Scientific predictability of solid rocket performance: Analyses of the processing parameters.

Abstract

The objective of this dissertation is to present a computational model of the suspensions composing uncured composite solid propellant. The work examined highly concentrated suspensions of more than 50% solid volume, with attention to bimodal mixtures. Investigation of propellant processing was conducted to determine how this model can be applied to processing. Experimental work was conducted to supply data for comparison to the computational results. This involved data gathered from an orifice viscometer on viscosity and flow behavior. This model is a tool to investigate goodness of mixing throughout the processing stages of the propellant. The investigation into processing focused both on mixing and casting of the suspension. By studying this model for concentration, velocity and thermal behaviors, a better understanding of how well the propellant composition progresses in processing was obtained. A multiphase mixture approach was taken. This involved a continuum description for the mixture and each constituent. A Fortran program was written to construct this routine. It was run on both a VAXstation 3100, Model 40 using VMS Digital operating system, and a SUN IPX, using SUN UNIX operating system. The code examined two-dimensional monomodal and bimodel mixture flows through a pipe. It examined concentrations between 65% and 75%. Due to the high concentration, it was necessary to apply all inertial and viscous terms within each constituent and the entire mixture. Proper boundary conditions and initial conditions to produce stable runs were found. Both monomodal and bimodal computational results showed good correlations with the experimental data, although a slight dilatation was produced by the program. No dilatation appeared in the experimental work. No concentration drop was detected in either the computational results or experimental work.