Suppression of hydrogen-air detonation using porous materials in the channels of different cross section

Propagation of a detonation wave in a porous channel with different cross-section was experimentally studied. Experiments were performed in three rectangular channels with cross-sectional dimensions of 20 x 40 mm, 10 x 40 mm and 10 x 30 mm with two opposite walls covered with porous material to study the detonation suppression in stoichiometric hydrogen-air mixtures at atmospheric pressure. Detonation was initiated in 3000 mm long circular channel 20 mm in diameter. Porous material was covering 1/2 or 1/3 of the channel internal surface. Polyurethane foam with a number of pores per inch ranging from 10 to 80 was used for detonation attenuation. Piezoelectric pressure sensors were used to obtain the shock wave pressure. Detonation decay into the shock wave and the flame front was visualized using schlieren photography. Shock wave velocity was also calculated using high-speed schlieren image sequences. The strongest pressure attenuation was recorded in a 10 mm wide channel with a porous coating with largest pores (2.5 mm) covering 1/3 of the internal walls. The results indicate that even covering 1/3 of the internal surface of the channel leads to detonation decay and significant shock wave attenuation. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.