Experimental and numerical investigation of the scale-up criterion of solid-viscous fluid mixing in a stirred tank

The scale-up of mixing processes is crucial for process engineering and power optimization in the chemical industry. Scale-up of fluid mixing in stirred systems becomes a challenging task, especially when using non-Newtonian fluids. In this study, computational fluid dynamics (CFD) has been applied to simulate the solid-liquid mixing of silica particles with non-Newtonian fluids of carboxymethyl cellulose (CMC) solutions (1.0, 1.5, and 2.0). The model is validated by experimental measurement of power consumption and solid-phase concentration. The scale-up criterion based on geometric similarity and constant tip speed is proved to be valid for non-Newtonian systems by comparing kinematic similarity. The transformation of flow regime is discussed based on modified Reynolds number and local Reynolds number. The scale-up criterion performs well in terms of the scale effect of power consumption, especially for the CMC2.0 solution system. This study is instructive for the scale-up of non-Newtonian fluid mixing in stirred tanks.

Automated summary

This study validates the scale-up criterion for non-Newtonian fluid mixing in stirred tanks through CFD simulation and experimental verification. The effectiveness of the scale-up criterion is proven by comparing kinematic similarity in non-Newtonian systems. The study also discusses the mechanism of flow regime transformation and demonstrates good performance in terms of scale effect of power consumption, particularly for the CMC2.0 solution system.