Numerical study of single-loop pulsating heat pipe with porous wicking layer

Pulsating heat pipe (PHP) has attracted much attention due to its simple structure and high thermal performance. Incorporating a wicking layer in the PHP is considered to be a promising approach to enhance the PHP thermal performance, but its heat transfer mechanism is still unclear. In this study, we built a numerical model of WPHP (viz. single loop PHP with a wicking layer) to explore the effects of the wicking layer property and the inclination angle on the heat pipe thermal performance under different filling ratios of 30%, 50%, and 70%. This model regarded the fluid circulation within the heat pipe as compressible flow and considered the variations of the saturated temperature and latent heat. We found that the working fluid performed as a mist flow in the WPHP and exhibited a sudden liquid condensation within the WPHP channel at the filling ratios of 50% and 70%, which could enhance the heat pipe thermal performance by 57% and 76%, respectively. However, the WPHP worked as a traditional heat pipe at the low filling ratio of 30%, with the performance even worse than SPHP (viz. single loop PHP with smooth wall). This study is significant for the thermal performance enhancement of pulsating heat pipes incorporating wicking layers.