超声速气流中液体横向射流的气液相互作用过程数值研究

Numerical Simulation of the Gas-Liquid Interaction of Cross Liquid Jet in Supersonic Flow

采用Euler-Lagrange方法对来流马赫数为1.94的超声速气流中液体横向射流的气液相互作用过程进行数值研究。计算给出的射流穿透深度、液滴Sauter平均直径(SMD)及液滴速度分布均与实验吻合较好。仿真结果较详细地揭示液体射流喷雾与气流之间的强烈相互作用过程。受液雾影响,射流前形成较强激波,气流依次经过激波及液雾区域,气流速度存在两次下降过程。计算结果揭示,超声速来流可以与射流的液滴轨迹相交,气流经液雾前沿进入液雾区域后,流向往壁面偏折。本文首次发现并提出,由于气液相互作用诱导形成两组反向反转漩涡对,这对于理解两相混合过程具有重要意义。气液相对滑移速度的分析表明,液滴在穿透自由来流并开始转向时受气流作用最为显著,完成转向后气液相互作用逐渐减弱。

The gas-liquid interaction process of cross liquid jet in Ma = 1. 94 supersonic flow is investigated numerically by using the Euler-Lagrange method. It is found that the main spray properties including spray penetration,Sauter mean diameter（ SMD） and axial velocities agree reasonably well with the experiment. Numerical results indicate that there are strong interactions between the airflow and liquid spray. Under the influence of spray,a bow shock wave forms ahead of the jet. Airflow passes through both shock and spray zone in turn,there are twice decreases of the velocity of airflow. The results reveal that the streamlines of supersonic flow can intersect with the trajectory of droplet of the jet. The direction of airflow deflects to the wall after it enter into spray zone in the center plane. Two groups of reversed vortex pair induced by the gas-liquid interaction are first discovered. This could help to understand the mixed process between two phases. The analysis of gas-liquid relative velocity shows that the most notable effect of airflow occurs when droplets begin to turn around after penetrating into free flow,and the gas-liquid interaction gradually weakens while flowing downstream.