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Pool Boiling Heat Transfer in a Vertical Annulus with a Longer Outside Tube

외부 튜브 길이가 긴 수직 환상공간 내부의 풀비등 열전달

  • Received : 2011.10.11
  • Accepted : 2012.05.29
  • Published : 2012.08.01

Abstract

To investigate pool boiling heat transfer in a vertical annulus with closed bottoms, the length of an outer tube was varied between 0.3 and 0.6 m. For the test, a heated tube of 0.2-m length and 19.1-mm diameter and water at atmospheric pressure were used. To elucidate the effects of the outer tube length on heat transfer, the results for the annulus were compared with data for a single unrestricted tube. The increase in the outer tube length resulted in an increase or decrease in heat transfer depending on the gap size. This tendency is mainly attributed to the difference in the intensity of liquid agitation.

수직으로 설치된 하부폐쇄 환상공간 내부의 풀비등 열전달 메카니즘을 알기 위하여 환상공간의 튜브 길이를 0.3m와 0.6m 사이에서 변경하였다. 실험을 위해 0.2m의 가열 길이를 갖는 직경 19.1mm인 스테인리스강 튜브와 대기압 상태 하에 있는 물을 사용하였다. 외부 튜브 길이가 열전달에 미치는 영향을 분명하게 살펴보기 위해 환상공간에 대한 결과를 환상공간이 없는 단일튜브에 대한 결과와 서로 비교하였다. 동일 열유속에서 외부튜브 길이의 증가는 틈새간격이 3.5mm인 경우에는 열전달계수의 증가하지만 틈새간격이 15.5mm인 경우에는 열전달계수가 감소하였다. 이러한 경향의 주된 원인은 액체교란의 차이로서 설명된다.

Keywords

References

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