Design Optimization of an Aluminum-Pentane Grooved Heat Pipe Embedded in a Device Wall

Two-phase passive heat spreaders are widely utilized in component-level thermal management. Among them, grooved heat pipes play a vital role especially in the applications where the waste heat needs to be transferred to the heat sinks positioned far away from the heat sources such as the thermal management of satellites. Capillary pumping scales with the extent of the variation of the edge angle, which is the angle of the three-phase contact line with the groove wall. Consequently, the contact angle of the working fluid with the heat pipe material determines the overall performance of the heat pipe. In this work, we first measure the contact angle of n-pentane on Al6063-T6 substrates with varying surface roughness values, which are all relevant to engineering applications as well as common surface finishes of various machining processes. Selection of the working fluid and container material is made based on the reported compatibility of the solid-fluid couple as well as the non-toxicity of the fluid. After the measurement of the contact angles, a recently developed heat pipe performance evaluation software Heat-Pipe Analysis Toolbox (H-PAT) is utilized to generate the performance curves corresponding to different groove geometries. Investigated groove geometries are selected based on the criteria of lightness, machin-ability, and mechanical strength. Finally, optimum geometries are determined for the application of interest.