Enhancement mechanism on heat and mass transfer of tall fin with cycloid thermosyphon loop

The aluminum fin integrated with thermosyphon loop is a good alternative for improving the thermal dissipation from the heat source, which has light-weight and high-efficiency features due to the charge of phase change working fluid. However, the criteria for flow channel arrangement and corresponding heat transfer mechanism in thermosyphon fins are still not clearly acknowledged. In present study, the cellular thermosyphon fin (CET fin) and the cycloid thermosyphon fin (CYT fin) are experimentally tested. Result shows that the CYT fin always illustrates much better temperature distribution and performs about 10.1% improvement on the average thermal resistance. Then, the pool boiling and condensation in CET and CYT fins are further explored via numerical investigation. It is found that the existence of vapor cavity in blind channels may enhance the condensation as well as promote the liquid level on the heat source side. Consequently, a total of four optimized configurations based on the tested CYT fin are proposed and numerically studied. Result shows that the optimum configuration with four vapor zones in one partition (4-in-1 case) possesses 8.7% higher liquid level compared with the original CYT fin. The increments on the evaporation rate and condensation rate can reach 12.7% and 10.7%, respectively, and lower fin root temperature is also achieved.