夹气喷嘴瞬态喷雾的CFD仿真及试验

通过CFD仿真和试验的方法研究了夹气喷嘴的瞬态喷雾特性并验证了喷雾仿真模型的准确性.利用Fluent软件在不同环境背压和不同喷气压力的条件下进行了瞬态喷雾的CFD仿真计算,同时利用高速摄影机拍摄定容弹内部的喷雾形态,以及通过激光粒径测试仪对大气环境下的喷雾进行燃油液滴SMD的测量.结果表明:喷嘴出口处高速流出的压缩气体与燃油发生强烈的耦合,并于下游处产生强烈的涡环结构;试验中环境背压减少0.2MPa时所增加的平均贯穿速率是喷气压力增加0.2MPa时的3.62倍;喷雾平均贯穿速率的试验结果与仿真结果的平均误差为9.94%;试验得到的喷嘴外围的喷雾平均索特直径与仿真平均索特直径的平均误差为4.33%.

CFD simulation and experiment of transient spray for an air-assisted injector

In order to research the transient spray characteristics of the air-assisted injector and verify the accuracy of the simulation model, the spray characteristics of the air-assisted injector were investigated by CFD simulation and experiment. The CFD simulation had been carried out that the transient injection with different back pressure and inject pressure was simulated. The spray development in the constant volume bomb had visualized by the high speed camera. The SMD of the fuel droplets in the atmospheric environmenthad measured by the laser particles test device. The results show that the high speed compressed air from the injector and the fuel are strongly coupled, and the vortex ring structures come out in the downstream; the increased average rate in experiment by reducing 0.2MPa of back pressure is 3.62 times than increasing 0.2MPa of inject pressure; the average error of average rate between experiment and simulation is 9.94%; the SMD average error of the outlying of injector between experiment and simulation is 4.33%.