Numerical Study On Flow Field In A Small Compartment Double-pulse Solid Rocket Motor

Multi-pulse solid rocket motor is a new type of solid rocket motor with high controllability which can start and stop several times.It can reduce the peak of missile flight speed and aerodynamic drag effectively,and improve the terminal speed and penetration ability of missile.As a kind of pulse solid rocket motor,the dual-pulse solid rocket motor is widely used because of its simple structure and high stability.At present,the influence of the Pulse Separation Device(PSD)of dual-pulse solid rocket motor on the two phase flow,the second pulse ignition process and other related issues need to be further studied.The main objective of this research is through the calculation of the flow field in the dual-pulse motor,to analysis the influence of the PSD channel diameter and the opening angle on the two phase flow,and effect of different factors on the second pulse ignition delay.The main research contents and conclusions of this paper are as follows:(1)The theoretical model of gas phase flow and gas-solid two phase flow in the internal flow field of motor is established.Numerical simulation of influence of PSD on the two-phase flow is conducted by using FLUENT software.The results show that in order to reduce the wall erosion and particle erosion on the wall,the ratio of the PSD channel diameter to throat diameter should be around 6.7,and avoiding to use the PSD channel which has a certain angle.(2)The model of ignition delay of dual-pulse solid rocket motor is established.The ignition delay of dual-pulse motor is calculated and simulated.The effects of different factors such as the opening pressure of the aluminum diaphragm,the mass flow rate of the ignition device,the free volume and the burning rate of the propellant on the ignition delay are studied.The results show that the free volume and burning rate of the propellant are the main factors influencing the ignition delay of the second pulse working process.(3)The structure of the PSD and metal diaphragm are designed.The ANSYS software is used to simulate the pressure and damage of the metal diaphragm.The related experiments are carried out on the PSD and metal diaphragm,by comparing the simulation results with the experimental results,it is found that the two results are similar,and the design of the PSD and metal diaphragm can meet the requirements.