Research Papers: Flows in Complex Systems

Flow Pulsation and Geometry Effects on Mixing of Two Miscible Fluids in Microchannels

[+] Author and Article Information
Houssein Ammar, Ahmed Ould el Moctar, Bertrand Garnier

Laboratoire de Thermocinétique
Lunam, Polytech Nantes
UMR CNRS 6607,
Nantes 44306, France

Hassan Peerhossaini

Laboratoire Interdisciplinaire des Energies de Demain (LIED)
Université Paris-Diderot,
Sorbonne Paris Cité UMR CNRS 8236,
Paris 75013, France
email: hassan.peerhossaini@univ-paris-diderot.fr

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 31, 2013; final manuscript received April 6, 2014; published online September 10, 2014. Assoc. Editor: Daniel Maynes.

J. Fluids Eng 136(12), 121101 (Sep 10, 2014) (9 pages) Paper No: FE-13-1463; doi: 10.1115/1.4027550 History: Received July 31, 2013; Revised April 06, 2014

Many microfluidic applications involve chemical reactions. Most often, the flow is predominantly laminar, and without active or passive mixing enhancement the reaction time can be extremely long compared to the residence time. In this work we demonstrate the merits of the combination of flow pulsation and geometrical characteristics in enhancing mixing efficiency in microchannels. Mixing was studied by introducing a mixing index based on the gray level observed in a heterogeneous flow of pure water and water colored by rhodamine B. The effects of the injection geometry at the microchannel inlet and the use of pulsed flows with average Reynolds numbers between 0.8 and 2 were studied experimentally and numerically. It appeared that the mixing index increases with the nondimensional residence time (τ), which is inversely proportional to the Reynolds number. In addition, we show that the mixing efficiency depends strongly on the geometry of the intersection between the two fluids. Better mixing was achieved with sharp corners (arrowhead and T intersections) in all cases investigated. In pulsed flow, the mixing efficiency is shown to depend strongly on the ratio (β) between the peak amplitude and the mean flow rate. Optimal conditions for mixing in the microchannels are summarized as a function of Reynolds number Re, the ratio β, and the geometries.

Copyright © 2014 by ASME
Your Session has timed out. Please sign back in to continue.


Chen, G. G., Luo, G. S., Li, S. W., Xu, J. H., and Wang, J. D., 2005, “Experimental Approaches for Understanding Mixing Performance of a Minireactor,” AIChE J., 51(11), pp. 2923–2929. [CrossRef]
Janicke, M. T., Kestenbaum, H., Hagendorf, U., Schüth, F., Fichtner, M., and Schubert, K., 2000, “The Controlled Oxidation of Hydrogen From an Explosive Mixture of Gases Using a Microstructured Reactor/Heat Exchanger at Pt/Al2O3 Catalyst,” J. Catal., 191(2), pp. 282–293. [CrossRef]
Luther, M., Brandner, J. J., Schubert, K., Renken, A., and Kiwi-Minsker, L., 2008, “Novel Design of a Microstructured Reactor Allowing Fast Temperature Oscillations,” Chem. Eng. J., 135(S1), pp. 254–258. [CrossRef]
Kumar, V., Parascivoiu, M., and Nigam, K. D. P., 2011, “Single-Phase Fluid Flow and Mixing in Microchannels,” Chem. Eng. Sci., 66(7), pp. 1329–1373. [CrossRef]
Rebrov, E. V., Schouten, J. C., and de Croon, M. H. J. M., 2011, “Single-Phase Fluid Flow Distribution and Heat Transfer in Microstructured Reactors,” Chem. Eng. Sci., 66(7), pp. 1374–1393. [CrossRef]
Hamadi, D., Garnier, B., Willaime, H., Monti, F., and Peerhossaini, H., 2012, “A Novel Thin Film Temperature and Heat Flux Microsensor for Heat Transfer Measurements in Microchannels,” Lab Chip, 12(3), pp. 652–658. [CrossRef] [PubMed]
Nguyen, N. T., and Wu, Z., 2005, “Micromixers—A Review,” J. Micromech. Microeng., 15(2), pp. R1–R16. [CrossRef]
Hessel, V., Löwe, H., and Schönfeld, F., 2005, “Micromixers—A Review of Passive and Active Mixing Principles,” Chem. Eng. Sci., 60(8–9), pp. 2479–2501. [CrossRef]
Suh, Y. K., and Kang, S., 2010, “A Review of Mixing in Microfluidics,” Micromachines, 1(3), pp. 82–111. [CrossRef]
Hessel, V., Hardt, S., Löwe, H., and Schönfeld, F., 2003, “Laminar Mixing in Different Interdigital Micromixers: I. Experimental Characterization,” AIChE J., 49(3), pp. 566–577. [CrossRef]
Löb, P., Pennemann, H., Hessel, V., and Men, Y., 2006, “Impact of Fluid Path Geometry and Operating Parameters on L/L-Dispersion in Interdigital Micromixers,” Chem. Eng. Sci., 61(9), pp. 2959–2967. [CrossRef]
Ghanem, A., Lemenand, T., Della Valle, D., and Peerhossaini, H., 2013, “Transport Phenomena in Passively Manipulated Chaotic Flows: Split-and-Recombine Reactors,” ASME Paper No. FEDSM2013-16077. [CrossRef]
Hoffmann, M., Raebiger, N., Schlueter, M., Blazy, S., Bothe, D., Stemich, C., and Warnecke, A., 2003, “Experimental and Numerical Investigations of T-Shaped Micromixers,” 11th European Conference on Mixing, Bamberg, Germany, October 14–17, pp. 269–276.
Engler, M., Kockmann, N., Kiefer, T., and Woias, P., 2004, “Numerical and Experimental Investigations on Liquid Mixing in Static Micromixers,” Chem. Eng. J., 101(1–3), pp. 315–322. [CrossRef]
Yi, M., and Bau, H. H., 2003, “The Kinematics of Bend-Induced Mixing in Micro-Conduits,” Int. J. Heat Fluid Flow, 24(5), pp. 645–656. [CrossRef]
Adeosun, J. T., and LawalA., 2005, “Mass Transfer Enhancement in Microchannel Reactors by Reorientation of Fluid Interfaces and Stretching,” Sens. Act., 110(1), pp. 101–111. [CrossRef]
Adeosun, J. T., and Lawal, A., 2010, “Residence-Time Distribution As a Measure of Mixing in T-Junction and Multilaminated/Elongational Flow Micromixers,” Chem. Eng. Sci., 65(5), pp. 1865–1874. [CrossRef]
Lee, J., and Kwon, S., 2009, “Mixing Efficiency of a Multilamination Micromixer With Consecutive Recirculation Zones,” Chem. Eng. J., 64(6), pp. 1223–1231. [CrossRef]
Fang, W. F., and Yang, J. T., 2009, “A Novel Microreactor With 3D Rotating Flow to Boost Fluid Reaction and Mixing of Viscous Fluids,” Sens. Act. B: Chem., 140(2), pp. 629–642. [CrossRef]
Ghanem, A., Lemenand, Th., Della Valle, D., and Peerhossaini, H., 2012, “Transport Phenomena in Chaotic Minichannels: Flux Recombination Reactors,” ASME 10th International Conference on Nanochannels, Microchannels and Minichannels, Rio Grande, Puerto Rico, July 8–12, ASME Paper No. ICNMM2012-73030.
Habchi, C., Lemenand, D., Della Valle, D., and Peerhossaini, H., 2010, “Alternating Mixing Tabs in Multifunctional Heat Exchanger-Reactor,” Chem. Eng. Process., 49(7), pp. 653–661. [CrossRef]
Hessel, V., and Zimmerman, W. B., 2006, “Investigation of the Convective Motion Through a Staggered Herringbone Micromixer at Low Reynolds Number Flow,” Chem. Eng. Sci., 61(9), pp. 2977–2985. [CrossRef]
Ho, C. K., Altman, S. J., Jones, H. D. T., Khalsa, S. S., McGrath, L. K., and Clem, P. G., 2008, “Analysis of Micromixers to Reduce Biofouling on Reverse-Osmosis Membranes,” Environ. Progr., 27(2), pp. 195–203. [CrossRef]
Johnson, T. J., Ross, D., and Locascio, L. E., 2002, “Rapid Microfluidic Mixing,” Anal. Chem., 74(1), pp. 45–51. [CrossRef] [PubMed]
Liu, R. H., Stremler, M. A., Sharp, K. V., Olsen, M. G., Santiego, J. G., Adrien, R. J. H., Aref, H., and Beebe, D. J., 2000, “Passive Mixing in a Three-Dimensional Serpentine Microchannel,” J. Microelectrochem. Syst., 9(2), pp. 190–197. [CrossRef]
Kim, D. J., Oh, H. J., Park, T. H., Choo, J. B., and Lee, S. H., 2005, “An Easily Integrative and Efficient Micromixer and Its Application to the Spectroscopic Detection of Glucose—Catalyst Reactions,” Analyst, 130(3), pp. 293–298. [CrossRef] [PubMed]
Ren, Y., and Woon-Fong Leung, W., 2013, “Flow and Mixing in Rotating Zigzag Microchannel,” Chem. Eng. J., 215–216, pp. 561–578. [CrossRef]
Heo, H. S., and Suh, Y. K., 2005, “Enhancement of Stirring in a Straight Channel at Low Reynolds Numbers With Various Block Arrangements,” J. Mech. Sci. Technol., 19(1), pp. 199–208. [CrossRef]
Mouza, A. A., Pasta, C. M., and Schönfeld, F., 2008, “Mixing Performance of a Chaotic Micro-Mixer,” Chem. Eng. Res. Design, 86(10), pp. 1128–1134. [CrossRef]
Furtaw, M. D., Lin, D., Wu, L., and Anderson, J. P., 2009, “Near-Infrared Metal-Enhanced Fluorescence Using a Liquid–Liquid Droplet Micromixer in a Disposable Poly (Methyl Methacrylate) Microchip,” Plasmonics, 4(4), pp. 273–280. [CrossRef]
Fujii, T., Sando, Y., Higashino, K., and Fujii, Y., 2003, “A Plug-and-Play Microfluidic Device,” Lab Chip, 3(3), pp. 193–197. [CrossRef] [PubMed]
Ahmed, D., Mao, X., Shi, J., Juluri, B. K., and Huang, T. J., 2009, “A Millisecond Micromixer Via Single-Bubble-Based Acoustic Streaming,” Lab Chip, 9(18), pp. 2738–2741. [CrossRef] [PubMed]
Ould El Moctar, A., Aubry, N., and Batton, J., 2003, “Electro-Hydrodynamic Micro-Fluidic Mixer,” Lab Chip, 3(4), pp. 273–280. [CrossRef] [PubMed]
Timite, B., Jarrahi, M., Castelain, C., and Peerhossaini, H., 2009, “Pulsating Flow for Mixing Intensification in a Twisted Curved Pipe,” ASME J. Fluids Eng., 131(12), p. 121104. [CrossRef]
Timité, B., Castelain, C., and Peerhossaini, H., 2011, “Mixing and Mass Transfer by Pulsatile Three-Dimensional Chaotic Flow in Alternating Curved Pipes,” Int. J. Heat Mass Transfer, 54(17–18), pp. 3933–3950. [CrossRef]
Jarrahi, M., Castelain, C., and Peerhossaini, H., 2011, “Secondary Flow Patterns and Mixing in Laminar Pulsating Flow Through a Curved Pipe,” Exp. Fluids, 50(6), pp. 1539–1558. [CrossRef]
Jarrahi, M., Castelain, C., and Peerhossaini, H., 2011, “Laminar Sinusoidal and Pulsatile Flows in a Curved Pipe,” J. Appl. Fluid Mech., 4(8), pp. 21–26.
Jarrahi, M., Castelain, C., and Peerhossaini, H., 2013, “Mixing Enhancement by Pulsating Chaotic Advection,” Chem. Eng. Proc., 74, pp. 1–13. [CrossRef]
Karami, M., Shirani, E., Jarrahi, M., and Peerhossaini, H., 2014, “Mixing by Time-Dependent Orbits in Spatiotemporal Chaotic Advection,” ASME J. Fluids Eng. (in press). [CrossRef]
Mao, W. B., and Xu, J. L., 2009, “Micromixing Enhanced by Pulsating Flows,” Int. J. Heat Mass Transfer, 52(21–22), pp. 5258–5261. [CrossRef]
Ammar, H., Garnier, B., Ould el Moctar, A., Willaime, H., Monti, F., and Peerhossaini, H., 2013, “Thermal Analysis of Chemical Reactions in Microchannels Using Highly Sensitive Thin-Film Heat-Flux Microsensor,” Chem. Eng. Sci., 94, pp. 150–155. [CrossRef]
Glasgow, I., and Aubry, N., 2003, “Enhancement of Microfluidic Mixing Using Time Pulsing,” Lab Chip, 3(2), pp. 114–120. [CrossRef] [PubMed]
Glasgow, I., Batton, J., and Aubry, N., 2004, “Electroosmotic Mixing in Microchannels,” Lab Chip4(6), pp. 558–562. [CrossRef] [PubMed]
Glasgow, I., Lieber, S., and Aubry, N., 2004, “Parameters Influencing Pulsed Flow Mixing in Microchannels,” Anal. Chem., 76(16), pp. 4825–4832. [CrossRef] [PubMed]
Goullet, A., Glasgow, I., and Aubry, N., 2005, “Dynamics of Microfluidic Mixing Using Time Pulsing,” Discrete Cont. Dyn. Syst., Suppl., pp. 327–336.
Goullet, A., Glasgow, I., and Aubry, N., 2006, “Effects of Microchannel Geometry on Pulsed Flow Mixing,” Mech. Res. Commun., 33(5), pp. 739–746. [CrossRef]
Soleymani, A., Kolehmainen, E., and Turunen, I., 2007, “Numerical and Experimental Investigations of Liquid Mixing in T-Type Micromixers,” Chem. Eng. J., 135(S1), pp. S219–S228. [CrossRef]
Hoffmann, M., Schluter, M., and Rabiger, N., 2006, “Experimental Investigation of Liquid–Liquid Mixing in T-Shaped Micro-Mixers Using µ-LIF and µ-PIV,” Chem. Eng. Sci., 61(9), pp. 2968–2976. [CrossRef]
Bothe, D., Stemich, C., and Warnecke, H. J., 2006, “Fluid Mixing in a T-Shaped Micro-Mixer,” Chem. Eng. Sci., 61(9), pp. 2950–2958. [CrossRef]
ISS, 2014, ISS, Inc., Champaign, IL, http://www.iss.com
Bottausci, F., Mezic, I., Meinhart, C. D., and Cardonne, C., 2004, “Mixing in the Shear Superposition Mixer: Three-Dimensional Analysis,” R. Soc. London Trans. Ser., 362(1818), pp. 1001–1018. [CrossRef]
Lee, Y. K., Deval, J., Tabeling, P., and Ho, C. M., 2001, “Chaotic Mixing in Electrokinetically and Pressure Driven Micro Flows,” 14th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2001), Interlaken, Switzerland, January 21–25, pp. 483–486. [CrossRef]
Peerhossaini, H., and Wesfreid, J. E., 1988, “On the Inner Structure of Görtler Vortices,” Int. J. Heat Fluid Flow, 9(1), pp. 12–18. [CrossRef]
Mutabazi, I., Normand, C., Peerhossaini, H., and Wesfreid, J. E., 1989, “Oscillatory Modes in the Flow Between Two Horizontal Corotating Cylinders With a Partially Filled Gap,” Phys. Rev. A, 39(2), pp. 763–771. [CrossRef] [PubMed]
Ammar, H., Garnier, B., Sediame, D., Ould El Moctar, A., and Peerhossaini, H., 2013, “Heat-Transfer Analysis and Improved Mixing in Multifunctional Microreactor Using Sapphire Window and Infrared Thermography,” Int. J. Micro. Nano. Therm. Fluid Transp. Phenom., 4(3–4), pp. 1–19.


Grahic Jump Location
Fig. 1

The four intersection geometries studied, consisting of two inlet channels and one micromixer outlet channel: (a) right angle intersection, (b) “Y” intersection, (c) “T” intersection, and (d) arrowhead intersection. All channels are 500 μm wide, 50 μm deep, and 38 mm long.

Grahic Jump Location
Fig. 2

Schematic diagram of flow visualization in the microchannel by fluorescence technique

Grahic Jump Location
Fig. 3

The excitation and emission spectra (λmax(ex) = 554 nm, λmax(em) = 579 nm) of rhodamine B in water [50]

Grahic Jump Location
Fig. 4

Flow cross section at the entrance of Y intersection channel for a continuous flow with V0 = 0.022 m s−1, Re = 2: (a) experiment and (b) numerical simulation

Grahic Jump Location
Fig. 5

Experimental and numerical profiles of Mi in the flow cross sections (Fig. 4) in a Y intersection with continuous flow rate for average velocity V0 = 0.022 m s−1 and Re = 2: (a) cross section CD in Figs. 4(a) and 4(b) cross section AB in Fig. 4(a)

Grahic Jump Location
Fig. 6

Experimental mixing index as a function of the nondimensional residence time in the microchannel for the confluence geometry with continuous flow rate

Grahic Jump Location
Fig. 7

Numerical mixing index as a function of the nondimensional residence time in the microchannel for the confluence geometry with continuous flow rate

Grahic Jump Location
Fig. 8

Experimental mixing index at the micromixer channel outlet as a function of Reynolds number for all geometries with a continuous flow rate

Grahic Jump Location
Fig. 9

Experimental mixing index as a function of position in micromixer channel for different values of β for all geometries (Re = 0.8)

Grahic Jump Location
Fig. 10

Experimental mixing index as a function of the position in the microchannel for β = 2 (pulsed) and β = 0 (continuous) for the right angle intersection (Re = 0.8)

Grahic Jump Location
Fig. 11

Numerical mixing index as a function of position in microchannel for different β values for all geometries (Re = 0.8)

Grahic Jump Location
Fig. 12

Experimental mixing index at microchannel outlet versus β ratio for all geometries (Re = 0.8)



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In