• 제목/요약/키워드: Pendant Droplet

검색결과 3건 처리시간 0.016초

가열된 평판위에 매달려 있는 액적의 음향공진에 의한 열 및 물질 전달 촉진에 관한 연구 (Heat and Mass Transfer Enhancement of a pendant droplet on heated horizontal surface by acoustic resonance)

  • 문종훈;강병하
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2005년도 동계학술발표대회 논문집
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    • pp.335-340
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    • 2005
  • Nonlinear and forced oscillations of supported viscous droplet were focused in the present study. The droplet has a free contact line with solid plate and inviscid fluid. Natural frequencies of a pendant droplet have been investigated experimentally by imposing the acoustic wave while the frequency is being increased at a fixed amplitude. The evaporation was observed at atmosphere pressure. The droplet was recorded throughout the entire evaporation process and transient variations of the volume was measured. The evaporation process of oscillating droplet with thermofoil has been also observed to investigate analyzing the resonance effect on the thermal characteristics of droplet. It is found that a pendant droplet shows the resonant behaviors at each mode similar to the theoretical analysis. During imposing the acoustic wave, the pendant droplet makes a rotating motion in its longitudinal axis which is a new shape oscillation mode. The evaporation rate of a pendant droplet at resonant frequency is significantly enhanced.

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음향 가진을 이용한 매달려 있는 액적의 형상 진동 모드에 관한 실험적 연구 (An Experimental Study on Shape Oscillation Mode of a Pendant Droplet by an Acoustic Wave)

  • 강병하;문종훈;김호영
    • 대한기계학회논문집B
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    • 제30권6호
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    • pp.523-530
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    • 2006
  • One of the fascinating prospects is the possibility of new hydrodynamics technology on micro-scale system since oscillations of micro-droplets are of practical and scientific importance. It has been widely conceived that the lowest oscillation mode of a pendant droplet is the longitudinal vibration, i.e. periodic elongation and contraction along the longitudinal direction. Nonlinear and forced oscillations of supported viscous droplet were focused in the present study. The droplet has a free contact line with solid plate and inviscid fluid. Natural frequencies of a pendant droplet have been investigated experimentally by imposing the acoustic wave while the frequency is being increased at a fixed amplitude. It is found that a pendant droplet shows the resonant behaviors at each mode similar to the theoretical analysis. The rotation of the droplet about the longitudinal axis is the oscillation mode of the lowest resonance frequency. This rotational mode can be invoked by periodic acoustic forcing and is analogous to the pendulum rotation. It is also found that the natural frequency of a pendant droplet is independent of the drop density and surface tension but inversely proportional to the square root of the droplet size.