Research on the combustion machanism of the high burning rate solid propellant under high transient pressure conditions

The high burning rate solid propellant is widely used in the microthrusters for the attitude control of hypervelocity flight vehicle. To explore the combustion machanism of this type solid propellant under high transient pressure conditions, a series of closed bomb vessel test and some exploratory test of the impulsive microthruster have been conducted. The pressure exponent saltation was found during the test, this phenomenon will bring a baneful in uence to the future application of the solid propellant under high transient pressure in such microthrusters. The in uence of high pressure and heat feedback from gas phase to the temperature rising process of solid propellant was studied using a modified dp/dt model, the thickness of different zone in condensed phase was obtained using one- step reaction model. The theoritcal analysis and experimental data met each well, which indicated the transient effect strengthening as the activiation energy and thermal conduc- tivity on the propellant surface growing. The modified model explaining the experimental burning rate pressure curve and internal ballistics curve of the impulsive microthruster fitted the experiment data well.