Study on internal flow characteristics of multiple evaporators loop heat pipe (Visualization in evaporators and condenser under microgravity)

Loop Heat Pipes (LHPs) have been used in thermal control of spacecraft as next generation heat transport devices. Recently, multiple-evaporators LHP (MLHP) is under studied since the MLHP supplies autonomous thermal control function. However, some physical phenomena in the MLHP have not been clarified yet. The purpose of this study is to clarify thermal behavior of the MLHP under the microgravity. The MLHP used in this research has two evaporators and one condenser. Distilled water is used as the working fluid. 40W/40W, 80W/80W, 120W/0W, 0W/120W heat load were applied during the test. This experiment was conducted under microgravity for about 20 seconds, which was realized by parabolic flight. The vapor-liquid distribution in the wick core and the compensation chamber (CC) under the microgravity is presented. The effect of the microgravity for the working the MLHP is also discussed. The heat distributions in the MLHP when one and both evaporators were heated is also clarified