CFD Simulation on Gas-Liquid Hydrodynamics in a Dual-Impeller Stirred Reactor

摘要

Multiphase mixtures occur very frequently in process industries. The paper deals with the study of liquid and gas flow behavior in a gas sparged tank equipped with multiple impellers, i.e. combination of Rushton turbine and upflow pitched-blade turbine. Single-phase flow is investigatedrnusing Laser Doppler Velocimetry (LDV) and computational fluid dynamics (CFD). Gas - liquidrnhydrodynamics are simulated with three-dimensional CFD model, in which a multiple frames of reference method is used to account for the relative movement between impeller and baffles. Fluid flow is calculated with a two-fluid model along with standard k-ε turbulence model using finite-volume method. The velocity distribution for single phase in mixing tanks measured by LDV is used to validate the results of CFD. The simulation results for gas-liquid flow are compared with other available experimental data. In addition, two alternative drag coefficient approaches are tested for studying their influence on gas-liquid hydrodynamics. Further work is needed to improve the quantitative agreement with experimental data.