Hydrodynamic Measurement And CFD Simulation Of A Novel Guide Composite Tray

As an important mass transfer and separation equipment,the column is widely used in chemical,oil refining,pharmaceutical,fertilizer,environmental protection and other industries.The column's performance directly affects the energy consumption and product quality of industrial production.Therefore,the study and improvement of the column have been an inexhaustible driving force for the development of the chemical industry.Aiming at the current research of column and actual industrial requirements,this paper combines guide holes,three-dimensional caps and high-efficiency fillers and takes the bottom gap of the caps as the research object,so a three-dimensional composite tray is developed and carried out.Then the fluid mechanics experiments and CFD simulations were studied.In a Plexiglas tower with an inner diameter of 500 mm and a plate spacing of 450 mm,air-water(oxygen enriched)was used as the medium and cold-mould experiments were performed on composite trays with double-bottom-gap and composite trays with folded plates in the bottom-gap.At the room temperature and normal pressure,the hydrodynamic parameters such as the dry and wet pressure drop,weeping,entrainment,the height of the clear liquid and the mass transfer efficiency under different gas velocity and flow intensity were measured.Judging from the experimental results,the double bottom gap composite tray has higher processing capacity and higher mass transfer efficiency than the single bottom gap composite tray,when the upper bottom gap height is 7mm,the processing capacity and mass transfer effect are best;After the folding plate is added to the bottom gap of the cap,the breaking effect of the ascending liquid is obviously enhanced,the entrainment and wepping are slightly improved,but the mass transfer efficiency is improved,and when the folding plate length is 15 mm and the folding plate angle is 45°,the tray performance is the best.The Euler-Euler multiphase flow model and k-? turbulence model were used to determine the momentum source terms in different regions of the tray,then reasonable boundary conditions were set and a three-dimensional two-phase CFD model was established.Fitting regression was performed on the height of the liquid in the column to obtain a suitable model of drag between gas and liquid phases.According to the CFD simulation results,it can be known that the composite tray with the folded plate has a more even distribution of gas and liquid in the cap,when the gas-liquid contact area is larger,the higher its mass transfer efficiency is.ANSYS Fluent 19.0 software was used to initialize initialization parameters to simulate the three-dimensional composite trays to obtain the simulated values of fluid mechanics parameters.The simulated fluid mechanics data and experimental data were in good agreement.The deviations of the dry plate pressure drop are within 5%,and the clear liquid layer height deviations are within 10%.This paper examines the hydrodynamic performance of three-dimensional composite trays from the perspective of experiments and simulations,and verifies the effect of structural optimization of composite trays from the macro and micro perspectives.The experimental results show that two type of the three-dimensional composite tray has good hydrodynamic properties,and further optimization design can make it more practical.