Numerical modeling of composite propellant combustion

Abstract

An innovative 2-D numerical model of composite propellant combustion is proposed. It takes into acount the detailed description of the propellant topology, five chemical reactions, gas molecular diffusion, and heat transfer in the gas phase. Partial differential equations are numerically solved introducing a topological matrix. The propellant surface is determined by scanning the topological matrix and performing a series of logical tests. The bidimensional profiles of the temperature and molar fractions in the spatial domain are obtained. The average surface temperatures are also evaluated in both binder and oxidizer regions, as well as the linear burning rate. The model can predict the time evolution of the composite for different propellant topologies in agreement with experimental observations of the propellant surface reported in the literature. The propellant topology, the pressure, the oxidizer-binder mass ratio, and the characteristic dimension play a large role on surface temperatures and linear burning rate. They increase with pressure and decrease, with asymptotic tendency, with increase of both mass ratio and characteristic size. High burning rates are predicted for topologies that enhance the mixing betwen binder and oxidizer in particular when fine spherical particles of the oxidizer are dispersed within a binder matrix.