The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Peng Zhang - One of the best experts on this subject based on the ideXlab platform.
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computational realization of multiple Flame Stabilization modes in dlr strut injection hydrogen supersonic combustor
Proceedings of the Combustion Institute, 2019Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Abstract Inspired by the existence of multiple Flame Stabilization modes in cavity-assisted supersonic combustor, multiple Flame Stabilization modes of DLR hydrogen-fueled strut injection supersonic combustor were numerically realized and analyzed for a wide ranges of inflow stagnation temperature from 607 to 2141 K and overall equivalence ratio from 0.022 to 0.110. Finite-rate chemistry large eddy simulation with detailed hydrogen mechanism was employed to capture unsteady flow characteristics and the effects of chemical kinetics. Two typical Flame Stabilization modes were identified and presented in a regime nomogram, which shows the dominant influence of the stagnation temperature and the secondary influence of overall equivalence ratio. At relatively low stagnation temperatures, the Flame is stabilized in an “attached Flame” mode, which requires a low-speed recirculation zone behind the strut for radical production and a high-speed intense combustion zone for heat release. At relatively high stagnation temperatures, the Flame is stabilized in a “lifted Flame” mode, in which the effect of the low-speed recirculation zone is negligible, rendering most reactions take place in supersonic flow. At intermediate stagnation temperatures, blow-out was always observed and Flame cannot be stabilized in the combustor even with initially forced ignition.
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LES Study of Flame Stabilization in DLR Hydrogen Supersonic Combustor with Strut Injection
2017Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Supersonic combustion in the hydrogen fueled DLR model scramjet combustor was computationally investigated by using Large Eddy Simulation (LES) combined with the latest detailed reaction mechanism for hydrogen combustion. Two computational models were employed including a two-dimensional reduced model and a three-dimensional model with periodicity in the spanwise direction. The two-dimensional model was fully validated against the three-dimensional model and the experimental data for the wall pressure measurements and the axial velocity under non-reacting flow condition. For reacting flow, the present model shows good agreement with the experimental axial velocity and static temperature measurements. Furthermore, radical evolution and heat release analysis were conducted both qualitatively and quantitatively to reveal the Flame Stabilization mechanism in the DLR combustor. The results show that the combustion is characterized by a three-stage combustion mode, namely induction, radical transportation and intense turbulent combustion stages. 漏 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
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characterization of Flame Stabilization modes in an ethylene fueled supersonic combustor using time resolved ch chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.
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Characterization of Flame Stabilization modes in an ethylene-fueled supersonic combustor using time-resolved CH* chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes.Department of Mechanical Engineering2016-2017 > Academic research: refereed > Publication in refereed journalbcr
Xuejun Fan - One of the best experts on this subject based on the ideXlab platform.
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computational realization of multiple Flame Stabilization modes in dlr strut injection hydrogen supersonic combustor
Proceedings of the Combustion Institute, 2019Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Abstract Inspired by the existence of multiple Flame Stabilization modes in cavity-assisted supersonic combustor, multiple Flame Stabilization modes of DLR hydrogen-fueled strut injection supersonic combustor were numerically realized and analyzed for a wide ranges of inflow stagnation temperature from 607 to 2141 K and overall equivalence ratio from 0.022 to 0.110. Finite-rate chemistry large eddy simulation with detailed hydrogen mechanism was employed to capture unsteady flow characteristics and the effects of chemical kinetics. Two typical Flame Stabilization modes were identified and presented in a regime nomogram, which shows the dominant influence of the stagnation temperature and the secondary influence of overall equivalence ratio. At relatively low stagnation temperatures, the Flame is stabilized in an “attached Flame” mode, which requires a low-speed recirculation zone behind the strut for radical production and a high-speed intense combustion zone for heat release. At relatively high stagnation temperatures, the Flame is stabilized in a “lifted Flame” mode, in which the effect of the low-speed recirculation zone is negligible, rendering most reactions take place in supersonic flow. At intermediate stagnation temperatures, blow-out was always observed and Flame cannot be stabilized in the combustor even with initially forced ignition.
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LES Study of Flame Stabilization in DLR Hydrogen Supersonic Combustor with Strut Injection
2017Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Supersonic combustion in the hydrogen fueled DLR model scramjet combustor was computationally investigated by using Large Eddy Simulation (LES) combined with the latest detailed reaction mechanism for hydrogen combustion. Two computational models were employed including a two-dimensional reduced model and a three-dimensional model with periodicity in the spanwise direction. The two-dimensional model was fully validated against the three-dimensional model and the experimental data for the wall pressure measurements and the axial velocity under non-reacting flow condition. For reacting flow, the present model shows good agreement with the experimental axial velocity and static temperature measurements. Furthermore, radical evolution and heat release analysis were conducted both qualitatively and quantitatively to reveal the Flame Stabilization mechanism in the DLR combustor. The results show that the combustion is characterized by a three-stage combustion mode, namely induction, radical transportation and intense turbulent combustion stages. 漏 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
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characterization of Flame Stabilization modes in an ethylene fueled supersonic combustor using time resolved ch chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.
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Characterization of Flame Stabilization modes in an ethylene-fueled supersonic combustor using time-resolved CH* chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes.Department of Mechanical Engineering2016-2017 > Academic research: refereed > Publication in refereed journalbcr
Wei Yao - One of the best experts on this subject based on the ideXlab platform.
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computational realization of multiple Flame Stabilization modes in dlr strut injection hydrogen supersonic combustor
Proceedings of the Combustion Institute, 2019Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Abstract Inspired by the existence of multiple Flame Stabilization modes in cavity-assisted supersonic combustor, multiple Flame Stabilization modes of DLR hydrogen-fueled strut injection supersonic combustor were numerically realized and analyzed for a wide ranges of inflow stagnation temperature from 607 to 2141 K and overall equivalence ratio from 0.022 to 0.110. Finite-rate chemistry large eddy simulation with detailed hydrogen mechanism was employed to capture unsteady flow characteristics and the effects of chemical kinetics. Two typical Flame Stabilization modes were identified and presented in a regime nomogram, which shows the dominant influence of the stagnation temperature and the secondary influence of overall equivalence ratio. At relatively low stagnation temperatures, the Flame is stabilized in an “attached Flame” mode, which requires a low-speed recirculation zone behind the strut for radical production and a high-speed intense combustion zone for heat release. At relatively high stagnation temperatures, the Flame is stabilized in a “lifted Flame” mode, in which the effect of the low-speed recirculation zone is negligible, rendering most reactions take place in supersonic flow. At intermediate stagnation temperatures, blow-out was always observed and Flame cannot be stabilized in the combustor even with initially forced ignition.
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LES Study of Flame Stabilization in DLR Hydrogen Supersonic Combustor with Strut Injection
2017Co-Authors: Peng Zhang, Wei Yao, Xuejun FanAbstract:Supersonic combustion in the hydrogen fueled DLR model scramjet combustor was computationally investigated by using Large Eddy Simulation (LES) combined with the latest detailed reaction mechanism for hydrogen combustion. Two computational models were employed including a two-dimensional reduced model and a three-dimensional model with periodicity in the spanwise direction. The two-dimensional model was fully validated against the three-dimensional model and the experimental data for the wall pressure measurements and the axial velocity under non-reacting flow condition. For reacting flow, the present model shows good agreement with the experimental axial velocity and static temperature measurements. Furthermore, radical evolution and heat release analysis were conducted both qualitatively and quantitatively to reveal the Flame Stabilization mechanism in the DLR combustor. The results show that the combustion is characterized by a three-stage combustion mode, namely induction, radical transportation and intense turbulent combustion stages. 漏 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
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characterization of Flame Stabilization modes in an ethylene fueled supersonic combustor using time resolved ch chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.
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Characterization of Flame Stabilization modes in an ethylene-fueled supersonic combustor using time-resolved CH* chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes.Department of Mechanical Engineering2016-2017 > Academic research: refereed > Publication in refereed journalbcr
Yueming Yuan - One of the best experts on this subject based on the ideXlab platform.
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characterization of Flame Stabilization modes in an ethylene fueled supersonic combustor using time resolved ch chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes. (C) 2016 by The Combustion Institute. Published by Elsevier Inc.
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Characterization of Flame Stabilization modes in an ethylene-fueled supersonic combustor using time-resolved CH* chemiluminescence
Proceedings of the Combustion Institute, 2017Co-Authors: Yueming Yuan, Xuejun Fan, Wei Yao, Taichang Zhang, Peng ZhangAbstract:Flame Stabilization in a Ma = 2.5 direct-connect supersonic combustor was experimentally characterized with a fixed stagnation pressure of 1.0 MPa and wide ranges of stagnation temperature (T-0) from 1200 K to 1800 K and global equivalence ratio (Phi) of ethylene/air from 0.1 to 0.8. Four typical Flame Stabilization modes were identified by using the time resolved CH* chemiluminescence and presented as a regime nomogram in the T-0-Phi parameter space. As increasing T-0, the range of Phi for the Flame Stabilization modes is widened and that for the oscillation mode is therefore narrowed. The widely used quasi-1D analysis, with the experimentally determined wall static pressure distribution as input parameters, suggests that the combustor operates in a scramjet mode when the Flame is stabilized in the cavity shear layer and in a ramjet mode when the Flame is in the jet-wake. The Flame oscillation mode, observed only for a narrow range of Phi, was found to correlate with the combustor transition between the scramjet and ramjet modes.Department of Mechanical Engineering2016-2017 > Academic research: refereed > Publication in refereed journalbcr
J.h. Chen - One of the best experts on this subject based on the ideXlab platform.
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Direct numerical simulation of Flame Stabilization downstream of a transverse fuel jet in cross-flow
Proceedings of the Combustion Institute, 2011Co-Authors: Ray Grout, Andrea Gruber, Chun Sang Yoo, J.h. ChenAbstract:A reactive transverse fuel jet in cross-flow (JICF) configuration is studied using three-dimensional direct numerical simulation (DNS) with detailed chemical kinetics in order to investigate the mechanism of Flame Stabilization in the near field of a fuel jet nozzle. JICF configurations are used in practical applications where high mixing rates are desirable between the jet and the cross-flow fluids such as fuel injection nozzles and dilution holes in gas turbine combustors. This study examines a nitrogen-diluted hydrogen transverse jet exiting a square nozzle perpendicularly into a cross-flow of heated air. Improved understanding of the Flame Stabilization mechanism acting downstream of the transverse fuel jet will enable the formulation of more reliable guidelines for design of fuel injection nozzles which promote intrinsic flashback safety by reducing the likelihood of the Flame anchoring at the injection site. The core of the heat release is located near the trailing edge of the fuel jet, at approximately 4 nozzle diameters away from the wall, and is characterized by the simultaneous occurrence of locally stoichiometric reactants and low flow velocities in the mean. The location where the most upstream tendrils of the Flame are found is in the region where coherent vortical structures originating from the jet shear layer interaction are present. Instantaneously, upstream Flame movement is observed through propagation into the outer layers of jet vortices.close1
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direct numerical simulation of Flame Stabilization downstream of a transverse fuel jet in cross flow
Proceedings of the Combustion Institute, 2011Co-Authors: Ray Grout, Andrea Gruber, Chun Sang Yoo, J.h. ChenAbstract:Abstract A reactive transverse fuel jet in cross-flow (JICF) configuration is studied using three-dimensional direct numerical simulation (DNS) with detailed chemical kinetics in order to investigate the mechanism of Flame Stabilization in the near field of a fuel jet nozzle. JICF configurations are used in practical applications where high mixing rates are desirable between the jet and the cross-flow fluids such as fuel injection nozzles and dilution holes in gas turbine combustors. This study examines a nitrogen-diluted hydrogen transverse jet exiting a square nozzle perpendicularly into a cross-flow of heated air. Improved understanding of the Flame Stabilization mechanism acting downstream of the transverse fuel jet will enable the formulation of more reliable guidelines for design of fuel injection nozzles which promote intrinsic flashback safety by reducing the likelihood of the Flame anchoring at the injection site. The core of the heat release is located near the trailing edge of the fuel jet, at approximately 4 nozzle diameters away from the wall, and is characterized by the simultaneous occurrence of locally stoichiometric reactants and low flow velocities in the mean.The location where the most upstream tendrils of the Flame are found is in the region where coherent vortical structures originating from the jet shear layer interaction are present. Instantaneously, upstream Flame movement is observed through propagation into the outer layers of jet vortices.