| Structured packings have been widely used in separation industry since they offer excellent mass transfer efficiency, low pressure drop and high capacity. It has good advantages in many areas, such as energy-saving, improving product quality, increasing capacity and gas absorption. Especially, structured packings may have a good performance in CO2 capture field.Flim is the main way of liquid flow in the packed tower,which has a significant effect on mass transfer of gas-liquid;the structured packing surface has diferent microstructures prefer to smooth,such as grooves,small ripples,holes and so on.So,study the characteristics of film flow over complex surfaces is important for improving the performance of structured packing.In this paper, The statistical characteristics of falling films flow over surfaces with two different textures of vertical grooves and diamond-shaped grooves on aluminum plate was studied at intermediate Reynolds numbers (30<Re<200) in water system. The results showed that:the average amplitude and film thickness of film over microstructure surface are larger than those over smooth stainless steel plate by 30% and 17% on average.This paper also establishes a two-dimensional falling film flow CFD model, using VOF method to capture the interface,firstly simulating falling film flow on smooth surface, the simulation results agree well with the experimental data, it is proved that the model is reliable, on the basis of this study,investigated the effect of periodic structure of grooves on falling liquid film, the results show that:when A/T=0.06,the amplitude has a point with maximum value;also,the wave length and velocity have points with maximum value when A/T=0.03.Finally,the mass transfer perfermance of liquid film on microstructure surface was studied,to explore the relationship between the liquid film dynamics and the mass transfer kinetics of liquid falling film. |
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