The effect of porous coating on the flame acceleration in hydrogen–air mixture

Abstract

Flame acceleration in the hydrogen–air mixture in the presence of porous materials was investigated experimentally. Polyurethane foam with different pore size placed on top and button sides of the channel was found to greatly affect flame acceleration in the channel. High–speed schlieren images showed, that polyurethane foam with larger pores leads to flame wrinkling. Dependencies of the flame velocity on the pore size were presented. It was found that final flame velocity by the end of the porous section can be up to 5 times higher while using polyurethane foam with 10 pores per inch compared to polyurethane foam with 80 pores per inch. The flame velocity in the smooth channel was lower than the flame velocity in the porous channel for all tested cases. Polyurethane foam with smaller pore size led to pressure decrease compared to solid channel. Supersonic combustion with velocity around 1600m/s was registered in the channel with PF10 on the walls. It was discovered, that the use of such a porous coating can lead to preventing the increase in the shock wave pressure during the combustion of hydrogen–air mixtures.