Effect of the number of grooves on a wick's surface on the heat transfer performance of loop heat pipe

This study investigated the effects of increasing the number of grooves on a wick's surface, thereby increasing the evaporation surface area, on the performance of loop heat pipe (LHP). In this paper, wicks were manufactured, and the effect of increasing evaporation area (from 0% (8 grooves) to 100% (16 grooves)) on LHP heat transfer performance was examined. Results indicated that heat transfer performance increases with the number of grooves and the wick evaporation area; when the evaporation area was increased by 75% (14 grooves), the optimal heat load of 500 W was achieved, with lowest thermal resistance of 0.14 °C/W. Compared with results from literature (using wicks with 0% increase in evaporation area), the heat transfer performance was increased by about 60%. The wick parameters in this study were as follows: permeability 1.3–3.25 m2 × 10−13, largest effective pore radius 1.9–2.5 μm, and porosity 63–67%. Taking into consideration the manufacturing process and the resulting structural strength and durability of the wick, 50% increase (12 grooves) in evaporation area yielded the best overall results. Therefore, this paper suggests 12 grooves for the wick; a relationship between LHP performance enhancement and evaporation area was suggested based on empirical results, which can be used to guide future wick designs. •We increased evaporation area by increasing groove number on wick's surface.•There exists an optimal groove number for LHP wick; for our system, it is 14.•Highest heat load increased by 60%, and lowest thermal resistance decreased by 50%.•Logarithmic relation was established between maximum heat load and % area increase.