Effect of liquid charging process on the operational characteristics of pump-assisted capillary phase change loop

In this work, two different liquid charging methods are designed to use in different pump-assisted capillary phase change loops. The aim of present work is to investigate the impact of the liquid charging processes on the operational characteristics of the loop. For the two pump-assisted capillary loops, the loop structure and the main parameters of the components keep the same. In addition, methanol is used as the working fluid in both loops. The experimental results demonstrate that the vaporization temperature of the loop 2 has a notable decrease due to the optimized liquid charging process. The corresponding thin film boiling in the evaporator of loop 2 occurs even though a lower heat load is applied. Meanwhile, with a high heat load applied to loop 2, the unique vapor superheating in the vapor chamber is observed. Comparing the heat transfer performance between the loops, the loop 2 presents a superior capability at low heat loads, while loop 1 can transfer a higher heat load for the upper bound of the heater surface temperature. For both of the loops, the evaporator thermal resistance, if not included the heat load of 10 W at a pumping power of 2 W in loop 2, varies between 0.15 K/W and 0.3 K/W.