基于VOF-DPM的横向射流雾化过程数值模拟

Numerical simulation of the atomization process of liquid jet in a crossflow based on VOF-DPM

为高效精确模拟航空动力系统的液态燃料横向射流多尺度雾化过程,分别采用离散相模型(discrete phase model,DPM)、流体体积(volume of fluid,VOF)法耦合DPM(VOF-DPM)对横向射流雾化过程进行数值模拟,对比2种模型对横向射流雾化过程的仿真结果,并研究模型转换直径与破碎模型对横向射流雾化过程仿真结果的影响。仿真结果表明:相比DPM,VOF-DPM仿真得到的射流穿透深度更接近试验结果,射流雾化过程更真实,并且能够捕捉到更详细的流场信息;当模型转换直径较小时,不能转换为离散相颗粒的液滴相对较多,这些液滴仍由VOF求解,并阻挡气流导致在其周围产生小涡团;添加破碎模型对射流穿透深度和流场结构几乎没有影响,但导致离散相颗粒继续破碎成更多更小的颗粒。

In order to efficiently and accurately simulate the multi-scale atomization process of liquid jet in crossflow(LJIC)in aerospace power system,the LJIC atomization process is simulated using the discrete phase model(DPM)and coupled the volume of fluid(VOF)and DPM(VOF-DPM).The simulation results of the two models on the atomization process of LJIC are compared,and the effects of model conversion diameter and breakup model on the simulation results are investigated.The simulation results indicate that,compared with DPM,the jet penetration depth obtained by VOF-DPM is closer to the experimental results,the atomization process is more realistic and more detailed flow field information can be captured.When the model conversion diameter is smaller,there are more droplets that cannot be converted into discrete phase particles,which are still solved by VOF and block the flow causing small vortex clusters to form around them.Breakup model has little effect on the jet penetration depth and the flow field structure,but it causes the discrete phase particles to be further breakup into more and smaller particles.