疏水表面蒸发液滴下气液界面形态演化研究

Evaporation Induced Droplet Menisci Morphologic Evolution on the Hydrophobic Microgrooved Surface

研究蒸发液滴下气液界面的形态演化可为换热表面性能改进提供指导。本文以单个微槽及槽内液滴下气液界面为研究对象,运用能量分析法确定了疏水微槽表面放置液滴下气液界面的初始形态,提出了蒸发液滴上下气液界面同步演变理论,并利用该理论对液滴下气液界面失稳的原因、条件及下气液界面曲率的变化规律进行了探讨。结果表明,放置在疏水微槽表面上的液滴,其初始下气液界面与槽壁形成的微观接触角会介于0和本征接触角之间,在形态上呈现为曲率圆。当蒸发液滴下气液界面与槽壁形成的微观接触角大于一定数值后,会引发液滴下气液界面失稳,失稳后的液滴下气液界面形态受槽壁与水平面夹角的影响较大。

Studying evaporating droplet meniscus morphology can provide guidance for improving heat exchange surfaces performance. In this article, The energy analysis method was used to estimate the initial morphology of the droplet meniscus on the hydrophobic microgrooved surface. By analyzing droplet evaporating experimental results, the macro gas-liquid interface and the micro menisci are believed changing synchronously in this article. The reason and condition of the droplet meniscus unstability and the meniscus evolution trend were also studied. The results manifest that the initial micro contact angle formed by the meniscus and the groove wall is between 0 and the intrinsic contact angle and its morphology is curvature circle. The depinning of the meniscus will be triggered when the micro contact angle is bigger than a certain value. The meniscus evolution process is mostly influenced bv the angle formed bv the groove wall and the horizontal plane.