EXPERIMENTAL INVESTIGATION OF HEAT AND FLUID FLOW IN A TWO-PHASE HEAT TRANSPORT DEVICE WITH PARALLEL TUBES

摘要

A new type of two-phase heat transport device called the parallel-tube heat transport device (PT-HTD) has been experimentally investigated for the heat transfer characteristics in its evaporator and condenser and for the attainable heat transport rate by using water as the working fluid. It consists of two rectangular chambers (50 x 50 x 10 mm) connected by five tubes in the same inner diameter of 3.6 mm. PT-HTD was tested in the vertical orientation with the lower chamber as the evaporator and the upper chamber as the condenser. A series of experiments was performed in the range of 20-1100 W heat transport rates and 0.3-2.0 filling ratio of the evaporator volume. It was found that the total thermal resistance of PT-HTD decreases with increasing heat input and is strongly dependent on heat transfer in the evaporator. The heat transport rate of PT-HTD is always higher than the maximum heat transfer rate by the flooding condition of an equivalent thermosyphon. Re-circulation of the working fluid inside the PT-HTD was observed in the wall temperature distribution of tubes measured by an infrared camera.