Experimental Study on the Effect of Heat Loads, Fill Ratio and Extra Volume on Performance of a Partial-Vacuumed Thermosyphon

This paper reports a study on the effect of the heat flux, cooling water flow rate, jillratio and extra volume on the overall pe rformance of a partially vacuumedthermosyphon. a rig was made fr om a i m coppe r tube with an inner and outerdiameter of 17.5 and 19 mm. the heights of the evap orator, the adiabatic section andthe condenser are 40, 20 and 40 em, respectively. the temperatures at different placeson the thermosyphon and on the inlet/outlet ofthe cooling water were measur ed. it wasobserved that change in heat flux, jill ratio and employing different extra volumes, hasa significant effe ct on its perf ormance. on the other hand, with changes in the coolingwater flow rate the performance ofthe thermosyphon was altered regarding the trappedair movement. in order to illustrate the effec t ofthe existence ofair in deactivating thethermosyphon, the pip e was cooled down by disconnecting the evap orator power input.it was seen that the thermosyphon loses its perfo rmance as the trapp ed gas occupies thewhole condenser. the whole study shows that due to the existence ofthe trapped air, theheat loads can have significant effects on the thermosyph on perfo rmance.