Experimental investigation of liquid–liquid mixing in T-shaped micro-mixers using <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si31.gif" display="inline" overflow="scroll"><mml:mi mathvariant="normal">μ</mml:mi></mml:math>-LIF and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si32.gif" display="inline" overflow="scroll"><mml:mi mathvariant="normal">μ</mml:mi></mml:math>-PIV

Hoffmann, Marko; Schlüter, Michael; Räbiger, Norbert

doi:10.1016/j.ces.2005.11.029

Cited by 249 publications

(62 citation statements)

References 17 publications

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“…This leads to a considerable mixing efficiency, which motivates the interest in the literature for the engulfment regime (ER) (see, e.g., Refs. [1][2][3][4][5][6][7][8][9]. Geometrical parameters such as the width ratio between the outflowing and inlet channels W o /W and the width to height ratio W o /H have been found to have a significant impact on the value of the critical Reynolds number for engulfment regime (see, e.g., the review by Santos and Sultan 10 and the references therein).…”

Section: Introductionmentioning

confidence: 97%

Unsteady asymmetric engulfment regime in a T-mixer

2014

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Unsteady flow regimes in a micro T-mixer are investigated. Direct numerical simulations\ud (DNS) show that, in agreement with experimental and numerical results in\ud the literature, when the Reynolds number is increased above a critical value larger\ud than those typical of the steady engulfment regime, the flow remains asymmetric in\ud the mean but becomes periodic in time. The dynamics of this regime is characterized\ud by analyzing the evolution of the three-dimensional vortical structures forming\ud at the confluence of the two inlet flow streams. As the Reynolds number is further\ud increased, the flowremains time-periodic but it continuously switches between a symmetric\ud configuration, similar to that of the vortical regime, and an asymmetric one,\ud close to the engulfment configuration. Three-dimensional linear stability analysis is\ud successively used to characterize the instability leading to the unsteady asymmetric\ud regime,which is also interesting for applications due to its high mixing efficiency. The\ud critical Reynolds number and the instability frequency are in very good agreement\ud with those found in DNS. The sensitivity of this instability to a generic perturbation\ud of the base flow is also investigated. It is shown that the largest sensitivity is to\ud base-flow modifications introduced close to the three-dimensional vortical structures\ud forming at the confluence between the inlet channels. Finally, the sensitivity analysis\ud is specialized to investigate the effect of a generic perturbation of the inlet velocity\ud profile

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Section: Introductionmentioning

confidence: 97%

Unsteady asymmetric engulfment regime in a T-mixer

2014

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“…Small devices-reactors, heat exchangers, static mixers and concepts like lab-on-a-chip (Fair 2007;Hunt and Wilkinson 2008;Hüttner et al 2011, Walowski et al 2011)-can be fabricated in configurations scaled in millimetres and embedded with micrometer-sized channels (Hoffmann et al 2006;Rinke et al 2011a, b). The miniaturization of reaction systems offers a lot of advantages over conventional bench top systems such as small samples and reduced waste volumes, automated sample preparations and reduced reaction time (Janasek et al 2006).…”

Section: Introductionmentioning

confidence: 98%

“…Other research groups often work with T-shaped micromixers (Hoffmann et al 2006;Bothe et al 2006;Lindken et al 2006;Mouheb et al 2011) or cross-channel geometry (Devasenathipathy et al 2003;Mouheb et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Combined measurement of concentration distribution and velocity field of two components in a micromixing process

Wellhausen

Rinke²,

Wackerbarth

2011

Microfluid Nanofluid

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A lot of production processes involve mixing steps. The understanding of fluid flows in mixing processes of liquid components is needed in order to develop appropriate mixers for the chemical and pharmaceutical industry. Especially mixing in microfluidic systems is a challenge due to the diffusion-based processes. A multilamination micromixer with chessboard outlet geometry is used to induce the mixing process. To get comprehensive information about the mixing process, the velocity profile of the fluid flow and the species concentration distribution during the mixing process should be measured. Thus, we have combined particle image velocimetry (PIV) and Raman scattering. To enable rapid detection, the Raman imaging mode is used to visualise the concentration distribution. By this setup light sheets along and orthogonal to the outlet of the micromixer are recorded and synchronized with PIV measurement. As a model system we have used water and ethanol/methanol, enabling a selective monitoring of the substances by choosing appropriate spectral areas. The PIV is recorded based on Mie scattering and fluorescence using microsphere tracers. In this study, we present a setup for determination of the velocity profile field and the spatial concentration distribution of water and ethanol/methanol in a micromixer.

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“…This difficulty can be overcome using confocal laser scanning microscopy (CLSM) where a pinhole is placed in front of the detector to reject out-of-focus light. 20,21 Two rotating mirrors are used to scan the entire imaging region in a point-by-point manner using a photomultiplier tube (PMT), generating a planar image.…”

Section: 12mentioning

confidence: 99%

Confocal imaging of laminar and turbulent mixing in a microscale multi-inlet vortex nanoprecipitation reactor

Shi

Fox

Olsen

2011

Applied Physics Letters

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Mass production of functional nanoparticles may be realized through flash nanoprecipiation in microscale reactors such as the multi-inlet vortex reactor (MIVR). A comprehensive understanding of mixing in the MIVR is required for process control and reactor design. Mixing in the MIVR is studied using a technique coupling laser induced fluorescence with confocal laser scanning microscopy. It is shown to provide meaningful qualitative and statistical data of the scalar field for analysis and comparison with numerical simulations. Data were collected for four flow rates, showing that mixing is incomplete even at the highest flow rate.

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Experimental investigation of liquid–liquid mixing in T-shaped micro-mixers using μ-LIF and μ-PIV

Cited by 249 publications

References 17 publications

Unsteady asymmetric engulfment regime in a T-mixer

Unsteady asymmetric engulfment regime in a T-mixer

Combined measurement of concentration distribution and velocity field of two components in a micromixing process

Confocal imaging of laminar and turbulent mixing in a microscale multi-inlet vortex nanoprecipitation reactor

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