垂直及倾斜上升管内气液两相弹状流壁面切应力的模拟

用VOF模型对垂直及倾斜上升管内弹状流壁面切应力进行数值模拟。计算结果表明，垂直上升流动时，液膜厚度始终小于对应位置倾斜上升弹状流的液膜厚度，壁面切应力从气弹头部至尾部逐渐增大至恒定不变，在尾流区呈杂乱无章状态。倾斜上升流动时，气泡头部顶点偏向管中心线上方，倾角越小，相同轴向位置处测得的液膜厚度越大。当FrTB较小时，倾斜管内弹状流上管壁面的切应力曲线在液膜区有明显波动，而下管壁面在对应区域的切应力分布则比较光滑。随着FrTB的增大，上下壁面切应力分布曲线越来越靠近。

CFD simulation of wall shear stress in gas-liquid vertical and inclined upward slug flow

Based on the VOF model，CFD simulations were carried out for wall shear stress in gas-liquid vertical and inclined upward slug flow.The simulation results showed that the thickness of the falling film in the vertical upward slug flow was always smaller than that in the inclined upward slug flow.In the vertical tubes，wall shear stress increased gradually from Taylor bubble nose to the falling liquid film until it became stable in the developed falling liquid film，but in the wake zone the wall shear stress appeared irregular.In the inclined tubes，the tip of the Taylor bubble nose was above the centerline of the tube and the smaller the angle，the greater the thickness of the falling liquid film.Meanwhile，for the wall shear stress of slug flow in an inclined tube，when FrTB was small，the shear stress profile of falling liquid film on the top wall fluctuated significantly，but it was smooth on the bottom wall.With increasing FrTB， the difference between the shear stress profile on the top wall and the shear stress profile on the bottom wall gradually disappeared.