Documents disponibles écrits par cet auteur

High temperature fast response aerodynamic probe / Christian Lenherr in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 1 (Janvier 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 1 (Janvier 2011) . - 10 p. Titre : High temperature fast response aerodynamic probe Type de document : texte imprimé Auteurs : Christian Lenherr, Auteur ; Anestis I. Kalfas, Auteur ; Reza S. Abhari, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Aerodynamics  Gas  turbines  Piezoresistive  devices  Pressure  transducers  Probes  Shafts  Strain  gauges  Strain  sensors  Temperature  sensors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In order to advance the technology for measurements in higher temperature flows, a novel miniature (diameter 2.5 mm) fast response probe that can be applied in flows with temperatures of up to 533 K (500°F) has been developed. The primary elements of the probe are two piezoresistive pressure transducers that are used to measure the unsteady pressure and unsteady velocity field, as well as the steady temperature. Additional temperature and strain gauge sensors are embedded in the shaft to allow a much higher degree of robustness in the use of this probe. The additional temperature sensor in the shaft is used to monitor and correct the heat flux through the probe shaft, facilitating thermal management of the probe. The strain gauge sensor is used to monitor and control probe shaft vibration. Entirely new packaging technology had to be developed to make possible the use of this probe at such high temperatures. Extensive calibration and thermal cycling of the probe used to bind the accuracy and the robustness of the probe. This novel probe is applied in the one-and-1/2-stage, unshrouded axial turbine at ETH Zurich; this turbine configuration is representative of a high work aero-engine. The flow conditioning stretch upstream of the first stator is equipped with a recently designed hot streak generator. Several parameters of the hot streak, including temperature, radial and circumferential position, and shape and size can be independently controlled. The interactions between the hot streak and the secondary flow present a perfect scenario to verify the probe's capability to measure under real engine conditions. Therefore, measurements with the novel probe have been made in order to prove the principle and to detail the interaction effects with blade row pressure gradients and secondary flows. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] High temperature fast response aerodynamic probe [texte imprimé] / Christian Lenherr, Auteur ; Anestis I. Kalfas, Auteur ; Reza S. Abhari, Auteur . - 2012 . - 10 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 1 (Janvier 2011) . - 10 p. Mots-clés : Aerodynamics  Gas  turbines  Piezoresistive  devices  Pressure  transducers  Probes  Shafts  Strain  gauges  Strain  sensors  Temperature  sensors Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In order to advance the technology for measurements in higher temperature flows, a novel miniature (diameter 2.5 mm) fast response probe that can be applied in flows with temperatures of up to 533 K (500°F) has been developed. The primary elements of the probe are two piezoresistive pressure transducers that are used to measure the unsteady pressure and unsteady velocity field, as well as the steady temperature. Additional temperature and strain gauge sensors are embedded in the shaft to allow a much higher degree of robustness in the use of this probe. The additional temperature sensor in the shaft is used to monitor and correct the heat flux through the probe shaft, facilitating thermal management of the probe. The strain gauge sensor is used to monitor and control probe shaft vibration. Entirely new packaging technology had to be developed to make possible the use of this probe at such high temperatures. Extensive calibration and thermal cycling of the probe used to bind the accuracy and the robustness of the probe. This novel probe is applied in the one-and-1/2-stage, unshrouded axial turbine at ETH Zurich; this turbine configuration is representative of a high work aero-engine. The flow conditioning stretch upstream of the first stator is equipped with a recently designed hot streak generator. Several parameters of the hot streak, including temperature, radial and circumferential position, and shape and size can be independently controlled. The interactions between the hot streak and the secondary flow present a perfect scenario to verify the probe's capability to measure under real engine conditions. Therefore, measurements with the novel probe have been made in order to prove the principle and to detail the interaction effects with blade row pressure gradients and secondary flows. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

Integrated combustor turbine design for improved aerothermal performance / Altug M. Basol in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 134 N° 9 (Septembre 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 9 (Septembre 2012) . - 08 p. Titre : Integrated combustor turbine design for improved aerothermal performance : effect of dilution air control Type de document : texte imprimé Auteurs : Altug M. Basol, Auteur ; Regina Kai, Auteur ; Anestis I. Kalfas, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Dilution  air  control  Combustor  turbine  Aerothermal  performance Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The effect of dilution air control in a combustor on the heat load distribution of an axial turbine with nonaxisymmetric endwall profiling is examined. Endwall profiling is a more common design feature in new engine types, due to its effectiveness in reducing secondary flows and their associated losses. In the present work, the effect of dilution air control is examined by using two different circumferentially nonuniform hot-streak shapes; the two cases differ in their spanwise extents either side of the stator and, therefore, represent different approaches for dilution air control. This numerical study details the impact of these two different strategies for dilution air control on the rotor blade heat load distribution. The inlet boundary conditions simulate the experiment that is conducted in the axial research turbine facility LISA at ETH Zurich. A circumferential nonuniformity in the spanwise migration pattern of the hot streak inside the stator is observed that is found to be alleviated by the effect of the endwall profiling. Due to the observed spanwise migration pattern inside the stator the two hot-streak cases result in considerably different heat load distributions on the rotor blade, emphasizing the importance of the integrated combustor turbine approach. Finally, the implications for dilution air control on the liner are discussed for the realization of the simulated hot-streak shapes in real combustors. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000009 [...] [article] Integrated combustor turbine design for improved aerothermal performance : effect of dilution air control [texte imprimé] / Altug M. Basol, Auteur ; Regina Kai, Auteur ; Anestis I. Kalfas, Auteur . - 2012 . - 08 p. Génie mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 9 (Septembre 2012) . - 08 p. Mots-clés : Dilution  air  control  Combustor  turbine  Aerothermal  performance Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The effect of dilution air control in a combustor on the heat load distribution of an axial turbine with nonaxisymmetric endwall profiling is examined. Endwall profiling is a more common design feature in new engine types, due to its effectiveness in reducing secondary flows and their associated losses. In the present work, the effect of dilution air control is examined by using two different circumferentially nonuniform hot-streak shapes; the two cases differ in their spanwise extents either side of the stator and, therefore, represent different approaches for dilution air control. This numerical study details the impact of these two different strategies for dilution air control on the rotor blade heat load distribution. The inlet boundary conditions simulate the experiment that is conducted in the axial research turbine facility LISA at ETH Zurich. A circumferential nonuniformity in the spanwise migration pattern of the hot streak inside the stator is observed that is found to be alleviated by the effect of the endwall profiling. Due to the observed spanwise migration pattern inside the stator the two hot-streak cases result in considerably different heat load distributions on the rotor blade, emphasizing the importance of the integrated combustor turbine approach. Finally, the implications for dilution air control on the liner are discussed for the realization of the simulated hot-streak shapes in real combustors. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000009 [...]

Performance benefits of a portable hybrid micro-gas turbine power system for automotive applications / Fanos Christodoulou in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 2 (Fevrier 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 2 (Fevrier 2011) . - 08 p. Titre : Performance benefits of a portable hybrid micro-gas turbine power system for automotive applications Type de document : texte imprimé Auteurs : Fanos Christodoulou, Auteur ; Panagiotis Giannakakis, Auteur ; Anestis I. Kalfas, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air  pollution  control  Gas  turbines  Hybrid  electric  vehicles  Hybrid  power  systems  Micromechanical  devices  Secondary  cells  Traction Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The lower fuel burn and pollutant emissions of hybrid electric vehicles give a strong motivation and encourage further investigations in this field. The know-how on hybrid vehicle technology is maturing, and the reliability of such power schemes is being tested in the mass production. The current research effort is to investigate novel configurations, which could achieve further performance benefits. This paper presents an assessment of a novel hybrid configuration comprising a micro-gas turbine, a battery bank, and a traction motor, focusing on its potential contribution to the reduction in fuel burn and emissions. The power required for the propulsion of the vehicle is provided by the electric motor. The electric power is stored by the batteries, which are charged by a periodic function of the micro-gas turbine. The micro-gas turbine starts up when the battery depth of discharge exceeds 80%, and its function continues until the batteries are full. The performance of the vehicle is investigated using an integrated software platform. The calculated acceleration performance and fuel economy are compared with those of conventional vehicles of the same power. The sensitivity of the results to the variation in the vehicle parameters such as mass, kinetic energy recovery, and battery type is calculated to identify the conditions under which the application of this hybrid technology offers potential benefits. The results indicate that if no mass penalties are incurred by the installation of additional components, the fuel savings can exceed 23%. However, an increase in the vehicle's weight can shrink this benefit especially in the case of light vehicles. Lightweight batteries and kinetic energy recovery systems are deemed essential, enabling technologies for a realistic application of this hybrid system. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Performance benefits of a portable hybrid micro-gas turbine power system for automotive applications [texte imprimé] / Fanos Christodoulou, Auteur ; Panagiotis Giannakakis, Auteur ; Anestis I. Kalfas, Auteur . - 2012 . - 08 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 2 (Fevrier 2011) . - 08 p. Mots-clés : Air  pollution  control  Gas  turbines  Hybrid  electric  vehicles  Hybrid  power  systems  Micromechanical  devices  Secondary  cells  Traction Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : The lower fuel burn and pollutant emissions of hybrid electric vehicles give a strong motivation and encourage further investigations in this field. The know-how on hybrid vehicle technology is maturing, and the reliability of such power schemes is being tested in the mass production. The current research effort is to investigate novel configurations, which could achieve further performance benefits. This paper presents an assessment of a novel hybrid configuration comprising a micro-gas turbine, a battery bank, and a traction motor, focusing on its potential contribution to the reduction in fuel burn and emissions. The power required for the propulsion of the vehicle is provided by the electric motor. The electric power is stored by the batteries, which are charged by a periodic function of the micro-gas turbine. The micro-gas turbine starts up when the battery depth of discharge exceeds 80%, and its function continues until the batteries are full. The performance of the vehicle is investigated using an integrated software platform. The calculated acceleration performance and fuel economy are compared with those of conventional vehicles of the same power. The sensitivity of the results to the variation in the vehicle parameters such as mass, kinetic energy recovery, and battery type is calculated to identify the conditions under which the application of this hybrid technology offers potential benefits. The results indicate that if no mass penalties are incurred by the installation of additional components, the fuel savings can exceed 23%. However, an increase in the vehicle's weight can shrink this benefit especially in the case of light vehicles. Lightweight batteries and kinetic energy recovery systems are deemed essential, enabling technologies for a realistic application of this hybrid system. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]