Ballistics modeling of combustion heat loss through chambers and nozzles of solid rocket motors

A thesis. — California State University. 2004. — 80 р.There are several assumptions made when the ballistics of a solid rocket motor (SRM) is being modeled. Among them is the assumption that the case wall of the motor is adiabatic, i.e., no heat from combustion is lost through the case and nozzle walls as a solid rocket motor burns. However, this adiabatic assumption is usually not numerically validated. This work is intended to prove or disprove such an assumptions through computational studies. First, CAD models are built using ProE, that represent successive layers of a solid fuel as it burns back. Each individual model is then meshed in the computational fluid dynamics (CFD) preprocessor, GAMBIT. The individual mesh files are then imported into the CFD program FLUENT and the simulations are finally run in FLUENT. Heat loss models are compared to adiabatic models. The results show radiative heat loss is most significant inside the motor case whereas convective heat loss is greater in the nozzle. Convective losses in the nozzle dominate the overall heat loss. The heat loss in general does not significantly affect ballistic performance, validating the adiabatic assumption, however the CAD-CFD method is useful for other ballistics analysis.