LES-CMC Simulations of Different Auto-ignition Regimes of Hydrogen in a Hot Turbulent Air Co-flow

Large-Eddy Simulation (LES) results in combination with first-order Conditional Moment Closure (CMC) are presented for a hydrogen jet, diluted with nitrogen, issued into a turbulent co-flowing hot air stream. The fuel mixes with the co-flow air, ignites and forms a lifted-like flame. Global trends i...

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Bibliographic Details
Published in:Flow, turbulence and combustion turbulence and combustion, 2013-04, Vol.90 (3), p.583-604
Main Authors: Stanković, I., Mastorakos, E., Merci, B.
Format: Article
Language:English
Subjects:
Aerodynamics
Applied sciences
Automotive Engineering
Combustion
Combustion of gaseous fuels
Combustion. Flame
Energy
Energy. Thermal use of fuels
Engineering
Engineering Fluid Dynamics
Engineering Thermodynamics
Exact sciences and technology
Fluid dynamics
Fluid flow
Fluid- and Aerodynamics
Fundamental areas of phenomenology (including applications)
Heat and Mass Transfer
Physics
Simulation
Spots
Theoretical studies. Data and constants. Metering
Turbulence
Turbulence simulation and modeling
Turbulent flow
Turbulent flows, convection, and heat transfer
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Summary:Large-Eddy Simulation (LES) results in combination with first-order Conditional Moment Closure (CMC) are presented for a hydrogen jet, diluted with nitrogen, issued into a turbulent co-flowing hot air stream. The fuel mixes with the co-flow air, ignites and forms a lifted-like flame. Global trends in the experimental observations are in general well reproduced: the auto-ignition length decreases with increase in co-flow temperature and increases with increase in co-flow velocity. In the experiments, the co-flow temperature was varied, so that different auto-ignition regimes, including low Damköhler number situations, were obtained (no ignition, random spots, flashback and lifted flame). All regimes are recovered in the simulations. Auto-ignition is found to be the stabilizing mechanism. The impact of different detailed chemistry mechanisms on the auto-ignition predictions is discussed. With increasing air temperature, the differences between the mechanisms considered diminish. The evolution of temperature, H 2 O, H, HO 2 and OH from inert to burning conditions is discussed in mixture fraction space.
ISSN:1386-6184
1573-1987
DOI:10.1007/s10494-013-9443-2