CFD in Industrial Mixing: Mixer sizing for solids suspension

We have conducted two separate CFD simulations comparing the impact of mixer diameter versus tank diameter on particle suspension using the same mixer type. The tank in both cases was cylindrical with a diameter and water height of 1.0m, and featured 4 baffles to enhance axial flow. The mixer diameter in the first simulation was 1/3 of the tank diameter, and in the second it was increased to 2/3 of the tank diameter.

Despite maintaining the same power input for both scenarios, the results were rather eye-opening! The smaller mixer, contrary to what many might expect, showed superior particle suspension and homogenization ability. Even though this phenomenon has been described by many authors in technical literature, there’s nothing quite like seeing it with your own eyes.

These simulations underline the significance of the ratio between tank diameter and mixer diameter in industrial applications. But there’s a bigger lesson here – one should not blindly follow traditional wisdom or rules of thumb without in-depth understanding. Witnessing and comprehending these phenomena personally is vital.

Simulations with M-STAR CFD offer a compelling and cost-effective way for analyzing different designs of chemical reactors and developing a comprehensive understanding of complex mixing phenomena. This innovative tool empowers us to traverse beyond the traditional boundaries of design exploration.