Experimental research on the thermal performance of a flat evaporator loop heat pipe with a new composite wick

Abstract

The heat leakage in evaporator is still a key challenge that impacts the heat transfer performance of the loop heat pipe (LHP). In this study, a new composite wick structure LHP, including sintered copper powder and sintered ceramic powder, was designed and fabricated to reduce the heat leakage into compensation chamber and enhance the heat transfer characteristics of LHP. The copper powder and ceramic powder were sintered as a whole by a low temperature-pressureless dry sintering technology. The heat transfer performance of water/air-cooled LHP with a new composite wick, including startup characteristics, operational characteristics and thermal resistance analysis, were investigated at the horizontal position. The experimental results indicated that the water/air-cooled LHP with a new composited wick can start up successfully when the heating power was not less than 30 W. And the maximum heating power of the new water/air-cooled LHP can reach 550 W and 500 W corresponding junction temperature of 83.42 °C and 94.22 °C, respectively. In addition, compared with the water/air-cooled LHP with a mono wick, the water/air-cooled LHP with a new composite wick has a lower startup temperature at the heating power of 20–50 W, and a lower steady-state junction temperature when the heating power was less than 500 W and 300 W, respectively.