高空模拟试车台扩压器两相流数值模拟

Numerical simulation of two-phase flow in diffuser of simulated altitude test stand

利用组元输运模型和颗粒轨道模型,对某型号固体火箭发动机高模试车台扩压器内的两相流进行数值计算,分析了扩压器稳定工作时的内流场结构,探讨了燃烧产物中凝相颗粒Al2O3及其粒径大小对流场的影响。计算结果表明,在扩压器中形成了复杂的激波串,气流通过激波减速增压,为了达到最大的压力恢复,应保证扩压器有一定的长径比;加入粒子后,流场的速度相对降低,颗粒与激波的相互作用在局部改变了激波原有的分布,粒子集中的区域燃气流速较低、温度较高;不同粒径的Al2O3粒子扩散速度不同,分布范围差别较大,造成扩压器内速度、温度、压强的分布有较大区别;扩压器壁面的最高温度基本与粒径大小无关,都在3 200 K左右。

The two-phase flow field in the diffuser of altitude simulated test system for the solid rocket engine was numerically simulated by using species transport model and particle trajectory model. The inner flow field structure of the diffuser is analyzed. The effects ofAl2O3 particles and their sizes on the flow field of the diffuser were discussed. The results show that the complex shock train is formed in the diffuser and the flow deceleration and pressurization is realized. In order to achieve the biggest pressure recovery, the diffuser should possess a certain length to diameter ratio; The velocity of flow field is relatively low after adding Al2O3 particles. The distribution of shock wave was changed in the local areas because of particles and shock wave interaction. The gas velocity is lower and temperature is higher in the particles concentration areas; different particle size has different diffusion velocity, and the difference of distribution range is bigger, which leads to great differences in the velocity, temperature, and pressure distri- bution in the diffuser; The highest temperature on the wall of the diffuser has no relations with the particle size, which is about 3200 K.