| Title |
Thermal Performance of the Bubble Jet Loop Heat Pipe Using Eccentric Heater in Evaporating Section |
| Authors |
Jong-Soo Kim ; Sung-Bok Kim |
| DOI |
http://dx.doi.org/10.6110/KJACR.2015.27.12.652 |
| Keywords |
유효열전도도 ; 버블젯 루프 히트 파이프 ; 편심 히터 ; 동심 히터 Effective thermal conductivity ; Bubble jet loop heat pipe ; Eccentric heater ; Concentric heater |
| Abstract |
The Bubble Jet Loop Heat Pipe (BJLHP) is designed to operate in the horizontal orientation. The motion of the bubble generated by boiling working fluid on a heater surface in the evaporating section of the BJLHP helps the working fluid transfer heat to the condensing portion. In this study, we changed the position of the heater in the evaporating section from concentric to eccentric. The concentric heater is located at the center of the tube in the evaporating part, and the eccentric heater is located at the bottom of the inner surface of the same tube. We used R-134a as the working fluid, and the charging ratio was 50%vol. We measured the temperatures of the evaporating and condensing sections by changing the input electric power from 50 W to 200 W, measuring every 50 W. The results of the experiment show that the effective thermal conductivity of BJLHP using an eccentric heater is four times higher than the BJLHP obtained using a concentric heater. Additionally, we conducted a visualization experiment on the evaporating portion of BJLHP to determine why the effective thermal conductivity was higher. The working fluid was water, and we took pictures of the flow visualization for BJLHP. Nucleate boiling with the eccentric heater was more intense and generated more bubbles. Therefore, the eccentric heater was more saturated by the liquefied working fluid. |