ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Evaluation of mixing effects in dual impeller reactors through computational fluid dynamics and an exponential decay model

Wenbo Shi, Hui Sun, Jianwei Zhang, Jianxin Xu, and Hua Wang

School of Metallurgical and Energy Engineering Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, People’s Republic of China

E-mail: xujianxina@163.com

Received: 11 October 2025  Accepted: 2 April 2026

Abstract:

Mixing equipment is critical in the chemical and energy industries, directly affecting mixing time, reducing power, and specific mixing energy per unit volume. This study applied computational fluid dynamics to examine flow and mixing in a dual-impeller reactor with fluids of varying viscosities. Four impeller combinations were evaluated based on flow patterns, tracer dispersion, mixing time, and single-exponential decay model. Under low-viscosity conditions, RT-DBOT (Rushton Turbine with Disk-Blade Open Turbine) reduces the mixing time by only 3.9% relative to PBT-RT (Pitched-Blade Turbine with Rushton Turbine), whereas PBT-RT lowers the specific mixing energy \({W}_{r}\) by 7.1% and the power by 11.3% compared with RT-DBOT, indicating a more favorable energy-performance trade-off. Under medium-to-high viscosity, BCBDT-RT (Backward-Curved Blade Disk Turbine with Rushton Turbine) achieves a mixing time about 6% shorter than PBT-BCBDT (Pitched-Blade Turbine with Backward-Curved Blade Disk Turbine) and reduces \({W}_{r}\) by 1.6%, indicating a more favorable time and energy balance. Based on mixing time and specific mixing energy, PBT-RT is the optimal configuration for low-viscosity fluids, whereas BCBDT-RT is the optimal configuration for medium-to-high-viscosity fluids. Meanwhile, the exponential decay model validated the simulation results and clarified inter-impeller synergy, providing practical guidance for energy and efficient mixing across fluids with different viscosities.

Keywords: Dual-impeller mixer; Computational fluid dynamics; Impeller combination design; Exponential decay model; Cooperative interaction

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04870-x

Chemical Papers 80 (7) 8007–8029 (2026)