A Study of the Accuracy, Global Performance, and Computational Expenses of k–ε, k–ω, and RSM Turbulent Models for Flow in an Industrial Static Mixer

Abstract

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. The use of static mixers has been utilized over a wide range of applications such as continuous mixing, blending, heat and mass transfer processes, chemical reactions, etc. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream purification processes and increased waste disposal costs. This paper extends previous studies by the authors on an industrial helical static mixer and illustrates how static mixing processes of single-phase viscous liquids can be simulated numerically. It also intends to present an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Three-dimensional finite volume simulations are used to study the performance of the mixer for a range of practical Reynolds numbers, using three different turbulent models: k–ε model, k–ω model, and RSM model. The accuracy, global performance and costs of the different turbulent models have been examined. The flow velocities, pressure drops, etc. are calculated for each model. The calculated pressure drop of each case is compared with experimental results. Using different tools, the mixing results obtained from the different models are studied and compared.