Slowdown of oxyhydrogen detonation by surface catalysis

Abstract

The propagation velocities of stoichiometric oxyhydrogen detonations were measured in thin tubes of different wall materials. From 4 to 6% velocity differences were observed consistently for pyrex and γ-alumina walls. By changing the tube geometries, it was confirmed that this velocity difference can be explained only by the catalysis of the wall material. To elucidate this result, one-dimensional gasdynamic analysis was performed, including various possible wall reactions. The solutions of this eigenvalue problem gave the relation of each reaction and its catalytic efficiency to the calculated detonation velocity. The results showed that the observed velocity difference can be explained only if we assume that H+OH→H 2 O or H→1/2 H 2 occurs with the maximum catalytic efficiency, i.e., unity. After some speculations, H+OH→ H 2 O was considered more probable, the catalytic efficiency of γ-alumina being nearly unit for this reaction at 300 K.