Pocket model application to the combustion of AP/RDX/Al/HTPB propellants

Abstract

Aluminum powders tend to agglomerate on the burning surface of the high energy low burn rate APRDWAUHTPB propellants, thus resulting in a lower combustion and n o d e expansion efficiencies, and consequently degrading the propulsion performance of the solid rocket motor. During the past two decades, tremendous experimental and analytical works had been done to deal with the problems. The current study is a continuation of our previous w r k on the similar subject, but the focus is skifted to analyze whether Cohen’s Pocket Model can be applied to the aluminized composite propellants containing RDX as the secondary oxidizer. The results show that the cinephotomicrography measured mean aluminum agglomerates size and the quenched particle collection bomb experimental data deduced fractional agglomeration can be correlated with the Pocket Model parameters after making some minor modifications on the original model. Also the specifc impulse under the conditions of different aluminum combustion efficiencies is assessed. The significance of this study is to provide an approach to improve the aluminum combustion efficiency of an existing APRDWA!JHTPB propellant, or to design a new propellant with higher aluminum combustion efficiency through carefully modulating the effective pocket fine structure. ‘d