Experimental investigation on startup performances of a separator assisted two-phase loop thermosyphon

In this study, visual experiment facilities of the two-phase loop thermosyphon with reservoir (RTLTP) and the separator assisted two-phase loop thermosyphon (STLTP) were established, and the startup performances of two systems, including the overshoot temperature, startup time and stabilized time were measured and compared. The results showed that compared with RTLTP, the stabilized time of STLTP was shorter about 420 s with less oscillation during startup process due to its lower pressure drop of fluid in the two-phase tube. The oscillation mechanism of fluid mass flow rate in RTLTP were analyzed. The reason for oscillation of fluid mass flow rate was because vapor generated in evaporator reversely flows back into the liquid tube and separator and the insufficient driven force. Furthermore, the effects of the charge, cooling water inlet temperature and heat load on the startup performances of two systems were studied as well.