Laminar flow and mass transport in a twice–folded microchannel

The flow and mass transport within a twice–folded microchannel is investigated. For the measurement of the concentration field the microlaser–induced fluorescence technique (μLIF) is engaged. Microparticle image velocimetry (μPIV) is further employed to obtain the velocity field. Deviation from standard μPIV by seeding a partial stream of the flow only, results in partial velocity profiles. This procedure allows for the observation of the contact interface between the seeded and the unseeded liquid. Distorted contact interfaces is recognized within and after each bend, indicating strong secondary flows. The measurements are compared to numerical simulations, solving for both the flow, and the mass-transport equations, and, subsequently, performing particle tracking. The results are, on one hand, in reasonable agreement with the experiments. On the other hand, the differences between the contact interface from the mass-transport equation and from particle tracking clarifies the effect of diffusion. © 2007 American Institute of Chemical Engineers AIChE J, 2008

[1]  W. R. Dean.  LXXII. The stream-line motion of fluid in a curved pipe (Second paper) , 1928 .

[2]  A. Manz,et al.  Miniaturized total chemical analysis systems: A novel concept for chemical sensing , 1990 .

[3]  E. O. Schulz-Dubois,et al.  The development and structure of primary and secondary flow in a curved square duct , 1985, Journal of Fluid Mechanics.

[4]  D. Beebe,et al.  A particle image velocimetry system for microfluidics , 1998 .

[5]  Wolfgang Ehrfeld,et al.  Microreactors: New Technology for Modern Chemistry , 2000 .

[6]  K. C. Cheng,et al.  Fully Developed Laminar Flow in Curved Rectangular Channels , 1976 .

[7]  Ryosuke Matsumoto,et al.  Quantitative measurement of depth–averaged concentration fields in microchannels by means of a fluorescence intensity method , 2005 .

[8]  Takehiko Kitamori,et al.  Fast and high conversion phase-transfer synthesis exploiting the liquid–liquid interface formed in a microchannel chip , 2001 .

[9]  Klaus Schubert,et al.  Characterisation of electrically powered micro-heat exchangers☆ , 2004 .

[10]  A. J. Ward-Smith.  Internal Fluid Flow: The Fluid Dynamics of Flow in Pipes and Ducts , 1980 .

[11]  P. Ehrhard,et al.  Electrically-excited (electroosmotic) flows in microchannels for mixing applications , 2006 .

[12]  Joel H. Ferziger,et al.  Computational methods for fluid dynamics , 1996 .

[13]  M. Sommerfeld,et al.  Multiphase Flows with Droplets and Particles , 2011 .

[14]  Yoshiko Yamaguchi,et al.  3-D Simulation and Visualization of Laminar Flow in a Microchannel with Hair-Pin Curves , 2004 .

[15]  R. Adrian,et al.  Whole field measurement of temperature in water using two-color laser induced fluorescence , 1997 .

[16]  J. Michael Ramsey,et al.  The burgeoning power of the shrinking laboratory , 1999, Nature Biotechnology.

[17]  G. Whitesides,et al.  Microfabrication inside capillaries using multiphase laminar flow patterning , 1999, Science.

[18]  B. Joseph,et al.  Numerical treatment of laminar flow in helically coiled tubes of square cross section. Part I. Stationary helically coiled tubes , 1975 .

[19]  Stephen C Jacobson,et al.  Diffusion coefficient measurements in microfluidic devices. , 2002, Talanta.

[20]  Steffen Hardt,et al.  Simulation of helical flows in microchannels , 2004 .

[21]  J. S. Sokhey,et al.  Laminar Incompressible Viscous Flow in Curved Ducts of Regular Cross-Sections , 1977 .

[22]  W. R. Dean.  XVI. Note on the motion of fluid in a curved pipe , 1927 .

[23]  S. Wereley,et al.  PIV measurements of a microchannel flow , 1999 .

[24]  A Manz,et al.  Microfabricated devices for fluid mixing and their application for chemical synthesis. , 2001, Chemical record.