Abstract
This paper describes the gravity effect on heat transport characteristics in a miniature loop heat pipe with multiple evaporators and multiple condensers. Tests were conducted in three different orientations: horizontal, 45 deg tilt, and vertical. The gravity affected the loop's operating temperature, the maximum heat transport capability, and the thermal conductance. In the case that temperatures of compensation chambers (CCs) were actively controlled, the required control heater power was also dependent on the test configuration. In the vertical configuration, the secondary wick was not able to pump the liquid from the CC to the evaporator against the gravity. Thus, the loop could operate stably or display some peculiar behaviors depending on the initial liquid distribution between the evaporator and the CC. Because such an initial condition was not known prior to the test, the subsequent loop performance was unpredictable.
