Abstract
Adding droplets to air is used to improve the cooling efficiency for warm surfaces. When the surfaces are horizontal, the liquid film is generated by the droplets. If the heat flux is low, the film becomes a thermal resistance. In order to reduce this thermal resistance, we have created a new functional surface, which consists of hydrophilic bare part and super-hydrophilic part covered with nano-pin structure. Our experimental results show that the water droplet deposited onto the plate move promptly from the edge of the hydrophilic part to the super-hydrophilic part. Furthermore, the local, instantaneous heat transfer coefficient in the case of the new surface is found to be higher than that of hydrophilic surface.
