喷管内雾状气液两相流场计算分析

Numerical simulation of gas-droplet two-phase flow field in nozzle

摘要:

基于双流体模型,考虑两相间动量和热量传递,采用变步长的Runge-Kutta法,对喷管内雾状气液两相流场进行了数值模拟.分析了亚声速及超声速流场特性,重点研究了液滴尺寸及初始含气率对两相流动的影响.计算结果表明:液相速度增长相对缓慢,喷管出口处两相速度差异最大;液相出口速度随液滴尺寸减小而增大,气相出口速度随其减小而减小;液相、气相出口速度均随着初始含气率的增大而增大;在超声速流动中,喉部马赫数小于1,喉部面积随初始含气率及液滴尺寸的增大而减小.这将为喷雾发动机性能的研究分析奠定基础.

Abstract:

Based on two-fluid model,the gas-droplet flows in nozzle were studied numerically using variable step Runge-Kutta scheme.Heat interaction between the two phases was introduced in the model.The characters of subsonic and supersonic flows were analyzed,and the impacts of droplet size and initial void fraction on the flow field were investigated.Simulation results show that the liquid velocity increases more slowly compared with the gas velocity.With the decreasing droplet size,the exit liquid velocity increases,but the gas velocity decreases.Both gas and liquid velocities increase with the increasing initial void fraction.For the supersonic flow,the Mach number at the throat is less than 1,and the throat area decreases with the increasing initial void fraction and droplet size.The results are useful for the investigation on the performance of mist jet propulsion system.