发动机尾焰注水降温数值计算与试验研究

Simulation and Experiment Research on Temperature Reduction of Engine Jet by Water Injection

针对火箭发动机尾焰注水流场,组织并实施了火箭发动机系留点火及燃气流场注水降温缩比试验,研究了燃气冲击射流流场和注水作用下两相流场的分布状态以及降温效果。并通过研究在高温高速对流冲击作用下气液两相流的传热和传质理论,在Mixture多相流模型的基础上添加质量和能量源项,建立了多组分气液两相流非定常数值计算模型,通过对比试验结论,结果表明:所建立的数值计算模型具有较高的计算精度和可靠性,能够准确地反映物理现象。利用数值计算模型研究了注水后燃气、液态水和水蒸气三种主要组分在流场中的组成,通过与自由射流对比得到了注水燃气流场的包络线长度与宽度变化,注水对燃气流场降温效果显著。

For rapid cooling the rocket exhaust gas with water injection, the mooring ignition and the cooling effect with water injection are tested for a sub-scale rocket engine. The distribution of the impinging jet and the two-phase flow with water injection are studied, and the cooling effect is also compared by collecting the temperature data of the two flow states. By studying the heat and mass transfer mechanism of the gas-liquid two-phase flow theory under the high temperature and high speed convection impact conditions, a program to solve the mass and energy transfer based on the mixture multiphase model is added into the unsteady gas-liquid two-phase flow field model. Verified by the experiment, the results show that the numerical model has higher calculation accuracy and reliability, and the physical phenomenon of water injection into the jet flow can be reflected accurately. Through the numerical simulation, the three main components including the rocket exhaust gas, the liquid water and the water vapor are analyzed, and the envelope size such as length and width of the jet flow and the temperature data are analyzed by comparing with the free jet flow field. The cooling effect is conspicuous with water injection.