대한기계학회:학술대회논문집 (Proceedings of the KSME Conference)
- 대한기계학회 2003년도 춘계학술대회
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- Pages.1491-1498
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- 2003
액적 열전달 향상에 미치는 Dissolved 가스의 영향에 관한 연구
Effect of Dissolved Gases on Liquid Droplet Heat Transfer Enhancement
- 이정호 (삼성코닝정밀유리 유리기술연구소) ;
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- Lee, Jung-Ho ;
- Kim, Jung-Ho (Department of Mechanical Engineering University of Maryland College Park) ;
- Kiger, Kenneth T. (Department of Mechanical Engineering University of Maryland College Park)
- 발행 : 2003.04.23
초록
Droplet evaporation can be used to transfer large amounts of energy since heat is transferred across a thin liquid film. Spreading the drop over a larger area can enhance this heat transfer. One method of accomplishing this is to dissolve gas into the liquid. When the drop strikes the surface, a gas bubble nucleates and can grow and merge within the liquid, resulting in an increase in the droplet diameter. In this study, time and space resolved heat transfer characteristics for a single droplet striking a heated surface were experimentally investigated. The local wall heat flux and temperature measurements were provided by a novel experimental technique in which 96 individually controlled heaters were used to map the heat transfer coefficient contour on the surface. A high-speed digital video camera was used to simultaneously record images of the drop from below. The measurements to date indicate that significantly smaller droplet evaporation times can be achieved. The splat diameter was observed to increase with time just after the initial transient dies out due to the growth of the bubble, in contrast to a monotonically decreasing splat diameter for the case of no bubbles. Bursting of the bubble corresponded to a sudden decrease in droplet heat transfer.