Experimental Study And Numerical Simulation Of The Flow Field Of Newtonian And Non-Newtonian Fluid In Stirred Vessels

A modified Particle Image Velocimetry (PIV) was developed in this work with simplified data acquisition and image processing system. The modified PIV could be used in the flow field measurement of big size tank and poor transparence fluid.Experiments were carried out in a baffled stirred tank of 0.5m diameter filled with 0.6 wt % CMC aqueous solution and water respectively. The flow fields generated by a 4-blade 45 pitched-blade turbine (PBT) and a 2-blade CBY at different rotational speeds were measured by using the modified PIV. Also the similar flow fields but generated by double 45?PBTs and double 2-blade CBYs were measured. All the comparable experiments were carried out at the same power input.The velocity fields were dominated by axial flow in water but by tangent and radial flow in 0.6% CMC aqueous solution. The more the rotational speed, the more apparent the trend of axial flow; There exist stagnant area between the two impellors, especially in the flow fields generated by double PBTs, which seriously hampered the axial flow.The flow fields at the same conditions with those of the experiments were numerically simulated by the CFD (Computational Fluid Dynamics) software-CFX. The simulation results approximately agreed with the experimental data, especially in the trend of the velocity curves. Generally, the simulation velocity curves were smoother than those of the experiments and showed greater values.