Comparative study of heat pipes performances in different orientations

The orientation of a heat pipe plays an important role in its performance. The performance of a heat pipe under specific orientations is directly related to its wick structure. Wick structures with low capillary limit work best under gravity-assisted conditions, where the evaporator is located below the condenser. There are numerous published studies that explore heat pipe performance limits, however none of them explicitly looked into the effect of orientation on heat pipe performance with different wick structures. The paper conducts a comparative study on heat pipe performance with different wick structures subjected to different orientations. The published results may serve as a reference for mechanical and electrical engineers when they try to incorporate heat pipes into their thermal solutions.