Rational design of the inlet configuration of flow systems for enhanced mixing

Abstract

High mass transfer rate is a key advantage of microreactors however, under their characteristic laminar flow, it is dominated by slow diffusion rather than fast convection. In this paper, we demonstrate how the configuration of the inlet, i.e. mixers, can promote different flow patterns to greatly enhance mixing efficiency downstream. A systematic evaluation and comparison of different widely adopted mixers as well as advanced designs is presented using a combination of computational fluid dynamics (CFD) and backward particle tracking to accurately calculate diffusion, in the absence of numerical diffusion (false diffusion). In the method, the convection contributed concentration profile is obtained by tracking sampling points from a cross-sectional plane to the inlet point, and diffusion is estimated subsequently. In conventional T- and Y-mixers, the shape of channel, circular or square, is key with only the latter promoting engulfment flow. In cyclone mixers, the resulting average inlet velocity, independent of Reynolds number or geometry, is the dominating design parameter to predict mixing efficiency. This work will serve as a guideline for the design of efficient flow systems with predicted mixing as a way of maximising selectivity and product quality.

The importance of transport phenomena on the flow synthesis of monodispersed sharp blue-emitting perovskite CsPbBr3 nanoplatelets

“…The simulation results by the method are validated by experimental results captured by planar laser induced fluorescence in a T-mixer and a spiral channel, as shown in our previous papers [44,27]. The simulation method shows a higher accuracy than the commercial software.…”

“…The physical mixing process in the microreactor is accurately simulated by a novel approached based on backward particle tracking [39,44]. Three steps are needed to simulate the concentration profiles of one reactant, Cs-oleate, without considering the reaction.…”

“…The concentrations of sampling points in the middle of the cross section are functions of concentrations of their neighboring sampling points as Equation ( 4) and Equation 5. The concentrations of sampling points on the edge are set as equal to these of their neighboring sampling points, adopting a boundary treatment method [44]. Thus, a linear equation group is formed and solved with Matlab to calculate the concentration profile of Cs-oleate.…”

Continuous synthesis of ruthenium nanoparticles with tuneable sizes using ruthenium nitrosyl nitrate precursor

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