Effect of Impeller’s Blade Number on The Performance of Mixing Flow in Stirred Tank using CFD Simulation Method

The component of an impeller in stirred tank plays an important role in the mixing process for a wide range of industries. The present study conducted the analysis of impeller design specifically on the number of blades to investigate the flow performance in the stirred tank. The analysis was also performed to identify the location of the particle flow dead zone at the bottom of the tank. The grid development and fluid flow study were accomplished using the CFD simulation method via the Ansys Fluent software package. The impeller design with the arrangement of 3,4 and 5 blades number was involved in this study. The rotational speed of the blade was set constant at 90 rpm. The flow characteristic at the vertical position of a tank at 0.01, 0.1, 0.2 and 0.3 m has been investigated. The general governing equation and solution approach used in this simulation were also presented in this paper. The results showed that 5 blades impeller produced a broader region of high-velocity magnitude distribution compared to the 3 and 4 blades. Hence, 5 blades impeller also relatively produced a higher distribution of velocity magnitude compared to the 3 and 4 blades impeller, typically in the upper region of the tank. However, the effect of a number of blades seemed not significant in the region close to the rotating impeller.