Hydrodynamic Performances And CFD Simulation Of Active Rotated Valve Tray

Our group found that it could speed up the gas-liquid surface renewal and accelerate the mass transfer of gas and liquid phase when the float vale was rotated.We presented a new rotary float valve tray with the characteristics of bigger operational flexibility,lower entrainments and weep,and the average gas holdup was more uniform.However,the friction of valve legs and tray limited the rotation of the valve in a certain extent when gas load was larger.Based on the above problem,in this paper I optimized the structure of rotary float valve and presented a new bubbling element-active rotated valve,in order to strengthen the role of rotation and further research the influence of rotation on hydrodynamic performance of trays.Hydrodynamic of active rotated valve were studied with air-water system in a rectangular organic glass column with an inner diameter of 300×400 mm.And still,effects of the active rotation of valve on hydrodynamic properties were studied.Three dimensional flow field of single phase in the inside space and surrounding of active rotated valve were simulated and visually inspected by computational fluid dynamic software Fluent6.3.Pressure drops and entrainments of active rotated valve were measured under the different gas flow and clear liquid height on a tray.The local gas holdup fraction which had a fixed clear liquid height was measured by the self-made double-sensor conductivity probe.Research shows that the active rotation of valve have lower wet pressure drops and more entrainments than that of the non-rotation with a characteristic of similar dry pressure drops.Moreover,the distribution of local gas holdup fraction becomes more uniform due to rotating.The active rotation of valve can significantly reduce the impacts of airflow and improve the gas holdup fraction near the wall effectively.The gas flow field of single active rotated valve and liquid flow field of more valves were simulated by Fluent6.3.The simulation results of gas flow field show that the rotation of valve can change the direction of gas and make it diffuse into space in a spin manner when the rate of gas is small.Meanwhile,it can accelerate the speed of gas by rotation of valve in a certain range.However,the density of gas is so small that the rotation has a little influence on the gas when the rate is larger.The simulation results of liquid phase show that the rotation of valve has a more obvious influence on liquid than that of gas,and the rotation can also lead to the rotary movement of liquid.Besides,effects of the direction of rotation on liquid phase are different due to the wing of valve.The results will be helpful to optimizing and designing of active rotated valve and establish bases for further study the active rotated valve and rotary flow field...