Experimental Investigation And Numerical Simulation Of The Mixing Equipment With High Viscous Fluids

The power consumption and mixing performance of two different combined agitators were experimentally investigated in a stirred tank with the diameter of0.48m and standard elliptical bottom. The agitators are consisted of helical ribbon as upper impeller and modified frame or helical ribbon as bottom. The experimental liquids are74%,75%,78%(mass fraction) syrup solutions and1%,2%,3%(mass fraction) CMC (Carboxy Methylcellulose Sodium) solutions. Numerical simulation of the power consumption was also carried out by CFD software. A reasonable agreement between numerical simulation and experimental measurement of power consumption could be obtained.In the laminar flow, it was shown that the Kp of the combined agitator with modified frame bottom impeller was about158while the Kp of the combined agitator with new helical bottom impeller was about101. However, the modified frame bottom impeller’s Kp was about90.3and the new helical bottom impeller’s Kp number was only about30.9. The power number correlation between two bottom impeller’s Kp and the liquid level height was fitted, respectively. The result showed that the power consumption of two bottom impellers was rarely affected by liquid level.When the liquid level was0.6m (H/T is1.4), given the same power input, the absolute mixing time of the impeller with asymmetric frame as bottom was similar that with the helical ribbon as bottom. The mixing performance of the impeller with asymmetric frame as bottom was better than that for the impeller with helical ribbon as bottom based on the same Re. As far as the mixing in the bottom of the tank are concerned, the absolute mixing time of the impeller with helical ribbon as bottom was one time more than that of the impeller with the asymmetric frame as bottom.Besides, the power consumption and mixing performance of Pfaulder impeller and CBY impeller was studied.