Effects of aluminized propellant on the performance of a rotating-valve pressure oscillation apparatus in solid rocket motors

The rotating-valve solid propellant pressure-coupled response (PCR) testing method is a key technique for evaluating combustion stability. Although the performance of the rotating valve apparatus critically influences measurement accuracy, few studies have examined its behavior with aluminized formulations. To address this, we developed a transient simulation model incorporating two-way gas-particle coupling, validated through three ignition tests. Furthermore, the effects of alumina particle parameters and port blockage on the dynamic performance are investigated through this model. Results indicate that particle parameters significantly influence particle dynamics and pressure characteristics. Increasing particle content from 0 % to 25 % raised the gas-to-solid mass ratio to 42.67 %, markedly increasing blockage risk, while equilibrium pressure and pressure amplitude increased by 6.7 % and 5.2 %, respectively. Increasing the minimum particle size from 10 μm to 110 μm resulted in a higher Stokes number, prolonging particle expulsion phase delay by 11.1 % and reducing expulsion efficiency. Equilibrium pressure and amplitude also rose by 4.6 % and 5.1 %. At 85 % blockage, reverse flow and choking occurred: the gas-to-solid ratio dropped by over 84 %, equilibrium pressure increased by 48.88 %, and pressure amplitude attenuated by 54.49 %, significantly compromising the accuracy of PCR measurements. This study elucidates the multi-parameter influence of alumina particles on the dynamic performance of rotating-valve pressure oscillation apparatus, providing a theoretical basis for improving measurement accuracy and anti-blockage design.