Study on the effect of the adiabatic section parameters on the performance of pulsating heat pipes

Abstract In this paper, a numerical model of the Pulsating Heat Pipe (PHP) is established, based on the two-phase flow theory and the Volume of Fluid (VOF) method in Computational Fluid Dynamics (CFD). Under the condition that the structure, liquid Filling Rate (FR) and heating power of the PHP remain unchanged, the effect of the length and the convective heat transfer coefficient of the adiabatic section on the start-up performance, heat transfer performance and anti-dry-out ability of the PHP are studied by changing the adiabatic section parameters. The results show that, with the increase of the adiabatic section length, the start-up time of the PHP becomes shorter, but the thermal resistance increases and the anti-dry-out ability is weakened. When the adiabatic sections absorb heat from the outside, with the increase of the convective heat transfer coefficient, the change of the start-up time is relatively small, but the thermal resistance increases, and the anti-dry-out ability is weakened. When the adiabatic sections dissipate heat to the outside, with the increase of the convective heat transfer coefficient, the change of the start-up time is relatively small, but the thermal resistance decreases, and the anti-dry-out ability is enhanced. Comparatively speaking, when considering the heat exchange between the adiabatic sections and the environment, lower ambient temperature is more conducive to improving the anti-dry-out ability of the PHP.