CFD Modeling Of Gas-Liquid Flow And Mass Transfer In Rotating Packed Beds

As a novel multiphase contactor, Rotating Packed Bed (RPB) can greatly intensify the processes of micromixing and mass transfer herein. Recently, RPB has been successfully applied to manufacturing nanomaterials by reactive precipitation and for separation in process industry. The fundamental studies concerning the phenomena of fluid flow and mass transfer within RPB, which can conduce to more detailed understanding for flow characteristics of the gas phase and the discrete liquid particle phase in addition to the mass transfer process in the packing region, can provide theoretic support for the application of RPB.In this paper, a CFD modeling methodology is established to simulate the gas flow and dispersed liquid flow as well as the mass transfer process in RPB. Based on the analysis of the studies on the fluids flow and mass transfer in RPB along with the experimental results of visual study on the flow pattern of the liquid phase, a physical modeling of two-phase fluid flow is obtained. With appropriate simplifications on the geometricalstructure of the net packing and the effect of packing on the break up of the droplets as well as the variation on the diameter of the droplets flying in RPB, the modeling of the gas flow and the trajectory of the liquid droplets in RPB along with the mass transfer process is established accordingly. The flow field of the gas phase is obtained by solving the Reynolds time-averaged conservative equations under Euler coordinate system while the motion of droplets is simulated using Lagranian particle trajectory model respectively. Upon the numerical results of the gas phase and the dispersed liquid flow, the mass transfer coefficient of the liquid phase is obtained.The model is verified by the results of visual studies and data from the literatures and good agreement is achieved. The comparison illustrates that the model can reasonably reflect the actual process. The model is further applied to numerically study the effect of rotating packing in RPB with different geometries on the intensification on the turbulence and the droplets motion with different incident angle. Further, the influences of various operation parameters on the mass transfer coefficient are also discussed. The simulation will be helpful to understand the mass transfer process in RPB and provide support for the design and operation of RPB.