Effect of inclination angle on the thermal performance of a three-phase closed thermosyphon containing SiC particles

Three-phase closed thermosyphon (THPCT) with variable inclination angle (0 degrees-30 degrees) is designed and built to investigate thermal performance by applying fluidized bed heat transfer technology to the two-phase closed thermosyphon (TPCT). Visual experiments were conducted to help explain the flow in THPCT. Water and silicon carbide (SiC) particles are selected as working media. The effect of solid holdup (0-20%) and input power (100-300 W) is also discussed. Results show that the addition of SiC particles can improve the thermal performance of the thermosyphon and reduce the overall thermal resistance under different inclination angles. The reduction rate of the overall thermal resistance fluctuates with the increase in inclination angle. The maximum reduction rates of the overall thermal resistance for the inclination angles of 0 degrees, 10 degrees, 20 degrees, and 30 degrees are 32.9%, 26.7%, 37.0%, and 30.5%, respectively. The maximum reduction rates of the overall thermal resistance exist at low input power, depending on the solid holdup. The overall thermal resistances of the TPCT and THPCT generally decrease with the increase in input power but fluctuate with the increase in inclination angle. In most cases, the minimum overall thermal resistance is obtained at the inclination angle of 0 degrees. The convective heat transfer coefficient of the condensation section is obviously lower than that of the evaporation section under different inclination angles. The input power and particle addition have a more obvious influence on the heat transfer of the condensation section compared with the evaporation section. The results are beneficial to the application of the THPCT in some industrial fields, such as solar collector and frozen earth. (C) 2022 Elsevier Ltd. All rights reserved.