Experimental investigation of the evaporator section tilted angle and filling ratio on the thermal charateristics of a two-phase closed thermosyphon

Abstract

An experimental study was conducted in order to investigate the effect of filling ratio (F.R) and tilted angle (Φ) of the evaporator section on the thermal efficiency in a two-phase closed thermosyphon (TS) with the vertical condenser and adiabatic sections. Therefore, a copper tube with inner diameter of 14.5 mm was used with distilled water in the filling ratio 15 % to 60 % and input heat 100 to 250 watt. The evaporator section of TS (from the junction of an adiabatic section) is bent and compare with vertical positions. Through this study, it was found that optimum of F.R was 45 % and the best-tilted angle for the evaporator was 60ºrelative to the horizontal axis. Also, the boiling heat transfer coefficient rises about 15.2 % when the evaporator section will be bent 60ºin optimized filling ratio. Furthermore, boiling heat transfer coefficient obtained from the experimental results of this research were compared with Rohsenow's correlation, who showed good agreement.