Performance Testing of Loop Heat Pipes with Vapor Chamber in the Evaporator

This work develops a loop heat pipes (LHP) with the advantages of long distance (2050 mm) transport capability and high heat removal capacity (up to NOW). The evaporator of LHP is constructed by vapor chamber (VC) and compensation chamber (CC), which is separated by a 3 mm-thick sinter layer The experiment incorporates five parameters, including as vapor channel layout, orientation, filling ratio (F.R.), wick material and heat capacity. The study results demonstrate that flow resistance is successfully used to design the vapor channel layout. The LHP has better thermal performance in the verticality, and the optimal F.R. is 80%. A wick material with low thermal conductivity prevents the residual heat to leak into the CC, and hence the boiling efficiency and thermal cycle is enhanced. The minimum thermal resistance of LHP with radial channel layout is 0.212 degrees C/W when the heat load is 200W. Therefore, the equilibrium between boiling and condensation established at 200W.