High overload yields great influence on the grain combustion of SRM(solid rocket motor) in working process.Under nonuniform combustion of grain

a nonparallel combustion model of complicated grain was developed.The level set method was applied to calculate burning face location and internal ballistics property at different intervals.The computed results show that overload has little effect on SRM internal ballistics

since local burning rate of grain increases greatly in overload direction

leading to exposure of thermo-protection layer in high temperature gas and enhanced erosion in this position.