A study on heat transfer enhancement of boiling two-phase flow in a narrow channel by thermal spray coating

Boiling heat transfer enhancement is efficient for development of a cold plate used in a two-phase flow loop type thermal control system. This study deals with boiling heat transfer enhancement for a narrow channel by thermal spray coating. Copper particles were coated on the heating surface by vacuum plasma spraying. Two kinds of surface were manufactured using different particle size, about 200 and 50 micrometer. The heat transfer performance was evaluated in saturated flow boiling experiments of HCFC123 for ranges of mass flux of 100 to 400 kg m(exp -2) s(exp -1), inlet quality of 0 to 0.60, and heat flux of 25 to 251 kW/sq m. The test channel with the channel width of 20 mm, and heated length of 100 mm was placed horizontally and heated from the bottom by cartridge heaters through a copper block. The channel gap was set to 2 and 4 mm. As the result, the coating surface produced higher heat transfer coefficient than the smooth surface, especially, the heat transfer performance of the surface using finer particle was higher and was about five to 10 times higher than that of the smooth surface. While the effect of gaps on the heat transfer coefficient was a little, the critical heat flux increased with increasing the channel gap.
資料番号: AA0063706054