Numerical investigation of the slag behavior in the aft-end cavity of solid rocket motors

The 2-D RSRM geometry at 67 seconds is used for the analysis of the slag behavior in the aft-end cavity using the FDNS (Finite Difference Navier-Stokes) code to obtain a better understanding of the relationship between slag behavior and SRM performance. The FDNS flow solver is a finite difference method for solving NavierStokes equations using non-staggered curvilinear grid system with multi-zone multi-block option for multiple species to simulate the complex flow problems. A Lagrangian-Eulerian particle tracking method is employed in the FDNS to provide effects of momentum and energy exchanges between the gas phase and the particle phase. The particle trajectories are calculated using a one-step implicit method. The VOF (Volume of Fluid) method is employed to investigate the slag behavior in the aft-end cavity of the solid rocket motors. The obtained results reveal the potential impact of the particles on the operation of the motor as well as its performance. It is believed that the heat flux and the pressure distributions in the aft-end cavity will cause recirculation and influence the design requirements. The influence becomes more serious due to the accumulation of the slag in the aft-end cavity. In the present study, the particulate phase is assumed to be aluminum oxide (A1203) only. The accumulated slag changes the shape of the aft-end cavity and influences the flowfield. The obtained analyses of the flowfield and the slag behavior in the aft-end cavity using the FDNS code in the present study could provide necessary assistance for the designers to improve the performance of solid rocket motors.