Multi-impeller mixing performance prediction in stirred tanks using mean age theory approach

Abstract

The mixing performance and power consumption for four dual-impeller configurations in a stirred tank are studied using the mean age theory (MAT) approach, the fully transient techniques (FTT), and experiments. A novel method is developed based on the scaled mean age probability distribution curve, allowing the MAT method to be applied to multi-impeller systems for the first time. The MAT approach provides three-dimensional tracer distribution within the vessel, which is confirmed by FTT and experiments. Compared to the experimental data, the predicted mixing time from the MAT approach shows a deviation within 20%. This is a good degree of accuracy compared to FTT and correlations. For steady-state predicted power numbers, a 20% deviation from the experimental data is observed, while the transient approach exhibits a lower deviation at 10%. However, the computational time can be reduced significantly using the steady-state MAT approach.