop a sufficient knowledge on the behavior of ethanol-hydrocarbon blends in order to establish the safety analysis and address in particular the risks of (i) potential uncontrolled ignition event in the air blanket of fuel tanks and (ii) flash vaporization of potential fuel pond in a confined environment. Although some results exist in the car engine literature for ethanol-gasoline blends, it was necessary to take into account the specificities of gas turbine applications, namely, (i) the much greater potential ethanol concentration range (from 0% to 100%) and (ii) the vast composition spectrum of naphtha likely to generate a much larger Reid vapor pressure envelope as compared with automotive applications. In order to fulfill the safety needs of this field test, the “Laboratoire de Thermodynamique des Milieux Polyphasés” of Nancy, France has developed a thermodynamic model to approach the vaporization equilibria of ethanol-hydrocarbons mixtures with variable ethanol strength and naphtha composition. This model, named PPR78, is based on the 1978 Peng–Robinson equation of state and allows the estimation of the thermodynamic properties of a multicomponent mixture made of ethanol and naphtha compounds by using the group contribution concept. The saturation equilibrium partial pressure of such fluids in the various situations of relevance for the safety analysis can thus be calculated. The paper reports the elaboration of this model and illustrates the results obtained when using it in different safety configurations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Ethanol-hydrocarbon blend vapor prediction [texte imprimé] / Romain Privat, Auteur ; Jaubert, Jean-Noël, Auteur ; Freddy Garcia, Auteur . - 2011 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 08 p. Mots-clés : Combustion  Gas  turbine  power  stations  Ignition  Safety  systems  Vaporisation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the volatile fuel price environment of today, the quest for alternative fuels has become a heavy and long term trend in power generation worldwide. Incorporating alternative fuels in gas turbine installations raises multiple engineering questions relating to combustion, emissions, on-base and auxiliary hardware capability, safety, etc. In 2008, GE carried out a field test aimed at characterizing the combustion of ethanol in a naphtha fuelled gas turbine plant. The testing strategy has been to locally prepare and burn ethanol-naphtha blends with a fraction of ethanol increasing from 0% to nearly 100%. During the engineering phase prior to this field test, it appeared necessary to develop a sufficient knowledge on the behavior of ethanol-hydrocarbon blends in order to establish the safety analysis and address in particular the risks of (i) potential uncontrolled ignition event in the air blanket of fuel tanks and (ii) flash vaporization of potential fuel pond in a confined environment. Although some results exist in the car engine literature for ethanol-gasoline blends, it was necessary to take into account the specificities of gas turbine applications, namely, (i) the much greater potential ethanol concentration range (from 0% to 100%) and (ii) the vast composition spectrum of naphtha likely to generate a much larger Reid vapor pressure envelope as compared with automotive applications. In order to fulfill the safety needs of this field test, the “Laboratoire de Thermodynamique des Milieux Polyphasés” of Nancy, France has developed a thermodynamic model to approach the vaporization equilibria of ethanol-hydrocarbons mixtures with variable ethanol strength and naphtha composition. This model, named PPR78, is based on the 1978 Peng–Robinson equation of state and allows the estimation of the thermodynamic properties of a multicomponent mixture made of ethanol and naphtha compounds by using the group contribution concept. The saturation equilibrium partial pressure of such fluids in the various situations of relevance for the safety analysis can thus be calculated. The paper reports the elaboration of this model and illustrates the results obtained when using it in different safety configurations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Design overview of a three kilowatt recuperated ceramic turboshaft engine / Michael J. Vick in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Titre : Design overview of a three kilowatt recuperated ceramic turboshaft engine Type de document : texte imprimé Auteurs : Michael J. Vick, Auteur ; Andrew Heyes, Auteur ; Keith Pullen, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ceramics  Gas  turbines  Heat  exchangers  Jet  engines  Power  generation  reliability  Silicon  compounds Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A three kilowatt turboshaft engine with a ceramic recuperator and turbine has been designed for small unmanned air vehicle (UAV) propulsion and portable power generation. Compared with internal combustion (IC) engines, gas turbines offer superior reliability, engine life, noise and vibration characteristics, and compatibility with military fuels. However, the efficiency of miniature gas turbines must be improved substantially, without severely compromising weight and cost, if they are to compete effectively with small IC engines for long-endurance UAV propulsion. This paper presents a design overview and supporting analytical results for an engine that could meet this goal. The system architecture was chosen to accommodate the limitations of mature, cost-effective ceramic materials: silicon nitride for the turbine rotors and toughened mullite for the heat exchanger and turbine stators. An engine with a cycle pressure ratio below 2:1, a multistage turbine, and a highly effective recuperator is shown to have numerous advantages in this context. A key benefit is a very low water vapor-induced surface recession rate for silicon nitride, due to an extremely low partial pressure of water in the combustion products. Others include reduced sensitivity to internal flaws, creep, and foreign object damage; an output shaft speed low enough for grease-lubricated bearings; and the potential viability of a novel premixed heat-recirculating combustor. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Design overview of a three kilowatt recuperated ceramic turboshaft engine [texte imprimé] / Michael J. Vick, Auteur ; Andrew Heyes, Auteur ; Keith Pullen, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Mots-clés : Ceramics  Gas  turbines  Heat  exchangers  Jet  engines  Power  generation  reliability  Silicon  compounds Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A three kilowatt turboshaft engine with a ceramic recuperator and turbine has been designed for small unmanned air vehicle (UAV) propulsion and portable power generation. Compared with internal combustion (IC) engines, gas turbines offer superior reliability, engine life, noise and vibration characteristics, and compatibility with military fuels. However, the efficiency of miniature gas turbines must be improved substantially, without severely compromising weight and cost, if they are to compete effectively with small IC engines for long-endurance UAV propulsion. This paper presents a design overview and supporting analytical results for an engine that could meet this goal. The system architecture was chosen to accommodate the limitations of mature, cost-effective ceramic materials: silicon nitride for the turbine rotors and toughened mullite for the heat exchanger and turbine stators. An engine with a cycle pressure ratio below 2:1, a multistage turbine, and a highly effective recuperator is shown to have numerous advantages in this context. A key benefit is a very low water vapor-induced surface recession rate for silicon nitride, due to an extremely low partial pressure of water in the combustion products. Others include reduced sensitivity to internal flaws, creep, and foreign object damage; an output shaft speed low enough for grease-lubricated bearings; and the potential viability of a novel premixed heat-recirculating combustor. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Nonparametric stochastic modeling of uncertainty in rotordynamics / Raghavendra Murthy in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Titre : Nonparametric stochastic modeling of uncertainty in rotordynamics : part I: formulation Type de document : texte imprimé Auteurs : Raghavendra Murthy, Auteur ; Marc P. Mignolet, Auteur ; Aly El-Shafei, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Damping  Elastic  constants  Machine  bearings  Matrix  algebra  Rotors  Stochastic  processes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A systematic and rational approach is presented for the consideration of uncertainty in rotordynamics systems, i.e., in rotor mass and gyroscopic matrices, stiffness matrix, and bearing coefficients. The approach is based on the nonparametric stochastic modeling technique, which permits the consideration of both data and modeling uncertainty. The former is induced by a lack of exact knowledge of properties such as density, Young's modulus, etc. The latter occurs in the generation of the computational model from the physical structure as some of its features are invariably ignored, e.g., small anisotropies, or approximately represented, e.g., detailed meshing of gears. The nonparametric stochastic modeling approach, which is briefly reviewed first, introduces uncertainty in reduced order models through the randomization of their system matrices (e.g., stiffness, mass, and damping matrices of nonrotating structural dynamic systems). Here, this methodology is extended to permit the consideration of uncertainty in symmetric and asymmetric rotor dynamic systems. More specifically, uncertainties on the rotor stiffness (stiffness matrix) and/or mass properties (mass and gyroscopic matrices) are first introduced that maintain the symmetry of the rotor. The generalization of these concepts to uncertainty in the bearing coefficients is achieved next. Finally, the consideration of uncertainty in asymmetric rotors is described in detail. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Nonparametric stochastic modeling of uncertainty in rotordynamics : part I: formulation [texte imprimé] / Raghavendra Murthy, Auteur ; Marc P. Mignolet, Auteur ; Aly El-Shafei, Auteur . - 2011 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Mots-clés : Damping  Elastic  constants  Machine  bearings  Matrix  algebra  Rotors  Stochastic  processes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A systematic and rational approach is presented for the consideration of uncertainty in rotordynamics systems, i.e., in rotor mass and gyroscopic matrices, stiffness matrix, and bearing coefficients. The approach is based on the nonparametric stochastic modeling technique, which permits the consideration of both data and modeling uncertainty. The former is induced by a lack of exact knowledge of properties such as density, Young's modulus, etc. The latter occurs in the generation of the computational model from the physical structure as some of its features are invariably ignored, e.g., small anisotropies, or approximately represented, e.g., detailed meshing of gears. The nonparametric stochastic modeling approach, which is briefly reviewed first, introduces uncertainty in reduced order models through the randomization of their system matrices (e.g., stiffness, mass, and damping matrices of nonrotating structural dynamic systems). Here, this methodology is extended to permit the consideration of uncertainty in symmetric and asymmetric rotor dynamic systems. More specifically, uncertainties on the rotor stiffness (stiffness matrix) and/or mass properties (mass and gyroscopic matrices) are first introduced that maintain the symmetry of the rotor. The generalization of these concepts to uncertainty in the bearing coefficients is achieved next. Finally, the consideration of uncertainty in asymmetric rotors is described in detail. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Nonparametric stochastic modeling of uncertainty in rotordynamics / Raghavendra Murthy in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Titre : Nonparametric stochastic modeling of uncertainty in rotordynamics : part II: applications Type de document : texte imprimé Auteurs : Raghavendra Murthy, Auteur ; Marc P. Mignolet, Auteur ; Aly El-Shafei, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Eigenvalues  and  eigenfunctions  Machine  bearings  Rotors  Stochastic  processes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the first part of this series, a comprehensive methodology was proposed for the consideration of uncertainty in rotordynamic systems. This second part focuses on the application of this approach to a simple, yet representative, symmetric rotor supported by two journal bearings exhibiting linear, asymmetric properties. The effects of uncertainty in rotor properties (i.e., mass, gyroscopic, and stiffness matrices) that maintain the symmetry of the rotor are first considered. The parameter lambda that specifies the level of uncertainty in the simulation of stiffness and mass uncertain properties (the latter with algorithm I) is obtained by imposing a standard deviation of the first nonzero natural frequency of the free nonrotating rotor. Then, the effects of these uncertainties on the Campbell diagram, eigenvalues and eigenvectors of the rotating rotor on its bearings, forced unbalance response, and oil whip instability threshold are predicted and discussed. A similar effort is also carried out for uncertainties in the bearing stiffness and damping matrices. Next, uncertainties that violate the asymmetry of the present rotor are considered to exemplify the simulation of uncertain asymmetric rotors. A comparison of the effects of symmetric and asymmetric uncertainties on the eigenvalues and eigenvectors of the rotating rotor on symmetric bearings is finally performed to provide a first perspective on the importance of uncertainty-born asymmetry in the response of rotordynamic systems. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Nonparametric stochastic modeling of uncertainty in rotordynamics : part II: applications [texte imprimé] / Raghavendra Murthy, Auteur ; Marc P. Mignolet, Auteur ; Aly El-Shafei, Auteur . - 2011 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Mots-clés : Eigenvalues  and  eigenfunctions  Machine  bearings  Rotors  Stochastic  processes Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In the first part of this series, a comprehensive methodology was proposed for the consideration of uncertainty in rotordynamic systems. This second part focuses on the application of this approach to a simple, yet representative, symmetric rotor supported by two journal bearings exhibiting linear, asymmetric properties. The effects of uncertainty in rotor properties (i.e., mass, gyroscopic, and stiffness matrices) that maintain the symmetry of the rotor are first considered. The parameter lambda that specifies the level of uncertainty in the simulation of stiffness and mass uncertain properties (the latter with algorithm I) is obtained by imposing a standard deviation of the first nonzero natural frequency of the free nonrotating rotor. Then, the effects of these uncertainties on the Campbell diagram, eigenvalues and eigenvectors of the rotating rotor on its bearings, forced unbalance response, and oil whip instability threshold are predicted and discussed. A similar effort is also carried out for uncertainties in the bearing stiffness and damping matrices. Next, uncertainties that violate the asymmetry of the present rotor are considered to exemplify the simulation of uncertain asymmetric rotors. A comparison of the effects of symmetric and asymmetric uncertainties on the eigenvalues and eigenvectors of the rotating rotor on symmetric bearings is finally performed to provide a first perspective on the importance of uncertainty-born asymmetry in the response of rotordynamic systems. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

On damping entire bladed disks through dampers on only a few blades / Javier Avalos in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Titre : On damping entire bladed disks through dampers on only a few blades Type de document : texte imprimé Auteurs : Javier Avalos, Auteur ; Marc P. Mignolet, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Blades  Damping  Discs  (structures)  Reduced  order  systems  Shock  absorbers  Turbomachinery  Vibration  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The focus of this paper is on demonstrating the potential to damp entire bladed disks using dampers on only a fraction of the blades. This problem is first considered without the presence of random mistuning, and it is demonstrated that a few dampers at optimized locations can lead to a significant reduction in the forced response of the entire bladed disk. Unfortunately, this optimum design may not be robust with respect to random mistuning and a notable fraction of the reduction in forced response obtained may disappear because of mistuning. To regain the reduction in forced response but with mistuning present, robustness to mistuning is enhanced by using intentional mistuning in addition to dampers. The intentional mistuning strategy selected here is the A/B pattern mistuning in which the blades all belong to either type A or B. An optimization effort is then performed to obtain the best combination of A/B pattern and damper location to minimize the mistuned forced response of the disk. The addition of intentional mistuning in the system is shown to be very efficient, and the optimum bladed disk design does indeed exhibit a significant reduction in mistuned forced response as compared with the tuned system. These findings were obtained on both single-degree-of-freedom per blade-disk models and a reduced order model of a blisk. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] On damping entire bladed disks through dampers on only a few blades [texte imprimé] / Javier Avalos, Auteur ; Marc P. Mignolet, Auteur . - 2011 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Mots-clés : Blades  Damping  Discs  (structures)  Reduced  order  systems  Shock  absorbers  Turbomachinery  Vibration  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The focus of this paper is on demonstrating the potential to damp entire bladed disks using dampers on only a fraction of the blades. This problem is first considered without the presence of random mistuning, and it is demonstrated that a few dampers at optimized locations can lead to a significant reduction in the forced response of the entire bladed disk. Unfortunately, this optimum design may not be robust with respect to random mistuning and a notable fraction of the reduction in forced response obtained may disappear because of mistuning. To regain the reduction in forced response but with mistuning present, robustness to mistuning is enhanced by using intentional mistuning in addition to dampers. The intentional mistuning strategy selected here is the A/B pattern mistuning in which the blades all belong to either type A or B. An optimization effort is then performed to obtain the best combination of A/B pattern and damper location to minimize the mistuned forced response of the disk. The addition of intentional mistuning in the system is shown to be very efficient, and the optimum bladed disk design does indeed exhibit a significant reduction in mistuned forced response as compared with the tuned system. These findings were obtained on both single-degree-of-freedom per blade-disk models and a reduced order model of a blisk. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Blade forcing function and aerodynamic work measurements in a high speed centrifugal compressor with inlet distortion / Albert Kammerer in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Titre : Blade forcing function and aerodynamic work measurements in a high speed centrifugal compressor with inlet distortion Type de document : texte imprimé Auteurs : Albert Kammerer, Auteur ; Reza S. Abhari, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aerodynamics  Blades  Calibration  Compressors  Distortion  Impellers  Measurement  uncertainty  Pressure  measurement  Pressure  sensors  Strain  gauges Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Centrifugal compressors operating at varying rotational speeds, such as in helicopters or turbochargers, can experience forced response failure modes. The response of the compressors can be triggered by aerodynamic flow nonuniformities such as with diffuser-impeller interaction or with inlet distortions. The work presented here addresses experimental investigations of forced response in centrifugal compressors with inlet distortions. This research is part of an ongoing effort to develop related experimental techniques and to provide data for validation of computational tools. In this work, measurements of blade surface pressure and aerodynamic work distribution were addressed. A series of pressure sensors were designed and installed on rotating impeller blades and simultaneous measurements with blade-mounted strain gauges were performed under engine representative conditions. To the best knowledge of the authors, this is the first publication, which presents comprehensive experimental unsteady pressure measurements during forced response, for high-speed radial compressors. The experimental data were obtained for both resonance and off-resonance conditions with uniquely tailored inlet distortion. This paper covers aspects relating to the design of fast response pressure sensors and their installation on thin impeller blades. Additionally, sensor properties are outlined with a focus on calibration and measurement uncertainty estimations. The second part of this paper presents unsteady pressure results taken for a number of inlet distortion cases. It will be shown that the intended excitation order due to inlet flow distortion is of comparable magnitude to the second and third harmonics, which are consistently observed in all measurements. Finally, an experimental method will be outlined that enables the measurement of aerodynamic work on the blade surface during resonant crossing. This approach quantifies the energy exchange between the blade and the flow in terms of cyclic work along the blade surface. The phase angle between the unsteady pressure and the blade movement will be shown to determine the direction of energy transfer. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Blade forcing function and aerodynamic work measurements in a high speed centrifugal compressor with inlet distortion [texte imprimé] / Albert Kammerer, Auteur ; Reza S. Abhari, Auteur . - 2011 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Mots-clés : Aerodynamics  Blades  Calibration  Compressors  Distortion  Impellers  Measurement  uncertainty  Pressure  measurement  Pressure  sensors  Strain  gauges Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Centrifugal compressors operating at varying rotational speeds, such as in helicopters or turbochargers, can experience forced response failure modes. The response of the compressors can be triggered by aerodynamic flow nonuniformities such as with diffuser-impeller interaction or with inlet distortions. The work presented here addresses experimental investigations of forced response in centrifugal compressors with inlet distortions. This research is part of an ongoing effort to develop related experimental techniques and to provide data for validation of computational tools. In this work, measurements of blade surface pressure and aerodynamic work distribution were addressed. A series of pressure sensors were designed and installed on rotating impeller blades and simultaneous measurements with blade-mounted strain gauges were performed under engine representative conditions. To the best knowledge of the authors, this is the first publication, which presents comprehensive experimental unsteady pressure measurements during forced response, for high-speed radial compressors. The experimental data were obtained for both resonance and off-resonance conditions with uniquely tailored inlet distortion. This paper covers aspects relating to the design of fast response pressure sensors and their installation on thin impeller blades. Additionally, sensor properties are outlined with a focus on calibration and measurement uncertainty estimations. The second part of this paper presents unsteady pressure results taken for a number of inlet distortion cases. It will be shown that the intended excitation order due to inlet flow distortion is of comparable magnitude to the second and third harmonics, which are consistently observed in all measurements. Finally, an experimental method will be outlined that enables the measurement of aerodynamic work on the blade surface during resonant crossing. This approach quantifies the energy exchange between the blade and the flow in terms of cyclic work along the blade surface. The phase angle between the unsteady pressure and the blade movement will be shown to determine the direction of energy transfer. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Analytical model to predict thermomechanical relaxation of shot peening induced residual stresses / Min Huang in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 05 p. Titre : Analytical model to predict thermomechanical relaxation of shot peening induced residual stresses Type de document : texte imprimé Auteurs : Min Huang, Auteur ; Yogesh K. Potdar, Auteur ; Srikanth Akkaram, Auteur Année de publication : 2011 Article en page(s) : 05 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Blades  Engines  Fatigue  Internal  stresses  Rotors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Shot peening is widely used to improve the fatigue life of engine blades and rotors by inducing compressive residual stress on component surfaces. However, the residual stresses can relax due to exposure at high service temperature and mechanical loading. A physics-motivated analytical solution is developed to predict the residual stress relaxation at high temperature and under mechanical loading. In this thermomechanical relaxation model, the plastic strains in the shot peening layer and the substrate are obtained analytically by using linear kinematic hardening material law, and the plastic strain evolution at high temperature is modeled by using a recovery strain term. The final residual stress as a function of time, temperature, and mechanical loading is obtained analytically by combining this recovery strain with equilibrium and compatibility conditions. The whole method can be implemented into Microsoft Excel, and is easy to use and validate. As a special case, an analytical closed-form solution to predict the pure thermal relaxation of a shot peening residual stress is developed. The model predictions agree satisfactorily with published experimental measurements. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Analytical model to predict thermomechanical relaxation of shot peening induced residual stresses [texte imprimé] / Min Huang, Auteur ; Yogesh K. Potdar, Auteur ; Srikanth Akkaram, Auteur . - 2011 . - 05 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 05 p. Mots-clés : Blades  Engines  Fatigue  Internal  stresses  Rotors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Shot peening is widely used to improve the fatigue life of engine blades and rotors by inducing compressive residual stress on component surfaces. However, the residual stresses can relax due to exposure at high service temperature and mechanical loading. A physics-motivated analytical solution is developed to predict the residual stress relaxation at high temperature and under mechanical loading. In this thermomechanical relaxation model, the plastic strains in the shot peening layer and the substrate are obtained analytically by using linear kinematic hardening material law, and the plastic strain evolution at high temperature is modeled by using a recovery strain term. The final residual stress as a function of time, temperature, and mechanical loading is obtained analytically by combining this recovery strain with equilibrium and compatibility conditions. The whole method can be implemented into Microsoft Excel, and is easy to use and validate. As a special case, an analytical closed-form solution to predict the pure thermal relaxation of a shot peening residual stress is developed. The model predictions agree satisfactorily with published experimental measurements. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Performance and combustion characteristics of OM314 diesel engine fueled with DME / L. Savadkouhi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Titre : Performance and combustion characteristics of OM314 diesel engine fueled with DME : a theoretical and experimental analysis Type de document : texte imprimé Auteurs : L. Savadkouhi, Auteur ; S. A. Jazayeri, Auteur ; N. Shahangian, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Diesel  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Use of dimethyl ether (DME) as a diesel fuel alternative has been increased due to the unique combustion characteristics of this oxygenated fuel. We have investigated performance and combustion characteristics of a naturally aspirated diesel engine using DME as the main fuel. In the experimental part of this work, OM314 direct-injection diesel engine was used as a base engine. A comprehensive full cycle was coupled with a multizone combustion model to simulate performance characteristics of the engine. Results of the volumetric efficiency showed that the highest brake torque was achievable in midspeed range. The power speed diagram showed that the brake torque tended to be much higher for diesel fuel than for DME when the engine speed was less than 1900 rpm. However, in engine speeds higher than 1900 rpm, brake torque in DME mode of operation was larger. Calculated emission results also suggested that negligible soot is produced in DME mode operation. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Performance and combustion characteristics of OM314 diesel engine fueled with DME : a theoretical and experimental analysis [texte imprimé] / L. Savadkouhi, Auteur ; S. A. Jazayeri, Auteur ; N. Shahangian, Auteur . - 2011 . - 06 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Mots-clés : Combustion  Diesel  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Use of dimethyl ether (DME) as a diesel fuel alternative has been increased due to the unique combustion characteristics of this oxygenated fuel. We have investigated performance and combustion characteristics of a naturally aspirated diesel engine using DME as the main fuel. In the experimental part of this work, OM314 direct-injection diesel engine was used as a base engine. A comprehensive full cycle was coupled with a multizone combustion model to simulate performance characteristics of the engine. Results of the volumetric efficiency showed that the highest brake torque was achievable in midspeed range. The power speed diagram showed that the brake torque tended to be much higher for diesel fuel than for DME when the engine speed was less than 1900 rpm. However, in engine speeds higher than 1900 rpm, brake torque in DME mode of operation was larger. Calculated emission results also suggested that negligible soot is produced in DME mode operation. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Design of vehicle cooling system architecture for a heavy duty series-hybrid electric vehicle using numerical system simulations / Sungjin Park in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Titre : Design of vehicle cooling system architecture for a heavy duty series-hybrid electric vehicle using numerical system simulations Type de document : texte imprimé Auteurs : Sungjin Park, Auteur ; Dohoy Jung, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cooling  Hybrid  electric  vehicles  Numerical  analysis  Power  transmission  (mechanical) Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In this study, numerical simulations of the vehicle cooling system and the vehicle powertrain system of a virtual heavy duty tracked series hybrid electric vehicle (SHEV) is developed to investigate the thermal responses and power consumptions of the cooling system. The output data from the powertrain system simulation are fed into the cooling system simulation to provide the operating conditions of powertrain components. Three different cooling system architectures constructed with different concepts are modeled and the factors that affect the performance and power consumption of each cooling system are identified and compared with each other. The results show that the cooling system architecture of the SHEV should be developed considering various cooling requirements of powertrain components, power management strategy, performance, parasitic power consumption, and the effect of driving conditions. It is also demonstrated that a numerical model of the SHEV cooling system is an efficient tool to assess design concepts and architectures of the system during the early stage of system development. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Design of vehicle cooling system architecture for a heavy duty series-hybrid electric vehicle using numerical system simulations [texte imprimé] / Sungjin Park, Auteur ; Dohoy Jung, Auteur . - 2011 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 11 p. Mots-clés : Cooling  Hybrid  electric  vehicles  Numerical  analysis  Power  transmission  (mechanical) Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In this study, numerical simulations of the vehicle cooling system and the vehicle powertrain system of a virtual heavy duty tracked series hybrid electric vehicle (SHEV) is developed to investigate the thermal responses and power consumptions of the cooling system. The output data from the powertrain system simulation are fed into the cooling system simulation to provide the operating conditions of powertrain components. Three different cooling system architectures constructed with different concepts are modeled and the factors that affect the performance and power consumption of each cooling system are identified and compared with each other. The results show that the cooling system architecture of the SHEV should be developed considering various cooling requirements of powertrain components, power management strategy, performance, parasitic power consumption, and the effect of driving conditions. It is also demonstrated that a numerical model of the SHEV cooling system is an efficient tool to assess design concepts and architectures of the system during the early stage of system development. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Low NOx and low smoke operation of a diesel engine using gasolinelike fuels / Gautam Kalghatgi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Titre : Low NOx and low smoke operation of a diesel engine using gasolinelike fuels Type de document : texte imprimé Auteurs : Gautam Kalghatgi, Auteur ; Leif Hildingsson, Auteur ; Bengt Johansson, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Diesel  engines  Petroleum Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Much of the technology in advanced diesel engines, such as high injection pressures, is aimed at overcoming the short ignition delay of conventional diesel fuels to promote premixed combustion in order to reduce NOx and smoke. Previous work in a 2 l single-cylinder diesel engine with a compression ratio of 14 has demonstrated that gasoline fuel, because of its high ignition delay, is very beneficial for premixed compression-ignition compared with a conventional diesel fuel. We have now done similar studies in a smaller—0.537 l—single-cylinder diesel engine with a compression ratio of 15.8. The engine was run on three fuels of very different auto-ignition quality—a typical European diesel fuel with a cetane number (CN) of 56, a typical European gasoline of 95 RON and 85 MON with an estimated CN of 16 and another gasoline of 84 RON and 78 MON (estimated CN of 21). The previous results with gasoline were obtained only at 1200 rpm—here we compare the fuels also at 2000 rpm and 3000 rpm. At 1200 rpm, at low loads (~4 bars indicated mean effective pressure (IMEP)) when smoke is negligible, NOx levels below 0.4 g/kWh can be easily attained with gasoline without using exhaust gas recirculation (EGR), while this is not possible with the 56 CN European diesel. At these loads, the maximum pressure-rise rate is also significantly lower for gasoline. At 2000 rpm, with 2 bars absolute intake pressure, NOx can be reduced below 0.4 g/kW h with negligible smoke (FSN<0.1) with gasoline between 10 bars and 12 bars IMEP using sufficient EGR, while this is not possible with the diesel fuel. At 3000 rpm, with the intake pressure at 2.4 bars absolute, NOx of 0.4 g/kW h with negligible smoke was attainable with gasoline at 13 bars IMEP. Hydrocarbon and CO emissions are higher for gasoline and will require after-treatment. High peak heat release rates can be alleviated using multiple injections. Large amounts of gasoline, unlike diesel, can be injected very early in the cycle without causing heat release during the compression stroke and this enables the heat release profile to be shaped. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Low NOx and low smoke operation of a diesel engine using gasolinelike fuels [texte imprimé] / Gautam Kalghatgi, Auteur ; Leif Hildingsson, Auteur ; Bengt Johansson, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 09 p. Mots-clés : Diesel  engines  Petroleum Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Much of the technology in advanced diesel engines, such as high injection pressures, is aimed at overcoming the short ignition delay of conventional diesel fuels to promote premixed combustion in order to reduce NOx and smoke. Previous work in a 2 l single-cylinder diesel engine with a compression ratio of 14 has demonstrated that gasoline fuel, because of its high ignition delay, is very beneficial for premixed compression-ignition compared with a conventional diesel fuel. We have now done similar studies in a smaller—0.537 l—single-cylinder diesel engine with a compression ratio of 15.8. The engine was run on three fuels of very different auto-ignition quality—a typical European diesel fuel with a cetane number (CN) of 56, a typical European gasoline of 95 RON and 85 MON with an estimated CN of 16 and another gasoline of 84 RON and 78 MON (estimated CN of 21). The previous results with gasoline were obtained only at 1200 rpm—here we compare the fuels also at 2000 rpm and 3000 rpm. At 1200 rpm, at low loads (~4 bars indicated mean effective pressure (IMEP)) when smoke is negligible, NOx levels below 0.4 g/kWh can be easily attained with gasoline without using exhaust gas recirculation (EGR), while this is not possible with the 56 CN European diesel. At these loads, the maximum pressure-rise rate is also significantly lower for gasoline. At 2000 rpm, with 2 bars absolute intake pressure, NOx can be reduced below 0.4 g/kW h with negligible smoke (FSN<0.1) with gasoline between 10 bars and 12 bars IMEP using sufficient EGR, while this is not possible with the diesel fuel. At 3000 rpm, with the intake pressure at 2.4 bars absolute, NOx of 0.4 g/kW h with negligible smoke was attainable with gasoline at 13 bars IMEP. Hydrocarbon and CO emissions are higher for gasoline and will require after-treatment. High peak heat release rates can be alleviated using multiple injections. Large amounts of gasoline, unlike diesel, can be injected very early in the cycle without causing heat release during the compression stroke and this enables the heat release profile to be shaped. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

High-resolution scalar and velocity measurements in an internal combustion engine / B. R. Petersen in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Titre : High-resolution scalar and velocity measurements in an internal combustion engine Type de document : texte imprimé Auteurs : B. R. Petersen, Auteur ; D. M. Heim, Auteur ; J. B. Ghandhi, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Flow  visualisation  Fluorescence  spectroscopy  Internal  combustion  engines  Turbulence  Velocity  measurement Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : High-resolution planar laser-induced fluorescence and particle image velocimetry (PIV) measurements were acquired during the intake stroke in a motored engine to investigate the mixing behavior of in-cylinder flows. The data were analyzed to determine the scalar energy and kinetic energy spectra, which were used to find the corresponding dissipation spectra. The results were compared with a model turbulent spectrum. The scalar energy and scalar dissipation spectra were shown to be resolved through the full dissipation range, enabling the determination of the Batchelor/Kolmogorov length scale and agreed well with the model turbulent spectrum at all but the highest wavenumbers where the effects of random noise were present. The 2% point in the scalar dissipation spectra was used to estimate the Batchelor scale, which was found to be approximately 32 µm. The PIV data, which had a 675 µm interrogation region, were used to calculate a one-dimensional kinetic energy spectrum. The kinetic energy spectrum agreed well with the scalar energy spectrum and the model spectrum up to wavenumbers corresponding to approximately two times the PIV interrogation region size. For the present measurements, this meant that the PIV data were not able to resolve the peak in the dissipation spectrum, i.e., the full high-wavenumber part of the inertial subrange. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] High-resolution scalar and velocity measurements in an internal combustion engine [texte imprimé] / B. R. Petersen, Auteur ; D. M. Heim, Auteur ; J. B. Ghandhi, Auteur . - 2011 . - 06 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Mots-clés : Flow  visualisation  Fluorescence  spectroscopy  Internal  combustion  engines  Turbulence  Velocity  measurement Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : High-resolution planar laser-induced fluorescence and particle image velocimetry (PIV) measurements were acquired during the intake stroke in a motored engine to investigate the mixing behavior of in-cylinder flows. The data were analyzed to determine the scalar energy and kinetic energy spectra, which were used to find the corresponding dissipation spectra. The results were compared with a model turbulent spectrum. The scalar energy and scalar dissipation spectra were shown to be resolved through the full dissipation range, enabling the determination of the Batchelor/Kolmogorov length scale and agreed well with the model turbulent spectrum at all but the highest wavenumbers where the effects of random noise were present. The 2% point in the scalar dissipation spectra was used to estimate the Batchelor scale, which was found to be approximately 32 µm. The PIV data, which had a 675 µm interrogation region, were used to calculate a one-dimensional kinetic energy spectrum. The kinetic energy spectrum agreed well with the scalar energy spectrum and the model spectrum up to wavenumbers corresponding to approximately two times the PIV interrogation region size. For the present measurements, this meant that the PIV data were not able to resolve the peak in the dissipation spectrum, i.e., the full high-wavenumber part of the inertial subrange. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Transient control of combustion phasing and lambda in a six-cylinder port-injected natural-gas engine / Mehrzad Kaiadi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Titre : Transient control of combustion phasing and lambda in a six-cylinder port-injected natural-gas engine Type de document : texte imprimé Auteurs : Mehrzad Kaiadi, Auteur ; Magnus Lewander, Auteur ; Patrick Borgqvist, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air  pollution  Catalysts  Combustion  Diesel  engines  Feedforward  PI  control  Predictive  control  Transients Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fuel economy and emissions are the two central parameters in heavy duty engines. High exhaust gas recirculation rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition engines. With stoichiometric conditions, a three way catalyst can be used, which keeps the regulated emissions at very low levels. The Lambda window, which results in very low emissions, is very narrow. This issue is more complex with transient operation, resulting in losing brake efficiency and also catalyst converting efficiency. This paper presents different control strategies to maximize the reliability for maintaining efficiency and emissions levels under transient conditions. Different controllers are developed and tested successfully on a heavy duty six-cylinder port injected natural gas engine. Model predictive control was used to control lambda, which was modeled using system identification. Furthermore, a proportional integral regulator combined with a feedforward map for obtaining maximum brake torque timing was applied. The results show that excellent steady-state and transient performance can be achieved. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Transient control of combustion phasing and lambda in a six-cylinder port-injected natural-gas engine [texte imprimé] / Mehrzad Kaiadi, Auteur ; Magnus Lewander, Auteur ; Patrick Borgqvist, Auteur . - 2011 . - 06 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Mots-clés : Air  pollution  Catalysts  Combustion  Diesel  engines  Feedforward  PI  control  Predictive  control  Transients Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fuel economy and emissions are the two central parameters in heavy duty engines. High exhaust gas recirculation rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition engines. With stoichiometric conditions, a three way catalyst can be used, which keeps the regulated emissions at very low levels. The Lambda window, which results in very low emissions, is very narrow. This issue is more complex with transient operation, resulting in losing brake efficiency and also catalyst converting efficiency. This paper presents different control strategies to maximize the reliability for maintaining efficiency and emissions levels under transient conditions. Different controllers are developed and tested successfully on a heavy duty six-cylinder port injected natural gas engine. Model predictive control was used to control lambda, which was modeled using system identification. Furthermore, a proportional integral regulator combined with a feedforward map for obtaining maximum brake torque timing was applied. The results show that excellent steady-state and transient performance can be achieved. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Combustion and emissions characterization of soy methyl ester biodiesel blends in an automotive turbocharged diesel engine / Benjamin W. Moscherosch in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Titre : Combustion and emissions characterization of soy methyl ester biodiesel blends in an automotive turbocharged diesel engine Type de document : texte imprimé Auteurs : Benjamin W. Moscherosch, Auteur ; Christopher J. Polonowski, Auteur ; Scott A. Miers, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Biofuel  Combustion  Diesel  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Recent increases in petroleum fuel costs, corporate average fuel economy (CAFE) regulations, and environmental concerns about CO2 emissions from petroleum based fuels have created an increased opportunity for diesel engines and non-petroleum renewable fuels such as biodiesel. Additionally, the Environmental Protection Agencies Tier II heavy duty and light duty emissions regulations require significant reductions in NOx and diesel particulate matter emissions for diesel engines. As a result, the diesel engine and aftertreatment system is a highly calibrated system that is sensitive to fuel characteristics. This study focuses on the impact of soy methyl ester biodiesel blends on combustion performance, NOx, and carbonaceous soot matter emissions. Tests were completed using a 1.9 L, turbocharged direct injection diesel engine using commercially available 15 ppm ultra low sulfur (ULS) diesel, a soy methyl ester B20 biodiesel blend (20 vol % B100 and 80 vol % ULS diesel), and a pure soy methyl ester biodiesel. Results show a reduction in NOx and carbonaceous soot matter emissions, and an increase in brake specific fuel consumption with the use of biodiesel. Further, traditional methodology assumes that diesel fuels with a high cetane number have a reduced ignition delay. However, results from this study show the cetane number is not the only parameter effecting ignition delay due to increased diffusion burn. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Combustion and emissions characterization of soy methyl ester biodiesel blends in an automotive turbocharged diesel engine [texte imprimé] / Benjamin W. Moscherosch, Auteur ; Christopher J. Polonowski, Auteur ; Scott A. Miers, Auteur . - 2011 . - 06 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 06 p. Mots-clés : Biofuel  Combustion  Diesel  engines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Recent increases in petroleum fuel costs, corporate average fuel economy (CAFE) regulations, and environmental concerns about CO2 emissions from petroleum based fuels have created an increased opportunity for diesel engines and non-petroleum renewable fuels such as biodiesel. Additionally, the Environmental Protection Agencies Tier II heavy duty and light duty emissions regulations require significant reductions in NOx and diesel particulate matter emissions for diesel engines. As a result, the diesel engine and aftertreatment system is a highly calibrated system that is sensitive to fuel characteristics. This study focuses on the impact of soy methyl ester biodiesel blends on combustion performance, NOx, and carbonaceous soot matter emissions. Tests were completed using a 1.9 L, turbocharged direct injection diesel engine using commercially available 15 ppm ultra low sulfur (ULS) diesel, a soy methyl ester B20 biodiesel blend (20 vol % B100 and 80 vol % ULS diesel), and a pure soy methyl ester biodiesel. Results show a reduction in NOx and carbonaceous soot matter emissions, and an increase in brake specific fuel consumption with the use of biodiesel. Further, traditional methodology assumes that diesel fuels with a high cetane number have a reduced ignition delay. However, results from this study show the cetane number is not the only parameter effecting ignition delay due to increased diffusion burn. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Tri-axial force measurements on the cylinder of a motored SI engine operated on lubricants of differing viscosity / Bryan O'Rourke in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Titre : Tri-axial force measurements on the cylinder of a motored SI engine operated on lubricants of differing viscosity Type de document : texte imprimé Auteurs : Bryan O'Rourke, Auteur ; Donald Radford, Auteur ; Rudolf Stanglmaier, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Force  measurement  Friction  Internal  combustion  engines  Lubricants  Lubrication  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Friction is a determining factor in the efficiency and performance of internal combustion engines. Losses in the form of friction work typically account for 10–20% of an engine's output. Improvements in the friction characteristics of the power cylinder assembly are essential for reducing total engine friction and improving the mechanical efficiency of internal combustion engines. This paper describes the development and implementation of a new concept of the “floating liner” engine at Colorado State University that allows 0.5 crank angle deg resolved measurement of the forces on the cylinder along three axes—in the axial direction, the thrust direction, and along the wrist pin. Three different lubricants with differing properties were tested to observe the friction characteristics of each. The experimental results showed that the floating liner engine was able to resolve changes in friction characteristics coinciding with changes in lubricant viscosity and temperature. The axial force increases at TDC and BDC were observed as lubricant viscosity was decreased and larger amounts of mixed and boundary lubrication began to occur. For each test the axial friction force data was used to calculate total cycle friction work. The thrust and off-axis (wrist pin direction) forces are discussed under the same circumstances. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Tri-axial force measurements on the cylinder of a motored SI engine operated on lubricants of differing viscosity [texte imprimé] / Bryan O'Rourke, Auteur ; Donald Radford, Auteur ; Rudolf Stanglmaier, Auteur . - 2011 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 07 p. Mots-clés : Force  measurement  Friction  Internal  combustion  engines  Lubricants  Lubrication  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Friction is a determining factor in the efficiency and performance of internal combustion engines. Losses in the form of friction work typically account for 10–20% of an engine's output. Improvements in the friction characteristics of the power cylinder assembly are essential for reducing total engine friction and improving the mechanical efficiency of internal combustion engines. This paper describes the development and implementation of a new concept of the “floating liner” engine at Colorado State University that allows 0.5 crank angle deg resolved measurement of the forces on the cylinder along three axes—in the axial direction, the thrust direction, and along the wrist pin. Three different lubricants with differing properties were tested to observe the friction characteristics of each. The experimental results showed that the floating liner engine was able to resolve changes in friction characteristics coinciding with changes in lubricant viscosity and temperature. The axial force increases at TDC and BDC were observed as lubricant viscosity was decreased and larger amounts of mixed and boundary lubrication began to occur. For each test the axial friction force data was used to calculate total cycle friction work. The thrust and off-axis (wrist pin direction) forces are discussed under the same circumstances. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Analysis of thermal effects in a cavitating orifice using rayleigh equation and experiments / Maria Grazia De Giorgi in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Titre : Analysis of thermal effects in a cavitating orifice using rayleigh equation and experiments Type de document : texte imprimé Auteurs : Maria Grazia De Giorgi, Auteur ; Daniela Bello, Auteur ; Antonio Ficarella, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Bubbles  Cavitation  Computational  fluid  dynamics  Confined  flow  Convection  Cryogenics  Hydraulic  systems  Internal  combustion  engines  Multiphase  flow  Orifices  (mechanical)  Turbines  Vaporisation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The cavitation phenomenon interests a wide range of machines, from internal combustion engines to turbines and pumps of all sizes. It affects negatively the hydraulic machines' performance and may cause materials' erosion. The cavitation, in most cases, is a phenomenon that develops at a constant temperature, and only a relatively small amount of heat is required for the formation of a significant volume of vapor, and the flow is assumed isothermal. However, in some cases, such as thermosensible fluids and cryogenic liquid, the heat transfer needed for the vaporization is such that phase change occurs at a temperature lower than the ambient liquid temperature. The focus of this research is the experimental and analytical studies of the cavitation phenomena in internal flows in the presence of thermal effects. Experiments have been done on water and nitrogen cavitating flows in orifices at different operating conditions. Transient growth process of the cloud cavitation induced by flow through the throat is observed using high-speed video images and analyzed by pressure signals. The experiments show different cavitating behaviors at different temperatures and different fluids; this is related to the bubble dynamics inside the flow. So to investigate possible explanations for the influence of fluid temperature and of heat transfer during the phase change, initially, a steady, quasi-one-dimensional model has been implemented to study an internal cavitating flow. The nonlinear dynamics of the bubbles has been modeled by Rayleigh–Plesset equation. In the case of nitrogen, thermal effects in the Rayleigh equation are taken into account by considering the vapor pressure at the actual bubble temperature, which is different from the liquid temperature far from the bubble. A convective approach has been used to estimate the bubble temperature. The quasisteady one-dimensional model can be extensively used to conduct parametric studies useful for fast estimation of the overall performance of any geometric design. For complex geometry, three-dimensional computational fluid dynamic (CFD) codes are necessary. In the present work good agreements have been found between numerical predictions by the CFD FLUENT code, in which a simplified form of the Rayleigh equation taking into account thermal effects has been implemented by external user routines and some experimental observations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Analysis of thermal effects in a cavitating orifice using rayleigh equation and experiments [texte imprimé] / Maria Grazia De Giorgi, Auteur ; Daniela Bello, Auteur ; Antonio Ficarella, Auteur . - 2011 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 10 p. Mots-clés : Bubbles  Cavitation  Computational  fluid  dynamics  Confined  flow  Convection  Cryogenics  Hydraulic  systems  Internal  combustion  engines  Multiphase  flow  Orifices  (mechanical)  Turbines  Vaporisation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The cavitation phenomenon interests a wide range of machines, from internal combustion engines to turbines and pumps of all sizes. It affects negatively the hydraulic machines' performance and may cause materials' erosion. The cavitation, in most cases, is a phenomenon that develops at a constant temperature, and only a relatively small amount of heat is required for the formation of a significant volume of vapor, and the flow is assumed isothermal. However, in some cases, such as thermosensible fluids and cryogenic liquid, the heat transfer needed for the vaporization is such that phase change occurs at a temperature lower than the ambient liquid temperature. The focus of this research is the experimental and analytical studies of the cavitation phenomena in internal flows in the presence of thermal effects. Experiments have been done on water and nitrogen cavitating flows in orifices at different operating conditions. Transient growth process of the cloud cavitation induced by flow through the throat is observed using high-speed video images and analyzed by pressure signals. The experiments show different cavitating behaviors at different temperatures and different fluids; this is related to the bubble dynamics inside the flow. So to investigate possible explanations for the influence of fluid temperature and of heat transfer during the phase change, initially, a steady, quasi-one-dimensional model has been implemented to study an internal cavitating flow. The nonlinear dynamics of the bubbles has been modeled by Rayleigh–Plesset equation. In the case of nitrogen, thermal effects in the Rayleigh equation are taken into account by considering the vapor pressure at the actual bubble temperature, which is different from the liquid temperature far from the bubble. A convective approach has been used to estimate the bubble temperature. The quasisteady one-dimensional model can be extensively used to conduct parametric studies useful for fast estimation of the overall performance of any geometric design. For complex geometry, three-dimensional computational fluid dynamic (CFD) codes are necessary. In the present work good agreements have been found between numerical predictions by the CFD FLUENT code, in which a simplified form of the Rayleigh equation taking into account thermal effects has been implemented by external user routines and some experimental observations. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Properties of humid air for calculating power cycles / Sebastian Herrmann in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 08 p. Titre : Properties of humid air for calculating power cycles Type de document : texte imprimé Auteurs : Sebastian Herrmann, Auteur ; Hans-Joachim Kretzschmar, Auteur ; Viola Teske, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Compressed  air  energy  storage  Thermal  conductivity  Thermodynamic  properties  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Accurate calculation algorithms for the thermodynamic and transport properties of humid air are required for modeling compressed air energy-storage power cycles and designing their individual components. The development of such algorithms was part of the Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) project, which had been supported by the European Commission. To obtain the statements of this paper, all available experimental data and new experimental data generated within the AA-CAES project were used as basis for comparisons between the different models for thermodynamic and transport properties. As a result, one model for calculating thermodynamic and one model for transport properties of humid air in AA-CAES cycle design and operation is recommended. Their application is possible for wide ranges of temperature from 243 K up to 2000 K, total pressure from 0.611 kPa up to 100 MPa, and water content up to 10% mass fraction with some restrictions concerning the calculation of viscosity eta and thermal conductivity lambda (up to 1000 K for both and up to 40 MPa for lambda). These models have been implemented into a property library, which meets the requirements of programs for calculating compressed air energy-storage cycles. The developed property library can be used for the daily work of an engineer who calculates such cycles. The results summarized in this paper have been used for preparing Section 6, “Real Gas” of the ASME Report No. STP-TS-012, “Thermophysical Properties of Gases used in Working Gas Turbine Applications.” DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Properties of humid air for calculating power cycles [texte imprimé] / Sebastian Herrmann, Auteur ; Hans-Joachim Kretzschmar, Auteur ; Viola Teske, Auteur . - 2011 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 08 p. Mots-clés : Compressed  air  energy  storage  Thermal  conductivity  Thermodynamic  properties  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Accurate calculation algorithms for the thermodynamic and transport properties of humid air are required for modeling compressed air energy-storage power cycles and designing their individual components. The development of such algorithms was part of the Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) project, which had been supported by the European Commission. To obtain the statements of this paper, all available experimental data and new experimental data generated within the AA-CAES project were used as basis for comparisons between the different models for thermodynamic and transport properties. As a result, one model for calculating thermodynamic and one model for transport properties of humid air in AA-CAES cycle design and operation is recommended. Their application is possible for wide ranges of temperature from 243 K up to 2000 K, total pressure from 0.611 kPa up to 100 MPa, and water content up to 10% mass fraction with some restrictions concerning the calculation of viscosity eta and thermal conductivity lambda (up to 1000 K for both and up to 40 MPa for lambda). These models have been implemented into a property library, which meets the requirements of programs for calculating compressed air energy-storage cycles. The developed property library can be used for the daily work of an engineer who calculates such cycles. The results summarized in this paper have been used for preparing Section 6, “Real Gas” of the ASME Report No. STP-TS-012, “Thermophysical Properties of Gases used in Working Gas Turbine Applications.” DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Determination of contact stiffness of rod-fastened rotors based on modal test and finite element analysis / Yanchun Zhang in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 04 p. Titre : Determination of contact stiffness of rod-fastened rotors based on modal test and finite element analysis Type de document : texte imprimé Auteurs : Yanchun Zhang, Auteur ; Zhaogang Du, Auteur ; Liming Shi, Auteur Année de publication : 2011 Article en page(s) : 04 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Finite  element  analysis  Gas  turbines  Modal  analysis  Rods  (structures)  Rotors  Stress  analysis  Surface  roughness Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A series of simplified rod-fastened rotors, which have different surface contact roughness are manufactured and their modal parameters under different pretightening force, are measured in free-free state. The concept of surface contact stiffness is introduced to simulate the influence of pretightening force on modal parameters of these simplified rod-fastened rotors using finite element method. The experiment measured results are compared and fitted to the finite element analysis results and the relationship between contact stiffness and contact stress is established in which the contact stress is defined by the pretightening force. The relationship is then applied on the modal analysis of a real gas turbine rotor, and its modal test results and finite element analysis results are consistent with each other, proving that the relationship and the described determination method of contact stiffness based on modal test and finite element analysis are effective. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Determination of contact stiffness of rod-fastened rotors based on modal test and finite element analysis [texte imprimé] / Yanchun Zhang, Auteur ; Zhaogang Du, Auteur ; Liming Shi, Auteur . - 2011 . - 04 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 04 p. Mots-clés : Finite  element  analysis  Gas  turbines  Modal  analysis  Rods  (structures)  Rotors  Stress  analysis  Surface  roughness Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A series of simplified rod-fastened rotors, which have different surface contact roughness are manufactured and their modal parameters under different pretightening force, are measured in free-free state. The concept of surface contact stiffness is introduced to simulate the influence of pretightening force on modal parameters of these simplified rod-fastened rotors using finite element method. The experiment measured results are compared and fitted to the finite element analysis results and the relationship between contact stiffness and contact stress is established in which the contact stress is defined by the pretightening force. The relationship is then applied on the modal analysis of a real gas turbine rotor, and its modal test results and finite element analysis results are consistent with each other, proving that the relationship and the described determination method of contact stiffness based on modal test and finite element analysis are effective. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

The effect of size on optimization of solid oxide fuel cell/gas turbine hybrid cycles / Michael J. Brear in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 04 p. Titre : The effect of size on optimization of solid oxide fuel cell/gas turbine hybrid cycles Type de document : texte imprimé Auteurs : Michael J. Brear, Auteur ; Michael J. Dunkley, Auteur Année de publication : 2011 Article en page(s) : 04 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Gas  turbines  Hybrid  power  systems  Solid  oxide  fuel  cells Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The coupling of solid oxide fuel cells (SOFCs) and recuperated gas turbines (GTs) in a hybrid system has the potential to lead to efficiencies exceeding 60%. SOFC/GT hybrids have been proposed at power outputs from 20 MW down to power outputs as low as 25 kW. The optimum configuration for high and low power outputs is therefore likely to be significantly different. This paper proposes a simple model of the SOFC/GT hybrid to investigate the desired flow rate and pressure ratio for optimum hybrid efficiency with varying component performance and, hence, varying inferred size. The overall hybrid specific power will be dominated by the fuel cell and is therefore of secondary importance when matching with a gas turbine. The results presented suggest that hybrid cycles with total power output of the order MW or greater are preferable. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] The effect of size on optimization of solid oxide fuel cell/gas turbine hybrid cycles [texte imprimé] / Michael J. Brear, Auteur ; Michael J. Dunkley, Auteur . - 2011 . - 04 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 04 p. Mots-clés : Gas  turbines  Hybrid  power  systems  Solid  oxide  fuel  cells Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The coupling of solid oxide fuel cells (SOFCs) and recuperated gas turbines (GTs) in a hybrid system has the potential to lead to efficiencies exceeding 60%. SOFC/GT hybrids have been proposed at power outputs from 20 MW down to power outputs as low as 25 kW. The optimum configuration for high and low power outputs is therefore likely to be significantly different. This paper proposes a simple model of the SOFC/GT hybrid to investigate the desired flow rate and pressure ratio for optimum hybrid efficiency with varying component performance and, hence, varying inferred size. The overall hybrid specific power will be dominated by the fuel cell and is therefore of secondary importance when matching with a gas turbine. The results presented suggest that hybrid cycles with total power output of the order MW or greater are preferable. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Effect of injection strategy on the combustion and exhaust emission characteristics of a biodiesel-ethanol blend in a DI diesel engine / Seung Hyun Yoon in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 9 (Septembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 03 p. Titre : Effect of injection strategy on the combustion and exhaust emission characteristics of a biodiesel-ethanol blend in a DI diesel engine Type de document : texte imprimé Auteurs : Seung Hyun Yoon, Auteur ; Jin Woo Hwang, Auteur ; Chang Sik Lee, Auteur Année de publication : 2011 Article en page(s) : 03 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air  pollution  control  Biofuel  Combustion  Diesel  engines  Exhaust  systems  Ignition Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : An experimental investigation was performed on the effect of injection strategy on the combustion, exhaust emission characteristics and the particle size distribution in a small direct-injection (DI) compression ignition engine fueled with a biodiesel-ethanol blended fuel. The results obtained from the experiment of the particle distributions for the blended fuel are compared with that of diesel fuel. In addition to the distribution of the particles, exhaust emissions, such as oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO) emissions, and combustion characteristics under different injection parameters were investigated. The injection parameters in terms of first injection mass and second injection mass were varied to investigate the combustion and emission reduction in the biodiesel and ethanol blended fuel. The results show that the first combustion and heat release generated from the first injection, and then the second injected fuel rapidly combusted with an extremely short ignition delay. The maximum combustion pressures and heat releases of a biodiesel-ethanol blend are generally higher than those of the ultra-low sulfur diesel (ULSD) in all cases, regardless if an equal quantity of fuel is injected. The soot and NOx emissions for a blend are relatively lower than the ULSD at all test ranges. In addition, HC and CO emissions for a blend also indicated relatively low levels compared with those of the ULSD. Double injection cases for biodiesel-ethanol blend, the number concentrations of larger size particles which are closely related to the weight of smoke emissions mass were significantly reduced. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Effect of injection strategy on the combustion and exhaust emission characteristics of a biodiesel-ethanol blend in a DI diesel engine [texte imprimé] / Seung Hyun Yoon, Auteur ; Jin Woo Hwang, Auteur ; Chang Sik Lee, Auteur . - 2011 . - 03 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 9 (Septembre 2010) . - 03 p. Mots-clés : Air  pollution  control  Biofuel  Combustion  Diesel  engines  Exhaust  systems  Ignition Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : An experimental investigation was performed on the effect of injection strategy on the combustion, exhaust emission characteristics and the particle size distribution in a small direct-injection (DI) compression ignition engine fueled with a biodiesel-ethanol blended fuel. The results obtained from the experiment of the particle distributions for the blended fuel are compared with that of diesel fuel. In addition to the distribution of the particles, exhaust emissions, such as oxides of nitrogen (NOx), hydrocarbon (HC), and carbon monoxide (CO) emissions, and combustion characteristics under different injection parameters were investigated. The injection parameters in terms of first injection mass and second injection mass were varied to investigate the combustion and emission reduction in the biodiesel and ethanol blended fuel. The results show that the first combustion and heat release generated from the first injection, and then the second injected fuel rapidly combusted with an extremely short ignition delay. The maximum combustion pressures and heat releases of a biodiesel-ethanol blend are generally higher than those of the ultra-low sulfur diesel (ULSD) in all cases, regardless if an equal quantity of fuel is injected. The soot and NOx emissions for a blend are relatively lower than the ULSD at all test ranges. In addition, HC and CO emissions for a blend also indicated relatively low levels compared with those of the ULSD. Double injection cases for biodiesel-ethanol blend, the number concentrations of larger size particles which are closely related to the weight of smoke emissions mass were significantly reduced. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Exemplaires

Bibliothèque Ecole Nationale Polytechnique d'Alger

Accueil

Se connecter

Météo

Adresse