AN EXPERIMENTAL AND ANALYTICAL INVESTIGATION OF IGNITION AND AXI-SYMMETRIC TURBULENT FLAME PROPAGATION IN HYDROGENAIR MIXTURES AT SUPERSONIC SPEEDS,

The report is concerned with the experimental study of turbulent combustion processes in high speed flows and the comparison of the experimental results with those obtained by means of a newly available numerical approach for the computation of flows with diffusion and finite rate chemistry. It is shown that stable ignition may be insured in a jet of hydrogen-air or ethylene-air mixture by a pilot flame of small dimensions and very low heat liberation compared to that of the main stream (of the order of 0.4%). Under proper conditions the premixed jet is ignited without fluctuations, periodic flashes or oscillations. A strong dependence of the flame propagation velocity on the mixture composition has been found experimentally for given constant flow conditions, i.e., flow velocity and total temperature of the mixture. This dependence correlated well with the predictions of the numerical computations. (Author)