Abstract:

The liquid film flow on the corrugated plate is common in the industrial field. But the characteristics of liquid film flow on the corrugated plate are pretty complicated. Thus, based on the VOF method, the vortex characteristics of the three-dimensional liquid film flow on the inclined corrugated plate are simulated by using FLUENT software. The evolution of vortex structure with time is studied, and the influence of inlet Reynolds number, waviness, wall inclined angle, fluid viscosity and surface tension on the vortex structure in corrugated plate structure is investigated. The results show that the size and shape of vortex are constantly changing with the time evolution and ultimately achieve stability. The change of vortex structure has significant influence on the fluctuation of free surface. With smaller Re and waviness, the vortex is not easy to form in the corrugated structure. With the increase of Re and waviness, the vortex is produced and its size is increasing, and the morphology of the vortex is changed. Meanwhile, the position of the free surface is increased and there is a phase lag compared with the wave wall. When the wall inclination angle is altered, the vortex characteristics in the corrugated structure change greatly. But the phase of the free surface and the thickness of the liquid film vary slightly. Surface tension has a significant effect on the vortex structure, and it cannot be ignored in the numerical simulation of liquid film flow. Nevertheless, when the fluid viscosity is changed, there is no significant change in the size and shape of the vortex in the corrugated structure. But if the viscosity is small and the surface tension is neglected, the thickness of the liquid film becomes thin. These conclusions are very important to predict and understand the characteristics of liquid film flow in industrial field.

Key words: gas-liquid flow, corrugated plate, vortex structure, numerical simulation, influence factors, CFD

摘要：

针对液膜在非平整壁面上流动过程中生成涡的现象，基于VOF方法，采用FLUENT软件模拟了三维波纹壁面上的液膜流动。研究了波纹结构内涡结构的演化过程，分析入口Reynolds数、波纹结构、壁面倾角、流体黏度和表面张力对波纹结构内涡结构的影响。结果表明：随着时间的演化，涡的大小和形状不断变化，最终达到稳定。且涡结构变化对自由液面的波动影响显著。较低Re和波形度时，波纹结构内不易形成涡，随着Re和波形度增大，产生涡且涡呈增大趋势，涡的形态也随之改变，自由液面位置升高，其相位滞后于波纹壁面。当壁面倾角改变时，波纹结构内的涡特性变化较大，液膜厚度略有增加，而自由液面相位不明显。表面张力对涡结构有显著影响，液膜流动过程中不容忽视。流体黏性改变时，波纹结构内涡的大小和形状无明显的变化。黏度变小和忽略表面张力时，液膜厚度均变薄。以上结果为工业设备生产、运行和设计提供了一定参考依据。

关键词: 气液两相流, 波纹壁面, 涡结构, 数值模拟, 影响因素, 计算流体力学