Effect of the State-of-the-Art Condenser Configuration on the Performance of Axially Rotating Wickless Heat Pipes

This experimental study aimed to investigate the effect of a newly shaped condenser on the thermal performance and operational parameters of a horizontally rotating wickless heat pipe. The new condenser shape has been developed based on assessing the effect of conical external ends and inner tapered wall condensers. The newly developed condenser configuration implies an external conical end of 60 deg and an inner tapered walls condenser of 3 deg. The heat pipe was subjected to a consistent rotational speed of 1500 rpm while being exposed to different heat loads, ranging from 25 to 200 W. Various filling ratios of water, from 5% to 55% of the total inner volume of the heat pipe, have been tested at rotation speeds of 750, 1000, and 1500 rpm. The results indicated that the heat pipe with the advanced condenser has a superior performance over the ones with the plain condenser by 46.75%, the conical end condenser by about 31.15%, and the tapered condenser by about 7.54%, on average over the tested heat loads from 25 to 200 W. The filling ratio of 25% achieved better performance than the other tested filling ratios as the effective thermal resistance of the heat pipe decreased by 3.1–10.1%, 2.8–19.5%, and 8.9–24.8% for rotational speeds 750, 1000, and 1500 rpm, respectively.