Aspects of solid propellant combustion

Abstract

Internal ballistics describes the combustion of solid propellant within a closed combustion chamber. This is achieved by modelling a mixture of incompressible solid particles and compressible reactive gases with averaged equations of two–phase flow. The combustion of the solid is described with interaction terms that define the rate of mass, momentum and energy exchange from solid into gas. This work concentrates on modelling ignition and the initial stages of combustion, proposing the concept of ‘gaseous ignition’ by including time–scales of chemical reaction in the gas–phase. These non–equilibrium effects are placed firmly within the context of internal ballistics by making direct comparisons between experimental pressure–time histories. In particular, excellent agreement can be achieved between numerical simulations and experimental work by assuming a two–stage reaction process during which the rate of chemical energy release will significantly differ from a single exothermic reaction.