Role of Finite-Rate Kinetics on the Performance Predictions of Solid Rocket Motor Nozzles

The performance of solid rocket motors is limited by finite-rate chemical reactions occurring in the nozzle expansion. In the present work, a numerical approach is adopted in order to investigate the properties of the reactive flow and their impact on the motor specific impulse. Numerical simulations are performed on two different test cases, the second stage of the Minuteman III and the third stage of the Vega launcher, comparing the impact that different chemical mechanisms have on flow evolution and specific impulse estimate. The outcomes of the analysis suggest that CFD simulations represent a viable and robust method to provide a satisfactory prediction of the chemical non-equilibrium efficiency, outperforming semi-empirical laws when it comes to dealing with new solid motors of latest generation.