Large eddy simulation of hydrogen auto-ignition with a probability density function method

Large eddy simulation is applied to the auto-ignition of a hydrogen jet issuing into a turbulent co-flowing air stream. A 19 step, nine species detailed mechanism is used for reaction. The influence of sub-grid species concentration and temperature fluctuations are accounted for by a sub-grid joint PDF for the reactive scalars, obtained from solution of a modelled transport equation. The method is able to reproduce ignition lengths and different regimes observed experimentally without any adjustment or calibration of the model constants.