Heterogeneous solid propellants: from microstructure to macroscale properties

Abstract

Composite solid propellants are inherently heterogeneous at microscopic level. Consequently, global mixture laws are often inappropriate because they cannot capture the underlying microstructural features. This paper intends to give an overview of some recent multiscale efforts in three different industrial issues related to solid propellants: combustion, electric breakdown, and aluminum agglomeration. For each physical process, direct simulations are performed at microscale level using sphere packs to model the propellant. Parametric computations help devising some global models that occur to be fairly well validated by experimental data. The benefit of such approach is that it can naturally account for microstructural features. In particular, it is shown that percolation process can often arise in composite propellants and significantly alter macroscopic properties.