04. Boiling and Multi-Phase Flow

Thermosyphon fin is a novel fin structure that integrates two-phase closed thermosyphon inside thin fin structure for enhanced temperature uniformity. With the advantages of both high thermal performance and light weight, the thermosyphon fin is potential for the next-generation cooling fin architecture. However, insufficient studies on evaporation-condensation process inside thermosyphon fin impedes their practical application. This study provides systematic research on heat transfer characteristics of thermosyphon fins, using a combination of experimental measurements and numerical simulations. The investigation covers a range of operational conditions, including heating powers from 20 to 50 W, both uniform and non-uniform power distributions, filling ratios of 40% to 70%, and inclination angles from 30° to 75°, with comparative analysis against solid fins of the same dimensions. Connections between thermal performance and internal phase change mechanisms are provided by visualization of vapor-liquid distribution, bubble behavior, and mass transfer rates, with simulation data. With the findings from these varied conditions, four region characteristics are proposed, which delineate the factors influencing the heat and mass transfer within the thermosyphon fin. The finding provides a clear direction for enhancing heat and mass transfer inside thermosyphon fins.