Influence of Impeller Characteristics on Isolated Mixing Region

Identifying the location of the isolated mixing region (IMR) that forms in a laminar stirred tank is useful for improving the design of impellers. In this study, the IMR was visualized using induced fluorescence, and its position was measured through image analysis. The effects of impeller diameter, blade width, and the number of blades of a paddle-type impeller on the IMR location were investigated. The results showed that the radial position of the IMR was affected by the impeller diameter, while the vertical position was influenced by both the impeller diameter and blade width. Furthermore, multivariable power-law regression using a nonlinear least-squares method yielded a correlation coefficient of 0.96 for predicting the radial position of the IMR.