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孤波中的涡流被认为是波动强化传热传质机理之一。本文通过数值模拟方法计算了溴化锂溶液沿平板降膜的流动过程。利用VOF方法捕捉降液膜的自由流动表面,利用CSF模型考虑表面张力对降液膜流动的作用,重点研究了扰动频率,Re和倾斜角对孤波中的涡流的影响。模拟结果表明,随着入口扰动频率的增加,涡流经历了完全开式涡,半开式涡至消失的过程。随着Re的增加,除了在孤波前第一个毛细波波谷处出现完全开式涡,在第二个毛细波波谷处也出现涡流。随着倾斜角的降低,最小液膜厚度处的完全开式涡尺度逐渐降低,变为近壁面处的微小涡流,最后消失。
Eddy currents in solitary waves are considered as one of the mechanisms of heat transfer and mass transfer. In this paper, the flow of lithium bromide solution along the plate falling film was calculated by numerical simulation method. VOF method was used to capture the free-flowing surface of the falling liquid film. The CSF model was used to consider the effect of surface tension on the falling liquid film flow. The effects of the perturbation frequency, Re and tilt angle on the vortex flow in the solitary wave were studied emphatically. The simulation results show that the vortices undergo a complete open vortex and a semi-open vortex to disappear as the frequency of entrance disturbance increases. With the increase of Re, in addition to the complete open eddy at the first wavy valley of the solitary wave, eddy currents also appear at the second wavy valley. As the tilt angle decreases, the fully open vortex scale at the minimum liquid film thickness gradually decreases and becomes a small eddy at the near wall, eventually disappearing.