Analysis Of Two Phase Flowfield In The Forward Dome Of SRM Under Overload

For the missiles with high requirements for penetration capability,the particles may accumulate locally in the forward dome under the high-speed maneuvering process.The two-phase flow field in the forward dome is computed under different overload conditions to analyze the effects of the axial overload and pitch overload on the two-phase flow field in this paper.It will be a reference for the design of the insulation lay of the forward dome in such solid rocket motors.The contents is as follows:(1)The appropriate calculation method was selected and verified.According to the physical problems and the application range of the calculation modeling,this paper selects the pseudo-homogeneous model and the discrete phase model to calculate the two-phase flow in the combustor.The physical properties and size distribution of the particles in the solid rocket motor are then determined based on the relevant literature.Grid independence verification and numerical model verification are performed according to the selected numerical model and particle characteristics.(2)The pseudo-homogeneous model is used to calculate the two-phase flow field of the combustor under different axial overload and different elevation angular velocity conditions.And the effects of axial overload and constant pitch overload on the two-phase flow in the forward dome are analyzed.By analyzing the flow parameters and streamline in the forward dome,it's obtained that the axial overload causes the vorticity and velocity to decrease in the forward dome.But the axial overload has little effect on the vortex size and position.The constant pitch overload reduces the vortex size in the forward dome,and causes the gas gathering point to move up from the geometric center.It reduces the vorticity and velocity in the windward region of the forward dome,and increases the vorticity and velocity in the leeward region.(3)The discrete phase model is used to calculate the two-phase flow field of the combustor under different axial overload conditions,different angular velocity conditions and different angular acceleration conditions.And the effect of the axial overload and pitch overload on the two-phase are analyzed in the forward dome.The impact of the flow.By analyzing the particle concentration distribution and the force of the particles in the forward dome,it is obtained that the particle concentration increases under the influence of the gravityin the forward dome under the little axial overload.And the smaller the axial overload is,the higher the particle concentration is.The particle concentration in the windward region increases under the constant pitch overload and it decreases in the leeward region.When the pitch angular velocity changes to the same as it under the constant pitch overload,the particle concentration under the non-constant overload is lower than that under the constant pitch overload.The particle concentration reduction in the windward region is larger than that in the leeward region under the angular velocity acceleration state,and the opposite is true in the decelerating state.Under the combined influence of aerodynamic force and Coriolis force,the particles concentration in the vortex of the reverse nozzle base is the highest in the forward dome.(4)The results obtained by the two numerical models are compared to analyze the difference.By comparing the streamline and the flow parameters in the forward dome,it's obtained that the regulation is consistent by using the pseudo-homogeneous model and the discrete phase model.But the parameters variation range is different.In summary,it is studied that the two-phase flow in the forward dome of a solid rocket motor under different acceleration conditions in this paper,and provides a reference for the design of the insulation lay in the forward dome of a solid rocket motor with reversed nozzles.