基于数值模拟的蘑菇状喷雾液柱形成机理

Mushroom Shape Injection Flow Based on Numerical Simulation

采用MARS法对初始喷雾液柱进行数值模拟,得到顶端有奇特的蘑菇状结构的喷雾液柱,与试验结果吻合。通过对喷雾液柱形成过程的分析,发现低环境压力下的喷雾液柱顶端蘑菇状的结构,是在燃油速度、空气速度、燃油压力和空气阻力的共同作用下形成的;通过对数值模拟结果影响因素的分析,发现计算时间步长、网格密度、初始液面高度、喷射压力和环境压力都对模拟计算结果有影响,说明模拟计算要选取合适的时间步长、较密的网格和合理的初始液面高度,考察喷嘴内部的压力损失。

The multi-interfaces advection and reconstruction solver（MARS） method is used to simulate the initial injection flow. It is found that the tip of injection flow forms a shape of mushroom, which agrees well with the experimental photos. By analysis developing process of the injection flow, it is found that the combined effect of fuel speed, air speed, fuel pressure and air resistance results in the mushroom spray at low ambient pressure. By analysis the influencing factors of numerical simulation results, it is found that time step, grid density, initial fuel surface height, injecting pressure and ambient pressure have the influence on the simulation results. Thus, desirable time step, dense grid density and appropriate initial liquid surface height should be selected in the numerical simulation where pressure loss needs to be considered.