Study On The Computational Fluid Dynamics And Mass Transfer Process Of Gas-liquid Flow With VOF Technology

In recent years,the retrenching of natural resources has led to higher demands on the utilization rate of resources,and the solution dehumidification has been paid more and more attention by scholars as a kind of energy-saving air conditioning technology.At present,the research on solution dehumidification is mainly focused on experimental research and NTU-Le method,and the specific physical process of the packing internal dehumidification can be obtained through the CFD method,and its advantages are self-evident.In this paper,by using the VOF technology simulation to study the flow regularity of multiphase flow on structured packing,including several different types of structured packing,to simulate the triangular packing,trapezoidal and rectangular packing on the formation process of liquid membrane,and the different packing for the increase of gas-liquid contact area is analyzed,found that rectangle packing for augmenting the gas-liquid contact area is not obvious,is not suitable as desiccant packing.For different wave from,the triangular packing of the liquid film flow is simulated and analyzed,found that the wave from have affect on the flow of the liquid film,when wave from is small,the desiccant solution in the packing groove starts to cause adhesion.The effects of different packing inclinations and different dehumidification solutions on the liquid film were discussed,and the simulation results showed that the uniformity of the liquid film on the packing was influenced by too large inclination or too small.The influence of the interphase shear stressmomentum source term on the liquid film was discussed by the velocity field of the film in detail,it is concluded that the source term of the momentum can only reach a certain value of air velocity will have effect on velocity field of the film..For trapezoidal packing and triangle packing,gas-liquid flow is simulated and compared,discussed the two different structure of structured packing for the influence of the velocity field,pressure field,draw conclusion from the velocity vector diagram and pressure distribution cloud in trapezoidal packing that groove parts will form a larger flow vortex,its pressure drop is much larger than the triangle packing also.This paper also simulates the different packing structure on the liquid film flow and the dynamic process of mass transfer at the same time in different time of several water vapor mass fraction distribution,and then study the dynamic process of dehumidification.By adjusting the air velocity to study it's influence to structured packing of dehumidifying.By comparing the mass fraction of water vapor at outlet of triangular packing and trapezoidal packing,we find that as air flow rate increase,the dehumidifying performance of the packing decrease.When improve the air velocity,the effect of packing structure on dehumidifying capacity will gradually decrease.Changing the value of the mass fraction of water vapor at the entrance to structured packing,the several kinds of cloud of mass fraction of water vapor quality distribution under different working conditions will be got.Take water vapor mass fraction gradient distribution on same cross section,illustrates that greater mass fraction of water vapour will increase the mass transfer rate.Keeping the air velocity constant,by adjusting the value of the solution flow rate,study it's influence to the capacity of packing dehumidification.Finding that the change of the flow in a certain range,the greater the desiccant inlet flow will reduce the dehumidifying capacity,because the solution will fill the structured packing groove part,cause gas-liquid contact area reduced,.For gas-liquid mass transfer occurred in the process of the Rayleigh-Bdnard-Marangoni effect is simulated,compared with the experimental results show that it's concentration field similarity,.By observing the distribution of pressure contours,it is concluded that the mass transfer process is in small scale..In this paper,the study of solution dehumidification not only provides some reference for the application of solution dehumidification technology in engineering practice,but also provides an idea for the related research in the academic field.