Heat transfer enhancement of dropwise condensation on a vertical surface with round shaped grooves

Abstract In dropwise condensation, the behavior of falling drops strongly affects the heat transfer. It is expected that the heat transfer during dropwise condensation would be enhanced if falling drops more frequently and widely sweep drops in the lower part. In this paper, we investigated heat transfer characteristics of dropwise condensation on the surface with grooves cut in a round shape. The heat transfer plate was made of copper with 30 mm square by 3 mm thick. The round shaped grooves were cut regularly on the surface. The plate was set vertically and the grooves were arranged in two positions, vertical and horizontal. The heat flux, surface temperature and sweeping cycle of falling drops were measured when steam flowed down and condensed on the grooved surface. As the results, it was found that the heat transfer on the vertical grooved surface was enhanced in the range of groove width from 2 to 3 mm. This indicated that the groove width of 2–3 mm was considered to be very effective in making falling drops sweep small droplets on the lower part of grooves.