CFD Simulation Of Highly Viscous Material On Combined Directed Valve Tray

In the petrochemical,pharmaceutical and food industries,distillation separation processes of high viscosity materials are common.The high viscosity of the material will make the flow on the tray unsmooth,reduce the efficiency of the tray,and affect the product's yield and quality.In the past,studies on trays were mostly concentrated on low-viscosity materials,and there were few studies on rectification trays adapted to high-viscosity materials.In this paper,for high-viscous materials,a trapezoidal oriented anti-blocking valve is used in the design of the tray,and the tongue-shaped valve is combined.For the first time,the computational fluid dynamics(CFD)method was used to study the hydrodynamic characteristics of highly viscous materials on the combined directed valve tray.In combination with industrial examples,for the trapezoidal directed valve tray with the tower diameter of 1.4m,the liquid phase single-phase flow model was first established to investigate the non-steady flow process and the stabilized flow field of highly viscous non-Newtonian fluids flowing through the tray.The distribution characteristics were compared with the flow field distribution characteristics of highviscosity Newtonian fluids and low-viscous Newtonian fluids.The distribution of liquid-phase flow field at different viscosities was obtained,and the material viscosity and flow intensity were examined.The effect of the liquid level gradient.A three-dimensional gas-phase single-phase flow model was established.The three-dimensional steady-state simulation of the gas phase flowed through the plate was conducted and the distribution of the gas-phase flow field was studied.In order to solve the problems existing in the directed valve trays,the structure of the trays has been improved.The tongue-shaped valves have been set up to form the combined directed trays.The simulation results show that the combined directed tray structure can effectively improve the shortcomings of the original tray and improve the efficiency of the tray.Based on the Euler-Euler two-phase flow model,the low Reynolds number modified SST k-? model that can accurately describe the high-viscosity gas-liquid twophase flow is used,and the user-defined function is used to consider the phasemomentum source term.The flow behavior of high-viscous non-Newtonian fluids on the trays was simulated.The distribution law of liquid volume fraction and liquid phase velocity field on different sections of the tray was obtained,and the variation law of the air charge coefficient in different directions on the tray was studied.The results show that the use of the combined directed valve tray with a tongue-trapezoidal directed valve structure for highly viscous materials can effectively improve the liquid surface gradient,enhance the promotion of high-viscosity materials,and enhance the mass transfer between the gas and liquid phases.