LAUSR

Abstract A vapor-liquid-solid three-phase closed thermosyphon (THPCT) with variable heating position at evaporation section is built by combining the fluidized bed heat transfer technology with the two-phase closed thermosyphon (TPCT). The effect of particle diameter and heating position on the thermal performance is investigated by varying the heating power (100–300 W) and solid holdup (5–15%). Results show that the addition of the glass beads with different diameters can enhance the heat transfer under certain conditions. The maximum reduction rates of the overall thermal resistance are 25.4% and 27.7% for Le = 200 mm and Le = 200 mm − up40, respectively. The upward movement of the heating position is beneficial to reducing the overall thermal resistances of the TPCT and the THPCT with small particles, but is not conducive to the heat transfer of the THPCT with large particles. A medium particle diameter and a low solid holdup are suggested for the THPCT with different heating positions.