Prediction of hydrogen flame propagation in a channel with exit contraction

Abstract

The propagation of a flame front in a homogeneous and initially quiescent hydrogen-air mixture in a channel with exit contraction is numerically analyzed by means of Computational Fluid Dynamics. For the given configuration, the compressibility effects are important, the average pressure increases in time due to the exit contraction, and pressure waves occur, which affect the flame propagation. Flowturbulence is modelled by the Realizable k-e model. In modelling combustion, turbulence-chemistry interactions are neglected. Predictions are compared with the measurements for evolution of the flame shape, propagation speed and pressure. It is observed that the flame propagation speed, and, thus, the rate of pressure increase are over-predicted by the present approach. Still, a fair qualitative agreementto measurements is observed.