In search of an idealized model of homogeneous solid propellant combustion

Abstract

A simple idealization of the steady-state deflagration of uncatalyzed, homogeneous solid propellants is examined to determine its adequacy in describing gross combustion features such as burn rate as a function of pressure and initial temperature. The idealization consists of a single condensed phase process (pyrolysis and evaporation are considered) and a single gas phase chemical reaction. Several analytic approximations (including one developed during the course of this work) are derived and discussed in relation to the work of other investigators. All of these approximations are shown to lead explicitly to approximate analytic expressions of the same functional form as empirical formulas for the burning rate pressure dependence. The approximation developed in this paper is shown to lead to a common empirical form for the temperature sensitivity. A means of testing the suitability of these approximations to a given propellant is also developed using temperature profiles obtained by the embedded thermocouple technique.