Structure Optimization of Dual Impellers in Solid-Liquid System by Numerical Simulation

The performance of solid-liquid suspension flow in a stirred tank with dual impellers was simulated numerically by Computational Fluid Dynamics(CFD) using Multiple Reference Frame(MRF) and Eulerian multiphase flow model. Effects of impeller combination and blade angle(θ) of dual impellers on solid suspension and power consumption are analyzed. The simulated results indicate that the synergistic effect generated by the combination of two pitched blade turbines can efficiently improve the main cycling flow, the degree of turbulent in the tank and the solid suspension performance. Though blade angels have little effect on flow pattern, axial velocity, turbulent kinetic energy and energy consumption are found to increase with blade angles. Dual impellers with blade angle of 45° can generate strong axial flow and turbulent fluctuation with lower energy consumption which is favorable for homogeneous distribution of solid particle in the tank.