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中文核心期刊

矩形疏水沟槽表面水滴振荡特性

CHARACTERISTIC OF DROPLET OSCILLATION ON THE SURFACE OF RECTANGULAR HYDROPHOBIC GROOVES

  • 摘要: 液滴振荡行为是液滴运动中的重要伴随现象,具有重要科研价值.由于液滴撞击疏水沟槽板时运动行为与光滑表面明显不同,可以推测疏水沟槽表面液滴振荡特性也将会呈现与众不同的行为特点.采用高速摄像技术,研究了矩形疏水沟槽表面上水滴高度和接触线振荡行为随沟槽尺寸和撞击速度的变化规律.结果发现,矩形疏水沟槽造成的各向润湿异性使得振荡过程中水滴在平行沟槽方向上的接触线长度大于垂直方向,但并不影响水滴高度方向上衰减振荡的周期,即水滴振荡周期与沟槽间距无关;同时由于疏水沟槽表面上存在能垒束缚效应,致使水滴振荡过程中接触线的铺展和回缩运动不服从典型阻尼振荡规律,而呈现振荡数次后直接趋稳的特点.如水滴以0.61 m/s撞击时,接触线经历2次振荡后即维持稳定,但此时水滴仍在持续振荡中.另外,还初步分析了水滴振荡周期与沟槽间距无关的原因.

     

    Abstract: Droplet oscillation is an important phenomenon in nature, it has important scientific research value. Since the liquid droplet behavior when impinging on the hydrophobic plate surface with grooved texture is obviously different from that on the smooth plate surface, the characteristics of the oscillation of the height and the contact line of water droplet on the rectangular hydrophobic grooves are studied via high-speed camera. Due to the anisotropic wetting of the rectangular hydrophobic grooves, the length of the contact line of water droplet in the parallel direction of the groove is longer than that in the vertical direction. However, it does not affect the period of the attenuation oscillation in the height direction, which means the droplet oscillation period has no relationship with the width of the slot. What's more, due to the binding effect of the barrier on the surface within hydrophobic grooves, the spreading and retraction of the contact line do not follow the typical damping oscillation law. It stabilizes rapidly after several oscillations. For example, when the velocity of water droplet is 0.61 m/s, the contact line is stable after 2 oscillations, but the water droplet is still oscillating. In addition, we give the reason why the water droplet oscillation period is irrelevant to the groove size.

     

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