Study On Hydrodynamics Of A Rotating Zigzag High-gravity Bed

Rotating Zigzag Bed(RZB)appears as a novel kind of highly efficient mass transfer equipment using centrifugal field to replace the gravitational field in which gas-liquid mass transfer process was greatly intensified.This paper established the two-dimensional,three-dimensional model by GAMBIT.The method of CFD was used to study the gas pressure drop and flow field.According to the simulation result,find out the weak areas of the RZB and provide theoretical support for structure improvement.The main study contents and results in this paper are as follow:(1)FLUENT successfully introduced in the rotating zigzag bed research work,greatly shortening the research process;This is the first time to simulate the rotating zigzag bed used FLUENT.The CFD model was validated by experimental results.The results show that the averaged relative error is less than 15%;(2)80% of the total velocity is tangential velocity.From outside rotor to inside rotor,gas velocity decreases,this is mainly caused by the friction of the corner.There is a large velocity gradient in the rotor outside the park,this could easily lead to energy loss.The liquid in the device is primarily in the form of film and droplets,this greatly increases the gas-liquid interfacial area,and the liquid can decrease the vortex generation in the following gaps of the static baffle and the gas outlet.Overall whether liquid or vapor flow,they are subject to the amount of intake air,the volume of into liquid,speed and the structure of the equipment;(3)The rotor drop contributions the vast majority of the pressure drop in the device.The result showed that the gas pressure drop increases with the increase speed,the gas flow rate and the liquid flow rate.The number of droplets increases as the increasing of the speed,this can conducive to the reaction of mass transfer.Increasing the amount of the gas flow rate can easily lead to greater gas velocity inner rotor,then liquid drops are blown out the rotor,this will bring increased liquid holdup,flooding and entrainment;Increasing the amount of the liquid flow rate will make the flow path becomes narrower,then gas velocity increases,it can also cause the flooding and entrainment.The flooding and entrainment is not conducive to mass transfer.(4)The equipment can get a optimal performance.The vortex can decrease if we can install a baffle in the equipment.Tilt gas inlet is better than the vertical gas inlet,it makes the gas into the rotor easily,then reduce the loss of energy.This paper studies flow conditions,the pressure drop distribution in the rotating zigzag bed,it will help us to find out the mechanism of mass transfer,thereby improving the device structure and improving the mass transfer performance of the device.