Abstract The formation of gas bubbles by submerged orifices is a fundamental process encountered in various industrial applications. The dynamics of the contact line and the contact angle may have a significant influence on the detached bubble size depending on the wettability of the system. In this study, the influence of wetting conditions on the dynamics of bubble formation from a submerged orifice is investigated experimentally and numerically. The experiments are performed using a hydrophobic orifice plate and a series of ethanol–water solutions to vary the wettability where the key characteristics of the bubbles are measured using a high-speed, high-resolution camera. An extensive analysis on the influence of wetting conditions on the bubble size, bubble growth mechanism and the behavior of the contact line is given. Bubble growth stages, termed (1) hemispherical spreading, (2) cylindrical spreading, (3) critical growth and (4) necking, are identified based on key geometrical parameters of the bubble and relevant forces acting on the bubble during the growth. The experimental results show that the apparent contact angle varies in a complicated manner as the bubble grows due to the surface roughness and heterogeneity. The experimental findings are finally used to validate the local front reconstruction method with a contact angle model to account for the contact angle hysteresis observed in the experiments. Graphic abstract

中文翻译：

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润湿条件对浸没孔口气泡形成的影响

摘要 浸没孔板气泡的形成是各种工业应用中遇到的基本过程。根据系统的润湿性，接触线的动力学和接触角可能对分离的气泡尺寸产生显着影响。在这项研究中，润湿条件对浸没孔口气泡形成动力学的影响进行了实验和数值研究。实验使用疏水孔板和一系列乙醇-水溶液来改变润湿性，其中使用高速、高分辨率相机测量气泡的关键特性。对润湿条件对气泡尺寸、气泡生长机制和接触线行为的影响进行了广泛的分析。泡泡成长阶段，根据气泡的关键几何参数和生长过程中作用在气泡上的相关力，确定了被称为 (1) 半球形扩展、(2) 圆柱形扩展、(3) 临界增长和 (4) 颈缩。实验结果表明，由于表面粗糙度和不均匀性，表观接触角随着气泡的增长而以复杂的方式变化。实验结果最终用于验证具有接触角模型的局部前沿重建方法，以解释在实验中观察到的接触角滞后。图形摘要 实验结果表明，由于表面粗糙度和不均匀性，表观接触角随着气泡的增长而以复杂的方式变化。实验结果最终用于验证具有接触角模型的局部前沿重建方法，以解释在实验中观察到的接触角滞后。图形摘要 实验结果表明，由于表面粗糙度和不均匀性，表观接触角随着气泡的增长而以复杂的方式变化。实验结果最终用于验证具有接触角模型的局部前沿重建方法，以解释在实验中观察到的接触角滞后。图形摘要