Computational study of convective–diffusive mixing in a microchannel mixer

Liu, Minye

doi:10.1016/j.ces.2011.02.036

Cited by 53 publications

(62 citation statements)

References 18 publications

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“…The kinematic viscosity ν and diffusion coefficient α, were set to 10 -6 m 2 s -1 (the kinematic viscosity of water at room temperature) and 10 -10 m 2 s -1 (a typical diffusivity value for microfluidic applications), respectively [16][17][18]. To study mixing, pure water and a solution of M a n u s c r i p t 7 A second-order upwind differencing scheme was used to discretize the advection terms in the governing equations [21]. For transient calculations, the discretization in time was performed using a second-order backward Euler scheme.…”

Section: Flow and Mixing Analysismentioning

confidence: 99%

Convergent–divergent micromixer coupled with pulsatile flow

Afzal

Kim

2015

Sensors and Actuators B: Chemical

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Section: Flow and Mixing Analysismentioning

confidence: 99%

Convergent–divergent micromixer coupled with pulsatile flow

Afzal

Kim

2015

Sensors and Actuators B: Chemical

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“…More specifically, in finite-difference or finite-volume methods, the influence of numerical or 'false' diffusion must be controlled so that it does not overwhelm the laminar diffusion-based mixing that is present in the physical problem [1]. In most cases, the Reynolds numbers associated with such flows are low enough that laminar conditions prevail.…”

Section: Introductionmentioning

confidence: 99%

“…Liu [1] notes that false diffusion is seldom discussed by investigators who utilize higher-order methods, and this is one reason. Liu [1] notes that false diffusion is seldom discussed by investigators who utilize higher-order methods, and this is one reason.…”

Section: Introductionmentioning

confidence: 99%

“…Accurate prediction of laminar mixing requires that the advective and diffusive transport of different fluids be properly captured by the numerical approach. More specifically, in finite-difference or finite-volume methods, the influence of numerical or 'false' diffusion must be controlled so that it does not overwhelm the laminar diffusion-based mixing that is present in the physical problem [1]. False diffusion arises because numerical approximations for the advective terms in the governing differential equations contain truncation errors that can artificially increase the diffusive transport of species in the numerical solution, smearing sharp gradients, and overpredicting the degree of mixing.…”

Section: Introductionmentioning

confidence: 99%

“…Higher-order upwind schemes are considered superior to the FOU method in terms of reducing false diffusion [1,5]. Of these, second-order upwind (SOU) methods are the most prevalent, balancing accuracy with complexity, computational time, and stability concerns.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Managing false diffusion during second‐order upwind simulations of liquid micromixing

Bailey

2016

Numerical Methods in Fluids

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Summary Liquid mixing is an important component of many microfluidic concepts and devices, and computational fluid dynamics (CFD) is playing a key role in their development and optimization. Because liquid mass diffusivities can be quite small, CFD simulation of liquid micromixing can over predict the degree of mixing unless numerical (or false) diffusion is properly controlled. Unfortunately, the false diffusion behavior of higher‐order finite volume schemes, which are often used for such simulations, is not well understood, especially on unstructured meshes. To examine and quantify the amount of false diffusion associated with the often recommended and versatile second‐order upwind method, a series of numerical simulations was conducted using a standardized two‐dimensional test problem on both structured and unstructured meshes. This enabled quantification of an ‘effective’ false diffusion coefficient (Dfalse) for the method as a function of mesh spacing. Based on the results of these simulations, expressions were developed for estimating the spacing required to reduce Dfalse to some desired (low) level. These expressions, together with additional insights from the standardized test problem and findings from other researchers, were then incorporated into a procedure for managing false diffusion when simulating steady, liquid micromixing. To demonstrate its utility, the procedure was applied to simulate flow and mixing within a representative micromixer geometry using both unstructured (triangular) and structured meshes. Copyright © 2016 John Wiley & Sons, Ltd.

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Liquid mixing intensification by adding swirling flow in the transverse jet mixer

Zhang

et al. 2021

AIChE Journal

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In this study, effect of swirling addition on the liquid mixing behavior of multiorifice‐impinging transverse jet mixer has been investigated by planar laser‐induced fluorescence as well as large eddy simulation (LES). In the case of swirling addition into the jet flow, there exists an optimized swirling jet angle or optimized jet‐to‐cross velocity ratio for the fixed mixer configuration. A larger swirling jet angle will make the flow dominated by the swirling, resulting in a slower mixing process. Interaction of swirling crossflow with no‐swirling‐injected streams, or with swirling‐injected streams in the opposite direction is beneficial for the mixing. LES predictions show that many small vortices are produced homogenously due to intensified impingement in the case of opposite swirling directions, leading to a relative fast mixing process in few milliseconds. Whereas the mixing is restrained when the swirling directions of two flows are the same.

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Computational study of convective–diffusive mixing in a microchannel mixer

Cited by 53 publications

References 18 publications

Convergent–divergent micromixer coupled with pulsatile flow

Convergent–divergent micromixer coupled with pulsatile flow

Managing false diffusion during second‐order upwind simulations of liquid micromixing

Liquid mixing intensification by adding swirling flow in the transverse jet mixer

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