Experimental thermal performance of different capillary structures for heat pipes

Abstract

The temperature control in electronic packaging is the key in numerous applications, to avoid overheating and hardware failure. Due to high capability of heat transfer, good temperature uniformity, and no power consumption, heat pipes can be widely used for heat dissipation of electronic components. This paper reports an experimental thermal analysis of different capillary structures for heat pipes. The wicks considered are metal screens, axial microgrooves, and sintered metal powder. The heat pipes are made of copper, a 200 mm length tube and a 9.45 mm external diameter. Working fluid used was distilled water. The devices are investigated in three positions: 0, 90, and 270° to the horizontal under powers of 5 up to 45 W. The results show that in horizontal (0°) and with the evaporator under the condenser (270°), the heat pipes showed similar results. Nevertheless, in the reverse condition (the position against the gravity with the evaporator above the condenser, 90°), the heat pipe with sintered wick presented the best thermal performance, as it has the lowest thermal resistance and supported a higher power. Besides that, the sintered powder capillary structure demonstrates the most homogeneous thermal behavior for every position, making the most suitable for applications susceptible to diverse inclinations.