超声速气流中横向煤油射流的数值模拟

Numerical simulation of kerosene spray in supersonic cross flow

关键词:  超声速流  液滴  液体雾化  气体液体互作用  数值模拟

Key words:  Supersonic flow  Drop  Liquid atomization  Gas-liquid interaction  Numerical simulation

摘要:

为了对超声速气流中液体横向射流进行数值模拟,采用Eulerian Lagrangian方法描述气液两相流动现象,用随机轨道模型追踪液滴的运动历程,并考虑气流可压缩性、流场不均匀性及液滴变形对液滴运动的影响,开发了相应的计算程序。计算结果发现,液体射流与气流之间存在着强烈的相互作用,液滴在进入气流中不久就破碎成很小的子液滴,受煤油液雾的影响气流速度、温度急剧下降,同时在喷孔上游出现一道弓形激波。与液雾结构的纹影图像和液雾穿透的实验结果对比显示,数值计算结果基本合理。

Abstract:

A code applied for kerosene spray in supersonic flow has been developed, in which Eulerian-Lagrangian method was adopted to describe two-phase flow, a stochastic particle method was used to calculate the liquid sprays. Meanwhile, the effect of gas compressibility, pressure gradient and the droplet distortion on the droplet motion has also been considered. It was found that there is strong interaction between the airflow and the kerosene spray. Initial parent drops are broken up into small drops soon after they enter the supersonic cross flow. Moreover, a bow shock wave is captured ahead of the kerosene jet. And the speed and the temperature of airflow decrease due to aerodynamic effect and droplets evaporation. The comparison of the numerical results with the Schlieren images of spray structure and experimental data of spray penetration showed good agreement.