Abstract:

Under the high temperature and high pressure environment, aluminum sheets with special shapes through wire-electrode cutting were embedded on the surface of the resin. Corroded by CuCl₂ solution and modified by thermostatic water bath of stearic acid anhydrous ethanol solution, the composite surface with the coexistence of hydrophilic zone and hydrophobic zone was obtained. High speed camera was used to record the drop dynamic process imping on the plate with alternating hydrophobic and hydrophilic stripes. The experiment results showed that when the plate was placed horizontally, the spreading processes on the composite surface and on a single wettability surface were similar, but the shrinkage behaviors subsequently were significantly different. The height difference of liquid film was caused by alternating hydrophobic and hydrophilic stripes when the droplet shrinking on the composite surface. In the case of droplet impacting on inclined hydrophilic and hydrophobic composite surface: The higher the velocity of the droplet impacting on the composite surface was, the larger the displacement was, and the droplet with excessive speed would not be captured by the plate with a length of 20mm. When the velocity was set to a certain value, the droplet could across more hydrophobic regions with a smaller Oh number. When other parameters kept being constant, the smaller the ratio H of the droplet radius r to the interval width w was, the more easily the droplet was captured by the functional surface.

Key words: heterogeneous surface, droplet, multiphase flow, contact angle

摘要：

在高温高压环境下，将线切割成特殊形状的铝片镶嵌在树脂表面，再通过CuCl₂溶液对铝表面腐蚀，利用硬脂酸无水乙醇溶液的恒温水浴，进行表面修饰，适当处理得到亲水区域与疏水区域共存的复合表面。采用高速相机记录了液滴撞击水平与倾斜表面的动力过程，实验结果表明：液滴撞击水平放置的亲疏水复合表面时，其铺展过程与液滴撞击单一润湿性表面相似，但收缩行为差异化明显。液滴在亲疏水间隔表面收缩时，液膜会因亲疏水性并存而产生高度差。液滴撞击倾斜亲疏水复合表面时，液滴撞击的速度越大，其在斜面进行的位移量越大，速度过大的情况下液滴不会被宽度为20mm的斜面捕获；当速度为定值，Oh数越小，液滴跨越的亲疏水段越多，Oh数过小的情况下液滴不会被斜面截留；其他参数不变，比值系数H越小，液滴更易被斜面捕获。

关键词: 非均质表面, 液滴, 多相流, 接触角