Effect of oxidizer-particle size on the unsteady-state combustion time of a composite solid fuel during a pressure drop

Abstract

A rapid variation of pressure during the combustion of a composite solid fuel alters considerable the composition and temperature of the combustion products during the unsteady-state-combustion period. The time required to reach a new steady-state combustion regime following a sharp rise in pressure is proportional to the burnup time of a grain of oxidizer. The authors considered the dependence of the duration of the transition regime of combustion on the size of PCA crystals during a pressure drop. The results indicate that, both for a pressure drop and for a rise in pressure, the time required to arrive at a steady-state combustion regime is proportional to the burnup time of a grain of oxidizer, rather than to the warm up time of the condensed phase as is the case for homogeneous fuels.