Study On Hydrodynamic Performances And CFD Simulation Of Rotary Valve Tray

Our group has studied mass transfer performance of Fl valve tray when it fully opened and that of F1was fixed tray. The experiment result seemed that F1valve tray efficiency is far higher than that of valve was fixed. After a long and in-depth study we found that there is still a slight rotary motion in F1valve when it is fully opened. Rotation can speed up the gas-liquid surface renewal that near the valves, also accelerate the mass transfer of gas and liquid phase. It improved the tray efficiency of mass transfer. Based on the above new discovery in experiment, in this paper I present a new class bubbling element of the float valve-rotary valve.Hydrodynamics of rotary valve trays was experimentally studied with air-water system in a600mm ID organic glass column. Gas flow field was simulated by computational fluid dynamics performance software FLUENT6.3. And the simulation results with the hydrodynamic performance of experimental contrast.Pressure drop, weeping and entrainment of rotary valve trays were measured and compared with those of F1valve trays..F-factor (kinetic energy factor) through holes of rotary valve trays was higher by3.70%than that through holes of F1valve trays at valve closed balance point, and higher by3.54%than that through holes of Fl valve trays at valve opened balance point. Pressure drop of rotary valve trays was similar to that of F1valve trays when F-factor through the holes was between closed balance point and opened balance point.When F-factor through the holes exceeded opened balance point, pressure drop of rotary valve trays was higher by3.79%～9.73than that of F1valve trays.Weeping of rotary valve trays was lower by21.19%than that of F1valve trays. Entrainment of rotary valve trays was far less than that of F1valve trays.Using computational fluid dynamics performance software FLUENT6.3, simulated three-dimensional gas flow field distribution in the rotating valve when it fully opened. The results showed that air goes through the valve openings on the tray into inside space of the valves by the sudden contraction, changed direction when touched the valve covers, then touched the wing of the rotary valve and changed direction again. Finally, the formation of spiral outflow from float valve and plate gap. And the air flow rate reached the maximum at the valve seams near the valve covers. Gas outflow from the adjacent valve hole will appear hedge, which is the main reason for the entrainment. The rotary valve trays hedge adjacent to the float valve is much weaker than that of F1valve. Obvious vortex formed around the float valve. Simulation of the rotary valve trays dry pressure drop, and compared simulated values with the experimentally measured dry pressure drop. Difference between the above two is about3.57%. In addition, simulated the gas flow field pressure distribution within the plate near the float valve, in the body at the plate surface there were veins shrink due to the solid wall blocking and airflow and higher the pressure field. There was obvious negative pressure zone near the valve cover.The results of this paper will be helpful to designing and operating of rotary valve tray and establish bases for further study and improve optimization.