Heat Transfer Characteristics of Oscillating Heat Pipe with Ethanol as Working Fluid

In this paper, experimental investigations on the heat transfer characteristics of OHP with ethanol as working fluid were conducted. The experimental results show that there exists a necessary temperature difference between evaporator and condenser section to keep the heat pipe working. The minimum temperature differences for the optimal operating conditions varied from 1.5 to 2.0 degrees C. The maximum effective conductivity achieved could reach up to 111 kW/m.degrees C. The heat pipe was obviously affected by the filling ratio in some cases but the influence law is irregular and related to inclination angles and heating temperatures. Not all OHPs operated well in the limiting case of a zero inclination angle. In most cases, the optimal value of the inclination angle went up when the heating temperature increased. An appropriate high heating temperature is helpful for the OHP to achieved excellent performances. The startup temperature varied from 40 degrees C to 50 degrees C without considering the horizontal heating mode.