双股射流撞击雾化的无网格MPS法数值研究

Numerical Study of Double Jet Impact Atomization Using Meshless MPS Method

为研究质量流量和撞击角对双股射流撞击雾场的影响规律,采取移动粒子半隐式(MPS)法对双股射流撞击雾化过程进行数值模拟,针对数值模拟结果提出了用于液滴空间弥散状态研究的染色法并对雾场进行后处理分析。首先通过对泊肃叶流动和方形液滴变圆的模拟,验证了充分发展速度进口模型和表面张力模型的正确性:随后通过分析质量流量和撞击角对雾化特性参数的影响,得到了典型工况下雾化后液膜生成并破碎为液丝、液丝发展为液滴的全过程。最终得到结论:质量流量从5g/s增加到25g/s,液滴平均粒径减少80.00%,雾化角增加42.13%;撞击角从30°增加到90°,液滴平均粒径减少94.22%,雾化角增加59.95%;当质量流量为20g/s,撞击角为75°时,雾化场能达到相对最优的状态。

In order to study the influence of mass flow rate as well as impact angle on the atomization field of double jet impingement,the moving particle semi-implicit(MPS)method is applied to simulate the liquid atomization process of double jets impingement,according to the results of numerical simulation,a staining method is proposed to study the spatial dispersion of droplets,and the post-processing analysis of the atomization field is carried out.Firstly,the correctness of the fully developed velocity inlet model and the surface tension model are verified by the simulation of Poiseuille flow and square droplet rounding;Then,by analyzing the influence of the mass fow rate and impact angle on the atomization characteristic parameters,the whole process of the formation of liquid film and fragmentation into liquid filaments,and the further formation of liquid filaments into droplets under typical conditions are obtained.Finally,it is concluded that when the mass flow rate increases from 5 g/s to 25 g/s,the average droplet size decreases by 80.00%,and the atomization angle increases by 42.13%;When the collision angle increases from 30°to 90°,the average droplet size decreases by 94.22%,and the atomization angle increases by 59.95%;When the mass flow rate is 20 g/s and the impact angle is 75°,the atomization field can reach the relatively optimal state.