Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Thermal Performance of the Bubble Jet Loop Heat Pipe Using Eccentric Heater in Evaporating Section

증발부에 편심 가열부를 사용한 버블젯 루프 히트파이프의 열성능

  • Kim, Jong-Soo (Department of Refrigeration and Air-Conditioning Engineering, Pukyong National University) ;
  • Kim, Sung-Bok (Department of Refrigeration and Air-Conditioning Engineering, Graduate School of Pukyong National University)
  • 김종수 (부경대학교 냉동공조공학과) ;
  • 김성복 (부경대학교 대학원 냉동공조공학과)
  • Received : 2015.09.17
  • Accepted : 2015.11.05
  • Published : 2015.12.10
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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.

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References

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Cited by

  1. Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2015 vol.28, pp.6, 2016, https://doi.org/10.6110/KJACR.2016.28.6.256
  2. Thermal Performance and Pressure Oscillation of Foldable Bubble Jet Loop Heat Pipe According to Folding Angle vol.30, pp.1, 2018, https://doi.org/10.13000/JFMSE.2018.02.30.1.199