Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Experimental Study on Geometry of a Microlayer During Single-Bubble Nucleate Boiling

단일기포 핵비등 시 미세액막층 구조에 대한 실험적 연구

  • 정승혁 (경희대학교 원자력공학과) ;
  • 정샛별 (경희대학교 원자력공학과) ;
  • 김형대 (경희대학교 원자력공학과)
  • Received : 2015.01.30
  • Accepted : 2015.04.08
  • Published : 2015.06.01
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Abstract

To measure the physical parameters of the simple microlayer model for the prediction of the heat flux and heat transfer rate due to the evaporation of the microlayer during nucleate boiling, the microlayer geometry was experimentally examined. The parameters, including initial thickness, moving velocity and microlayer radius, were measured by total reflection and interferometry techniques using a laser. Single-bubble nucleate boiling experiments were conducted using saturated water on a horizontal surface under atmospheric pressure. The geometric characteristics of the microlayer underneath the bubbles periodically nucleating at a nucleation site at an average heat flux of $200kW/m^2$ were analyzed. The experimental results in the present study show that the maximum initial thickness of the microlayer and the horizontal moving velocity are $5.4{\mu}m$ and 0.12 m/s, respectively.

본 연구에서는 핵비등 시 미세액막층의 증발에 의한 열유속과 열전달률 계산을 위한 simple microlayer model 의 물리적 변수들을 측정하기 위하여 미세액막층의 형상을 실험적으로 조사하였다. 레이저를 이용한 전반사 및 간섭 기법을 이용하여 simple microlayer model 을 구성하는 인자들인 미세액막층의 초기 두께 및 수평 이동속도를 측정하였다. 대기압 포화상태의 물을 이용하여 수평 벽면에서 단일기포 핵비등 실험을 수행하였고, 평균 열유속 $200kW/m^2$ 조건에서 동일한 위치에서 발생하는 기포들의 미세액막층의 구조적 특성을 분석하였다. 본 연구의 범위에서 측정한 미세액막층의 최대 초기 두께는 $5.4{\mu}m$ 이었으며, 증발에 의한 미세액막층의 수평 이동속도는 0.12 m/s 이었다.

Keywords

Acknowledgement

Supported by : 한국연구재단

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