Abstract
A two-phase loop thermosyphon transports thermal energy from a heat source to a heat sink by natural convective circulation under a body force field without any external power supply such as a pump. It is, therefore, thought that this could be applied to an energy-saving heat transportation system, and so forth. In practical use, an evaporator has several heated tubes and also the heat supplied to each of the heated tubes is not always equal. Therefore, the present study was performed both experimentally and theoretically on the flow and heat transfer characteristics in the two-phase loop thermosyphon installed with the evaporator with three heated tubes as a comparatively simple multi-tube evaporator in the lower part of the loop. The circulation mass flow rate, pressure and temperature distributions along the loop, as well as the heat transfer coefficients in the heated tubes were measured using water, ethanol and benzene, on which the effects of subcooling at the evaporator inlet and a heat input ratio of the three heated tubes were examined, and the experimental data were compared with the theoretically calculated results.
