Abstract Summary (Max 250 words)
Continuous-flow mixers operating under chaotic advection enable efficient mixing of both highly viscous and low-viscosity liquids, including those containing components sensitive to high shear rates typical of turbulent flow. Chaotic advection ensures rapid development of intermaterial surface area and a reduction in segregation scales, thereby accelerating mass transfer across the intermaterial surface. However, numerical modelling of mixing in such systems using computational fluid dynamics (CFD) requires very fine computational meshes to accurately resolve steep concentration gradients in regions where fast chemical reactions occur. When the local segregation scale becomes comparable to or smaller than the computational cell size, numerical diffusion smears concentration gradients and significantly affects the predicted reaction outcome. In this work, a hybrid mixing model was applied to simulate mixing in a tubular reactor operating under chaotic flow conditions. Premixing in the vicinity of the injection point for the limiting reactant was modelled using CFD. In the downstream region, where chaotic advection dominates, mixing was modelled in the Lagrangian framework by solving the reactants mass balance equations for deforming liquid striations. The segregation scale and reagent concentrations obtained in the initial CFD-based stage were used as initial conditions for the Lagrangian calculations. By comparing modelling results with experimentally determined selectivities of competitive-parallel reactions, the average rate of deformation of fluid elements in chaotic flow was determined as a function of the Reynolds number.
