Documents disponibles écrits par cet auteur

Computational modeling of turbulent mixing of a transverse jet / Elizaveta M. Ivanova 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) . - 07 p. Titre : Computational modeling of turbulent mixing of a transverse jet Type de document : texte imprimé Auteurs : Elizaveta M. Ivanova, Auteur ; Berthold E. Noll, Auteur ; Aigner, Manfred, Auteur Année de publication : 2012 Article en page(s) : 07 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Jets  Navier-Stokes  equations  Numerical  analysis  Turbulence Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper presents numerical simulations of turbulent mixing of a jet in crossflow. The test case is chosen to resemble scalar mixing processes in the premixing zones of gas turbine combustion chambers. Steady and unsteady simulations employing three different computational approaches are presented: steady Reynolds-averaged Navier–Stokes, unsteady Reynolds-averaged Navier–Stokes, and scale-adaptive simulations. Presented results comprise the (time-averaged) profiles of flow velocities, turbulent kinetic energy of the flow, Reynolds stresses, passive scalar distribution, turbulent scalar fluxes, and the turbulent variance of the passive scalar. All presented results are directly validated against experimental data. Additionally, two parameter studies are presented. Both studies are related to the accuracy of the turbulent scalar mixing predictions for all used simulation methods. In the first study, the dependence of the scalar mixing predictions on the value of the turbulent Schmidt number is considered. In the second study, the dependence of the predicted turbulent scalar variance on the used modeling approach is analyzed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Computational modeling of turbulent mixing of a transverse jet [texte imprimé] / Elizaveta M. Ivanova, Auteur ; Berthold E. Noll, Auteur ; Aigner, Manfred, Auteur . - 2012 . - 07 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) . - 07 p. Mots-clés : Jets  Navier-Stokes  equations  Numerical  analysis  Turbulence Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This paper presents numerical simulations of turbulent mixing of a jet in crossflow. The test case is chosen to resemble scalar mixing processes in the premixing zones of gas turbine combustion chambers. Steady and unsteady simulations employing three different computational approaches are presented: steady Reynolds-averaged Navier–Stokes, unsteady Reynolds-averaged Navier–Stokes, and scale-adaptive simulations. Presented results comprise the (time-averaged) profiles of flow velocities, turbulent kinetic energy of the flow, Reynolds stresses, passive scalar distribution, turbulent scalar fluxes, and the turbulent variance of the passive scalar. All presented results are directly validated against experimental data. Additionally, two parameter studies are presented. Both studies are related to the accuracy of the turbulent scalar mixing predictions for all used simulation methods. In the first study, the dependence of the scalar mixing predictions on the value of the turbulent Schmidt number is considered. In the second study, the dependence of the predicted turbulent scalar variance on the used modeling approach is analyzed. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

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

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

Experimental investigations of pressure losses on the performance of a micro gas turbine system / Zanger, Jan in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 133 N° 8 (Août 2011) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 8 (Août 2011) . - 09 p. Titre : Experimental investigations of pressure losses on the performance of a micro gas turbine system Type de document : texte imprimé Auteurs : Zanger, Jan, Auteur ; Widenhorn, Axel, Auteur ; Aigner, Manfred, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Fuel  cell  power  plants  Gas  turbines  Hybrid  power  systems  Power  system  stability  Solid  oxide  fuel  cells Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Pressure losses between the compressor outlet and the turbine inlet are a major issue of overall efficiency and system stability for a solid oxide fuel cell/micro gas turbine (MGT) hybrid power plant system. The goal of this work is the detailed analysis of the effects of additional pressure losses on MGT performance in terms of steady-state and transient conditions. The experiments were performed using the micro gas turbine test rig at the German Aerospace Centre in Stuttgart using a butterfly control valve to apply additional pressure loss. This paper reports electric power and pressure characteristics at steady-state conditions as well as a new surge limit for this Turbec T100 micro gas turbine test rig. Furthermore, the effects of additional pressure loss on the compressor surge margin are quantified and a linear relation between the relative surge margin and additional pressure loss is shown. For transient variation of pressure loss at constant turbine speed, time delays are presented and an instability issue of the commercial gas turbine controller is discussed. Finally, bleed-air blow-off and reduction of the turbine outlet temperature are introduced as methods of increasing the surge margin. It is quantified that both methods have a substantial effect on the compressor surge margin. Furthermore, a comparison between both methods is given in terms of electric power output. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] Experimental investigations of pressure losses on the performance of a micro gas turbine system [texte imprimé] / Zanger, Jan, Auteur ; Widenhorn, Axel, Auteur ; Aigner, Manfred, Auteur . - 2011 . - 09 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 133 N° 8 (Août 2011) . - 09 p. Mots-clés : Fuel  cell  power  plants  Gas  turbines  Hybrid  power  systems  Power  system  stability  Solid  oxide  fuel  cells Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Pressure losses between the compressor outlet and the turbine inlet are a major issue of overall efficiency and system stability for a solid oxide fuel cell/micro gas turbine (MGT) hybrid power plant system. The goal of this work is the detailed analysis of the effects of additional pressure losses on MGT performance in terms of steady-state and transient conditions. The experiments were performed using the micro gas turbine test rig at the German Aerospace Centre in Stuttgart using a butterfly control valve to apply additional pressure loss. This paper reports electric power and pressure characteristics at steady-state conditions as well as a new surge limit for this Turbec T100 micro gas turbine test rig. Furthermore, the effects of additional pressure loss on the compressor surge margin are quantified and a linear relation between the relative surge margin and additional pressure loss is shown. For transient variation of pressure loss at constant turbine speed, time delays are presented and an instability issue of the commercial gas turbine controller is discussed. Finally, bleed-air blow-off and reduction of the turbine outlet temperature are introduced as methods of increasing the surge margin. It is quantified that both methods have a substantial effect on the compressor surge margin. Furthermore, a comparison between both methods is given in terms of electric power output. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]

On model design of a surrogate fuel formulation / Nadezhda A. Slavinskaya in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 132 N° 11 (Novembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 11 (Novembre 2010) . - 11 p. Titre : On model design of a surrogate fuel formulation Type de document : texte imprimé Auteurs : Nadezhda A. Slavinskaya, Auteur ; Anton Zizin, Auteur ; Aigner, Manfred, Auteur Année de publication : 2011 Article en page(s) : 11 p. Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Combustion  Distillation  Enthalpy  Evaporation  Fuel  Phase  diagrams  Phase  equilibrium  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Calculations of evaporation characteristics (distillation curve, two-phase diagram, and critical points) of surrogates are described in detail. The efficiency of some surrogate blends, represented in literature, in reflecting the evaporation characteristics was analyzed. Based on the analysis, the chemical capabilities of surrogate models are not linked to their abilities to reflect the phase-equilibrium properties of real fuel. It is shown that model design of practical fuels must include the phase-equilibrium and distillation curve calculations. A surrogate mixture was selected, which closely matches the boiling-point curve and two-phase diagram for jet-A. Next, physical properties of reference fuel were taken into consideration: combustion enthalpy, formation enthalpy, molar weight, approximate formula (carbon per hydrogen ratio), sooting tendency index, critical point, two-phase diagram, and distillation curve. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...] [article] On model design of a surrogate fuel formulation [texte imprimé] / Nadezhda A. Slavinskaya, Auteur ; Anton Zizin, Auteur ; Aigner, Manfred, Auteur . - 2011 . - 11 p. Génie Mécanique Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 132 N° 11 (Novembre 2010) . - 11 p. Mots-clés : Combustion  Distillation  Enthalpy  Evaporation  Fuel  Phase  diagrams  Phase  equilibrium  Reaction  kinetics Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Calculations of evaporation characteristics (distillation curve, two-phase diagram, and critical points) of surrogates are described in detail. The efficiency of some surrogate blends, represented in literature, in reflecting the evaporation characteristics was analyzed. Based on the analysis, the chemical capabilities of surrogate models are not linked to their abilities to reflect the phase-equilibrium properties of real fuel. It is shown that model design of practical fuels must include the phase-equilibrium and distillation curve calculations. A surrogate mixture was selected, which closely matches the boiling-point curve and two-phase diagram for jet-A. Next, physical properties of reference fuel were taken into consideration: combustion enthalpy, formation enthalpy, molar weight, approximate formula (carbon per hydrogen ratio), sooting tendency index, critical point, two-phase diagram, and distillation curve. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ00013 [...]