Investigation pool boiling heat transfer in U-shaped mesochannel with electrodeposited porous coating

Abstract

Increasing the computational capability of microelectronics and growing miniaturization trend lead to high heat flux hot spots that require efficient thermal management. Pool boiling has the ability to remove large heat fluxes at low wall superheat and this can be further enhanced by using surface modification methods. In this paper, the experimental investigation of nucleate pool boiling heat transfer on copper mesochannel, microstructured porous coating and combination of them is performed. The mesochannel with a width of 400μm and a depth of 500μm is cut with Wire Electric Discharge Machine (WEDM) on copper surface. Microstructured porous coating is prepared by two-stage electrodeposition of copper on polished copper surface. Then by the combination of these methods, porous copper electrodeposited on mesochannel to achieve the high performance boiling surface. The morphology of three samples are examined with Scanning Electronic Microscopy (SEM). The nucleate pool boiling experiments were conducted under atmospheric pressure using a water under saturation conditions and their pool boiling heat transfer performances were compared. It was found that the integration of microporous copper on microchannel surface can effectively enhance the boiling performance. A critical heat flux (CHF) of 170W/cm2 (2.1-fold enhancement) and heat transfer coefficient (HTC) of 23.5W/cm2k (3.9-fold enhancement) was obtained in comparison to plain surface. A visualization study on bubble formation and release from individual plates was conducted to bolster the experimental results.