Ignition and combustion of ammonium perchlorate in a hydrogen atmosphere

Abstract

In the view to using ammonium perchlorate (AP) as an oxidizer in a hydrogen-breathing combustion engine in the Jupiter atmosphere, a fundamental study was performed experimentally on the ignition and combustion of a lump of AP in a hydrogen atmosphere. AP was found to ignite just after decomposition. The burning AP had a decomposition flame adjacent to the AP surface, and a flame of light-violet and orange color attributed to OH, ClO, and H2O emissions developed in the gas phase surrounding the decomposition flame. During combustion, the burning rate followed the same d2 law as that for liquid fuel droplets. The measured emission intensity distributions of OH, ClO and H2O showed that OH had a peak concentration away from the AP surface, and ClO was generated near the surface. The flame location was much closer to the AP surface in comparison with those of various hydrocarbon fuels in air, which was explained in terms of the large mass ratio of the stoichiometric oxidizer to fuel. To elucidate the combustion process of AP in an H2 atmosphere, the flame structure in the gas phase was calculated assuming that the oxidizing gases produced by an AP decomposition flame react with hydrogen and using a detailed gas-phase kinetic mechanism. The calculation results were compared with the measured emission intensity distributions.