Dépouillements

A monthly publication schedule for journal of engineering for gas turbines and power (JEGTP) / Ballal, Dilip R. in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 01 p. Titre : A monthly publication schedule for journal of engineering for gas turbines and power (JEGTP) Type de document : texte imprimé Auteurs : Ballal, Dilip R., Auteur Année de publication : 2010 Article en page(s) : 01 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fossil  fuels  Gas  turbines  Internal  combustion  engines  Nuclear  power Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] A monthly publication schedule for journal of engineering for gas turbines and power (JEGTP) [texte imprimé] / Ballal, Dilip R., Auteur . - 2010 . - 01 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 01 p. Mots-clés : Fossil  fuels  Gas  turbines  Internal  combustion  engines  Nuclear  power Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Ceramic gas turbine development: need for a 10 year plan / Mark van Roode in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : Ceramic gas turbine development: need for a 10 year plan Type de document : texte imprimé Auteurs : Mark van Roode, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Durability  Electric  machines  Engines  Fracture  toughness  Gas  turbines  Life  testing  Thermal  barrier  coatings  Thermal  insulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Ceramic gas turbine development that started in the 1950s has slowed considerably since most of the large-scale ceramic gas turbine development programs of the 1970s–1990s ended. While component durability still does not meet expectations, the prospect of significant energy savings and emission reductions, potentially achievable with ceramic gas turbines, continues to justify development efforts. Four gas turbine applications have been identified that could be commercially attractive: a small recuperated gas turbine (microturbine) with ~35% electrical efficiency, a recuperated gas turbine for transportation applications with ~40% electrical efficiency with potential applications for efficient small engine cogeneration, a ~40% efficient midsize industrial gas turbine, and a ~63% (combined cycle) efficient utility turbine. Key technologies have been identified to ensure performance and component durability targets can be met over the expected life cycle for these applications. These technologies include a Si3N4 or SiC with high fracture toughness, durable EBCs for Si3N4 and SiC, an effective EBC/TBC for SiC/SiC, a durable oxide/oxide ceramic matrix composite (CMC) with thermally insulating coating, and the next generation CMCs with high strength that can be used as structural materials for turbine components for small engines and for rotating components in engines of various sizes. The programs will require integrated partnerships between government, national laboratories, universities, and industry. The overall cost of the proposed development programs is estimated at U.S. $100M over 10 years, i.e., an annual average of U.S. $10M. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Ceramic gas turbine development: need for a 10 year plan [texte imprimé] / Mark van Roode, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Durability  Electric  machines  Engines  Fracture  toughness  Gas  turbines  Life  testing  Thermal  barrier  coatings  Thermal  insulation Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Ceramic gas turbine development that started in the 1950s has slowed considerably since most of the large-scale ceramic gas turbine development programs of the 1970s–1990s ended. While component durability still does not meet expectations, the prospect of significant energy savings and emission reductions, potentially achievable with ceramic gas turbines, continues to justify development efforts. Four gas turbine applications have been identified that could be commercially attractive: a small recuperated gas turbine (microturbine) with ~35% electrical efficiency, a recuperated gas turbine for transportation applications with ~40% electrical efficiency with potential applications for efficient small engine cogeneration, a ~40% efficient midsize industrial gas turbine, and a ~63% (combined cycle) efficient utility turbine. Key technologies have been identified to ensure performance and component durability targets can be met over the expected life cycle for these applications. These technologies include a Si3N4 or SiC with high fracture toughness, durable EBCs for Si3N4 and SiC, an effective EBC/TBC for SiC/SiC, a durable oxide/oxide ceramic matrix composite (CMC) with thermally insulating coating, and the next generation CMCs with high strength that can be used as structural materials for turbine components for small engines and for rotating components in engines of various sizes. The programs will require integrated partnerships between government, national laboratories, universities, and industry. The overall cost of the proposed development programs is estimated at U.S. $100M over 10 years, i.e., an annual average of U.S. $10M. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Biodiesel as an alternative fuel in siemens dry low emissions combustors / Kexin Liu in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : Biodiesel as an alternative fuel in siemens dry low emissions combustors : atmospheric and high pressure rig testing Type de document : texte imprimé Auteurs : Kexin Liu, Auteur ; John P. Wood, Auteur ; Eoghan R. Buchanan, Auteur Année de publication : 2010 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Biofuel  Combustion  equipment  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Atmospheric and high pressure rig tests were conducted to investigate the feasibility of using biodiesel as an alternative fuel to power industrial gas turbines in one of the world's leading dry low emissions (DLE) combustion systems, the SGT-100. At the same conditions, tests were also carried out for mineral diesel to provide reference information to evaluate biodiesel as an alternative fuel. In atmospheric pressure rig tests, the likelihood of the machine lighting was identified based on the measured probability of the ignition of a single combustor. Lean ignition and extinction limits at various air temperatures were also investigated with different air assist pressures. The ignition test results reveal that reliable ignition can be achieved with biodiesel across a range of air mass flow rates and air fuel ratios (AFRs). In high pressure rig tests, emissions and combustion dynamics were measured for various combustor air inlet pressures, temperatures, combustor wall pressure drops, and flame temperatures. These high pressure rig results show that biodiesel produced less NOx than mineral diesel. The test results indicate that the Siemens DLE combustion system can be adapted to use biodiesel as an alternative fuel without major modification. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Biodiesel as an alternative fuel in siemens dry low emissions combustors : atmospheric and high pressure rig testing [texte imprimé] / Kexin Liu, Auteur ; John P. Wood, Auteur ; Eoghan R. Buchanan, Auteur . - 2010 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Biofuel  Combustion  equipment  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Atmospheric and high pressure rig tests were conducted to investigate the feasibility of using biodiesel as an alternative fuel to power industrial gas turbines in one of the world's leading dry low emissions (DLE) combustion systems, the SGT-100. At the same conditions, tests were also carried out for mineral diesel to provide reference information to evaluate biodiesel as an alternative fuel. In atmospheric pressure rig tests, the likelihood of the machine lighting was identified based on the measured probability of the ignition of a single combustor. Lean ignition and extinction limits at various air temperatures were also investigated with different air assist pressures. The ignition test results reveal that reliable ignition can be achieved with biodiesel across a range of air mass flow rates and air fuel ratios (AFRs). In high pressure rig tests, emissions and combustion dynamics were measured for various combustor air inlet pressures, temperatures, combustor wall pressure drops, and flame temperatures. These high pressure rig results show that biodiesel produced less NOx than mineral diesel. The test results indicate that the Siemens DLE combustion system can be adapted to use biodiesel as an alternative fuel without major modification. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Laboratory investigations of low-swirl injectors operating with syngases / David Littlejohn in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : Laboratory investigations of low-swirl injectors operating with syngases Type de document : texte imprimé Auteurs : David Littlejohn, Auteur ; Robert K. Cheng, Auteur ; D. R. Noble, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Coal  Combined  cycle  power  stations  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The low-swirl injector (LSI) is a lean premixed combustion technology that has the potential for adaptation to fuel-flexible gas turbines operating on a variety of fuels. The objective of this study is to gain a fundamental understanding of the effect of syngas on the LSI flame behavior, the emissions, and the flowfield characteristics for adaptation to the combustion turbines in integrated gasification combined cycle clean coal power plants. The experiments were conducted in two facilities. Open atmospheric laboratory flames generated by a full size (6.35 cm) LSI were used to investigate the lean blow-off limits, emissions, and the flowfield characteristics. Verification of syngas operation at elevated temperatures and pressures were performed with a reduced scale (2.54 cm) LSI in a small pressurized combustion channel. The results show that the basic LSI design is amenable to burning syngases with up to 60% H2. Syngases with high H2 concentration have lower lean blow-off limits. From particle image velocimetry measurements, the flowfield similarity behavior and the turbulent flame speeds of syngases flames are consistent with those observed in hydrocarbon and pure or diluted hydrogen flames. The NOx emissions from syngas flames show log-linear dependency on the adiabatic flame temperature and are comparable to those reported for the gaseous fuels reported previously. Successful firing of the reduced-scale LSI at 450 K DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Laboratory investigations of low-swirl injectors operating with syngases [texte imprimé] / David Littlejohn, Auteur ; Robert K. Cheng, Auteur ; D. R. Noble, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Coal  Combined  cycle  power  stations  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The low-swirl injector (LSI) is a lean premixed combustion technology that has the potential for adaptation to fuel-flexible gas turbines operating on a variety of fuels. The objective of this study is to gain a fundamental understanding of the effect of syngas on the LSI flame behavior, the emissions, and the flowfield characteristics for adaptation to the combustion turbines in integrated gasification combined cycle clean coal power plants. The experiments were conducted in two facilities. Open atmospheric laboratory flames generated by a full size (6.35 cm) LSI were used to investigate the lean blow-off limits, emissions, and the flowfield characteristics. Verification of syngas operation at elevated temperatures and pressures were performed with a reduced scale (2.54 cm) LSI in a small pressurized combustion channel. The results show that the basic LSI design is amenable to burning syngases with up to 60% H2. Syngases with high H2 concentration have lower lean blow-off limits. From particle image velocimetry measurements, the flowfield similarity behavior and the turbulent flame speeds of syngases flames are consistent with those observed in hydrocarbon and pure or diluted hydrogen flames. The NOx emissions from syngas flames show log-linear dependency on the adiabatic flame temperature and are comparable to those reported for the gaseous fuels reported previously. Successful firing of the reduced-scale LSI at 450 K DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Second law efficiency of the rankine bottoming cycle of a combined cycle power plant / S. Can Gülen in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Titre : Second law efficiency of the rankine bottoming cycle of a combined cycle power plant Type de document : texte imprimé Auteurs : S. Can Gülen, Auteur ; Raub W. Smith, Auteur Année de publication : 2010 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combined  cycle  power  stations  Exergy  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A significant portion of the new electrical generating capacity installed in the past decade has employed heavy-duty gas turbines operating in a combined cycle configuration with a steam turbine bottoming cycle. In these power plants approximately one-third of the power is generated by the bottoming cycle. To ensure that the highest possible combined cycle efficiency is realized it is important to develop the combined cycle power plant as a system. Doing so requires a solid understanding of the efficiency entitlement of both, topping and bottoming, cycles separately and as a whole. This paper describes a simple but accurate method to estimate the Rankine bottoming cycle power output directly from the gas turbine exhaust exergy, utilizing the second law of thermodynamics. The classical first law approach, i.e., the heat and mass balance method, requires lengthy calculations and complex computer-based modeling tools to evaluate Rankine bottoming cycle performance. In this paper, a rigorous application of the fundamental thermodynamic principles embodied by the second law to the major cycle components clearly demonstrates that the Rankine cycle performance can be accurately represented by several key parameters. The power of the second law approach lies in its ability to highlight the theoretical entitlement and state-of-the-art design performances simultaneously via simple fundamental relationships. By considering economically and technologically feasible upper limits for the key parameters, the maximum achievable bottoming cycle power output is readily calculable for any given gas turbine from its exhaust exergy. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Second law efficiency of the rankine bottoming cycle of a combined cycle power plant [texte imprimé] / S. Can Gülen, Auteur ; Raub W. Smith, Auteur . - 2010 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Mots-clés : Combined  cycle  power  stations  Exergy  Gas  turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A significant portion of the new electrical generating capacity installed in the past decade has employed heavy-duty gas turbines operating in a combined cycle configuration with a steam turbine bottoming cycle. In these power plants approximately one-third of the power is generated by the bottoming cycle. To ensure that the highest possible combined cycle efficiency is realized it is important to develop the combined cycle power plant as a system. Doing so requires a solid understanding of the efficiency entitlement of both, topping and bottoming, cycles separately and as a whole. This paper describes a simple but accurate method to estimate the Rankine bottoming cycle power output directly from the gas turbine exhaust exergy, utilizing the second law of thermodynamics. The classical first law approach, i.e., the heat and mass balance method, requires lengthy calculations and complex computer-based modeling tools to evaluate Rankine bottoming cycle performance. In this paper, a rigorous application of the fundamental thermodynamic principles embodied by the second law to the major cycle components clearly demonstrates that the Rankine cycle performance can be accurately represented by several key parameters. The power of the second law approach lies in its ability to highlight the theoretical entitlement and state-of-the-art design performances simultaneously via simple fundamental relationships. By considering economically and technologically feasible upper limits for the key parameters, the maximum achievable bottoming cycle power output is readily calculable for any given gas turbine from its exhaust exergy. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Effect of film cooling on turbine capacity / Thomas Povey in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Titre : Effect of film cooling on turbine capacity Type de document : texte imprimé Auteurs : Thomas Povey, Auteur Année de publication : 2010 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cooling  Engines  Turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper describes a method that allows the effect of film cooling on the capacity of a turbine to be computed. The model is based on fundamental cooling performance parameters and is applicable to situations in which a mainstream flow is displaced by a partially mixed film cooling layer. The purpose is to quantify the error that is incurred in the engine situation when common—but simplified—assumptions are made regarding the flow, and where necessary, to provide a means of correcting the capacity for the effect of the film cooling flow. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Effect of film cooling on turbine capacity [texte imprimé] / Thomas Povey, Auteur . - 2010 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Mots-clés : Cooling  Engines  Turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper describes a method that allows the effect of film cooling on the capacity of a turbine to be computed. The model is based on fundamental cooling performance parameters and is applicable to situations in which a mainstream flow is displaced by a partially mixed film cooling layer. The purpose is to quantify the error that is incurred in the engine situation when common—but simplified—assumptions are made regarding the flow, and where necessary, to provide a means of correcting the capacity for the effect of the film cooling flow. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Thermomechanical fatigue behavior of bare and coated CMSX-4 / T. Coppola in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 05 p. Titre : Thermomechanical fatigue behavior of bare and coated CMSX-4 Type de document : texte imprimé Auteurs : T. Coppola, Auteur ; S. Riscifuli, Auteur ; O. Tassa, Auteur Année de publication : 2010 Article en page(s) : 05 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aerospace  engines  Blades  Fatigue  Nickel  alloys  Turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Highly cooled turbine blades undergo very high thermal gradients during rapid engine idle-max-idle cycling. Traditional isothermal fatigue data are often insufficient for predicting service lives. A complete set of high temperature tests, in the range of 750–1050°C, was performed on single crystal alloy CMSX-4. The test program comprised tensile, creep, low cycle fatigue, and thermomechanical fatigue (TMF) tests. In particular the cycle time for TMF was 3 min, aiming to simulate the real high-power transient conditions in aircraft engines. Clockwise and counterclockwise diamond cycle types were applied on bare and coated specimens to investigate their influence on the fatigue limit. The comparison of the results obtained with the available ones from open literature is discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Thermomechanical fatigue behavior of bare and coated CMSX-4 [texte imprimé] / T. Coppola, Auteur ; S. Riscifuli, Auteur ; O. Tassa, Auteur . - 2010 . - 05 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 05 p. Mots-clés : Aerospace  engines  Blades  Fatigue  Nickel  alloys  Turbines Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Highly cooled turbine blades undergo very high thermal gradients during rapid engine idle-max-idle cycling. Traditional isothermal fatigue data are often insufficient for predicting service lives. A complete set of high temperature tests, in the range of 750–1050°C, was performed on single crystal alloy CMSX-4. The test program comprised tensile, creep, low cycle fatigue, and thermomechanical fatigue (TMF) tests. In particular the cycle time for TMF was 3 min, aiming to simulate the real high-power transient conditions in aircraft engines. Clockwise and counterclockwise diamond cycle types were applied on bare and coated specimens to investigate their influence on the fatigue limit. The comparison of the results obtained with the available ones from open literature is discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

A study in the process modeling of the startup of fuel cell/gas turbine hybrid systems / Michael Shelton in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : A study in the process modeling of the startup of fuel cell/gas turbine hybrid systems Type de document : texte imprimé Auteurs : Michael Shelton, Auteur ; Ismail Celik, Auteur ; Eric Liese, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  Power  system  dynamic  stability Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : As energy demands increase and the associated costs increase with that demand, newer energy alternatives are becoming more important to society. Although not new, fuel cell technology is taking a lead role in the quest for a cleaner and competitive power generation system. High efficiencies on the order of 50% are now possible with stand-alone fuel cells. When coupled with a gas turbine, efficiencies of around 70% may be expected. However, the fuel cell/gas turbine hybrid has inherent problems of stability and unpredictable response to adverse transients that first must be addressed to make this technology viable. The National Energy Technology Laboratories (NETL) in Morgantown is involved in the development of such hybrid technology. This study details a process modeling approach based on a commercial modeling package, and is associated specifically with the NETL Hybrid Performance (HYPER) research effort. Simulation versus experimental test data are presented to validate the process model during the cold flow startup phase. The results provide insight into the transients of the system built at NETL. DEWEY : 62.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] A study in the process modeling of the startup of fuel cell/gas turbine hybrid systems [texte imprimé] / Michael Shelton, Auteur ; Ismail Celik, Auteur ; Eric Liese, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  Power  system  dynamic  stability Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : As energy demands increase and the associated costs increase with that demand, newer energy alternatives are becoming more important to society. Although not new, fuel cell technology is taking a lead role in the quest for a cleaner and competitive power generation system. High efficiencies on the order of 50% are now possible with stand-alone fuel cells. When coupled with a gas turbine, efficiencies of around 70% may be expected. However, the fuel cell/gas turbine hybrid has inherent problems of stability and unpredictable response to adverse transients that first must be addressed to make this technology viable. The National Energy Technology Laboratories (NETL) in Morgantown is involved in the development of such hybrid technology. This study details a process modeling approach based on a commercial modeling package, and is associated specifically with the NETL Hybrid Performance (HYPER) research effort. Simulation versus experimental test data are presented to validate the process model during the cold flow startup phase. The results provide insight into the transients of the system built at NETL. DEWEY : 62.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Fuel cell/gas turbine hybrid system control for daily load profile and ambient condition variation / Rory A. Roberts in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Titre : Fuel cell/gas turbine hybrid system control for daily load profile and ambient condition variation Type de document : texte imprimé Auteurs : Rory A. Roberts, Auteur ; Jack Brouwer, Auteur ; G. Scott Samuelsen, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  Power  generation  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fuel Cell/Gas Turbine (FC/GT) hybrid technology is promising, but introduces challenges in system operation and control. For base-load applications, changes in ambient conditions perturb the system and it becomes difficult to maintain constant power production by the FC/GT system. If the FC/GT hybrid system is load-following, then the problem becomes even more complex. In the current study, a dynamic model of a FC/GT power plant is developed with system controls. Two cases are evaluated: (1) system controls are developed to maintain constant power and process control within acceptable constraints and (2) the FC/GT power plant is set in power following mode connected in parallel to the grid for a daily load profile scenario. Changing ambient conditions are employed in the dynamic analysis for both cases. With appropriate attention to design of the system itself and the control logic, the challenges for dynamic system operation and control can be addressed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Fuel cell/gas turbine hybrid system control for daily load profile and ambient condition variation [texte imprimé] / Rory A. Roberts, Auteur ; Jack Brouwer, Auteur ; G. Scott Samuelsen, Auteur . - 2010 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Mots-clés : Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  Power  generation  control Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fuel Cell/Gas Turbine (FC/GT) hybrid technology is promising, but introduces challenges in system operation and control. For base-load applications, changes in ambient conditions perturb the system and it becomes difficult to maintain constant power production by the FC/GT system. If the FC/GT hybrid system is load-following, then the problem becomes even more complex. In the current study, a dynamic model of a FC/GT power plant is developed with system controls. Two cases are evaluated: (1) system controls are developed to maintain constant power and process control within acceptable constraints and (2) the FC/GT power plant is set in power following mode connected in parallel to the grid for a daily load profile scenario. Changing ambient conditions are employed in the dynamic analysis for both cases. With appropriate attention to design of the system itself and the control logic, the challenges for dynamic system operation and control can be addressed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

On the numerical prediction of finite length squeeze film dampers performance with free air entrainment / Tilmer H. Méndez in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Titre : On the numerical prediction of finite length squeeze film dampers performance with free air entrainment Type de document : texte imprimé Auteurs : Tilmer H. Méndez, Auteur ; Tonko Ćurko, Auteur ; Marco A. Ciaccia, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cavitation  Compressible  flow  Density  Finite  volume  methods  Fracture  Machine  bearings  Machine  control  Rotors  Stratified  flow  Turbomachinery  Vibration  control  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Squeeze film dampers (SFDs) are commonly used in turbomachinery to dampen shaft vibrations in rotor-bearing systems. The main factor deterring the success of analytical models for the prediction of SFD's performance lies on the modeling of dynamic film rupture. Usually, the cavitation models developed for journal bearings are applied to SFDs. Yet, the characteristic motion of the SFD results in the entrapment of air into the oil film, producing a bubbly mixture that cannot be represented by these models. There is a need to identify and understand the parameters that affect air entrainment and subsequent formation of a bubbly air-oil mixture within the lubricant film. A previous model by and Diazand San Andrés (2001, “A Model for Squeeze Film Dampers Operating With Air Entrapment and Validation With Experiments,” ASME J. Tribol., 123, pp. 125–133) advanced estimation of the amount of film-entrapped air based on a nondimensional number that related both geometrical and operating parameters but limited to the short bearing approximation (i.e., neglecting circumferential flow). The present study extends their work to consider the effects of finite length-to-diameter ratios. This is achieved by means of a finite volume integration of the two-dimensional, Newtonian, compressible Reynolds equation combined with the effective mixture density and viscosity defined in the work of Diaz and San Andrés. A flow balance at the open end of the film is devised to estimate the amount of air entrapped within the film. The results show, in dimensionless plots, a map of the amount of entrained air as a function of the feed-squeeze flow number, defined by Diaz and San Andrés, and the length-to-diameter ratio of the damper. Entrained air is shown to decrease as the L/D ratio increases, going from the approximate solution of Diaz and San Andrés for infinitely short SFDs down to no air entrainment for an infinite length SFD. The results of this research are of immediate engineering applicability. Furthermore, they represent a firm step to advance the understanding of the effects of air entrapment on the performance of SFDs. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] On the numerical prediction of finite length squeeze film dampers performance with free air entrainment [texte imprimé] / Tilmer H. Méndez, Auteur ; Tonko Ćurko, Auteur ; Marco A. Ciaccia, Auteur . - 2010 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Mots-clés : Cavitation  Compressible  flow  Density  Finite  volume  methods  Fracture  Machine  bearings  Machine  control  Rotors  Stratified  flow  Turbomachinery  Vibration  control  Viscosity Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Squeeze film dampers (SFDs) are commonly used in turbomachinery to dampen shaft vibrations in rotor-bearing systems. The main factor deterring the success of analytical models for the prediction of SFD's performance lies on the modeling of dynamic film rupture. Usually, the cavitation models developed for journal bearings are applied to SFDs. Yet, the characteristic motion of the SFD results in the entrapment of air into the oil film, producing a bubbly mixture that cannot be represented by these models. There is a need to identify and understand the parameters that affect air entrainment and subsequent formation of a bubbly air-oil mixture within the lubricant film. A previous model by and Diazand San Andrés (2001, “A Model for Squeeze Film Dampers Operating With Air Entrapment and Validation With Experiments,” ASME J. Tribol., 123, pp. 125–133) advanced estimation of the amount of film-entrapped air based on a nondimensional number that related both geometrical and operating parameters but limited to the short bearing approximation (i.e., neglecting circumferential flow). The present study extends their work to consider the effects of finite length-to-diameter ratios. This is achieved by means of a finite volume integration of the two-dimensional, Newtonian, compressible Reynolds equation combined with the effective mixture density and viscosity defined in the work of Diaz and San Andrés. A flow balance at the open end of the film is devised to estimate the amount of air entrapped within the film. The results show, in dimensionless plots, a map of the amount of entrained air as a function of the feed-squeeze flow number, defined by Diaz and San Andrés, and the length-to-diameter ratio of the damper. Entrained air is shown to decrease as the L/D ratio increases, going from the approximate solution of Diaz and San Andrés for infinitely short SFDs down to no air entrainment for an infinite length SFD. The results of this research are of immediate engineering applicability. Furthermore, they represent a firm step to advance the understanding of the effects of air entrapment on the performance of SFDs. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Controlling journal bearing instability using active magnetic bearings / Aly El-Shafei in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : Controlling journal bearing instability using active magnetic bearings Type de document : texte imprimé Auteurs : Aly El-Shafei, Auteur ; A. S. Dimitri, Auteur Année de publication : 2010 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Damping  Electric  machines  Machine  bearings  Machine  control  Magnetic  bearings  Mechanical  stability Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Journal bearings (JBs) are excellent bearings due to their large load carrying capacity and favorable damping characteristics. However, journal bearings are known to be prone to instabilities. The oil whirl and oil whip instabilities limit the rotor maximum rotating speed. In this paper, a novel approach is used to control the journal bearing instability. An active magnetic bearing (AMB) is used to overcome the JB instability and to increase its range of operation. The concept is quite simple: Rather than using the AMB as a load carrying element, the AMB is used as a controller only, resulting in a much smaller and more efficient AMB. The load carrying is done by the journal bearings, exploiting their excellent load carrying capabilities, and the JB instability is overcome with the AMB. This results in a combined AMB/JB that exploits the advantages of each device and eliminates the deficiencies of each bearing. Different controllers for the AMB to control the JB instability are examined and compared theoretically and numerically. The possibility of collocating the JB and the AMB is also examined. The results illustrate the effectiveness of the concept. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Controlling journal bearing instability using active magnetic bearings [texte imprimé] / Aly El-Shafei, Auteur ; A. S. Dimitri, Auteur . - 2010 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Damping  Electric  machines  Machine  bearings  Machine  control  Magnetic  bearings  Mechanical  stability Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Journal bearings (JBs) are excellent bearings due to their large load carrying capacity and favorable damping characteristics. However, journal bearings are known to be prone to instabilities. The oil whirl and oil whip instabilities limit the rotor maximum rotating speed. In this paper, a novel approach is used to control the journal bearing instability. An active magnetic bearing (AMB) is used to overcome the JB instability and to increase its range of operation. The concept is quite simple: Rather than using the AMB as a load carrying element, the AMB is used as a controller only, resulting in a much smaller and more efficient AMB. The load carrying is done by the journal bearings, exploiting their excellent load carrying capabilities, and the JB instability is overcome with the AMB. This results in a combined AMB/JB that exploits the advantages of each device and eliminates the deficiencies of each bearing. Different controllers for the AMB to control the JB instability are examined and compared theoretically and numerically. The possibility of collocating the JB and the AMB is also examined. The results illustrate the effectiveness of the concept. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Dynamic analysis of fretting-wear in friction contact interfaces / Loïc Salles in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : Dynamic analysis of fretting-wear in friction contact interfaces Type de document : texte imprimé Auteurs : Loïc Salles, Auteur ; Laurent Blanc, Auteur ; Fabrice Thouverez, Auteur Année de publication : 2010 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Friction  Mechanical  contact  Turbomachinery  Wear Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fretting wear is a very important phenomenon occurring in bladed disks. It causes the blades to be replaced in turbomachines during their life-cycle. Methods exist to predict fretting-wear in quasistatic analysis. However, they do not predict all the phenomena observed in blade attachments on real turbomachines. That is why this study assumes that dynamics plays a role in fretting-wear. This paper is devoted to the realistic modeling and calculation of fretting-wear and dynamical response of structures in unilateral contact with friction. Vibration and wear phenomena present very different scales both in time and space. Therefore the difficulty is in finding methods that enable one to solve the nonlinear problem with a good compromise between the approximations made about the dynamical aspects and those linked with fretting-wear issues. Here, phenomenological examples are studied. They involve a small number of degrees of freedom with a view to understanding the complex coupling between vibration and fretting-wear. This way, they will show the relative importance of parameters. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Dynamic analysis of fretting-wear in friction contact interfaces [texte imprimé] / Loïc Salles, Auteur ; Laurent Blanc, Auteur ; Fabrice Thouverez, Auteur . - 2010 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Friction  Mechanical  contact  Turbomachinery  Wear Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Fretting wear is a very important phenomenon occurring in bladed disks. It causes the blades to be replaced in turbomachines during their life-cycle. Methods exist to predict fretting-wear in quasistatic analysis. However, they do not predict all the phenomena observed in blade attachments on real turbomachines. That is why this study assumes that dynamics plays a role in fretting-wear. This paper is devoted to the realistic modeling and calculation of fretting-wear and dynamical response of structures in unilateral contact with friction. Vibration and wear phenomena present very different scales both in time and space. Therefore the difficulty is in finding methods that enable one to solve the nonlinear problem with a good compromise between the approximations made about the dynamical aspects and those linked with fretting-wear issues. Here, phenomenological examples are studied. They involve a small number of degrees of freedom with a view to understanding the complex coupling between vibration and fretting-wear. This way, they will show the relative importance of parameters. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Numerical analysis of the shaft motion in the journal bearing of a gear pump / R. Castilla in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Titre : Numerical analysis of the shaft motion in the journal bearing of a gear pump Type de document : texte imprimé Auteurs : R. Castilla, Auteur ; M. Gutes, Auteur ; P. J. Gamez-Montero, Auteur Année de publication : 2010 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Finite  element  analysis  Gears  Machine  bearings  Pumps  Runge-Kutta  methods  Shafts Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper describes a numerical analysis of the dynamics of the shaft in the journal bearing of a gear pump. The modulus and direction of the load is a function of the relative position of the gears, causing a precession motion around an equilibrium position. The mean load is the function of the working pressure of the gear pump. The numerical analysis presented in this paper combines the equation of motion of the journal-gear set, based on the linearization of the fluid film load, with calculation of the load due to the pressure distribution on the gears. The damping and stiffness coefficients for the motion equation are calculated with the distributions around the shaft of the pressure and its derivatives. These distributions are calculated from the Reynolds equations using an in-house 2D finite element code with quadrangular elements; the equation of motion is solved with a fifth-order Runge–Kutta scheme. The results provide the stabilized position of the shaft for certain conditions, and allow limitation of the working pressure and the angular velocity of the pump in order to minimize, or to avoid, metal-metal contact and consequent wear of material. The results are compared with experiments and previously reported numerical results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Numerical analysis of the shaft motion in the journal bearing of a gear pump [texte imprimé] / R. Castilla, Auteur ; M. Gutes, Auteur ; P. J. Gamez-Montero, Auteur . - 2010 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 10 p. Mots-clés : Finite  element  analysis  Gears  Machine  bearings  Pumps  Runge-Kutta  methods  Shafts Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper describes a numerical analysis of the dynamics of the shaft in the journal bearing of a gear pump. The modulus and direction of the load is a function of the relative position of the gears, causing a precession motion around an equilibrium position. The mean load is the function of the working pressure of the gear pump. The numerical analysis presented in this paper combines the equation of motion of the journal-gear set, based on the linearization of the fluid film load, with calculation of the load due to the pressure distribution on the gears. The damping and stiffness coefficients for the motion equation are calculated with the distributions around the shaft of the pressure and its derivatives. These distributions are calculated from the Reynolds equations using an in-house 2D finite element code with quadrangular elements; the equation of motion is solved with a fifth-order Runge–Kutta scheme. The results provide the stabilized position of the shaft for certain conditions, and allow limitation of the working pressure and the angular velocity of the pump in order to minimize, or to avoid, metal-metal contact and consequent wear of material. The results are compared with experiments and previously reported numerical results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Effect of experimental conditions on gas core length and downward velocity of free surface vortex in cylindrical vessel / Hideaki Monji in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : Effect of experimental conditions on gas core length and downward velocity of free surface vortex in cylindrical vessel Type de document : texte imprimé Auteurs : Hideaki Monji, Auteur ; Tatsuya Shinozaki, Auteur ; Hideki Kamide, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Confined  flow  Flow  measurement  Stratified  flow  Vortices Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper deals with characteristics of surface vortex in a cylindrical vessel. One of the characteristics is a gas core length, which is important to estimate the onset condition of the gas entrainment but influenced easily by the experimental condition. In the experiment using water, the effects of the water temperature, water level, and the surface tension on the gas core length were investigated. The onset condition of the gas entrainment is sometimes estimated by using the Burgers vortex model but the real flow in the vessel is different from the model. The velocity fields were measured by particle image velocimetry (PIV) and the velocity gradient of the downward flow was discussed. The proper flow conditions for the Burgers vortex model are a high water level and a high flow rate. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Effect of experimental conditions on gas core length and downward velocity of free surface vortex in cylindrical vessel [texte imprimé] / Hideaki Monji, Auteur ; Tatsuya Shinozaki, Auteur ; Hideki Kamide, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Confined  flow  Flow  measurement  Stratified  flow  Vortices Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper deals with characteristics of surface vortex in a cylindrical vessel. One of the characteristics is a gas core length, which is important to estimate the onset condition of the gas entrainment but influenced easily by the experimental condition. In the experiment using water, the effects of the water temperature, water level, and the surface tension on the gas core length were investigated. The onset condition of the gas entrainment is sometimes estimated by using the Burgers vortex model but the real flow in the vessel is different from the model. The velocity fields were measured by particle image velocimetry (PIV) and the velocity gradient of the downward flow was discussed. The proper flow conditions for the Burgers vortex model are a high water level and a high flow rate. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Advanced high temperature gas-cooled reactor systems / Yasuyoshi Kato in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Titre : Advanced high temperature gas-cooled reactor systems Type de document : texte imprimé Auteurs : Yasuyoshi Kato, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Gas  cooled  reactors  Gas  turbine  power  stations  Heat  exchangers  Heat  transfer  Microchannel  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Three systems have been proposed for advanced high-temperature gas-cooled reactors: a supercritical carbon dioxide (S-CO2) gas turbine power conversion system, a new microchannel heat exchanger (MCHE), and a once-through-then-out (OTTO) refueling scheme with burnable poison (BP) loading. A S-CO2 gas turbine cycle attains higher cycle efficiency than a He gas turbine cycle because of reduced compression work around the critical point of CO2. Considering temperature reduction at the turbine inlet by 30°C through intermediate heat exchange, the S-CO2 indirect cycle achieves an efficiency of 53.8% at a turbine inlet temperature of 820°C and a turbine inlet pressure of 20 MPa. This cycle efficiency value is higher by 4.5% than that (49.3%) of a He direct cycle at a turbine inlet temperature of 850°C and 7 MPa. A new MCHE has been proposed as an intermediate heat exchanger between the primary cooling He loop and the secondary S-CO2 gas turbine power conversion system and as recuperators of the S-CO2 gas turbine power conversion system. This MCHE has discontinuous “S-shaped” fins providing flow channels resembling sine curves. Its pressure drop is one-sixth that of a conventional MCHE with a zigzag flow channel configuration, but it has the same high heat transfer performance. The pressure drop reduction is ascribed to suppression of recirculation flows and eddies that appear around bend corners of the zigzag flow channels in the conventional MCHE. An optimal BP loading in an OTTO refueling scheme eliminates the shortcoming of its excessively high axial power peaking factor, reducing the power peaking factor from 4.44 to about 1.7, and inheriting advantages over the multipass scheme because it obviates reloading in addition to fuel handling and integrity checking systems. Because of the power peaking factor reduction, the maximum fuel temperatures are lower than the maximum permissible values of 1250°C for normal operation and 1600°C during a depressurization accident. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Advanced high temperature gas-cooled reactor systems [texte imprimé] / Yasuyoshi Kato, Auteur . - 2010 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Mots-clés : Gas  cooled  reactors  Gas  turbine  power  stations  Heat  exchangers  Heat  transfer  Microchannel  flow Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Three systems have been proposed for advanced high-temperature gas-cooled reactors: a supercritical carbon dioxide (S-CO2) gas turbine power conversion system, a new microchannel heat exchanger (MCHE), and a once-through-then-out (OTTO) refueling scheme with burnable poison (BP) loading. A S-CO2 gas turbine cycle attains higher cycle efficiency than a He gas turbine cycle because of reduced compression work around the critical point of CO2. Considering temperature reduction at the turbine inlet by 30°C through intermediate heat exchange, the S-CO2 indirect cycle achieves an efficiency of 53.8% at a turbine inlet temperature of 820°C and a turbine inlet pressure of 20 MPa. This cycle efficiency value is higher by 4.5% than that (49.3%) of a He direct cycle at a turbine inlet temperature of 850°C and 7 MPa. A new MCHE has been proposed as an intermediate heat exchanger between the primary cooling He loop and the secondary S-CO2 gas turbine power conversion system and as recuperators of the S-CO2 gas turbine power conversion system. This MCHE has discontinuous “S-shaped” fins providing flow channels resembling sine curves. Its pressure drop is one-sixth that of a conventional MCHE with a zigzag flow channel configuration, but it has the same high heat transfer performance. The pressure drop reduction is ascribed to suppression of recirculation flows and eddies that appear around bend corners of the zigzag flow channels in the conventional MCHE. An optimal BP loading in an OTTO refueling scheme eliminates the shortcoming of its excessively high axial power peaking factor, reducing the power peaking factor from 4.44 to about 1.7, and inheriting advantages over the multipass scheme because it obviates reloading in addition to fuel handling and integrity checking systems. Because of the power peaking factor reduction, the maximum fuel temperatures are lower than the maximum permissible values of 1250°C for normal operation and 1600°C during a depressurization accident. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

High temperature interaction between UO2 and carbon / Stéphane Gossé in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : High temperature interaction between UO2 and carbon : application to TRISO particles for very high temperature reactors Type de document : texte imprimé Auteurs : Stéphane Gossé, Auteur ; Christine Guéneau, Auteur ; Thierry Alpettaz, Auteur Année de publication : 2010 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Chemical  reactions  Chemical  reactors  High-temperature  techniques  Mass  spectroscopy  Powders  Stoichiometry  Thermodynamics  Uranium  compounds Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : For very high temperature reactors, the high level operating temperature of the fuel materials in normal and accidental conditions requires studying the possible chemical interaction between the UO2 fuel kernel and the surrounding structural materials (C, SiC) that could damage the tristructural isotropic particle. The partial pressures of the gaseous carbon oxides formed at the fuel (UO2)-buffer (C) interface leading to the build up of the internal pressure in the particle have to be predicted. A good knowledge of the phase diagram and thermodynamic properties of the uranium-carbon-oxygen (UCO) system is also required to optimize the fabrication process of “UCO” kernels made of a mixture of UO2 and UC2. Thermodynamic calculations using the FUELBASE database dedicated to Generation IV fuels (Guéneau, Chatain, Gossé, Rado, Rapaud, Lechelle, Dumas, and Chatillon, 2005, “A Thermodynamic Approach for Advanced Fuels of Gas Cooled Reactors,” J. Nucl. Mater., 344, pp. 191–197) allow predicting the phase equilibria involving carbide and/or oxycarbide phases at high temperature. Very high levels of CO(g) and CO2(g) equilibrium pressures are obtained above the UO2±x fuel in equilibrium with carbon that could lead to the failure of the particle in case of high oxygen stoichiometry of the uranium dioxide. To determine the deviation from thermodynamic equilibrium, measurements of the partial pressures of CO(g) and CO2(g) resulting from the UO2/C interaction have been performed by high temperature mass spectrometry on two types of samples: (i) pellets made of a mixture of UO2 and C powders or (ii) UO2 kernels embedded in carbon powder. Kinetics of the CO(g) and CO2(g) as a function of time and temperature was determined. The measured pressures are significantly lower than the equilibrium ones predicted by thermodynamic calculations. The major gaseous product is always CO(g), which starts to be released at 1473 K. From the analysis of the partial pressure profiles as a function of time and temperature, rates of CO(g) formation have been assessed. The influence of the different geometries of the samples is shown. The factors that limit the gas release can be related to interface or diffusion processes as a function of the type of sample. The present results show the utmost importance of kinetic factors that govern the UO2/C interaction. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] High temperature interaction between UO2 and carbon : application to TRISO particles for very high temperature reactors [texte imprimé] / Stéphane Gossé, Auteur ; Christine Guéneau, Auteur ; Thierry Alpettaz, Auteur . - 2010 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Chemical  reactions  Chemical  reactors  High-temperature  techniques  Mass  spectroscopy  Powders  Stoichiometry  Thermodynamics  Uranium  compounds Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : For very high temperature reactors, the high level operating temperature of the fuel materials in normal and accidental conditions requires studying the possible chemical interaction between the UO2 fuel kernel and the surrounding structural materials (C, SiC) that could damage the tristructural isotropic particle. The partial pressures of the gaseous carbon oxides formed at the fuel (UO2)-buffer (C) interface leading to the build up of the internal pressure in the particle have to be predicted. A good knowledge of the phase diagram and thermodynamic properties of the uranium-carbon-oxygen (UCO) system is also required to optimize the fabrication process of “UCO” kernels made of a mixture of UO2 and UC2. Thermodynamic calculations using the FUELBASE database dedicated to Generation IV fuels (Guéneau, Chatain, Gossé, Rado, Rapaud, Lechelle, Dumas, and Chatillon, 2005, “A Thermodynamic Approach for Advanced Fuels of Gas Cooled Reactors,” J. Nucl. Mater., 344, pp. 191–197) allow predicting the phase equilibria involving carbide and/or oxycarbide phases at high temperature. Very high levels of CO(g) and CO2(g) equilibrium pressures are obtained above the UO2±x fuel in equilibrium with carbon that could lead to the failure of the particle in case of high oxygen stoichiometry of the uranium dioxide. To determine the deviation from thermodynamic equilibrium, measurements of the partial pressures of CO(g) and CO2(g) resulting from the UO2/C interaction have been performed by high temperature mass spectrometry on two types of samples: (i) pellets made of a mixture of UO2 and C powders or (ii) UO2 kernels embedded in carbon powder. Kinetics of the CO(g) and CO2(g) as a function of time and temperature was determined. The measured pressures are significantly lower than the equilibrium ones predicted by thermodynamic calculations. The major gaseous product is always CO(g), which starts to be released at 1473 K. From the analysis of the partial pressure profiles as a function of time and temperature, rates of CO(g) formation have been assessed. The influence of the different geometries of the samples is shown. The factors that limit the gas release can be related to interface or diffusion processes as a function of the type of sample. The present results show the utmost importance of kinetic factors that govern the UO2/C interaction. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Creep effects on design below the temperature limits of ASME section III subsection NB / T.-L. Sham in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 06 p. Titre : Creep effects on design below the temperature limits of ASME section III subsection NB Type de document : texte imprimé Auteurs : T.-L. Sham, Auteur ; Robert I. Jetter, Auteur ; Daniel R. Eno, Auteur Année de publication : 2010 Article en page(s) : 06 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Austenitic  steel  Boilers  Creep  Thermal  stresses Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Some recent studies of material response have identified an issue that crosses over and blurs the boundary between ASME Boiler and Pressure Vessel Code Section III Subsection NB and Subsection NH. For very long design lives, the effects of creep show up at lower and lower temperature as the design life increases. Although true for the temperature at which the allowable stress is governed by creep properties, the effect is more apparent, e.g., creep effects show up sooner, at local structural discontinuities and peak thermal stress locations. This is because creep is a function of time, temperature, and stress, and the higher the localized stress, the lower in temperature creep begins to cause damage. If the threshold is below the Subsection NB to NH temperature boundary, 700°F for ferritic steels and 800°F for austenitic materials, then this potential failure mode will not be considered. Unfortunately, there is no experience base with very long lives at temperatures close to but under the Subsection NB to NH boundary to draw on. This issue is of particular interest in the application of Subsection NB rules of construction to some high temperature gas-cooled reactor concepts. The purpose of this paper is, thus, twofold: one part is about statistical treatment and extrapolation of sparse data for a specific material of interest, SA-533 Grade B Class 1; the other part is about how these results could impact current design procedures in Subsection NB. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Creep effects on design below the temperature limits of ASME section III subsection NB [texte imprimé] / T.-L. Sham, Auteur ; Robert I. Jetter, Auteur ; Daniel R. Eno, Auteur . - 2010 . - 06 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 06 p. Mots-clés : Austenitic  steel  Boilers  Creep  Thermal  stresses Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Some recent studies of material response have identified an issue that crosses over and blurs the boundary between ASME Boiler and Pressure Vessel Code Section III Subsection NB and Subsection NH. For very long design lives, the effects of creep show up at lower and lower temperature as the design life increases. Although true for the temperature at which the allowable stress is governed by creep properties, the effect is more apparent, e.g., creep effects show up sooner, at local structural discontinuities and peak thermal stress locations. This is because creep is a function of time, temperature, and stress, and the higher the localized stress, the lower in temperature creep begins to cause damage. If the threshold is below the Subsection NB to NH temperature boundary, 700°F for ferritic steels and 800°F for austenitic materials, then this potential failure mode will not be considered. Unfortunately, there is no experience base with very long lives at temperatures close to but under the Subsection NB to NH boundary to draw on. This issue is of particular interest in the application of Subsection NB rules of construction to some high temperature gas-cooled reactor concepts. The purpose of this paper is, thus, twofold: one part is about statistical treatment and extrapolation of sparse data for a specific material of interest, SA-533 Grade B Class 1; the other part is about how these results could impact current design procedures in Subsection NB. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Mining process and product information from pressure fluctuations within a fuel particle coater / Douglas W. Marshall in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Titre : Mining process and product information from pressure fluctuations within a fuel particle coater Type de document : texte imprimé Auteurs : Douglas W. Marshall, Auteur ; Charles M. Barnes, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fission  reactors  Fluidised  beds  Mining  Nuclear  power Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The next generation nuclear power/advanced gas reactor (NGNP/AGR) fuel development and qualification program included the design, installation, and testing of a 6-in. diameter nuclear fuel particle coater to demonstrate quality tri-structural isotropic (TRISO) fuel production on a small industrial scale. Scale-up from the laboratory-scale coater faced challenges associated with an increase in the kernel charge mass, kernel diameter, and a redesign of the gas distributor to achieve adequate fluidization throughout the deposition of the four TRISO coating layers. TRISO coatings are applied at very high temperatures in atmospheres of dense particulate clouds, corrosive gases, and hydrogen concentrations over 45% by volume. The severe environment, stringent product and process requirements, and the fragility of partially-formed coatings limit the insertion of probes or instruments into the coater vessel during operation. Pressure instrumentation were installed on the gas inlet line and exhaust line of the 6-in. coater to monitor the bed differential pressure and internal pressure fluctuations emanating from the fuel bed as a result of bed and gas “bubble” movements. These instruments are external to the particle bed and provide a glimpse into the dynamics of fuel particle bed during the coating process and data that could be used to help ascertain the adequacy of fluidization and, potentially, the dominant fluidization regimes. Pressure fluctuation and differential pressure data are not presently useful as process control instruments, but data suggest a link between the pressure signal structure and some measurable product attributes that could be exploited to get an early estimate of the attribute values. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Mining process and product information from pressure fluctuations within a fuel particle coater [texte imprimé] / Douglas W. Marshall, Auteur ; Charles M. Barnes, Auteur . - 2010 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Mots-clés : Fission  reactors  Fluidised  beds  Mining  Nuclear  power Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The next generation nuclear power/advanced gas reactor (NGNP/AGR) fuel development and qualification program included the design, installation, and testing of a 6-in. diameter nuclear fuel particle coater to demonstrate quality tri-structural isotropic (TRISO) fuel production on a small industrial scale. Scale-up from the laboratory-scale coater faced challenges associated with an increase in the kernel charge mass, kernel diameter, and a redesign of the gas distributor to achieve adequate fluidization throughout the deposition of the four TRISO coating layers. TRISO coatings are applied at very high temperatures in atmospheres of dense particulate clouds, corrosive gases, and hydrogen concentrations over 45% by volume. The severe environment, stringent product and process requirements, and the fragility of partially-formed coatings limit the insertion of probes or instruments into the coater vessel during operation. Pressure instrumentation were installed on the gas inlet line and exhaust line of the 6-in. coater to monitor the bed differential pressure and internal pressure fluctuations emanating from the fuel bed as a result of bed and gas “bubble” movements. These instruments are external to the particle bed and provide a glimpse into the dynamics of fuel particle bed during the coating process and data that could be used to help ascertain the adequacy of fluidization and, potentially, the dominant fluidization regimes. Pressure fluctuation and differential pressure data are not presently useful as process control instruments, but data suggest a link between the pressure signal structure and some measurable product attributes that could be exploited to get an early estimate of the attribute values. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Development of local heat transfer models for safety assessment of high temperature gas-cooled reactor cores—Part I: pebble bed reactors / Richard Stainsby in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Titre : Development of local heat transfer models for safety assessment of high temperature gas-cooled reactor cores—Part I: pebble bed reactors Type de document : texte imprimé Auteurs : Richard Stainsby, Auteur ; Matthew Worsley, Auteur ; Andrew Grief, Auteur Année de publication : 2010 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Computational  fluid  dynamics  Finite  element  analysis  Fission  reactor  safety  Gas  cooled  reactors  Heat  transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This and the subsequent paper present models developed for determining fuel particle and fuel element temperatures in normal operation and transient conditions in high temperature reactor cores. Multiscale modeling concepts are used to develop the models for both pebble bed and prismatic core types. This paper, Part I, presents the development of the model for pebble bed reactors. Comparison is made with finite element simulations of an idealized “two-dimensional” pebble in transient conditions, and with a steady-state analytical solution in a spherical pebble geometry. A method is presented for determining the fuel temperatures in the individual batches of a multibatch recycle refuelling regime. Implementation of the multiscale and multibatch fuel models in a whole-core computational fluid dynamics model is discussed together with the future intentions of the research program. Note de contenu : Development of Local Heat Transfer Models for the Safety Assessment of High Temperature Gas-Cooled Reactor Cores—Part II: Prismatic Modular Reactors Richard Stainsby et al. J. Eng. Gas Turbines Power 132, 012907 (2010) DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Development of local heat transfer models for safety assessment of high temperature gas-cooled reactor cores—Part I: pebble bed reactors [texte imprimé] / Richard Stainsby, Auteur ; Matthew Worsley, Auteur ; Andrew Grief, Auteur . - 2010 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 09 p. Mots-clés : Computational  fluid  dynamics  Finite  element  analysis  Fission  reactor  safety  Gas  cooled  reactors  Heat  transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This and the subsequent paper present models developed for determining fuel particle and fuel element temperatures in normal operation and transient conditions in high temperature reactor cores. Multiscale modeling concepts are used to develop the models for both pebble bed and prismatic core types. This paper, Part I, presents the development of the model for pebble bed reactors. Comparison is made with finite element simulations of an idealized “two-dimensional” pebble in transient conditions, and with a steady-state analytical solution in a spherical pebble geometry. A method is presented for determining the fuel temperatures in the individual batches of a multibatch recycle refuelling regime. Implementation of the multiscale and multibatch fuel models in a whole-core computational fluid dynamics model is discussed together with the future intentions of the research program. Note de contenu : Development of Local Heat Transfer Models for the Safety Assessment of High Temperature Gas-Cooled Reactor Cores—Part II: Prismatic Modular Reactors Richard Stainsby et al. J. Eng. Gas Turbines Power 132, 012907 (2010) DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Development of local heat transfer models for the safety assessment of high temperature gas-cooled reactor cores—Part II: prismatic modular reactors / Richard Stainsby in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Titre : Development of local heat transfer models for the safety assessment of high temperature gas-cooled reactor cores—Part II: prismatic modular reactors Type de document : texte imprimé Auteurs : Richard Stainsby, Auteur ; Matthew Worsley, Auteur ; Frances Dawson, Auteur Année de publication : 2010 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Finite  element  analysis  Gas  cooled  reactors  Heat  transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper extends the work of Part I to be applicable to prismatic block fuel elements and presents a model developed for determining fuel compact and fuel block temperatures of a prismatic core modular reactor. The model is applicable both in normal operation and under fault conditions and is an extension of the multiscale modeling techniques presented in Part I. The new model has been qualified by comparison with finite element simulations for both steady-state and transient conditions. Furthermore, a model for determining the effective conductivity of the block fuel elements—important for heat removal in loss of flow conditions—is presented and, again, qualified by comparison with finite element simulations. A numerical model for predicting conduction heat transfer both within and between block fuel elements has been developed, which, when coupled with the above multiscale model, allows simulations of whole cores to be carried out, while retaining the ability to predict the temperatures of individual coolant channels and individual coated particles in the fuel if required. Note de contenu : Development of Local Heat Transfer Models for Safety Assessment of High Temperature Gas-Cooled Reactor Cores—Part I: Pebble Bed Reactors Richard Stainsby et al. J. Eng. Gas Turbines Power 132, 012906 (2010) DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Development of local heat transfer models for the safety assessment of high temperature gas-cooled reactor cores—Part II: prismatic modular reactors [texte imprimé] / Richard Stainsby, Auteur ; Matthew Worsley, Auteur ; Frances Dawson, Auteur . - 2010 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 08 p. Mots-clés : Finite  element  analysis  Gas  cooled  reactors  Heat  transfer Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper extends the work of Part I to be applicable to prismatic block fuel elements and presents a model developed for determining fuel compact and fuel block temperatures of a prismatic core modular reactor. The model is applicable both in normal operation and under fault conditions and is an extension of the multiscale modeling techniques presented in Part I. The new model has been qualified by comparison with finite element simulations for both steady-state and transient conditions. Furthermore, a model for determining the effective conductivity of the block fuel elements—important for heat removal in loss of flow conditions—is presented and, again, qualified by comparison with finite element simulations. A numerical model for predicting conduction heat transfer both within and between block fuel elements has been developed, which, when coupled with the above multiscale model, allows simulations of whole cores to be carried out, while retaining the ability to predict the temperatures of individual coolant channels and individual coated particles in the fuel if required. Note de contenu : Development of Local Heat Transfer Models for Safety Assessment of High Temperature Gas-Cooled Reactor Cores—Part I: Pebble Bed Reactors Richard Stainsby et al. J. Eng. Gas Turbines Power 132, 012906 (2010) DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Condenser tube examination using acoustic pulse reflectometry / N. Amir in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 05 p. Titre : Condenser tube examination using acoustic pulse reflectometry Type de document : texte imprimé Auteurs : N. Amir, Auteur ; O. Barzelay, Auteur ; A. Yefet, Auteur Année de publication : 2010 Article en page(s) : 05 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Acoustic  pulses  Condensers  (steam  plant)  Pipes  Reflectometry Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Acoustic pulse reflectometry (APR) has been applied extensively to tubular systems in research laboratories for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of 6 m in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, in the order of 20 cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically with a measurement time on the order of 10 s per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Condenser tube examination using acoustic pulse reflectometry [texte imprimé] / N. Amir, Auteur ; O. Barzelay, Auteur ; A. Yefet, Auteur . - 2010 . - 05 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 05 p. Mots-clés : Acoustic  pulses  Condensers  (steam  plant)  Pipes  Reflectometry Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Acoustic pulse reflectometry (APR) has been applied extensively to tubular systems in research laboratories for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of 6 m in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, in the order of 20 cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically with a measurement time on the order of 10 s per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

Low temperature combustion using nitrogen enrichment to mitigate NOx from large bore natural gas fueled engines / Munidhar S. Biruduganti in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 04 p. Titre : Low temperature combustion using nitrogen enrichment to mitigate NOx from large bore natural gas fueled engines Type de document : texte imprimé Auteurs : Munidhar S. Biruduganti, Auteur ; Sreenath B. Gupta, Auteur ; Raj Sekar, Auteur Année de publication : 2010 Article en page(s) : 04 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air  pollution  Combustion  Engines  Fuel Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Low temperature combustion is identified as one of the pathways to meet the mandatory ultra low NOx emissions levels set by the regulatory agencies. Exhaust gas recirculation (EGR) is a well known technique to realize low NOx emissions. However, EGR has many built-in adverse ramifications that negate its advantages in the long term. This paper discusses nitrogen enrichment of intake air using air separation membranes as a better alternative to the mature EGR technique. This investigation was undertaken to determine the maximum acceptable level of nitrogen enrichment of air for a single-cylinder spark-ignited natural gas engine. NOx reduction as high as 70% was realized with a modest 2% nitrogen enrichment while maintaining power density and simultaneously improving fuel conversion efficiency (FCE). Any enrichment beyond this level degraded engine performance in terms of power density, FCE, and unburned hydrocarbon emissions. The effect of ignition timing was also studied with and without N2 enrichment. Finally, lean burn versus stoichiometric operation utilizing nitrogen enrichment was compared. Analysis showed that lean burn operation along with nitrogen enrichment is one of the effective pathways for realizing better FCE and lower NOx emissions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] Low temperature combustion using nitrogen enrichment to mitigate NOx from large bore natural gas fueled engines [texte imprimé] / Munidhar S. Biruduganti, Auteur ; Sreenath B. Gupta, Auteur ; Raj Sekar, Auteur . - 2010 . - 04 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 04 p. Mots-clés : Air  pollution  Combustion  Engines  Fuel Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Low temperature combustion is identified as one of the pathways to meet the mandatory ultra low NOx emissions levels set by the regulatory agencies. Exhaust gas recirculation (EGR) is a well known technique to realize low NOx emissions. However, EGR has many built-in adverse ramifications that negate its advantages in the long term. This paper discusses nitrogen enrichment of intake air using air separation membranes as a better alternative to the mature EGR technique. This investigation was undertaken to determine the maximum acceptable level of nitrogen enrichment of air for a single-cylinder spark-ignited natural gas engine. NOx reduction as high as 70% was realized with a modest 2% nitrogen enrichment while maintaining power density and simultaneously improving fuel conversion efficiency (FCE). Any enrichment beyond this level degraded engine performance in terms of power density, FCE, and unburned hydrocarbon emissions. The effect of ignition timing was also studied with and without N2 enrichment. Finally, lean burn versus stoichiometric operation utilizing nitrogen enrichment was compared. Analysis showed that lean burn operation along with nitrogen enrichment is one of the effective pathways for realizing better FCE and lower NOx emissions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

The plant feature and performance of double MS (modular simplified and medium small reactor) / Tomohiko Ikegawa in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 1 (Janvier 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Titre : The plant feature and performance of double MS (modular simplified and medium small reactor) Type de document : texte imprimé Auteurs : Tomohiko Ikegawa, Auteur ; Yukiko Kawabata, Auteur ; Yoshihiko Ishii, Auteur Année de publication : 2010 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fission  reactor  accidents  Fission  reactor  containment  Fission  reactor  cooling  Fission  reactor  safety  Light  water  reactors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A new concept of a small and medium sized light water reactor, named the double MS: modular simplified and medium small reactor (DMS) was developed. The main features of the DMS relative to overcoming the scale demerit are the miniaturization and simplification of systems and equipment, integrated modulation of construction, standardization of equipment layouts, and effective use of proven technology. The decrease in the primary containment vessel (PCV) height is achieved by reducing the active fuel length of the DMS core, which is about 2 m compared with 3.7 m in the conventional boiling water reactor (BWR). The short active fuel length reduces the drop in core pressure and overcomes the natural circulation system. By using the lower steam velocity in the upper plenum in the reactor pressure vessel (RPV), we can adopt a free surface separation (FSS) system. The FSS eliminates the need for a separator and thus helps minimize the RPV and PCV sizes. In order to confirm transient performance, the DMS plant performance under transient conditions was evaluated using the TRACG code. TRACG code, which can treat multidimensional hydrodynamic calculations in a RPV, is well suited for evaluating the DMS reactor transient performance because it can evaluate the void fraction in the chimney and therefore evaluate the natural circulation flow. As a result, the maximum change in the minimum critical power ratio of the DMS was 0.14, almost the same as for the current advanced boiling water reactor (ABWRs). In order to improve safety efficiency, developing an emergency core cooling system (ECCS) for the DMS was considered. The ECCS configuration in the DMS was examined to achieve core coverage and economic efficiency from the following: (1) eliminating high-pressure injection systems, (2) adopting passive safety-related systems, and (3) optimizing distribution for the systems and power source for the ECCS. In this way, the configuration of the ECCS for the DMS was established, providing the same level of safety as the ABWR and the passive systems. Based on the results of the loss of coolant accident analysis, we confirmed that the core can be covered by this configuration. Therefore, the plant concept was found to offer both economic efficiency and safety. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...] [article] The plant feature and performance of double MS (modular simplified and medium small reactor) [texte imprimé] / Tomohiko Ikegawa, Auteur ; Yukiko Kawabata, Auteur ; Yoshihiko Ishii, Auteur . - 2010 . - 07 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 1 (Janvier 2010) . - 07 p. Mots-clés : Fission  reactor  accidents  Fission  reactor  containment  Fission  reactor  cooling  Fission  reactor  safety  Light  water  reactors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : A new concept of a small and medium sized light water reactor, named the double MS: modular simplified and medium small reactor (DMS) was developed. The main features of the DMS relative to overcoming the scale demerit are the miniaturization and simplification of systems and equipment, integrated modulation of construction, standardization of equipment layouts, and effective use of proven technology. The decrease in the primary containment vessel (PCV) height is achieved by reducing the active fuel length of the DMS core, which is about 2 m compared with 3.7 m in the conventional boiling water reactor (BWR). The short active fuel length reduces the drop in core pressure and overcomes the natural circulation system. By using the lower steam velocity in the upper plenum in the reactor pressure vessel (RPV), we can adopt a free surface separation (FSS) system. The FSS eliminates the need for a separator and thus helps minimize the RPV and PCV sizes. In order to confirm transient performance, the DMS plant performance under transient conditions was evaluated using the TRACG code. TRACG code, which can treat multidimensional hydrodynamic calculations in a RPV, is well suited for evaluating the DMS reactor transient performance because it can evaluate the void fraction in the chimney and therefore evaluate the natural circulation flow. As a result, the maximum change in the minimum critical power ratio of the DMS was 0.14, almost the same as for the current advanced boiling water reactor (ABWRs). In order to improve safety efficiency, developing an emergency core cooling system (ECCS) for the DMS was considered. The ECCS configuration in the DMS was examined to achieve core coverage and economic efficiency from the following: (1) eliminating high-pressure injection systems, (2) adopting passive safety-related systems, and (3) optimizing distribution for the systems and power source for the ECCS. In this way, the configuration of the ECCS for the DMS was established, providing the same level of safety as the ABWR and the passive systems. Based on the results of the loss of coolant accident analysis, we confirmed that the core can be covered by this configuration. Therefore, the plant concept was found to offer both economic efficiency and safety. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000132000001 [...]

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