Comparative heat transfer characteristics of a flat two-phase closed thermosyphon (FTPCT) and a conventional two-phase closed thermosyphon (CTPCT)

This study investigated the effects of cross-sectional geometries, filling ratio and aspect ratio on thermal performance of thermosyphon at different rates of heat input. Two cross-sectional geometries of thermosyphon (circular and flat) were used. Each cross-sectional geometry was charged with distilled water with different filling ratios, aspect ratios and heat input. The results indicated that the FTPCT had a higher average wall temperature in the evaporator section than that of the CTPCT. The maximum heat input had a significant influence on the heat fluxes for each filling ratio and evaporator length. Heat fluxes were increased with an increase of aspect ratio and heat input and decreased slightly at the maximum aspect ratios.