| This thesis is a theoretical study of composite solid propellant combustion, built around a computational model of AP/HTPB propellants. The purpose of the thesis is to investigate the effect of composite solid structure on nonsteady, nonlinear combustion processes. Of particular interest is the effect of heterogeneity on the nonlinear, pressure-coupled frequency response of the system. The model is a system of eight equations, two of which depend on an implicit solution of temperature profiles in the propellant binder and oxidizer. It is very complicated and computationally intense, but it can potentially show trends and dependencies that disappear under the assumptions of other models.; Two issues have become significant in the development of the current model. First, the model seems to show an over-dependence of flame structure on the burning rates of the propellant. Second, the concept of "frequency response" appears to be ambiguous for wholly nonlinear analyses. The thesis contains recommendations on how to address the issues. It also contains preliminary results, which show how AP mass percentage, mean pressure, pressure oscillation magnitude, AP particle diameter, and other parameters affect the frequency response. |
