单液滴冲击超疏水壁面的压力特性研究

Study on the Pressure Characteristics of Single Droplet Impact Super-hydrophobic Wall Surface

雨滴撞击索类结构表面可能会激发振动及表面积冰等问题,现有研究多关注于疏水壁面及液滴撞击壁面铺展、回缩特性,鲜见涉及雨滴冲击超疏水壁面压力特性的研究。为此,采用CLSVOF方法对单液滴冲击超疏水固壁面这一过程进行数值计算,分析了液滴速度、初始直径等因素对液滴冲击超疏水壁面的压力特性、液滴动态行为特性及液滴与壁面接触时间的影响。结果表明:单液滴撞击超疏水壁面的过程中,接触瞬间在接触点附近产生局部高压区,而在液滴铺展过程中,对壁面几乎没有压力冲击:在回缩反弹阶段,壁面受到持续较长时间的压力波动,且压力波动区域不局限于初始接触点附近较小范围。撞击速度或液滴初始直径的增大使壁面受到的冲击更为剧烈,且初始速度对壁面受压的影响更为明显。一定范围内液滴初始直径的增大则会导致接触时间延长。

The impact of raindrops on the surface of the cable structure may stimulate vibration and surface ice.Existing research focuses on the hydrophobic wall and the spreading and shrinking characteristics of the droplet impacting the wall.There are few studies involving the pressure characteristics of the raindrop impacting on the super-hydrophobic wall.For this reason,the CLSVOF method is used to numerically calculate the process of a single droplet impacting on the super-hydrophobic solid wall,and the influence of factors such as droplet velocity and initial diameter on the pressure characteristics of the droplet impacting the super-hydrophobic wall,the dynamic behavior of the droplet,and the contact time of the droplet with the wall are analyzed.The results show that when a single droplet hits the super-hydrophobic wall,a local high pressure area is generated near the contact point,while during the spreading process of the droplet,there is almost no pressure impact on the wall;during the retraction and rebound stage,the wall is sustained more long-term pressure fluctuations,and the pressure fluctuation area is not limited to a small range near the initial contact point.The increase of the impact velocity or the initial diameter of the droplet makes the wall face more violent,and the initial velocity has a more obvious impact on the wall face pressure.An increase in the initial diameter of the droplets in a certain range can lead to longer contact times.