Experimental Study on Oscillating Heat Pipe with Three-dimensional Structure

The general structure of an oscillating heat pipe is a closed loop consisting of a meandering capillary tube over a two-dimensional (2D) plane. In this study, the performance of an oscillating heat pipe with a three-dimensional (3D) structure is investigated experimentally. Four glass tubes are connected perpendicular to the heating and cooling aluminum plates. The inner diameter of the glass tube is 1.2 mm. Ethanol, water, and Novec (HFE-7100) are used as working fluids. The flow pattern and thermal resistance are investigated as the heating power and filling ratio of working fluids are varied. The results show that the thermal resistance of the oscillating heat pipe decreases with increasing heating power. Oscillations in the capillary tube start earlier for a smaller filling ratio; however, dry-outs also occur earlier. Of the three working fluids, Novec shows the highest thermal performance.