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초음파 진동에 의한 대류 및 비등 열전달 촉진 원리에 관한 연구

Mechanisms of Convective and Boiling Heat Transfer Enhancement via Ultrasonic Vibration

  • 김이구 (한국과학기술연구원 열유동제어연구센터) ;
  • 김호영 (한국과학기술연구원 열유동제어연구센터) ;
  • 강승민 (한국과학기술연구원 열유동제어연구센터) ;
  • 강병하 (국민대학교 기계자동차 공학부) ;
  • 이진호 (연세대학교 기계공학과)
  • 발행 : 2003.05.01

초록

This work experimentally studies the fundamental mechanisms by which the ultrasonic vibration enhances convection and pool boiling heat transfer. A thin platinum wire is used as both a heat source and a temperature sensor. A high speed video imaging system is employed to observe the behavior of cavitation and thermal bubbles. It is found that when the liquid temperature is below its boiling point, cavitation takes place due to ultrasonic vibration while cavitation disappears when the liquid reaches the boiling point. Moreover, when the gas dissolved in liquid is removed by pre-degassing, the cavitation arises only locally. Depending on the liquid temperature, heat transfer rates in convection, subcooled boiling and saturated boiling regimes are examined. In convection heat transfer regime, fully agitated cavitation is the most efficient heat transfer enhancement mechanism. Subcooled boiling is most enhanced when tile local cavitation is induced after degassing. In saturated boiling regime, acoustic pressure is shown to be a dominant heat transfer enhancement mechanism.

키워드

참고문헌

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