Experimental study on transient performance of the loop heat pipe with a pouring porous wick

Abstract

The cost of manufacturing loop heat pipes (LHP) makes it difficult for engineering applications to be popularized on the ground. As for LHP components, the wick fabrication is the most difficult, important and expensive process. In this paper, we adopted a new way of the pouring porous wick. The morphology of the pouring porous wick was observed with the aid of scanning electronic micro-scope (SEM). Surface morphology analysis revealed that pore distribution was relatively uniform, and the pore size roughly distributed between 3 μm and 10 μm. At high resolution, Micro-structure of the pouring porous wick was similar to that of sintered biporous wick that distributed large pores and small pores. The selected samples’ porosity was tested by means of Archimedes drainage method, and ranged from 0.35 to 0.45. Meanwhile, the LHP with a pouring porous wick was constituted, and its transient performance was investigated at different heat sink temperatures. The experimental results demonstrated that this LHP system could start up at a heat load range from 5 W to 80 W with the evaporator surface temperature below 100 °C in the horizontal orientation. The LHP heat transfer characteristics were analyzed based on continuous operation with variable heat load.