Hydraulics Experiment Of Combined Directed Valve Tray And CFD Simulation

The gas-liquid two phase flow of distillation tray is the important factor of plate efficiency.In this work,hydraulic experiments were carried out on combined directed valve tray in a lm diameter and 6m high cold model column.The influence of operating conditions and column internals on plate pressure drop,weeping and entrainment were analyzed.The geometric models were established according to the structural parameters of experimental trays.The simulation of gas-liquid two phase flow of tray was carried by software Fluent 6.3.26 with float valves fully open based on Euler-Euler framework and RNG k-? turbulence model to investigate gas-liquid two phase flow characteristics on tray.By monitoring the change of the clear liquid height to judge whether the iterative computation was convergence.The simulation results of clear liquid height and entrainment agreed well with experimental data,which proved the validity of simulation.The liquid velocity vector diagrams of different location of x-y plane,x-z plane and y-z plane at different region were intercepted to analyze liquid flow field.The effect of floating valve,weir and tower wall on liquid velocity were investigated,distinct whirlpools and backflow were found at the area close to arcuate region,weir,tower wall and around the floating valves.The liquid backflow on tray were counted to analyze the effect of different operating conditions on liquid backflow ratio,and the regional distribution,time variance of liquid backflow were analyzed.A comparison of the liquid backflow of two trays showed that the liquid backflow could be efficiently decreased by properly arranging trapezoidal float valves with stronger orientation instead of rectangular float valves on tray,while the average of liquid backflow ratio decreased by 12.8%.The regional distribution characteristics and time variance of entrainment were analyzed and the simulation results showed that the entrainment ratio of rectangular region lager than arcuate region.The average entrainment ratio of experimental and simulation results decreased by 13.4%and 10.6%respectively by arrangement of float-valve.In this work,hydrodynamics characteristics of combined directed valve tray were investigated by experiment and CFD simulation.The results showed that CFD simulation was expected to provide a guidance for arrangement of two types of float valve and optimization design of the tray.