Abstract:

In previous researchers' studies, the evaporation of droplets were conducted on heating surfaces with constant wall temperature. However, no previous experiments were carried out on a constant heat flux heating surface. The evaporation of 3 μl sessile droplets on hydrophilic and hydrophobic heating surface with constant heat fluxes were observed and recorded by a high-speed photography. The evaporation time, dimensionless contact angle, dimensionless contact diameter and height were presented. The evaporation rate of the droplet on the hydrophilic surface was faster than that on the hydrophobic surface, and with the increase of the heat fluxes, the evaporation rate of the droplet increases. For both hydrophilic and hydrophobic surface, the evaporation mainly followed the CCR mode, and there was a mixed evaporation mode at the later stage of evaporation, but no CCA mode was found in the whole process.

Key words: hydrophilic and hydrophobic surface, evaporation, mass transfer, phase change, constant heat flux, contact angle

摘要：

以恒热流方式结合高速摄影技术同步观察记录3 μl的小液滴在不同亲疏水表面的蒸发过程。通过一系列的对比实验观察记录了不同亲疏水表面液滴蒸发时接触角、接触直径、蒸发时间等的动态特性。从实验分析中可以看出亲水表面液滴蒸发速率比疏水表面上液滴蒸发速率快，并且随着热通量的增大，液滴蒸发速率增大。在恒热流条件下亲疏水表面液滴蒸发以CCR模式为主，在蒸发后期呈现混合蒸发模式，全程未出现CCA模式。

关键词: 亲疏水表面, 蒸发, 传质, 相变, 恒热流, 接触角