Pocket Model with a Tetrahedral Cell for Aluminum Agglomeration in Composite Propellants

Abstract

A tetrahedral structure model has been proposed to estimate the size of metal agglomerates during combustion of a composite solid propellant. According to this model, oxidizer particles are located at the vertices of a regular tetrahedron and the internal volume of the pyramid is occupied by a mixture of a fuel-binder and metal—the so-called “pocket." Experimental data are compared with the results of calculations using the tetrahedral model, the Cohen model, and the empirical correlations proposed by Hermsen, Salita, Beckstead, Grigoriev, and Duterque. The comparison was made for a composite propellant containing ammonium perchlorate, a binder, and aluminum. It is shown that in some cases the tetrahedral model better predicts the diameter of agglomerates than the other models.