Thermal Behavior of Axial Groove Heat Pipe under Gravity: Dependence of Groove Shape and Orientation

This paper presents the experimental results of two kinds of axially-grooved-heat-pipes (AGHPs): The one has Ω shape grooves and the other has rectangular shape grooves. These AGHPs have been used as heat transfer devices of spacecraft. Before the launch of a heat pipe, it should work on the ground and be confirmed its thermal performance. It is important to understand the behavior of the heat pipe under the force of gravity. We studied thermal behavior of an Ω groove AGHP and a rectangular groove AGHP on the ground in low temperature(213K). At low heat load, we observed different behavior between the Ω AGHP and the rectangular AGHP. We observed the ‘effective length’ depends on a heating point and a tilt angle of the heat pipe. In the ground test, we have to pay attention to the heat position to check whether the heat pipe works appropriate.