Analysis of Miniature Loop Heat Pipe Under Varying Working Fluids and Wick Materials at Low Heat Inputs

Abstract

In modern electronic equipment, the use of heat pipes is steadily increasing as they have maximum heat transport capability per unit area. The driving mechanism in heat pipe is the capillary forces developed in fine porous wick to circulate the fluid. The heat transfer in heat pipe is by both condensation and evaporation. Loop heat pipe is one such kind, which has two-phase heat transfer. In this device, the working fluid is circulated due to surface tension forces formed in wick. It can be operated against gravity and can possess flexible transport lines. In the present work, the performance of loop heat pipe is investigated using different working fluids and wick materials. The results are obtained for low heat input ranging from 5 to 12 W. Results show that acetone fluid had better thermal performance when compared to other fluids as it has very low thermal resistance, which is almost half of the thermal resistance of water. As the heat load increased, the temperature difference also increased between the evaporator and condenser. A better thermal performance was obtained with nickel as wick material.