Experiment on evaporation heat transfer performance of porous surface

Abstract

Enhancement of evaporation heat transfer performance is important for cooling of electronic devices. Evaporation heat transfer coefficient of two types of porous surfaces supplied with water liquid film was studied experimentally. First porous surface was multi layers of meshed plates with micro-channel of 0.3 mm width. Thin water liquid film was supplied to the porous surface by bubbles. Evaporation heat transfer coefficient of the porous surface with one or two layers of meshed plates was 8×104 W/m2K and it was higher than pool boiling heat transfer coefficient. Second porous surface was 1 mm thickness of glass-beads of 0.4 mm in diameter on a heated cupper plate. Water was supplied to the porous layer at the center of the plate. Evaporation heat transfer coefficient was 1000 W/m2K after water was supplied. Evaporation heat transfer coefficient increased to 7000 W/m2K before appearance of dry portion on the plate, because water film thickness in the porous layer was thin.