Steady and unsteady regimes in a T-shaped micro-mixer: Synergic experimental and numerical investigation

Mariotti, Alessandro; Galletti, Chiara; Mauri, Roberto; Salvetti, Maria Vittoria; Brunazzi, Elisabetta

doi:10.1016/j.cej.2018.01.108

Cited by 98 publications

(113 citation statements)

References 30 publications

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“…There are many investigations on the mixing performance of flow reactors. It has been proposed that the flow regimes in a rectangular T‐shaped mixer can be classified into five groups according to Re . Moreover, empirical equations utilizing the mixer diameter and Re have been suggested for the mixing performance in a T‐shaped mixer, in which the increase of Re and decrease of the mixer diameter enhanced the mixing , .…”

Section: Resultsmentioning

confidence: 99%

Process Intensification of Living Cationic Polymerization of Isobutylene by a Flow Reaction System

et al. 2019

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Increasing the reaction temperature of the living cationic polymerization of isobutylene is crucial for industrial production due to the cost of refrigeration. The reaction temperature increase was achieved with an accelerated reaction rate using a flow reaction system. The polymerization conditions, including the flow reactor design, were based on the results of kinetic studies. Utilizing a milli‐scale flow reactor, polyisobutylene, which has a narrow molecular weight distribution, was obtained within a considerably short residence time at a high temperature. Furthermore, it was confirmed that the value of Mw/Mn correlates with the product of the Reynolds number and the angle of collision.

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Section: Resultsmentioning

confidence: 99%

Process Intensification of Living Cationic Polymerization of Isobutylene by a Flow Reaction System

et al. 2019

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“…In order to limit the uncertainty related to time fluctuation of pixel intensity, the references

{Iblank}_{ij}

and

{Imax}_{ij}

are chosen to be their arithmetic mean values over 100 frames each. Details on the calibration and image analysis procedures can be found in Mariotti et al together with a more detailed description of the whole experimental set‐up.…”

Section: Methodsmentioning

confidence: 99%

“…The pressure‐velocity coupling was treated by means of the SIMPLE algorithm. Convergence was ensured by very low values of the normalized residuals for all equations (i.e., below

1 \cdot 10^{- 11}

), as well as by checking the steadiness of the velocity and concentration fields with iterations . In the unsteady regimes, a transient solver with a second order implicit advancement method was employed using a time step corresponding to a CFL number

\approx 5

.…”

Section: Direct Numerical Simulationsmentioning

confidence: 99%

Numerical investigation of flow regimes in T‐shaped micromixers: Benchmark between finite volume and spectral element methods

et al. 2018

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Computational fluid dynamics (CFD) is very appealing to investigate mixing and reaction in microdevices, as it allows easily investigating different operating conditions as well as mixer geometries. This latter aspect is very important as the flow in microdevices is laminar so the mixing between reactants should be promoted by a clever mixer design, aimed at breaking the flow symmetries. Recently time periodic motions that improve mixing have been observed to take place in a T‐junction at low Reynolds numbers. In this case the numerical modelling should be based on direct numerical simulations (DNS), thus involving high computational resources. In this work, two different CFD approaches, i.e., finite volume and spectral element methods, are applied and compared for the analysis of the mixing process in the well known T‐shaped micromixer. Spectral elements methods are particularly suited for DNS; however, they have been scarcely applied to study micromixers, while plenty of works can be found with finite volume methods. The analysis is carried out using both ideal and non‐ideal liquid binary mixtures, the latter presenting a negative fluidity of mixing (i.e., the viscosity of the mixture is higher than that of the pure components). Moreover the numerical results are validated with simple flow visualization experiments.

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“…At a low Reynolds numbers, the mixing in the T-mixers is slow. When Re increases to an extent ( Re > 300) [ 18 , 19 , 20 ], rapid mixing can be achieved for a T-mixer because the fluids coming from the inlets can generate an asymmetric flow at the entrance of the mixing channel. Therefore, in order to obtain efficient mixing at an extensive range of Reynolds numbers, many researchers have studied various approaches to micromixer design, including bent or curved channel arrangement [ 21 , 22 , 23 , 24 ], wall structures [ 25 , 26 , 27 ], obstacles within the channel [ 28 , 29 ], and modified T-shaped channels [ 30 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Mixing Performance of a 3D Micro T-Mixer with Swirl-Inducing Inlets and Rectangular Constriction

Zhang

Luo

2018

Micromachines

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In this paper, three novel 3D micro T-mixers, namely, a micro T-mixer with swirl-inducing inlets (TMSI), a micro T-mixer with a rectangular constriction (TMRC), and a micro T-mixer with swirl-inducing inlets and a rectangular constriction (TMSC), were proposed on the basis of the original 3D micro T-mixer (OTM). The flow and mixing performance of these micromixers was numerically analyzed using COMSOL Multiphysics package at a range of Reynolds numbers from 10 to 70. Results show that the three proposed 3D micro T-mixers have achieved better mixing performance than OTM. Due to the coupling effect of two swirl-inducing inlets and a rectangular constriction, the maximum mixing index and pressure drop appeared in TMSC among the four micromixers especially; the mixing index of TMSC reaches 91.8% at Re = 70, indicating that TMSC can achieve effective mixing in a short channel length, but has a slightly higher pressure drop than TMSI and TMRC.

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Steady and unsteady regimes in a T-shaped micro-mixer: Synergic experimental and numerical investigation

Cited by 98 publications

References 30 publications

Process Intensification of Living Cationic Polymerization of Isobutylene by a Flow Reaction System

Process Intensification of Living Cationic Polymerization of Isobutylene by a Flow Reaction System

Numerical investigation of flow regimes in T‐shaped micromixers: Benchmark between finite volume and spectral element methods

Mixing Performance of a 3D Micro T-Mixer with Swirl-Inducing Inlets and Rectangular Constriction

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