A Compact Loop Heat Pipe With Flat Square Evaporator for High Power Chip Cooling

Abstract

In this paper, systematic experimental and theoretical investigations were carried out on a copper-water compact loop heat pipe with a flat square evaporator having a bottom area of 30 mm × 30 mm. Wick structure inside the evaporator was made of fine copper powder with carefully designed vapor removal channels sintered directly on the substrate. In addition, the design and fabrication of a 120 mm air-cooled condenser was given adequate consideration. From the experimental tests, it is found that such a small loop heat pipe can manage a heat load of more than 600 W, and no dry-out occurs. In the favorable vertical configuration, with an air velocity of 2.8 m/s, this compact loop heat pipe has a thermal resistance as low as 0.042°C/W, with a corresponding evaporator thermal resistance as low as 0.018°C/W . As well, the theoretical analysis agrees in principle with the experimental data.