Multiphase effects on solid rocket nozzle performance

In the present work, we discuss the employment of a computational fluid dynamics approach to evaluate the specific impulse of solid rocket motors. Particular care is focused on two-phase flow and divergence losses, which represent the most important contributions to the overall nozzle performance loss. A comprehensive parametric study is performed on the Zefiro 9A nozzle with the aim to evaluate the detrimental influence of relevant key features, such as alumina particle dimension, polydispersion, crystallization, and motor operating conditions. The capability of the present model to represent, with good accuracy, the overall performance of solid rocket motors is demonstrated by comparing the experimental specific impulse of several motors with numerical predictions.