標題: Investigation of the evacuation pressure on the performance of pulsating heat pipe
作者: Sun, Chien-Hung
Tseng, Chih-Yung
Yang, Kai-Shing
Wu, Shih-Kuo
Wang, Chi-Chuan
機械工程學系
Department of Mechanical Engineering
關鍵字: Pulsating heat pipe;Water;HFE-7000;Evacuation pressure;Thermal resistance
公開日期: 1-Jul-2017
摘要: This study examines the influence of evacuation pressure on the startup and overall performance of pulsating heat pipes (PHP). The outer diameter of the copper tube is 3 mm and 2 mm (double tube design) having a wall thickness of 0.3 mm and 0.2 mm, respectively. The working fluids in this study include water and HFE-7000 with filling ratios around 50%, and the evacuation pressure ranging from 0.01 Torr to atmosphere pressure. For an evacuation pressure of 0.01 Torr at a supplied power of 80 W, the thermal resistance of the PHP filling with water is 0.928 K/W while it is 1.161 K/W for HFE-7000. However, the trend is reversed and the thermal resistance for HFE-7000 is lower than water when the evacuation pressure is increased over 100 Torr. The corresponding effective thermal conductivity of waterfilling PHP reaches 51,448 W/m K in comparison with 12,692 W/m K for HFE-7000. However, the effective thermal conductivity for waterfilling PHP drops appreciably with rising evacuation pressure, and the PHP is not functional at the atmosphere pressure. Conversely, although the effective thermal conductivity for HFE-7000 PHP still drops with the rise of evacuation pressure, the HFE-7000 PHP is still in operation even without any evacuation. The gigantic difference in the startup and performance of PHP is related to the solubility of noncondensable gas amid water and HFE-7000.
URI: http://dx.doi.org/10.1016/j.icheatmasstransfer.2017.04.005
http://hdl.handle.net/11536/145714
ISSN: 0735-1933
DOI: 10.1016/j.icheatmasstransfer.2017.04.005
期刊: INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
Volume: 85
起始頁: 23
結束頁: 28
Appears in Collections:Articles