A Multiphase Modeling Framework for Solid Rocket Motor Slag Accumulation and Dynamics Prediction

Aluminized propellants used in solid rocket motor (SRM) are associated with aluminum and aluminum oxide particle formation, which eventually introduces slag (liquid aluminum oxide) in submerged nozzle. Accurate prediction of slag formation, accumulation/pooling, particle-slag interactions, and ejection of slag through nozzle is important for SRM design and operation. A multiphase modeling framework, Loci/SLAG is developed to address major issues/limitations involved in current state of the art SRM modeling, especially of slag accumulation, slag interaction with main flow and nozzle flow, effects of slag accumulation and dynamics on SRM performance parameters. Thermo-physical property models are incorporated into the framework to allow for temperature and composition dependent slag viscosity as well as variable thermal conductivity. Slag interface and transport modeling are incorporated to capture particle-wall interaction, particle-slag collision, and slag-wall interaction effects. Simulation strategies of slag accumulation, dynamics, and SRM performance/stability prediction under accelerated frame of reference are developed. Loci/SLAG framework is integrated with burning surface modules for capturing propellant grain recession and its effect on casing surface.