旋转对固体火箭发动机两相流点火过程影响仿真研究

Simulation study on the influence of spin on ignition process of two-phase in solid rocket motor

为研究高速旋转对内外燃管型装药固体火箭发动机凝聚相点火瞬态过程的影响规律,应用计算流体动力学(CFD)流体计算软件,使用用户定义函数(UDF)编程接口建立固体火箭发动机点火模型,对旋转条件下发动机凝聚相点火过程进行模拟。将数值计算结果与地面旋转实验内弹道进行对比分析,验证数值模型的正确性。计算结果表明:(1)点火药燃气颗粒因旋转做离心运动,大量粒子聚集在燃烧室头部上端,部分粒子附着在发动机壁面,且停留时间较长。(2)点火药燃气颗粒占比从20%增加到40%,点火压力峰值降低3.93%,发动机转速的升高会造成内弹道平衡压力升高,但点火压力峰会逐渐降低,且峰值出现时间发生延迟,转速达到15 000 r/min时点火压力峰消失。(3)转速增大,点火颗粒与推进剂传热增大,火焰传播期减小,但燃气填充期和点火延迟增大,点火药燃气颗粒占比为20%时,转速为15 000 r/min较静止条件下点火延迟增加了23.76%。

In order to study the influence law of high-speed spin on condensed phase ignition transient process of solid rocket motor with internal and external burning tubular propellants,the ignition model of solid rocket motor was established by the user defined function(UDF)of computational fluid dynamics(CFD)software,and the ignition process of condensed phase was simulated under the condition of spin.The correctness of the numerical model was verified by comparing the numerical results with the interior ballistics ground spin test results.The results showed that:(1)a large number of particles gathered at the front end of the combustion chamber due to the centrifugal motion of igniter gas particles,and some particles adhered to the solid rocket motor wall for a long time.(2)The particle ratio increased from 20% to 40%,and the ignition pressure peak decreased by 3.93%.The increase of solid rocket motor spin speed could lead to the increase of internal ballistic equilibrium pressure,but the ignition pressure peak gradually decreased,and the appearance time of pressure peak was delayed.When the spin speed reaching15 000 r/min,the ignition pressure peak disappeared.(3)With the increase of spin speed,the heat transfer between ignition particles and propellant increased,the flame-spread period decreased,but the chamber-filling period and ignition delay increased.Compared with static condition the ignition delay increased by 23.76% at 15 000 r/min when the particle ratio was 20%.