固体火箭发动机Al2O3凝结及颗粒破碎的数值模拟

Numerical simulation on accumulation and breaking of Al2O3 particles for solid rocket engine

关键词:  颗粒  凝结  破碎  燃烧效率

Key words:  Particle  Al₂O₃ accumulation  Break-up  Combustion efficiency

摘要:

Al2O3凝结对固体火箭发动机Al颗粒的燃烧效率及燃气流动有很大影响。结合拉格朗日方法,建立Al2O3凝结模型,分析了在Al2O3烟雾凝结及颗粒自身破碎作用下,不同初始直径Al颗粒的燃烧效率及燃烧室流场的变化规律。计算结果与同条件下的测试数据有较好的吻合,颗粒分布符合相关实验现象。结果表明,小颗粒燃烧后,流场温度及Al2O3烟雾分布均匀;随颗粒初始直径的增加,径向出现明显分层现象;在发动机出口,小颗粒燃烧效率较高,颗粒中Al2O3质量分数较大,但破碎程度较小;随初始直径增加,颗粒燃烧效率逐渐降低,颗粒中仍含有大量未燃烧的Al,破碎程度提高,颗粒数目急剧增加。

Abstract:

Al₂O₃ accumulation strongly influences the Al droplets combustion efficiency and mixture gas flow in the solid propellant rocket motor.Combined with Lagrange approach,Al₂O₃ accumulation model is established to simulate Al droplets combustion efficiency and flow field of the solid propellant rocket motor chamber for different initial diameter of particles by considering particles break-up.The results are close to the test which is exerted in same condition.The distribution of the particles tallies with relevant experiment phenomenon.The results show that,both temperature and Al₂O₃ smoke distribution are uniform in the motor with small particles.As particle diameter increases,layers appear in chamber radical direction.At the outlet of the motor,the combustion efficiency of the particles with small initial diameter is high.However,almost no break-up happens.As diameter increases,particles combustion efficiency decreases,and Al composition which is unburned is still high.However,particles strongly break up.