Experimental Investigation Andnumerical Simulation Of Liquid Phase Flow Field On The Large Combined Trapezoid Spray Tray

The Combined Trapezoid Spray Tray(CTST)is a novel spray tray with unique trapezoid spatial structure.With gas-liquid co-current contact,the CTST has a lot of advantages,such as high capacity,efficiency and operation flexibility,low pressure drop,excellent antiblockage performance,and foaming resistance.With the increasing demand for energy saving and environmental protection in chemical industry,and the maximization of enterprise benefit,the large scale of equipment has become a trend.For the maximization trend of tower devices,the new requirements for the research,design,manufacture and installation of the tower tray are put forward.At present,the experimental study and numerical simulation of CTST trays are mostly focused on small and medium sized trays,while the research on the large scale CTST tray is not complete.Because the flow field on the tray is important for the mass transfer efficiency of the tray,in this paper,the experimental study and numerical simulation of the liquid flow field on the large scale CTST tray were done.In this paper,an experiment study on the large scale double overflow CTST tray was carried out by using an air-water system in a semicircular cylinder tower with a diameter of 2600 mm.The flow field and height of the liquid layer on the plate and the vibration of the plate was measured.And,the number of cycles of water in the CTST cap was calculated.Results showed: the liquid flow field on the large CTST tray was more orderly and back flow existed in the supernatant layer surface;the liquid flow velocity among the caps was higher than that in other regions and the lateral flow near the bottom clearance was obvious;under the experiment conditions,the number of cycles of water in the CTST cap in the rectangular region was about 2.03 and 0.69 in the arched region;the liquid layer on the plate is not uniformly distributed,and the height of the liquid layer from the entrance side to exit side is gradually reduced as the same as from the center to the tower wall.Based on the Multi-Fluid VOF two-phase fluid model and Realizable k-? turbulence model,the mathematical model of large scale CTST tray was established by adding the surface tension and drag force as momentum source item.Based on unstructured meshing of the geometric model,the Phase Coupled SIMPLE pressure velocity coupling method is used to calculate the model.The accuracy of the CFD model is verified by the comparison between the experimental results and the simulation results.The simulation results showed the details of the liquid flow field on the large scale CTST tray,and results showed: there were a number of small independent back flow regions in the area behind the first row of the CTST caps;in the arcuate region,there was significant expansive back flow region;the gas holdup of the liquid layer on the large scale CTST tray was very low and only in the liquid surface region,the gas holdup was high.