Heat transfer characteristic of an ultra-thin flat plate heat pipe with surface-functional wicks for cooling electronics

A novel ultra-thin aluminum flat plate heat pipe (UAFHP) with dimensions of 120 x 120 x 2 mm was developed for the thermal management of concentrated electronic equipment. An evaporator container with support posts and a filling hole was manufactured integrally by the stamping method. The surface-functional wicks, which were fabricated by a micro-milling method, consisted of array orthogonal microgrooves and the groove surfaces were covered with grain-like microstructures. The effects of heat load, cooling-water temperature, and tilt angle on the heat transfer characteristic of UAFHP, including its thermal response performance, temperature distribution and thermal resistance, were investigated experimentally. The results showed that UAFHP exhibits a favorable thermal response performance and heat transfer performance. It can effectively dissipate 160 W and has a minimum thermal resistance of 0.156 degrees C/W in the horizontal orientation. Moreover, when the cooling-water temperature decreases, the wall temperature of UAFHP decreases while the thermal resistance of UAFHP increases. In addition, small tilt angles (theta <= 30 degrees) have a negligible effect on the heat transfer characteristic of UAFHP. Compared with the flat plate heat pipes reported in the literature, UAFHP could significantly meet the requirements of thermal management of concentrated ultra-slim portable electronic equipment because of its advantages such as light weight, favorable heat transfer characteristic, ease of fabrication and low cost.