EXPERIMENTAL INVESTIGATION ON THERMAL PERFORMANCE OF ULTRA-THIN FLATTENED HEAT PIPE WITH MIDDLE HEATING FOR ELECTRONICS COOLING

Abstract

For cooling the electronics in limited space, this study proposes ultra-thin flattened heat pipes (UTFHP) with two working modes, i.e., a short UTFHP with single-end heating and single-end cooling (SHSC) and a long UTFHP with middle heating and dual-end cooling (MHDC). The length of the short UTFHP is half that of the long UTFHP. The effects of input heat load and cooling temperature on the thermal performance of the short UTFHP with SHSC and long UTFHP with MHDC have been studied for the performance comparison. The input heat load ranges from 0-38 W and the cooling temperature ranges from 15°C to 65°C. The results show that the two layers wrapped 200 in<sup>-1</sup> screen mesh can provide adequate capillary pressure; hence, both of the two UTFHP working modes show good temperature uniformity. The short UTFHP with SHSC shows better thermal performance compared to the performance of long UTFHP with MHDC. In addition, the thermal resistances of both UTFHPs decrease with the increase of the input heat load and the decrease of the cooling temperature under the ranges of operating conditions.