Mass transfer enhancement in microchannel reactors by reorientation of fluid interfaces and stretching

Adeosun, John T.; Lawal, Adeniyi

doi:10.1016/j.snb.2005.01.016

Cited by 37 publications

(17 citation statements)

References 11 publications

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“…Figure 5 plots the particle residence time distribution E ( t ) and the cumulative distribution F ( t ) for the particles eluted from the outlet of the mixer over 0.025-millisecond time slots. For the pulse tracer input method, the RTD function E ( t ) is given by [38]:

E (t) = \frac{c (t)}{\int_{0}^{\infty} c false(t false) dt}

where c ( t ) is the tracer concentration at the outlet as a function of time. In this work, it is the particle number eluted from the outlet as a function of time.…”

Section: Resultsmentioning

confidence: 99%

“…In this work, it is the particle number eluted from the outlet as a function of time. The cumulative distribution function F ( t ) is defined by [38]:

F (t) = \int_{0}^{t} E false(t false) dt

As indicated in Figure 5, at the flow rates where thorough mixing is obtained, submillisecond mean residence time was achieved. For the flow rate of 5.0 µL/s, The simulated mean residence time of the particles inside the mixer are 0.54 ms and 0.61 ms for 90% and 95% of particles, which is comparable to the calculated mean residence time of 0.55 ms derived from the volumetric flow rate.…”

Section: Resultsmentioning

confidence: 99%

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Passive microfluidic device for submillisecond mixing

McMahon²,

Mohamed

et al. 2010

Sensors and Actuators B: Chemical

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We report the investigation of a novel microfluidic mixing device to achieve submillisecond mixing. The micromixer combines two fluid streams of several microliters per second into a mixing compartment integrated with two T-type premixers and 4 butterfly-shaped in-channel mixing elements. We have employed three dimensional fluidic simulations to evaluate the mixing efficiency, and have constructed physical devices utilizing conventional microfabrication techniques. The simulation indicated thorough mixing at flow rate as low as 6 µL/s. The corresponding mean residence time is 0.44 ms for 90% of the particles simulated, or 0.49 ms for 95% of the particles simulated, respectively. The mixing efficiency of the physical device was also evaluated using fluorescein dye solutions and FluoSphere-red nanoparticles suspensions. The constructed micromixers achieved thorough mixing at the same flow rate of 6 µL/s, with the mixing indices of 96% ± 1%, and 98% ± 1% for the dye and the nanoparticle, respectively. The experimental results are consistent with the simulation data. The device demonstrated promising capabilities for time resolved studies for macromolecular dynamics of biological macromolecules.

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E (t) = \frac{c (t)}{\int_{0}^{\infty} c false(t false) dt}

where c ( t ) is the tracer concentration at the outlet as a function of time. In this work, it is the particle number eluted from the outlet as a function of time.…”

Section: Resultsmentioning

confidence: 99%

“…In this work, it is the particle number eluted from the outlet as a function of time. The cumulative distribution function F ( t ) is defined by [38]:

F (t) = \int_{0}^{t} E false(t false) dt

Section: Resultsmentioning

confidence: 99%

Passive microfluidic device for submillisecond mixing

McMahon²,

Mohamed

et al. 2010

Sensors and Actuators B: Chemical

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“…It is implied in this paper that the Taylor dispersion can further enhance the mixing. Adeosun and Lawal [10,11] introduced the so-called multilaminated/elongational micromixers to mix two fluid samples ( Figure 7). Their design is composed of many mixing structures strategically arranged on the channel floor of the mixing device and blocks arranged in a staggered way at the inlets.…”

Section: Hydrodynamic Focusingmentioning

confidence: 99%

A Review on Mixing in Microfluidics

2010

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Small-scale mixing is of uttermost importance in bio-and chemical analyses using micro TAS (total analysis systems) or lab-on-chips. Many microfluidic applications involve chemical reactions where, most often, the fluid diffusivity is very low so that without the help of chaotic advection the reaction time can be extremely long. In this article, we will review various kinds of mixers developed for use in microfluidic devices. Our review starts by defining the terminology necessary to understand the fundamental concept of mixing and by introducing quantities for evaluating the mixing performance, such as mixing index and residence time. In particular, we will review the concept of chaotic advection and the mathematical terms, Poincare section and Lyapunov exponent. Since these concepts are developed from nonlinear dynamical systems, they should play important roles in devising microfluidic devices with enhanced mixing performance. Following, we review the various designs of mixers that are employed in applications. We will classify the designs in terms of the driving forces, including mechanical, electrical and magnetic forces, used to control fluid flow upon mixing. The advantages and disadvantages of each design will also be addressed. Finally, we will briefly touch on the expected future development regarding mixer design and related issues for the further enhancement of mixing performance.

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“…The examination of micromixers is also crucial for understanding micro-transport phenomena (Adeosun and Lawal, 2005). In reality, it is challenging to mix several different fluids on the micro-scale because the Reynolds numbers of flows for such dimension are usually below 100 (Liu et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

CFD-Based Optimization of a Diamond-Obstacles Inserted Micromixer with Boundary Protrusions

Tseng

Yang

Lee

et al. 2011

Engineering Applications of Computational Fluid Mechanics

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Effective mixing is vitally important to many microfluidic devices with applications in the areas of biotechnical industries, analytic chemistry and medical industries. In practice, passive micromixers are dependent on the proper layout of channel geometric configurations with obstacles deposited in microchannels to break-up and recombine the flow and reduce the diffusion path to improve the mixing performance. This study aims to investigate the mixing behavior of two different fluids in a passive micromixer with protruded boundary structures. The predicted mixing indexes at different longitudinal locations and Reynolds numbers achieved a good approximation of the experimental data in the literature for numerical simulations. The simulation results also indicated that intense vortices and secondary flows in spanwise planes were induced near the boundary protrusion regions to augment mixing efficiency along the flow course. In order to attain the optimal micromixer design, numerical calculations were attempted for the first time to thoroughly examine the effects of shape, length, width and placement of boundary protrusion structures on the mixing efficiency of a diamond-obstacles inserted micromixer.

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Mass transfer enhancement in microchannel reactors by reorientation of fluid interfaces and stretching

Cited by 37 publications

References 11 publications

Passive microfluidic device for submillisecond mixing

Passive microfluidic device for submillisecond mixing

A Review on Mixing in Microfluidics

CFD-Based Optimization of a Diamond-Obstacles Inserted Micromixer with Boundary Protrusions

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