Aspects of solid propellant combustion

Internal ballistics describes the combustion of solid propellant within a c losed combustion chamber. This is achieved by modelling a mixture of incomp ressible solid particles and compressible reactive gases with averaged equa tions of two-phase flow. The combustion of the solid is described with inte raction terms that define the rate of mass, momentum and energy exchange fr om solid into gas. This work concentrates on modelling ignition and the ini tial stages of combustion, proposing the concept of 'gaseous ignition' by i ncluding time-scales of chemical reaction in the gas phase. These non-equil ibrium 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 simula tions 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.