CFD Analysis of the Effects on Cooling Rate of Impeller Shape and Rotational Direction in a Cream Cooling Storage Tank with a Special Anchor Impeller

In a cream storage tank fitted with a special anchor impeller, the upper and lower blades move the fluid away from the tank wall and upwards with normal rotation, and onto the wall and downwards with reverse rotation; and changes in the rotational direction and the phase difference between the upper and lower blades are known to influence the cooling speed and degree of damage to the product. In this study, cooling was simulated using computational fluid dynamics for this phenomenon, and the computational results agreed well with previously reported experimental values, confirming the validity of this method of analysis. The results further showed that, during reverse rotation, the flow onto the tank wall from the upper blades increases heat flux, and that the down-flow from the lower end of the upper blades and the up-flow from the end of the lower blades improve uniformity inside the tank. It was also found that introducing a phase difference between the upper and lower blades tended to decrease the power consumption and shear stress.