关键词: 亲疏水表面, 蒸发, 传质, 相变, 恒热流, 接触角

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