Experimental study on heat transfer performance of a two-phase single thermosyphon using HFE-7100

In this study, the heat transfer performance of a two-phase single thermosyphon was experimentally measured and compared with respect to the aspect ratio and filling ratio. For the control experiments, we prepared three 1 m-long thermosyphons with the ratio of evaporator and condenser length by 5:5, 4:6 and 3:7. The working fluid, HFE-7100 was selected to consider the evaporator heat source temperature. The experiments were carried out with respect to the filling ratio and cooling air velocity. As a result, the highest heat transfer rate (about 1.0 kW) was obtained at the filling ratio of 40 % with the length ratio of 5:5 and the cooling air velocity of 2.0 m/s. Among the various parameters, we suggest that the filling ratio and the length ratio play a key role in the heat transfer performance. Out of the experimental data, we suggest the Kutateladze number based correlation between the heat transfer and operating parameters in the thermosyphon using HFE-7100 within the error of +/-2 %.