Abstract: A two-dimensional boundary layer model was established to describe the lateral flow of falling films driven by horizontal gas flow in the wave-plate channel based on boundary layer theory and independence assumption. The model reduction was presented through dimensionless analysis and ideal laminar flow assumption. The theoretical model was built to predict the films lateral migration and separation under the horizontal interface shear stress based on analytical force balance. The effects of wave-plate structure, both physical properties and flow conditions of gas-liquid were considered to give a critical separation criterion of the falling films along wave-plate. The criterion was compared with experimental measurements and some published theoretical models. The present model led to significantly better agreement with the experimental results and can be used to predict the breakdown of the films more accurately. Dimensionless analysis showed that inertial centrifugal force, shear stress, viscous force and surface tension controlled the movement, deformation and breakdown of liquid films, whose instability was associated with the equilibrium of these four forces.

Key words: wave-plate, film, laminar flow, model reduction, horizontal shear stress, breakdown, critical criterion

摘要： 以边界层理论为基础，基于独立假设建立了波形板通道内降液膜在横向气流驱动下沿屈折角横向偏移的二维边界层模型。通过量纲分析和理想层流假设进行模型简化及边界层方程求解，建立了横向切应力驱动下波形板壁降膜破裂的力平衡模型并给出破膜速度的临界准则，模型包括波形板通道几何参数、气液两相物性及流动参数等多种因素的影响，与本文实验结果和已有理论模型进行对比，所建模型能够更准确地预测液膜发生破裂的临界条件。进一步的量纲分析表明惯性离心力、气流剪切力、壁面黏性力和表面张力共同决定着液膜的运动、变形直至破裂，由它们之间的平衡关系可以确定液膜的稳定与否。

关键词: 波形板, 膜, 层流, 模型简化, 横向切应力, 破裂, 临界准则