Computational study on the thermal properties of a closed loop pulsating heat pipe

Abstract

Pulsating Heat Pipes (PHPs) are passive heat transfer devices, where heat transfer is higher than that in common heat transfer devices such as metal fins and heat pipes. The main reason for this is the two-phase phenomenon occurring inside the PHPs with oscillatory motion of the bubbles. The flow in the pipe is a multiphase flow, where vapor plugs and liquid slugs are created in PHPs due to capillary action. In this study, a CFD analysis was conducted on a two-turn PHP using the Analysis of Systems (ANSYS) Fluent software. The adiabatic section and overall height of the pipe were kept constant, whereas the height of the evaporation region varied at 32, 37, 42, 47, and 52 mm from the bottom. This study aims to investigate the performance of PHP and how heat transfer is affected. It also observed variations in the volume fraction and thermal resistance, considering other factors. The study was conducted under previously researched conditions with an inner diameter of 2.0 mm and an outer diameter of 3.0 mm. The PHP was made of copper, and the working fluid was methanol, which filled 50% of the volume. Heat inputs of 80 W, 85 W, 90 W, and 95 watts were supplied to the PHP. The simulation was performed, and the output results are presented in graphical and contour plots.