Fluid-structure Interaction Numerical Simulation Of Solid Rockt Motor Igition And Pressure Forming Process

The ignition process of solid rocket motor occurs within tens of milliseconds,during which the pressure in the combustion chamber rises rapidly and the flow field changes dramatically.It is difficult to visualize the details of the combustion chamber flow field during the ignition process in experiments,and it is not economical to conduct massive parametric analysis using experimental methods.Therefore,it is necessary to carry out numerical simulation of the solid rocket motor ignition process.The existing simulation method of ignition process often over-simplifies the combustion process of the ignition powder.The corresponding ignition gas mass flow history is fitted using experimental data to directly simulate the generation of ignition gas(named as pure gas phase ignition).Pure gas phase ignition ignores the process of combustion and flow of particles.It is impossible to describe the influence of parameters such as the size of the ignition powder particles and the proportion of the ignition powder on the ignition process.The determination of the mass flow history depends on experimental results.In order to improve the accuracy of the numerical simulation of the ignition process,the present work carries out a research on the simulation method of the ignition process based on the combustion of the ignition powder particles.The contents are as follows:(1)A method for simulating the ignition based on the combustion of ignition powder particles is established adopting the Heterogeneous Phase Interaction model.The present simulation results are compared with the experimental data,and the influence of parameters such as the reaction rate of the ignition powder and the initial ignition conditions on the boost rate of the ignition process is analyzed.Therefore the parameter correction is carried out.(2)The prediction of the ballistic history during the entire motor operation is achieved via combining the ignition process simulation method with the in-house surface regression method.(3)Based on the parameter correction,a general computation model of a tubular grain motor is established.The combustion flow of the ignition powder particles in the combustion chamber is presented.the ignition process of the grain surface subject to the ignition powder gas and hot particles flow is interpreted.The formation and development of ignition shock in the combustion chamber are demonstrated.A parameterized analysis of the influential factors of the ignition process is developed,the effects of the mass of ignition powder,the particle size of the ignition powder,and the opening pressure of the nozzle plug on the ignition delay time and the average motor boost are analyzed.(4)A three-dimensional model of the tubular grain motor is established to carry out fluidsolid coupling simulation of the ignition process.The dynamic response of the grain structure under compressive stress is recovered.A three-dimensional model of a star-shaped grain motor is built,and the influence of the shape of the grain on the stress-strain distribution is analyzed.The present work provides a new method for the numerical simulation of the ignition process of solid rocket motor.The new method improves the accuracy of the numerical simulation of the ignition process.