Dépouillements

Dynamic adaptation of aerodynamic flame stabilization of a premix swirl burner to fuel reactivity using fuel momentum / J. Sangl in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 11 p. Titre : Dynamic adaptation of aerodynamic flame stabilization of a premix swirl burner to fuel reactivity using fuel momentum Type de document : texte imprimé Auteurs : J. Sangl, Auteur ; C. Mayer, Auteur ; T. Sattelmayer, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Syngas  Hydrogen  Fuel  momentum  Swirl  stabilized  burner  Flame  stabilization Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Due to the expected increase in available fuel gas variants in the future and the interest in independence from a specific fuel, fuel flexible combustion systems are required for future gas turbine applications. Changing the fuel used for lean premixed combustion can lead to serious reliability problems in gas turbine engines caused by the different physical and chemical properties of these gases. A new innovative approach to reach efficient, safe, and low-emission operation for fuels such as natural gas, syntheses gas, and hydrogen with the same burner is presented in this paper. The basic idea is to use the additionally available fuel momentum of highly reactive gases stemming from their lower Wobbe index (lower volumetric heating value and density) compared with lowly reactive fuels. Using fuel momentum opens the opportunity to influence the vortex dynamics of swirl burners designed for lowly reactive gases in a favorable way for proper flame stabilization of highly reactive fuels without changing the hardware geometry. The investigations presented in this paper cover the development of the optimum basic aerodynamics of the burner and the determination of the potential of the fuel momentum in water channel experiments using particle image velocimetry. The results show that proper usage of the fuel momentum has enough potential to adjust the flow field to different fuels and their corresponding flame behavior. As the main challenge is to reach flashback safe fuel flexible burner operation, the main focus of the study lies on avoiding combustion induced vortex breakdown. The mixing quality of the resulting injection strategy is determined by applying laser induced fluorescence in water channel tests. Additional OH* chemiluminescence and flashback measurements in an atmospheric combustion test rig confirm the water channel results for CH4, CH4/H2 mixtures, H2 with N2 dilution, and pure H2 combustion. They also indicate a large operating window between flashback and lean blow out and show expected NOx emission levels. In summary, it is shown for a conical four slot swirl generator geometry that the proposed concept of using the fuel momentum for tuning of the vortex dynamics allows aerodynamic flame stabilization for different fuels in the same burner. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Dynamic adaptation of aerodynamic flame stabilization of a premix swirl burner to fuel reactivity using fuel momentum [texte imprimé] / J. Sangl, Auteur ; C. Mayer, Auteur ; T. Sattelmayer, Auteur . - 2011 . - 11 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 11 p. Mots-clés : Syngas  Hydrogen  Fuel  momentum  Swirl  stabilized  burner  Flame  stabilization Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Due to the expected increase in available fuel gas variants in the future and the interest in independence from a specific fuel, fuel flexible combustion systems are required for future gas turbine applications. Changing the fuel used for lean premixed combustion can lead to serious reliability problems in gas turbine engines caused by the different physical and chemical properties of these gases. A new innovative approach to reach efficient, safe, and low-emission operation for fuels such as natural gas, syntheses gas, and hydrogen with the same burner is presented in this paper. The basic idea is to use the additionally available fuel momentum of highly reactive gases stemming from their lower Wobbe index (lower volumetric heating value and density) compared with lowly reactive fuels. Using fuel momentum opens the opportunity to influence the vortex dynamics of swirl burners designed for lowly reactive gases in a favorable way for proper flame stabilization of highly reactive fuels without changing the hardware geometry. The investigations presented in this paper cover the development of the optimum basic aerodynamics of the burner and the determination of the potential of the fuel momentum in water channel experiments using particle image velocimetry. The results show that proper usage of the fuel momentum has enough potential to adjust the flow field to different fuels and their corresponding flame behavior. As the main challenge is to reach flashback safe fuel flexible burner operation, the main focus of the study lies on avoiding combustion induced vortex breakdown. The mixing quality of the resulting injection strategy is determined by applying laser induced fluorescence in water channel tests. Additional OH* chemiluminescence and flashback measurements in an atmospheric combustion test rig confirm the water channel results for CH4, CH4/H2 mixtures, H2 with N2 dilution, and pure H2 combustion. They also indicate a large operating window between flashback and lean blow out and show expected NOx emission levels. In summary, it is shown for a conical four slot swirl generator geometry that the proposed concept of using the fuel momentum for tuning of the vortex dynamics allows aerodynamic flame stabilization for different fuels in the same burner. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

CFD prediction of partload CO emissions using a two-timescale combustion model / Bernhard Wegner in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Titre : CFD prediction of partload CO emissions using a two-timescale combustion model Type de document : texte imprimé Auteurs : Bernhard Wegner, Auteur ; Uwe Gruschka, Auteur ; Werner Krebs, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : CFD  combustion  model  Emissions  CO  prediction Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Today's and future electric power generation is characterized by a large diversification using all kind of sources, including renewables resulting in noncoherent fluctuations of power supply and power usage. In this context, gas turbines offer a high operational flexibility and a good turn down ratio. In order to guide the design and down select promising solutions for improving partload emissions, a new combustion model based on the assumption of two separate timescales for the fast premixed flame stabilization and the slow post flame burnout zone is developed within the commercial computational fluid dynamics (CFD) code ANSYS CFX. This model enables the prediction of CO emissions generally limiting the turn down ratio of gas turbines equipped with modern low NOx combustion systems. The model is explained and validated at lab scale conditions. Finally, the application of the model for a full scale analysis of a gas turbine combustion system is demonstrated. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] CFD prediction of partload CO emissions using a two-timescale combustion model [texte imprimé] / Bernhard Wegner, Auteur ; Uwe Gruschka, Auteur ; Werner Krebs, Auteur . - 2011 . - 07 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Mots-clés : CFD  combustion  model  Emissions  CO  prediction Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Today's and future electric power generation is characterized by a large diversification using all kind of sources, including renewables resulting in noncoherent fluctuations of power supply and power usage. In this context, gas turbines offer a high operational flexibility and a good turn down ratio. In order to guide the design and down select promising solutions for improving partload emissions, a new combustion model based on the assumption of two separate timescales for the fast premixed flame stabilization and the slow post flame burnout zone is developed within the commercial computational fluid dynamics (CFD) code ANSYS CFX. This model enables the prediction of CO emissions generally limiting the turn down ratio of gas turbines equipped with modern low NOx combustion systems. The model is explained and validated at lab scale conditions. Finally, the application of the model for a full scale analysis of a gas turbine combustion system is demonstrated. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

A new method for measuring thermal contact conductance / Simon Woodland in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : A new method for measuring thermal contact conductance : experimental technique and results Type de document : texte imprimé Auteurs : Simon Woodland, Auteur ; Andrew D. Crocombe, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Heat  transfer  Mechanical  testing  Pipes  Surface  roughness  Thermal  conductivity  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Thermal contact conductance (TCC) is used to characterize heat transfer across interfaces in contact. It is important in thermal modeling of turbomachinery components and finds many other applications in the aerospace, microelectronic, automotive and metal working industries. In this paper, a new method for measuring TCC is described and demonstrated. A test rig is formed from an instrumented split tube with in-line washers and loading applied under controlled conditions. The experimental method and data analysis are described, and the effects on thermal contact conductance of important parameters such as the contact pressure, surface roughness, temperature, thermal conductivity, and material strength are investigated. Normalization of the TCC measured in the experimental program was carried out using appropriate surface and material parameters. The results of this normalization are used to compare the normalized experimental results with various models from the literature. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] A new method for measuring thermal contact conductance : experimental technique and results [texte imprimé] / Simon Woodland, Auteur ; Andrew D. Crocombe, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Heat  transfer  Mechanical  testing  Pipes  Surface  roughness  Thermal  conductivity  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Thermal contact conductance (TCC) is used to characterize heat transfer across interfaces in contact. It is important in thermal modeling of turbomachinery components and finds many other applications in the aerospace, microelectronic, automotive and metal working industries. In this paper, a new method for measuring TCC is described and demonstrated. A test rig is formed from an instrumented split tube with in-line washers and loading applied under controlled conditions. The experimental method and data analysis are described, and the effects on thermal contact conductance of important parameters such as the contact pressure, surface roughness, temperature, thermal conductivity, and material strength are investigated. Normalization of the TCC measured in the experimental program was carried out using appropriate surface and material parameters. The results of this normalization are used to compare the normalized experimental results with various models from the literature. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Minimizing sampling loss in trace gas emission measurements for aircraft engines by using a chemical quick-quench probe / de la Rosa Blanco, Elena in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Titre : Minimizing sampling loss in trace gas emission measurements for aircraft engines by using a chemical quick-quench probe Type de document : texte imprimé Auteurs : de la Rosa Blanco, Elena, Auteur ; Peck, Jay, Auteur ; Richard C. Miake-Lye, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Aerospace  engines  Air  pollution  control  Air  pollution  measurement  Losses Résumé : This paper describes the development and testing of a gas sampling probe that quenches chemical reactions by using supersonic expansion and helium dilution. Gas sampling probes are required for accurate measurement of exhaust emissions species, which is critical to determine the performance of an aircraft engine. The probe was designed through rounds of computational modeling and laboratory testing and was subsequently manufactured and then tested at the University of Tennessee Space Institute behind a General Electric J85 turbojet engine at different power settings: idle, maximum military, and afterburning. The experimental test results demonstrated that the chemical quick-quench (CQQ) probe suppressed the oxidation of carbon monoxide (CO) inside the probe system and preserved more CO at afterburning conditions. In addition, the CQQ probe prevented hydrocarbons from being partially oxidized to form CO at idle powers and measured higher hydrocarbons and lower CO emission compared with a conventional probe at that low power condition. The CQQ probe also suppressed nitrogen dioxide (NO2) to nitric oxide (NO) conversion through all engine power settings. These data strongly support the conclusion that the CQQ probe is able to quench unwanted chemical reactions inside the probe for all engine power levels. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Minimizing sampling loss in trace gas emission measurements for aircraft engines by using a chemical quick-quench probe [texte imprimé] / de la Rosa Blanco, Elena, Auteur ; Peck, Jay, Auteur ; Richard C. Miake-Lye, Auteur . - 2011 . - 07 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Mots-clés : Aerospace  engines  Air  pollution  control  Air  pollution  measurement  Losses Résumé : This paper describes the development and testing of a gas sampling probe that quenches chemical reactions by using supersonic expansion and helium dilution. Gas sampling probes are required for accurate measurement of exhaust emissions species, which is critical to determine the performance of an aircraft engine. The probe was designed through rounds of computational modeling and laboratory testing and was subsequently manufactured and then tested at the University of Tennessee Space Institute behind a General Electric J85 turbojet engine at different power settings: idle, maximum military, and afterburning. The experimental test results demonstrated that the chemical quick-quench (CQQ) probe suppressed the oxidation of carbon monoxide (CO) inside the probe system and preserved more CO at afterburning conditions. In addition, the CQQ probe prevented hydrocarbons from being partially oxidized to form CO at idle powers and measured higher hydrocarbons and lower CO emission compared with a conventional probe at that low power condition. The CQQ probe also suppressed nitrogen dioxide (NO2) to nitric oxide (NO) conversion through all engine power settings. These data strongly support the conclusion that the CQQ probe is able to quench unwanted chemical reactions inside the probe for all engine power levels. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

A data filter for identifying steady-state operating points in engine flight data for condition monitoring applications / Donald L. Simon in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : A data filter for identifying steady-state operating points in engine flight data for condition monitoring applications Type de document : texte imprimé Auteurs : Donald L. Simon, Auteur ; Jonathan S. Litt, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Aerospace  engineering  Aerospace  engines  Condition  monitoring  Data  handling  Helicopters Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper presents an algorithm that automatically identifies and extracts steady-state engine operating points from engine flight data. It calculates the mean and standard deviation of select parameters contained in the incoming flight data stream. If the standard deviation of the data falls below defined constraints, the engine is assumed to be at a steady-state operating point and the mean measurement data at that point are archived for subsequent condition monitoring purposes. The fundamental design of the steady-state data filter is completely generic and applicable for any dynamic system. Additional domain-specific logic constraints are applied to reduce data outliers and variance within the collected steady-state data. The filter is designed for on-line real-time processing of streaming data as opposed to post-processing of the data in batch mode. Results of applying the steady-state data filter to recorded helicopter engine flight data are shown, demonstrating its utility for engine condition monitoring applications. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] A data filter for identifying steady-state operating points in engine flight data for condition monitoring applications [texte imprimé] / Donald L. Simon, Auteur ; Jonathan S. Litt, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Aerospace  engineering  Aerospace  engines  Condition  monitoring  Data  handling  Helicopters Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper presents an algorithm that automatically identifies and extracts steady-state engine operating points from engine flight data. It calculates the mean and standard deviation of select parameters contained in the incoming flight data stream. If the standard deviation of the data falls below defined constraints, the engine is assumed to be at a steady-state operating point and the mean measurement data at that point are archived for subsequent condition monitoring purposes. The fundamental design of the steady-state data filter is completely generic and applicable for any dynamic system. Additional domain-specific logic constraints are applied to reduce data outliers and variance within the collected steady-state data. The filter is designed for on-line real-time processing of streaming data as opposed to post-processing of the data in batch mode. Results of applying the steady-state data filter to recorded helicopter engine flight data are shown, demonstrating its utility for engine condition monitoring applications. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Nonlinear multiple points gas turbine off-design performance adaptation using a genetic algorithm / Y. G. Li in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) Titre : Nonlinear multiple points gas turbine off-design performance adaptation using a genetic algorithm Type de document : texte imprimé Auteurs : Y. G. Li, Auteur ; M. F. Abdul Ghafir, Auteur ; L. Wang, Auteur Année de publication : 2011 Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Gas  turbines  Genetic  algorithms  Shafts  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Accurate gas turbine performance models are crucial in many gas turbine performance analysis and gas path diagnostic applications. With current thermodynamic performance modeling techniques, the accuracy of gas turbine performance models at off-design conditions is determined by engine component characteristic maps obtained in rig tests and these maps may not be available to gas turbine users or may not be accurate for individual engines. In this paper, a nonlinear multiple point performance adaptation approach using a genetic algorithm is introduced with the aim to improve the performance prediction accuracy of gas turbine engines at different off-design conditions by calibrating the engine performance models against available test data. Such calibration is carried out with introduced nonlinear map scaling factor functions by “modifying” initially implemented component characteristic maps in the gas turbine thermodynamic performance models. A genetic algorithm is used to search for an optimal set of nonlinear scaling factor functions for the maps via an objective function that measures the difference between the simulated and actual gas path measurements. The developed off-design performance adaptation approach has been applied to a model single spool turbo-shaft aero gas turbine engine and has demonstrated a significant improvement in the performance model accuracy at off-design operating conditions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Nonlinear multiple points gas turbine off-design performance adaptation using a genetic algorithm [texte imprimé] / Y. G. Li, Auteur ; M. F. Abdul Ghafir, Auteur ; L. Wang, Auteur . - 2011. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) Mots-clés : Gas  turbines  Genetic  algorithms  Shafts  Thermodynamics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Accurate gas turbine performance models are crucial in many gas turbine performance analysis and gas path diagnostic applications. With current thermodynamic performance modeling techniques, the accuracy of gas turbine performance models at off-design conditions is determined by engine component characteristic maps obtained in rig tests and these maps may not be available to gas turbine users or may not be accurate for individual engines. In this paper, a nonlinear multiple point performance adaptation approach using a genetic algorithm is introduced with the aim to improve the performance prediction accuracy of gas turbine engines at different off-design conditions by calibrating the engine performance models against available test data. Such calibration is carried out with introduced nonlinear map scaling factor functions by “modifying” initially implemented component characteristic maps in the gas turbine thermodynamic performance models. A genetic algorithm is used to search for an optimal set of nonlinear scaling factor functions for the maps via an objective function that measures the difference between the simulated and actual gas path measurements. The developed off-design performance adaptation approach has been applied to a model single spool turbo-shaft aero gas turbine engine and has demonstrated a significant improvement in the performance model accuracy at off-design operating conditions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Improved controller performance of selected hybrid SOFC-GT plant signals based on practical control schemes / Alex Tsai in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 11 p. Titre : Improved controller performance of selected hybrid SOFC-GT plant signals based on practical control schemes Type de document : texte imprimé Auteurs : Alex Tsai, Auteur ; David Tucker, Auteur ; Craig Groves, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Cathodes  Centralised  control  Decentralised  control  Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  MIMO  systems  Multivariable  control  systems  Power  generation  control  Solid  oxide  fuel  cells  Three-term  control  Transfer  functions Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper compares and demonstrates the efficacy of implementing two practical single input single output multiloop control schemes on the dynamic performance of selected signals of a solid oxide fuel cell gas turbine (SOFC-GT) hybrid simulation facility. The hybrid plant located at the U.S. Department of Energy National Energy Technology Laboratory in Morgantown, WV is capable of simulating the interaction between a 350 kW solid oxide fuel cell and a 120 kW gas turbine using a hardware in the loop configuration. Previous studies have shown that the thermal management of coal based SOFC-GT hybrid systems is accomplished by the careful control of the cathode air stream within the fuel cell (FC). Decoupled centralized and dynamic decentralized control schemes are tested for one critical airflow bypass loop to regulate cathode FC airflow and modulation of turbine electric load to maintain synchronous turbine speed during system transients. Improvements to the studied multivariate architectures include: feed-forward control for disturbance rejection, antiwindup compensation for actuator saturation, gain scheduling for adaptive operation, bumpless transfer for manual to auto switching, and adequate filter design for the inclusion of derivative action. Controller gain tuning is accomplished by Skogestad's internal model control tuning rules derived from empirical first order plus delay time transfer function models of the hybrid facility. Avoidance of strong input-output coupling interactions is achieved via relative gain array, Niederlinski index, and decomposed relative interaction analysis, following recent methodologies in proportional integral derivative control theory for multivariable processes. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Improved controller performance of selected hybrid SOFC-GT plant signals based on practical control schemes [texte imprimé] / Alex Tsai, Auteur ; David Tucker, Auteur ; Craig Groves, Auteur . - 2011 . - 11 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 11 p. Mots-clés : Cathodes  Centralised  control  Decentralised  control  Fuel  cell  power  plants  Gas  turbine  power  stations  Hybrid  power  systems  MIMO  systems  Multivariable  control  systems  Power  generation  control  Solid  oxide  fuel  cells  Three-term  control  Transfer  functions Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper compares and demonstrates the efficacy of implementing two practical single input single output multiloop control schemes on the dynamic performance of selected signals of a solid oxide fuel cell gas turbine (SOFC-GT) hybrid simulation facility. The hybrid plant located at the U.S. Department of Energy National Energy Technology Laboratory in Morgantown, WV is capable of simulating the interaction between a 350 kW solid oxide fuel cell and a 120 kW gas turbine using a hardware in the loop configuration. Previous studies have shown that the thermal management of coal based SOFC-GT hybrid systems is accomplished by the careful control of the cathode air stream within the fuel cell (FC). Decoupled centralized and dynamic decentralized control schemes are tested for one critical airflow bypass loop to regulate cathode FC airflow and modulation of turbine electric load to maintain synchronous turbine speed during system transients. Improvements to the studied multivariate architectures include: feed-forward control for disturbance rejection, antiwindup compensation for actuator saturation, gain scheduling for adaptive operation, bumpless transfer for manual to auto switching, and adequate filter design for the inclusion of derivative action. Controller gain tuning is accomplished by Skogestad's internal model control tuning rules derived from empirical first order plus delay time transfer function models of the hybrid facility. Avoidance of strong input-output coupling interactions is achieved via relative gain array, Niederlinski index, and decomposed relative interaction analysis, following recent methodologies in proportional integral derivative control theory for multivariable processes. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

An axial flow compressor for operation with humid air and water injection / Jesuino Takachi Tomita in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : An axial flow compressor for operation with humid air and water injection Type de document : texte imprimé Auteurs : Jesuino Takachi Tomita, Auteur ; Luciano Porto Bontempo, Auteur ; João Roberto Barbosa, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Compressors  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The first steps of the turbomachinery design usually rely on numerical tools based on inviscid formulation with corrections using loss models to account for viscous effects, secondary flows, tip clearances, and shock waves. The viscous effects are accounted for using semi-empirical correlations especially assembled for the chosen airfoils and range of operating conditions. Fast convergence and good accuracy are required from such design procedures. There are successful models that produce very accurate performance prediction. Among the methodologies commonly used, the streamline curvature (SLC) is used since those characteristics and the most important properties can be calculated reasonably well at any radial positions, assisting other more complex analysis programs. The SLC technique is, therefore, well suited for the design of axial flow compressors for reasons such as quick access to vital flow properties at the blade edges from which actions may be taken to improve its performance at the design stage. This work reports the association of a SLC computer program and commercial software for comparison purposes, as well as for grid generation required by a full 3D, turbulent Navier–Stokes computer program used for flow calculation in the blade passages. Application to a high performance three-stage axial flow compressor with inlet guide vane demonstrates the methodology adopted. The SLC program is also capable of calculating the compressor performance with humid air and water injection at any axial position along the compressor. The influence of water injection at different axial positions, water particle diameter, and temperature of water particles were studied for different humid air conditions. The positions of the evaporating water particles were calculated using their thermophysical and dynamic properties along the compressor. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] An axial flow compressor for operation with humid air and water injection [texte imprimé] / Jesuino Takachi Tomita, Auteur ; Luciano Porto Bontempo, Auteur ; João Roberto Barbosa, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Compressors  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The first steps of the turbomachinery design usually rely on numerical tools based on inviscid formulation with corrections using loss models to account for viscous effects, secondary flows, tip clearances, and shock waves. The viscous effects are accounted for using semi-empirical correlations especially assembled for the chosen airfoils and range of operating conditions. Fast convergence and good accuracy are required from such design procedures. There are successful models that produce very accurate performance prediction. Among the methodologies commonly used, the streamline curvature (SLC) is used since those characteristics and the most important properties can be calculated reasonably well at any radial positions, assisting other more complex analysis programs. The SLC technique is, therefore, well suited for the design of axial flow compressors for reasons such as quick access to vital flow properties at the blade edges from which actions may be taken to improve its performance at the design stage. This work reports the association of a SLC computer program and commercial software for comparison purposes, as well as for grid generation required by a full 3D, turbulent Navier–Stokes computer program used for flow calculation in the blade passages. Application to a high performance three-stage axial flow compressor with inlet guide vane demonstrates the methodology adopted. The SLC program is also capable of calculating the compressor performance with humid air and water injection at any axial position along the compressor. The influence of water injection at different axial positions, water particle diameter, and temperature of water particles were studied for different humid air conditions. The positions of the evaporating water particles were calculated using their thermophysical and dynamic properties along the compressor. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Risk analysis of gas turbines for natural gas liquefaction / Raja S. R. Khan in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : Risk analysis of gas turbines for natural gas liquefaction Type de document : texte imprimé Auteurs : Raja S. R. Khan, Auteur ; Maria C. Lagana, Auteur ; Stephen O. T. Ogaji, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Gas  turbines  Monte  Carlo  methods  Natural  gas  technology  Power  generation  reliability  Risk  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Procurement of process plant equipment involves decisions based not only on an economic agenda but also on long term plant capability, which in turn depends on equipment reliability. As the greater global community raises environmental concerns and pushes for economic reform, a tool is evermore required for a specific and critical selection of plant equipment. Risk assessments based on NASA's Technology Readiness Level (TRL) scale have been employed in many previous risk models to map technology in terms of risk and reliability. The authors envisage a scale for quantifying the technical risk. The focus of this paper is the technical risk assessment of gas turbines as mechanical drivers for producing liquefied natural gas (LNG). This risk assessment is a cornerstone of the technoeconomic environmental and risk analysis (TERA) philosophy developed by Cranfield University's Department of Power and Propulsion in U.K. Monte Carlo simulations are used in order to compare the risks of introducing new plant equipment against existing and established plant equipment. Three scenarios are investigated using an 87MW single spool, typical industrial machine, a baseline engine followed by an engine with increased firing temperature, and finally an engine with a zero staged compressor. The results suggest that if the baseline engine was to be upgraded, then the zero staging option would be a better solution than increasing the firing temperature since zero staging gives the lower rise in total time to repair (TTTR) or downtime. The authors suggest a scaling system based on NASA's TRL but with modified definition criteria for the separate technology readiness levels in order to better relate the scale to gas turbine technology. The intention is to link the modified TRL to downtime, since downtime has been identified as a quantitative measure of technical risk. Latest developments of the modeling are looking at integrating risk analysis and a maintenance cost and scheduling model to provide a platform for total risk assessment. This, coupled with emissions modeling, is set to provide the overall TERA tool for LNG technology selection. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Risk analysis of gas turbines for natural gas liquefaction [texte imprimé] / Raja S. R. Khan, Auteur ; Maria C. Lagana, Auteur ; Stephen O. T. Ogaji, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Gas  turbines  Monte  Carlo  methods  Natural  gas  technology  Power  generation  reliability  Risk  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Procurement of process plant equipment involves decisions based not only on an economic agenda but also on long term plant capability, which in turn depends on equipment reliability. As the greater global community raises environmental concerns and pushes for economic reform, a tool is evermore required for a specific and critical selection of plant equipment. Risk assessments based on NASA's Technology Readiness Level (TRL) scale have been employed in many previous risk models to map technology in terms of risk and reliability. The authors envisage a scale for quantifying the technical risk. The focus of this paper is the technical risk assessment of gas turbines as mechanical drivers for producing liquefied natural gas (LNG). This risk assessment is a cornerstone of the technoeconomic environmental and risk analysis (TERA) philosophy developed by Cranfield University's Department of Power and Propulsion in U.K. Monte Carlo simulations are used in order to compare the risks of introducing new plant equipment against existing and established plant equipment. Three scenarios are investigated using an 87MW single spool, typical industrial machine, a baseline engine followed by an engine with increased firing temperature, and finally an engine with a zero staged compressor. The results suggest that if the baseline engine was to be upgraded, then the zero staging option would be a better solution than increasing the firing temperature since zero staging gives the lower rise in total time to repair (TTTR) or downtime. The authors suggest a scaling system based on NASA's TRL but with modified definition criteria for the separate technology readiness levels in order to better relate the scale to gas turbine technology. The intention is to link the modified TRL to downtime, since downtime has been identified as a quantitative measure of technical risk. Latest developments of the modeling are looking at integrating risk analysis and a maintenance cost and scheduling model to provide a platform for total risk assessment. This, coupled with emissions modeling, is set to provide the overall TERA tool for LNG technology selection. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Analysis and comparison of reactivity and CO2 capture capacity of fresh calcium-based sorbents and samples from a lab-scale dual fluidized bed calcium looping facility / Senthoorselvan Sivalingam in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Titre : Analysis and comparison of reactivity and CO2 capture capacity of fresh calcium-based sorbents and samples from a lab-scale dual fluidized bed calcium looping facility Type de document : texte imprimé Auteurs : Senthoorselvan Sivalingam, Auteur ; Stephan Gleis, Auteur ; Hartmut Spliethoff, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Calcium  looping  Duel  fluidized  bed  CO2  separation  Carbonation  Calcination Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Naturally occurring limestone and samples from a lab-scale dual fluidized bed (DFB) calcium looping test facility were analyzed in a thermogravimetric analyzer. The reactivity of the samples evaluated at typical carbonation conditions prevailed in the carbonator was compared with raw samples. The rate of carbonation and carbonation capacity of the samples were compared with respect to the following three categories: number of calcination-carbonation cycles, carbonation temperature, and CO2 concentration. It is suspected that the much lower activity of the DFB sample is attributed to the differences in experimental conditions, i.e., partial carbonation of the DFB particles, fast heating rate in the calciner and thus a rapid calcination reaction, and particle attrition in the circulating fluidized bed calciner riser. These harsh conditions lead to sintering and thus a loss of surface area and reactivity. Sintered DFB samples showed low (nearly one-third of the raw samples) but stable conversions with increasing number of cycles. Hydration was used as an attempt to regenerate the lost capture capacity of partially carbonated and sintered DFB sample. Hydration of the DFB sample was successful in increasing the maximum capture capacity in the fast reaction regime to values almost as high as that of a fresh sample in its first carbonation cycle. Although more investigation is required to investigate the effect of hydration on the CaO particle morphology, a process modification to enhance the CO2 capture efficiency of the carbonator via particle hydration was proposed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Analysis and comparison of reactivity and CO2 capture capacity of fresh calcium-based sorbents and samples from a lab-scale dual fluidized bed calcium looping facility [texte imprimé] / Senthoorselvan Sivalingam, Auteur ; Stephan Gleis, Auteur ; Hartmut Spliethoff, Auteur . - 2011 . - 06 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Mots-clés : Calcium  looping  Duel  fluidized  bed  CO2  separation  Carbonation  Calcination Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Naturally occurring limestone and samples from a lab-scale dual fluidized bed (DFB) calcium looping test facility were analyzed in a thermogravimetric analyzer. The reactivity of the samples evaluated at typical carbonation conditions prevailed in the carbonator was compared with raw samples. The rate of carbonation and carbonation capacity of the samples were compared with respect to the following three categories: number of calcination-carbonation cycles, carbonation temperature, and CO2 concentration. It is suspected that the much lower activity of the DFB sample is attributed to the differences in experimental conditions, i.e., partial carbonation of the DFB particles, fast heating rate in the calciner and thus a rapid calcination reaction, and particle attrition in the circulating fluidized bed calciner riser. These harsh conditions lead to sintering and thus a loss of surface area and reactivity. Sintered DFB samples showed low (nearly one-third of the raw samples) but stable conversions with increasing number of cycles. Hydration was used as an attempt to regenerate the lost capture capacity of partially carbonated and sintered DFB sample. Hydration of the DFB sample was successful in increasing the maximum capture capacity in the fast reaction regime to values almost as high as that of a fresh sample in its first carbonation cycle. Although more investigation is required to investigate the effect of hydration on the CaO particle morphology, a process modification to enhance the CO2 capture efficiency of the carbonator via particle hydration was proposed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

A SOFC-based integrated gasification fuel cell cycle with CO2 capture / Vincenzo Spallina in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Titre : A SOFC-based integrated gasification fuel cell cycle with CO2 capture Type de document : texte imprimé Auteurs : Vincenzo Spallina, Auteur ; Matteo C. Romano, Auteur ; Stefano Campanari, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Boilers  Coal  gasification  Fuel  cell  power  plants  Pollution  control  Solid  oxide  fuel  cells  Steam  power  stations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The application of solid oxide fuel cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in integrated gasification fuel cell cycles (IGFC) considering the much lower emissions of conventional pollutants (NOx, CO, SOx, and particulate matter) typical of fuel cell-based systems. In addition, SOFC-based IGFCs appear particularly suited to applications in power plants with CO2 capture. This is evident by considering that SOFCs operate as air separators and partly oxidized fuel exiting the fuel cell does not contain nitrogen from air, such as in conventional oxyfuel processes. The aim of this paper is the thermodynamic analysis of a SOFC-based IGFC with CO2 capture. In the assessed plant, syngas produced in a high efficiency Shell gasifier is used in SOFC modules after heat recovery and cleaning. Anode exhausts, still containing combustible species, are burned with oxygen produced in the air separation unit, also used to generate the oxygen needed in the gasifier; the product gas is cooled down in a heat recovery steam generator before water condensation and CO2 compression. The plant layout is carefully designed to best exploit the heat generated in all the processes and, apart from the fuel cell exotic components, far from industrial state-of-the-art, are not included. Detailed energy and mass balances are presented for a better comprehension of the obtained results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] A SOFC-based integrated gasification fuel cell cycle with CO2 capture [texte imprimé] / Vincenzo Spallina, Auteur ; Matteo C. Romano, Auteur ; Stefano Campanari, Auteur . - 2011 . - 10 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Mots-clés : Boilers  Coal  gasification  Fuel  cell  power  plants  Pollution  control  Solid  oxide  fuel  cells  Steam  power  stations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The application of solid oxide fuel cells (SOFC) in gasification-based power plants would represent a turning point in the power generation sector, allowing to considerably increase the electric efficiency of coal-fired power stations. Pollutant emissions would also be significantly reduced in integrated gasification fuel cell cycles (IGFC) considering the much lower emissions of conventional pollutants (NOx, CO, SOx, and particulate matter) typical of fuel cell-based systems. In addition, SOFC-based IGFCs appear particularly suited to applications in power plants with CO2 capture. This is evident by considering that SOFCs operate as air separators and partly oxidized fuel exiting the fuel cell does not contain nitrogen from air, such as in conventional oxyfuel processes. The aim of this paper is the thermodynamic analysis of a SOFC-based IGFC with CO2 capture. In the assessed plant, syngas produced in a high efficiency Shell gasifier is used in SOFC modules after heat recovery and cleaning. Anode exhausts, still containing combustible species, are burned with oxygen produced in the air separation unit, also used to generate the oxygen needed in the gasifier; the product gas is cooled down in a heat recovery steam generator before water condensation and CO2 compression. The plant layout is carefully designed to best exploit the heat generated in all the processes and, apart from the fuel cell exotic components, far from industrial state-of-the-art, are not included. Detailed energy and mass balances are presented for a better comprehension of the obtained results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Evaluating the machinability of inconel 718 using polar diagrams / Pajazit Avdovic in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Titre : Evaluating the machinability of inconel 718 using polar diagrams Type de document : texte imprimé Auteurs : Pajazit Avdovic, Auteur ; Linhong Xu, Auteur ; Mats Andersson, Auteur Année de publication : 2011 Article en page(s) : 07 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Polar  diagram  Machinability  Inconel  718 Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The use of a polar diagram method for describing and evaluating the machinability of Inconel 718 was explored. Five key parameters of the work material, representing the mechanical and physical properties, which have the strongest influence on its machinability, were employed in the diagrams. These five parameters were integrated into a single polar diagram, used to describe the machinability of Inconel 718. Variations in the machinability of Inconel 718 products or components of a given type produced in different batches were analyzed. Industrial experiments were conducted to test the relationship between the polar diagram of the work material, its carbon content, and the tool wear of the ceramic cutting tools used in machining it. Work materials of Inconel 718 in which the polar diagrams of machinability were similar in size and shape exhibited very similar behavior during the cutting process. The polar diagram method employed appeared to be useful for selecting suitable cutting data for the machining of new materials. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Evaluating the machinability of inconel 718 using polar diagrams [texte imprimé] / Pajazit Avdovic, Auteur ; Linhong Xu, Auteur ; Mats Andersson, Auteur . - 2011 . - 07 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 07 p. Mots-clés : Polar  diagram  Machinability  Inconel  718 Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The use of a polar diagram method for describing and evaluating the machinability of Inconel 718 was explored. Five key parameters of the work material, representing the mechanical and physical properties, which have the strongest influence on its machinability, were employed in the diagrams. These five parameters were integrated into a single polar diagram, used to describe the machinability of Inconel 718. Variations in the machinability of Inconel 718 products or components of a given type produced in different batches were analyzed. Industrial experiments were conducted to test the relationship between the polar diagram of the work material, its carbon content, and the tool wear of the ceramic cutting tools used in machining it. Work materials of Inconel 718 in which the polar diagrams of machinability were similar in size and shape exhibited very similar behavior during the cutting process. The polar diagram method employed appeared to be useful for selecting suitable cutting data for the machining of new materials. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Metallurgical evaluation and condition assessment of FSX 414 nozzle segments in gas turbines by metallographic methods / Girish M. Shejale in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Titre : Metallurgical evaluation and condition assessment of FSX 414 nozzle segments in gas turbines by metallographic methods Type de document : texte imprimé Auteurs : Girish M. Shejale, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Creep-fatigue  Thermal  fatigue  Electropolishing  technique  Hot  corrosion  Nozzle  segment  Microstructure  Oxidation  And  repair Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine components such as nozzle segments, buckets, transition pieces, and combustion liners experience damages such as creep, fatigue, high temperature oxidation, and corrosion. The reliability, availability, and efficiency of high temperature gas turbine parts are based on condition assessment and remaining life analysis. These gas turbine components are normally repaired and refurbished after stipulated operating hours. The decision on the extent of repairs is based on various inspection stages. Among various methodologies of condition assessment, metallography followed by microscopic evaluation has gained wide acceptance since it is cost effective, quick, and reliable. Extensive in-house efforts have been put forth in this field in the development of improved techniques of metallography for accurate determination of material degradation and condition assessment. Experimental studies on frame 6, first stage nozzle segment (FSX 414—cobalt based alloy) were conducted to assess the condition of the nozzle segment by using a laboratory electropolishing technique for metallographic preparation. Sections taken from the nozzle segment were electropolished and examined in light optical microscope (LOM) and scanning electron microscope (SEM). It is concluded that the improved electropolishing technique is effective in assessing creep-fatigue, thermal fatigue, and hot corrosion damage. Based on this, the condition of the nozzle segment is assessed. Typical results of frame 6, first stage nozzle segment are presented and discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Metallurgical evaluation and condition assessment of FSX 414 nozzle segments in gas turbines by metallographic methods [texte imprimé] / Girish M. Shejale, Auteur . - 2011 . - 06 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Mots-clés : Creep-fatigue  Thermal  fatigue  Electropolishing  technique  Hot  corrosion  Nozzle  segment  Microstructure  Oxidation  And  repair Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine components such as nozzle segments, buckets, transition pieces, and combustion liners experience damages such as creep, fatigue, high temperature oxidation, and corrosion. The reliability, availability, and efficiency of high temperature gas turbine parts are based on condition assessment and remaining life analysis. These gas turbine components are normally repaired and refurbished after stipulated operating hours. The decision on the extent of repairs is based on various inspection stages. Among various methodologies of condition assessment, metallography followed by microscopic evaluation has gained wide acceptance since it is cost effective, quick, and reliable. Extensive in-house efforts have been put forth in this field in the development of improved techniques of metallography for accurate determination of material degradation and condition assessment. Experimental studies on frame 6, first stage nozzle segment (FSX 414—cobalt based alloy) were conducted to assess the condition of the nozzle segment by using a laboratory electropolishing technique for metallographic preparation. Sections taken from the nozzle segment were electropolished and examined in light optical microscope (LOM) and scanning electron microscope (SEM). It is concluded that the improved electropolishing technique is effective in assessing creep-fatigue, thermal fatigue, and hot corrosion damage. Based on this, the condition of the nozzle segment is assessed. Typical results of frame 6, first stage nozzle segment are presented and discussed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Design and characterization of a liquid-fueled microcombustor / Peck, Jay in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Titre : Design and characterization of a liquid-fueled microcombustor Type de document : texte imprimé Auteurs : Peck, Jay, Auteur ; Stuart A. Jacobson, Auteur ; Ian A. Waitz, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Combustion  Gas  turbines  Heat  engines  Thermal  stresses Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : As part of an effort to develop a microscale gas turbine engine, this paper presents the design and experimental characterization of a microcombustor that catalytically burns JP8 fuel. Due to the high energy densities of hydrocarbon fuels, microscale heat engines based on them may enable compact power sources with specific energies higher than those of current battery systems. In addition, utilizing a commonly available logistics fuel would provide advantages for military applications. Thus, a microscale engine burning JP8 fuel is attractive as a portable power source. A liquid-fueled microcombustor with a combustion chamber volume of 1.4 cm3 and an overall die size of 36.4×36.4×6.5 mm3 was designed, microfabricated, and experimentally characterized. Two configurations were tested and compared, one with the combustion chamber entirely filled with a catalyst and the other with the combustion chamber partially filled with a catalyst. In the configuration filled with a catalyst, JP8 combustion was sustained at mass flow rates up to 0.1 g/s and an exit gas temperature of 780 K; an overall combustor efficiency of 19% and a power density of 43 MW/m3 were achieved. The primary limitation on increasing the mass flow rates and temperature further was the structural failure of the device due to thermal stresses. With the partially filled configuration, a mass flow rate of 0.2 g/s and a corresponding power density of 54 MW/m3 were obtained. The exit gas temperature for the partially filled configuration was as high as 720 K, and the maximum overall efficiency was over 22%. Although the reduced amount of catalyst led to incomplete combustion, smaller thermal losses resulted in an increase in the overall combustor efficiency and power density. A nondimensional operating map was constructed based on the experiment, and it suggests that improving the thermal efficiency would be necessary to achieve higher efficiencies in the device. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Design and characterization of a liquid-fueled microcombustor [texte imprimé] / Peck, Jay, Auteur ; Stuart A. Jacobson, Auteur ; Ian A. Waitz, Auteur . - 2011 . - 10 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Mots-clés : Combustion  Gas  turbines  Heat  engines  Thermal  stresses Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : As part of an effort to develop a microscale gas turbine engine, this paper presents the design and experimental characterization of a microcombustor that catalytically burns JP8 fuel. Due to the high energy densities of hydrocarbon fuels, microscale heat engines based on them may enable compact power sources with specific energies higher than those of current battery systems. In addition, utilizing a commonly available logistics fuel would provide advantages for military applications. Thus, a microscale engine burning JP8 fuel is attractive as a portable power source. A liquid-fueled microcombustor with a combustion chamber volume of 1.4 cm3 and an overall die size of 36.4×36.4×6.5 mm3 was designed, microfabricated, and experimentally characterized. Two configurations were tested and compared, one with the combustion chamber entirely filled with a catalyst and the other with the combustion chamber partially filled with a catalyst. In the configuration filled with a catalyst, JP8 combustion was sustained at mass flow rates up to 0.1 g/s and an exit gas temperature of 780 K; an overall combustor efficiency of 19% and a power density of 43 MW/m3 were achieved. The primary limitation on increasing the mass flow rates and temperature further was the structural failure of the device due to thermal stresses. With the partially filled configuration, a mass flow rate of 0.2 g/s and a corresponding power density of 54 MW/m3 were obtained. The exit gas temperature for the partially filled configuration was as high as 720 K, and the maximum overall efficiency was over 22%. Although the reduced amount of catalyst led to incomplete combustion, smaller thermal losses resulted in an increase in the overall combustor efficiency and power density. A nondimensional operating map was constructed based on the experiment, and it suggests that improving the thermal efficiency would be necessary to achieve higher efficiencies in the device. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Centrifugal compressors during fast transients / Matthew Blieske in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : Centrifugal compressors during fast transients Type de document : texte imprimé Auteurs : Matthew Blieske, Auteur ; Rainer Kurz, Auteur ; Augusto Garcia-Hernandez, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Compressors  Machine  testing  Production  equipment  Transient  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Transient studies for compressor systems allow the prediction of the compressor system behavior during fast transients such as they occur during emergency shutdowns. For the system simulations, the compressor behavior is assumed to be quasi-steady-state. This means in particular that the steady-state compressor flow-head-efficiency-speed map remains valid. During well instrumented emergency shutdown tests conducted on a centrifugal compressor system under realistic operating conditions, data showing the head-flow-speed relationship of the rapidly decelerating compressor were taken. These data are compared with steady-state head-flow relationships taken at a number of speeds. This allows the determination of the relative deviation between the transient and steady-state head-flow-relationships and thus answers the question of the validity of steady-state assumptions during rapid transients. The impact of the fast transients on efficiency and consumed power, which can be derived from the speed decay of the system, as well as the impact of nonstationary heat transfer are also evaluated and reported. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Centrifugal compressors during fast transients [texte imprimé] / Matthew Blieske, Auteur ; Rainer Kurz, Auteur ; Augusto Garcia-Hernandez, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Compressors  Machine  testing  Production  equipment  Transient  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Transient studies for compressor systems allow the prediction of the compressor system behavior during fast transients such as they occur during emergency shutdowns. For the system simulations, the compressor behavior is assumed to be quasi-steady-state. This means in particular that the steady-state compressor flow-head-efficiency-speed map remains valid. During well instrumented emergency shutdown tests conducted on a centrifugal compressor system under realistic operating conditions, data showing the head-flow-speed relationship of the rapidly decelerating compressor were taken. These data are compared with steady-state head-flow relationships taken at a number of speeds. This allows the determination of the relative deviation between the transient and steady-state head-flow-relationships and thus answers the question of the validity of steady-state assumptions during rapid transients. The impact of the fast transients on efficiency and consumed power, which can be derived from the speed decay of the system, as well as the impact of nonstationary heat transfer are also evaluated and reported. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Numerical analysis of the effects of nonuniform surface roughness on compressor stage performance / Mirko Morini in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : Numerical analysis of the effects of nonuniform surface roughness on compressor stage performance Type de document : texte imprimé Auteurs : Mirko Morini, Auteur ; Michele Pinelli, Auteur ; Pier Ruggero Spina, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Blades  Compressors  Gas  turbines  Geometry  Numerical  analysis  Surface  roughness Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine performance degradation over time is mainly due to the deterioration of compressor and turbine blades, which, in turn, causes a modification of the compressor and turbine performance maps. Since the detailed information about the actual modification of the compressor and turbine performance maps is usually unavailable, the component performance can be modeled and investigated by the following: scaling the overall performance map, using stage-by-stage models of the compressor and turbine, and scaling each single stage performance map to account for each stage deterioration, or performing 3D numerical simulations, which allow to both highlight the fluid-dynamic phenomena occurring in the faulty component and grasp the effect on the overall performance of each affected component. In this paper, the authors address the most common and experienced source of loss for a gas turbine, i.e., compressor fouling. With respect to the traditional approach, which mainly aims at the identification of the overall effects of fouling, authors investigate a microscale representation of compressor fouling (i.e., blade surface deterioration and flow deviation). This allows (i) a more detailed investigation of the fouling effects (e.g., mechanism, location along blade height, etc.), (ii) a more extensive analysis of the causes of performance deterioration, and (iii) the assessment of the effect of fouling on stage performance coefficients and on stage performance maps. In this paper, the effect of nonuniform surface roughness on both rotor and stator blades of an axial compressor stage is investigated by using a commercial CFD code. The NASA Stage 37 test case is considered as the baseline geometry and a numerical model already validated against experimental data available in literature is used for the simulations. Different nonuniform combinations of surface roughness levels are imposed on rotor and stator blades. This makes it possible to highlight how the localization of fouling on compressor blades affects compressor performance both at an overall and at a fluid-dynamic level. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Numerical analysis of the effects of nonuniform surface roughness on compressor stage performance [texte imprimé] / Mirko Morini, Auteur ; Michele Pinelli, Auteur ; Pier Ruggero Spina, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Blades  Compressors  Gas  turbines  Geometry  Numerical  analysis  Surface  roughness Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Gas turbine performance degradation over time is mainly due to the deterioration of compressor and turbine blades, which, in turn, causes a modification of the compressor and turbine performance maps. Since the detailed information about the actual modification of the compressor and turbine performance maps is usually unavailable, the component performance can be modeled and investigated by the following: scaling the overall performance map, using stage-by-stage models of the compressor and turbine, and scaling each single stage performance map to account for each stage deterioration, or performing 3D numerical simulations, which allow to both highlight the fluid-dynamic phenomena occurring in the faulty component and grasp the effect on the overall performance of each affected component. In this paper, the authors address the most common and experienced source of loss for a gas turbine, i.e., compressor fouling. With respect to the traditional approach, which mainly aims at the identification of the overall effects of fouling, authors investigate a microscale representation of compressor fouling (i.e., blade surface deterioration and flow deviation). This allows (i) a more detailed investigation of the fouling effects (e.g., mechanism, location along blade height, etc.), (ii) a more extensive analysis of the causes of performance deterioration, and (iii) the assessment of the effect of fouling on stage performance coefficients and on stage performance maps. In this paper, the effect of nonuniform surface roughness on both rotor and stator blades of an axial compressor stage is investigated by using a commercial CFD code. The NASA Stage 37 test case is considered as the baseline geometry and a numerical model already validated against experimental data available in literature is used for the simulations. Different nonuniform combinations of surface roughness levels are imposed on rotor and stator blades. This makes it possible to highlight how the localization of fouling on compressor blades affects compressor performance both at an overall and at a fluid-dynamic level. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Reduction of forced response levels for bladed disks by mistuning / E. P. Petrov in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Titre : Reduction of forced response levels for bladed disks by mistuning : overview of the phenomenon Type de document : texte imprimé Auteurs : E. P. Petrov, Auteur Année de publication : 2011 Article en page(s) : 10 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Aerodynamics  Blades  Damping  Discs  (structures)  Statistical  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The newly revealed phenomenon of reduction of forced response levels in a mistuned bladed disk to levels significantly (e.g., by a factor of 2 and more) lower than that of its tuned counterpart is studied in detail on an example of a realistic bladed disk. Statistical properties of the amplification factor of the mistuned forced response calculated with aero-effects included have been studied for cases of random blade mistuning and for mistuned blade rearrangements. The optimization search for the best mistuning patterns providing maximum forced response reduction effect have been performed and the robustness of the optimum mistuning patterns has been demonstrated. The combined effect of the aerodynamic and structural damping on the response reduction is assessed. It is shown that the new phenomenon is of major practical significance and has to be taken into account in analysis of the forced response and design decisions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Reduction of forced response levels for bladed disks by mistuning : overview of the phenomenon [texte imprimé] / E. P. Petrov, Auteur . - 2011 . - 10 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 10 p. Mots-clés : Aerodynamics  Blades  Damping  Discs  (structures)  Statistical  analysis Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The newly revealed phenomenon of reduction of forced response levels in a mistuned bladed disk to levels significantly (e.g., by a factor of 2 and more) lower than that of its tuned counterpart is studied in detail on an example of a realistic bladed disk. Statistical properties of the amplification factor of the mistuned forced response calculated with aero-effects included have been studied for cases of random blade mistuning and for mistuned blade rearrangements. The optimization search for the best mistuning patterns providing maximum forced response reduction effect have been performed and the robustness of the optimum mistuning patterns has been demonstrated. The combined effect of the aerodynamic and structural damping on the response reduction is assessed. It is shown that the new phenomenon is of major practical significance and has to be taken into account in analysis of the forced response and design decisions. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Improving the design of a high pressure casing with the help of finite element analysis to ensure the rotor dynamic stability of a high pressure centrifugal compressor equipped with a hole pattern seal / Yves Bidaut in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Titre : Improving the design of a high pressure casing with the help of finite element analysis to ensure the rotor dynamic stability of a high pressure centrifugal compressor equipped with a hole pattern seal Type de document : texte imprimé Auteurs : Yves Bidaut, Auteur ; Urs Baumann, Auteur Année de publication : 2011 Article en page(s) : 08 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Compressors  Finite  element  analysis  Mechanical  stability  Pistons  Rotors  Seals  (stoppers)  Shock  absorbers  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper focuses on the casing geometry of high pressure compressors. It is common practice to use damper seals, typically the hole pattern type, at the balance piston to ensure the stability of the compressor when compressing fluids with high density levels. Special attention must be paid to the clearance of the hole pattern seal, which must be kept convergent at all operating conditions because a clearance divergence can lead to a rotor dynamic instability of the compressor. Furthermore, the clearance must be kept as low as possible to reduce the leakage losses through the balance piston. Therefore, extensive fine element analyses are performed to determine the mechanical casing deflections in operation and hence, the correct clearance behavior of such damper seals. This paper discusses the history of the casing design during the last 10 years and compares the configurations with respect to the clearance distribution along the damper seal length. To validate the analytical predictions, leakage and stability measurements (using a magnetic shaker) are performed for these high pressure compressors during the full-load, full-pressure testing. This paper presents the stability measurements carried out on two compressors (390 bars and 655 bars discharge pressure) and compares the results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Improving the design of a high pressure casing with the help of finite element analysis to ensure the rotor dynamic stability of a high pressure centrifugal compressor equipped with a hole pattern seal [texte imprimé] / Yves Bidaut, Auteur ; Urs Baumann, Auteur . - 2011 . - 08 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 08 p. Mots-clés : Compressors  Finite  element  analysis  Mechanical  stability  Pistons  Rotors  Seals  (stoppers)  Shock  absorbers  Turbomachinery Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper focuses on the casing geometry of high pressure compressors. It is common practice to use damper seals, typically the hole pattern type, at the balance piston to ensure the stability of the compressor when compressing fluids with high density levels. Special attention must be paid to the clearance of the hole pattern seal, which must be kept convergent at all operating conditions because a clearance divergence can lead to a rotor dynamic instability of the compressor. Furthermore, the clearance must be kept as low as possible to reduce the leakage losses through the balance piston. Therefore, extensive fine element analyses are performed to determine the mechanical casing deflections in operation and hence, the correct clearance behavior of such damper seals. This paper discusses the history of the casing design during the last 10 years and compares the configurations with respect to the clearance distribution along the damper seal length. To validate the analytical predictions, leakage and stability measurements (using a magnetic shaker) are performed for these high pressure compressors during the full-load, full-pressure testing. This paper presents the stability measurements carried out on two compressors (390 bars and 655 bars discharge pressure) and compares the results. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

Development of a 125 kW AMB expander/generator for waste heat recovery / Lawrence A. Hawkins in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Titre : Development of a 125 kW AMB expander/generator for waste heat recovery Type de document : texte imprimé Auteurs : Lawrence A. Hawkins, Auteur ; Lei Zhu, Auteur ; Eric J. Blumber, Auteur Année de publication : 2011 Article en page(s) : 06 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Active  magnetic  bearings  Waste  heat  recovery  Waste  heat  generator Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The development and testing of an integrated power module (IPM) for a waste heat recovery system is described. The IPM is part of a waste heat recovery system based on the organic Rankine cycle. The waste heat system can recover energy from a wide variety of heat sources including landfill gas, reciprocating engine exhaust, solar, geothermal, boilers, and other industrial processes. The IPM incorporates a high performance, high speed permanent magnet generator with an integrated expansion turbine and low loss magnetic bearings. The IPM operates between 20,000 rpm and 26,500 rpm depending on the energy available from the heat source. The varying frequency voltage supplied by the generator is connected to the grid using an active/active power electronics package that can deliver power at 400–480 Vac (50 Hz or 60 Hz). Active magnetic bearings (AMBs) were chosen for the application because they can operate directly in the working fluid, have low losses, and provide high reliability and remote monitoring capabilities. This system has a flow-through design and an inboard impeller layout that produces desirable rotordynamics for a simple magnetic bearing control. An extensive shop testing procedure is described, and measurements and predictions are presented, showing good correlation. Shop testing of the IPM in the waste heat system has been completed for 15 systems. The magnetic bearings and backup bearings have performed as designed. The thrust balancing system has limited the thrust load that must be reacted by the axial magnetic bearings to 25% of the design load capacity in the worst case. The first field unit was installed in April 2009 at a biogas site. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] Development of a 125 kW AMB expander/generator for waste heat recovery [texte imprimé] / Lawrence A. Hawkins, Auteur ; Lei Zhu, Auteur ; Eric J. Blumber, Auteur . - 2011 . - 06 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 06 p. Mots-clés : Active  magnetic  bearings  Waste  heat  recovery  Waste  heat  generator Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The development and testing of an integrated power module (IPM) for a waste heat recovery system is described. The IPM is part of a waste heat recovery system based on the organic Rankine cycle. The waste heat system can recover energy from a wide variety of heat sources including landfill gas, reciprocating engine exhaust, solar, geothermal, boilers, and other industrial processes. The IPM incorporates a high performance, high speed permanent magnet generator with an integrated expansion turbine and low loss magnetic bearings. The IPM operates between 20,000 rpm and 26,500 rpm depending on the energy available from the heat source. The varying frequency voltage supplied by the generator is connected to the grid using an active/active power electronics package that can deliver power at 400–480 Vac (50 Hz or 60 Hz). Active magnetic bearings (AMBs) were chosen for the application because they can operate directly in the working fluid, have low losses, and provide high reliability and remote monitoring capabilities. This system has a flow-through design and an inboard impeller layout that produces desirable rotordynamics for a simple magnetic bearing control. An extensive shop testing procedure is described, and measurements and predictions are presented, showing good correlation. Shop testing of the IPM in the waste heat system has been completed for 15 systems. The magnetic bearings and backup bearings have performed as designed. The thrust balancing system has limited the thrust load that must be reacted by the axial magnetic bearings to 25% of the design load capacity in the worst case. The first field unit was installed in April 2009 at a biogas site. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

A computational parametric analysis of the vibration of a three-spool aero-engine under multifrequency unbalance excitation / Pham Minh Hai in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 7 (Juillet 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 09 p. Titre : A computational parametric analysis of the vibration of a three-spool aero-engine under multifrequency unbalance excitation Type de document : texte imprimé Auteurs : Pham Minh Hai, Auteur ; Philip Bonello, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Turbines à gaz Langues : Anglais (eng) Mots-clés : Aerospace  engines  Damping  Frequency-domain  analysis  Harmonics  Springs  (mechanical)  Time-domain  analysis  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The integration of squeeze-film dampers (SFDs) in aero-engine assemblies is a highly cost-effective means of introducing damping in an otherwise lightly damped structure. However, their deployment requires careful unbalance response calculations that take due account of the SFDs' nonlinearity, particularly when they are unsupported by a centralizing spring. Until recently, such calculations were prohibitive due to the large number of assembly modes that typically need to be considered. This problem has been overcome by the authors through the novel impulsive receptance method (IRM) and the receptance harmonic balance method (RHBM), which efficiently solve the nonlinear problem in the time and frequency domains, respectively. These methods have been illustrated on a realistic twin-spool engine and have been shown to be effective for both single frequency unbalance excitation (unbalance on a single rotor) and multifrequency unbalance (MFU) excitation (unbalance on both rotors). In the present paper, the methods are applied to a realistic three-spool engine and the aims are twofold: (i) to present some preliminary results of a parametric study into a three-spool aero-engine assembly and (ii) to propose a technique that makes use of both IRM and RHBM in producing the speed responses under MFU excitation (from all three rotors) with a realistic speed relation between the rotors. The latter technique is necessary since the speed ratio will vary along a realistic speed characteristic and the authors have previously solved the twin-spool MFU problem under a constant speed ratio condition. The approach used here is to approximate the speed characteristic by one in which the speed ratios are ratios of low integers, enabling the use of RHBM to finish off (to steady-state) time-transient solutions obtained through IRM. The parameter study shows that the application of simple bump-spring supports to selected, otherwise unsupported, SFDs along with slight sealing should have a beneficial effect on the dynamic response of aero-engines with heavy rotors. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...] [article] A computational parametric analysis of the vibration of a three-spool aero-engine under multifrequency unbalance excitation [texte imprimé] / Pham Minh Hai, Auteur ; Philip Bonello, Auteur . - 2011 . - 09 p. Turbines à gaz Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 7 (Juillet 2011) . - 09 p. Mots-clés : Aerospace  engines  Damping  Frequency-domain  analysis  Harmonics  Springs  (mechanical)  Time-domain  analysis  Vibrations Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The integration of squeeze-film dampers (SFDs) in aero-engine assemblies is a highly cost-effective means of introducing damping in an otherwise lightly damped structure. However, their deployment requires careful unbalance response calculations that take due account of the SFDs' nonlinearity, particularly when they are unsupported by a centralizing spring. Until recently, such calculations were prohibitive due to the large number of assembly modes that typically need to be considered. This problem has been overcome by the authors through the novel impulsive receptance method (IRM) and the receptance harmonic balance method (RHBM), which efficiently solve the nonlinear problem in the time and frequency domains, respectively. These methods have been illustrated on a realistic twin-spool engine and have been shown to be effective for both single frequency unbalance excitation (unbalance on a single rotor) and multifrequency unbalance (MFU) excitation (unbalance on both rotors). In the present paper, the methods are applied to a realistic three-spool engine and the aims are twofold: (i) to present some preliminary results of a parametric study into a three-spool aero-engine assembly and (ii) to propose a technique that makes use of both IRM and RHBM in producing the speed responses under MFU excitation (from all three rotors) with a realistic speed relation between the rotors. The latter technique is necessary since the speed ratio will vary along a realistic speed characteristic and the authors have previously solved the twin-spool MFU problem under a constant speed ratio condition. The approach used here is to approximate the speed characteristic by one in which the speed ratios are ratios of low integers, enabling the use of RHBM to finish off (to steady-state) time-transient solutions obtained through IRM. The parameter study shows that the application of simple bump-spring supports to selected, otherwise unsupported, SFDs along with slight sealing should have a beneficial effect on the dynamic response of aero-engines with heavy rotors. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013300 [...]

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