非均匀润湿表面强化冷凝换热研究

In order to study the performance of enhanced heat transfer on non-uniform wetting structure, a wetting gradient surface with interlaced hydrophilic and hydrophobic stripes was prepared on the copper substrate by chemical etching combined with laser processing. In the experiment, the condensation and migration phenomenon on the surface were observed, and the kinetics analysis for the migration of the droplets was carried out. The results indicated that during the condensation process, the droplets in the hydrophobic region could quickly move to the hydrophilic region by the synergistic effect of the gravity and the Laplace pressure difference. Then the droplets in the hydrophilic flow channel were quickly removed by the effects of gravity. Compared with the smooth surface, the droplets replacement frequency of the non-uniform wetted surface was increased, the shedding size was reduced, and the surface heat transfer performance was enhanced. The subcooling and structural parameters affected discharge of droplets in the hydrophilic zone, and further influenced the effect of heat transfer enhancement of the surface. The heat flux of the surface increased with the increase of subcooling, but the trend gradually decreased. Besides, the heat flux increased first and then decreased with the increase of the ratio of the hydrophilic to hydrophobic regions, and increased first and then decreased with the increase of inclination angle.