Direct Numerical Simulation of hydrogen combustion at auto-ignitive conditions: Ignition, stability and turbulent reaction-front velocity

Direct Numerical Simulations (DNS) are performed to investigate the process of spontaneous ignition hydrogen flames at laminar, turbulent, adiabatic and non-adiabatic conditions. Mixtures vitiated air temperatures representing gas-turbine reheat combustion considered. Adiabatic processes investigated first, providing a quantitative characterization stable unstable flames. Results indicate that, in combustion, compressibility effects play key role flame stability that consistently encountered for reactant close mixture’s characteristic crossover temperature. Furthermore, it is also found valid presence non-adiabaticity due wall heat-loss. Finally, instantaneous fuel consumption rate within reaction front obtained its ability, auto-ignitive conditions, advance against approaching turbulent flow reactants, range different turbulence intensities, pressure levels.