A model for solid propellant burning fluctuations using mesoscale simulations

Abstract The combustion of composite solid propellants shows velocity fluctuations which are expected to have marked effects on turbulence or aeroacoustic instabilities. In this work, we propose a specific propellant boundary condition that models such fluctuations using a spectral synthetic turbulence approach. In order to feed this model with reliable input data, we consider mesoscale direct simulations of propellant combustion. This new propellant boundary condition is implemented in a CFD flow solver and applied to a real lab-scale motor. Simulations show that burning fluctuations can trigger aeroacoustic instabilities, in better agreement with experiments.