Solid Propellant Burn Rate Measurement in a Micro Closed Bomb

Abstract

In the present work experimental data from seven perforated (7PF) JA2 propellant combustion in a micro closed bomb is presented and the linear burning rate of the JA2 propellant is determined. The burn rate measurement is based on a sophisticated lumped parameter model which accounts among other things for arbitrary cross sectional propellant geometries with the help of the ICT-Cellular-Combustion-Algorithm (ICCA), pressure dependent thermophysical parameters and heat loss. The model is used to construct a vivacity based objective function which depends on the parameters of the empirical law for the linear burning velocity. With the Nelder-Mead downhill simplex optimization algorithm the objective function is minimized and the burn rate parameters determined. The comparison of the results to published data show that with the new burn rate measurement method the linear burning rate can be determined with great accuracy even when only a few propellant grains with a total propellant mass of less than 8 g per shot are used.