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对喷雾清洗过程中微颗粒所受到的流体力进行了研究.由于液滴撞击在平面上产生的不稳定流,无法用现有的层流作用力公式来预测颗粒所受到的作用力,本文采用了计算流体力学模拟的方法对流场分布进行了模拟,并且计算颗粒上相应受到的作用力.通过计算结果,讨论了影响颗粒清除效果的关键因素.研究表明,在微米尺度内,平面的可湿性质对液滴展开的初始阶段流场分布有显著影响,从而也大大影响了平面上颗粒所受到的作用力.此外,撞击在干燥表面时,颗粒受到的拖拽力会比撞击到湿表面上时大三个数量级以上.而在湿表面上时,提高撞击速度会比增大液滴大小来得更有效,主导颗粒去除的力为拖拽力.
The fluid forces exerted on the microparticles during the spray cleaning process are studied.Due to the unsteady flow caused by the droplet impinging on the plane, the existing laminar flow force formula can not be used to predict the force exerted by the particles. In this paper, The computational fluid dynamics simulation is used to simulate the flow field distribution and to calculate the corresponding forces acting on the particles. The key factors influencing the particle removal efficiency are discussed. The results show that in the micrometer scale, The wet nature has a significant effect on the flow field distribution in the initial stage of droplet development and also greatly affects the forces applied to the particles on the plane.In addition, the drag force exerted by the particles upon impact on the dry surface will be greater than the impact on the wet surface On the wet surface, increasing the impact velocity will be more effective than increasing the droplet size, with the dominant particle removal force being the drag force.