CAJ | 학술논문

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,并且汁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,撞击在下燥表面时,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.
대분무청세과정중미과립소수도적류체력진행료연구.유우액적당격재평면상산생적불은정류, 무법용현유적층류작용력공식래예측과립소수도적작용력,본문채용료계산류체역학모의적방법대류장분포진행료모의,병차즙산과립상상응수도적작용력.통과계산결과,토론료영향과립청제효과적관건인소.연구표명,재미미척도내,평면적가습성질대액적전개적초시계단류장분포유현저영향,종이야대대영향료평면상과립소수도적작용력.차외,당격재하조표면시,과립수도적타예력회비당격도습표면상시대삼개수량급이상.이재습표면상시,제고당격속도회비증대액적대소래득경유효,주도과립거제적력위타예력.
This paper presents the results of a numerical investigation of micro-sized particle removal by droplet impact.Computational fluid dynamics simulation is used to calculate the flow distribution of droplet impact on a flat surface. The hydrodynamic forces exerted on the particle are then computed. Key factors controlling particle removal are discussed.Both hydrophilic and hydrophobic surfaces are considered. The flow distributions, especially the front edge expanding upon impact at microscale,strongly depend on surface wettability. The associated hydrodynamic forces on the particles vary ac-cordingly. In addition, the impact on a dry surface can produce higher removal efficiency than that on a wet surface. Under the same impact conditions, the drag force exerted on a particle residing on a dry surface can be three orders of magnitudes larger than on a wet surface. Improving droplet impact velocity is more effective than improving droplet size.