Thermal performance of a top heat mode closed-loop oscillating heat pipe with a check valve (THMCLOHP/CV)

The aim of this research is to investigate the heat transfer characteristics of a top heat mode closed-looped oscillating heat pipe with check valves (THMCLOHP/CV). Ethanol is used as a working fluid with filling ratios of 30, 50, and 80% of the total volume of the tube. The THMCLOHP/CV is made of a copper tube with an inside diameter of 2.03 mm. The angle of inclination is 90$^\circ$C from the horizontal axis with 40 turns, two check valves, and an evaporator length of 50, 100, and 150 mm. The operating temperatures are 44 and 55$^\circ$C. It is found that the thermal resistance decreases significantly as the working temperature is increased. Thus, the evaporator length affects the thermal resistance of the THMCLOHP/CV. The presence of the THMCLOHP/CV is clearly demonstrated to contribute to thermal performance improvement.