Combustion Stability Analysis Of Solid Rocket Motor Under Overload

As the requirements of high performance and large mobility for tactical missiles, in recent years, almost all domestic and foreign tactical missile solid rocket motor under high overload during flight have appeared combustion instability, even leading to explosion. Therefore, it is necessary to study the influence factors of combustion instability of solid rocket motor under overload conditions.In this paper, a certain finocyl grain solid rocket motor that occurred combustion instability under overload condition is analyzed. Through the method of combining numerical simulation, theoretical and experimental research, the factors that influence combustion instability of solid rocket motor are researched, and the visions of inhibiting combustion instability are applied. The main work of this paper is as follows:(1) A mathematical model of the combustion chamber is established, the gas control equations are given for the combustion chamber, steady and unsteady decomposition of equations, time/space average are done, linear combustion stability theory and nonlinear theory are deduced, the acoustic gains and losses are summarized roundly, ordinary differential equations of nonlinear theory are established;(2) A numerical model about acoustic properties of the combustion chamber is established, acoustic properties of the combustion chamber at a particular moment are analyzed, the type of combustion instability of SRM is determined. T-Burner tests are carried out repeatedly for a certain propellant formulation, the combustion response is obtained at 216 Hz, and the necessary data for combustion instability analysis of SRM is obtained. The size of solid components in the original formulation is adjusted. T-Burner tests are carried out for two kinds of new propellant formulation. It is found the combustion response reduced. Adjustment propellant formulation is an effective way to improve the combustion stability of solid rocket motor;(3) Unsteady numerical simulation is done for the combustion chamber of solid rocketmotor. Three different pressure disturbances are added to the combustion chamber head. It is found changes in the amplitude and time of pressure disturbances can’t maintain pressure oscillations of the combustion chamber, and can’t lead to dramatic increase in average pressure. The results are well consistent with the ground pulse experiment.(4) Numerical simulations and theoretical calculations are carried out for the different particle diameters in the combustion chamber, aluminum contents and overload conditions. The results show that as the particle diameter in the combustion chamber and the aluminum content increase when the particle diameter is less than the best diameter, particle damping increases, the combustion stability of solid rocket motor is improved. Increase the amount of both can improve the combustion stability of solid rocket motor under overload during flight. With the increase of lateral and axial overload, particle damping reduces, the combustion stability of solid rocket motor deteriorates, and the influence of lateral overload on particle damping is greater than axial load. These three factors on flowing turning are small, resulted in small changes on the combustion stability of solid rocket motor;...