A mathematical model of mixing enhancement in microfluidic channel with a constriction under periodic electro-osmotic flow

2012 ◽  
Vol 100 (4) ◽  
pp. 041907 ◽  
Author(s):  
Zhongbin Xu ◽  
Yue Yang ◽  
Damien Vadillo ◽  
Xiaodong Ruan ◽  
Xin Fu
Keyword(s):  
Mathematical Model ◽  
Microfluidic Channel ◽  
Mixing Enhancement ◽  
Osmotic Flow ◽  
Electro Osmotic Flow

Lubrication theory for electro-osmotic flow in a microfluidic channel of slowly varying cross-section and wall charge

2002 ◽  
Vol 459 ◽  
pp. 103-128 ◽  
Author(s):  
SANDIP GHOSAL
Keyword(s):  
Cross Section ◽  
Microfluidic Channel ◽  
Lubrication Theory ◽  
Wall Material ◽  
Channel Cross Section ◽  
Microfluidic Channels ◽  
Osmotic Flow ◽  
Axial Variation ◽  
Wall Charge ◽  
Electro Osmotic Flow

Electro-osmotic flow is a convenient mechanism for transporting fluid in microfluidic devices. The flow is generated through the application of an external electric field that acts on the free charges that exist in a thin Debye layer at the channel walls. The charge on the wall is due to the particular chemistry of the solid–fluid interface and can vary along the channel either by design or because of various unavoidable inhomogeneities of the wall material or because of contamination of the wall by chemicals contained in the fluid stream. The channel cross-section could also vary in shape and area. The effect of such variability on the flow through microfluidic channels is of interest in the design of devices that use electro-osmotic flow. The problem of electro-osmotic flow in a straight microfluidic channel of arbitrary cross-sectional geometry and distribution of wall charge is solved in the lubrication approximation, which is justified when the characteristic length scales for axial variation of the wall charge and cross-section are both large compared to a characteristic width of the channel. It is thereby shown that the volume flux of fluid through such a microchannel is a linear function of the applied pressure drop and electric potential drop across it, the coefficients of which may be calculated explicitly in terms of the geometry and charge distribution on the wall. These coefficients characterize the ‘fluidic resistance’ of each segment of a microfluidic network in analogy to the electrical ‘resistance’ in a microelectronic circuit. A consequence of the axial variation in channel properties is the appearance of an induced pressure gradient and an associated secondary flow that leads to increased Taylor dispersion limiting the resolution of electrophoretic separations. The lubrication theory presented here offers a simple way of calculating the distortion of the flow profile in general geometries and could be useful in studies of dispersion induced by inhomogeneities in microfluidic channels.

LATTICE BOLTZMANN SIMULATIONS OF MIXING ENHANCEMENT BY THE ELECTRO-OSMOTIC FLOW IN MICROCHANNELS

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1515-1518 ◽  
Author(s):  
JINKU WANG ◽  
MORAN WANG ◽  
ZHIXIN LI
Keyword(s):  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Potential Distribution ◽  
Electrical Potential ◽  
Mixing Enhancement ◽  
Lattice Boltzmann Methods ◽  
Osmotic Flow ◽  
Lattice Boltzmann Simulations ◽  
Simulation Results ◽  
Electro Osmotic Flow

The Lattice Boltzmann methods are used to study the mixing enhancements by the electro-osmotic flow in microchannel. Three sets of lattice evolution methods are performed for the fluid flow, for the electrical potential distribution, and for the concentration propagation. The simulation results show that the electro-osmotic flow induces y-directional velocity which enhances the mixing in microchannels. The mixing enhancement is related with the surface zeta potential arrangement and the external electric field strength.

scholarly journals Towards bio-inspired artificial muscle: a mechanism based on electro-osmotic flow simulated using dissipative particle dynamics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramin Zakeri
Keyword(s):  
Zeta Potential ◽  
Electric Field ◽  
Dissipative Particle Dynamics ◽  
Artificial Muscle ◽  
Particle Dynamics ◽  
Polymer Membrane ◽  
Channel Width ◽  
Micro Channel ◽  
Osmotic Flow ◽  
Electro Osmotic Flow

AbstractOne of the unresolved issues in physiology is how exactly myosin moves in a filament as the smallest responsible organ for contracting of a natural muscle. In this research, inspired by nature, a model is presented consisting of DPD (dissipative particle dynamics) particles driven by electro-osmotic flow (EOF) in micro channel that a thin movable impermeable polymer membrane has been attached across channel width, thus momentum of fluid can directly transfer to myosin stem. At the first, by validation of electro-osmotic flow in micro channel in different conditions with accuracy of less than 10 percentage error compared to analytical results, the DPD results have been developed to displacement of an impermeable polymer membrane in EOF. It has been shown that by the presence of electric field of 250 V/m and Zeta potential − 25 mV and the dimensionless ratio of the channel width to the thickness of the electric double layer or kH = 8, about 15% displacement in 8 s time will be obtained compared to channel width. The influential parameters on the displacement of the polymer membrane from DPD particles in EOF such as changes in electric field, ion concentration, zeta potential effect, polymer material and the amount of membrane elasticity have been investigated which in each cases, the radius of gyration and auto correlation velocity of different polymer membrane cases have been compared together. This simulation method in addition of probably helping understand natural myosin displacement mechanism, can be extended to design the contraction of an artificial muscle tissue close to nature.

Modeling electro-osmotic flow and thermal transport of Caputo fractional Burgers fluid through a micro-channel

2021 ◽  
pp. 095440892110259
Author(s):  
Mohammed Abdulhameed ◽  
Garba Tahiru Adamu ◽  
Gulibur Yakubu Dauda
Keyword(s):  
Electric Field ◽  
Laplace Transform ◽  
Inverse Laplace Transform ◽  
Micro Channel ◽  
Osmotic Flow ◽  
Sine Transform ◽  
Fourier Sine ◽  
Fourier Sine Transform ◽  
Burgers Fluid ◽  
Electro Osmotic Flow

In this paper, we construct transient electro-osmotic flow of Burgers’ fluid with Caputo fractional derivative in a micro-channel, where the Poisson–Boltzmann equation described the potential electric field applied along the length of the microchannel. The analytical solution for the component of the velocity profile was obtained, first by applying the Laplace transform combined with the classical method of partial differential equations and, second by applying Laplace transform combined with the finite Fourier sine transform. The exact solution for the component of the temperature was obtained by applying Laplace transform and finite Fourier sine transform. Further, due to the complexity of the derived models of the governing equations for both velocity and temperature, the inverse Laplace transform was obtained with the aid of numerical inversion formula based on Stehfest's algorithms with the help of MATHCAD software. The graphical representations showing the effects of the time, retardation time, electro-kinetic width, and fractional parameters on the velocity of the fluid flow and the effects of time and fractional parameters on the temperature distribution in the micro-channel were presented and analyzed. The results show that the applied electric field, electro-osmotic force, electro-kinetic width, and relaxation time play a vital role on the velocity distribution in the micro-channel. The fractional parameters can be used to regulate both the velocity and temperature in the micro-channel. The study could be used in the design of various biomedical lab-on-chip devices, which could be useful for biomedical diagnosis and analysis.

scholarly journals AC-driven electro-osmotic flow in charged nanopores

2018 ◽  
Vol 123 (5) ◽  
pp. 58006 ◽  
Author(s):  
J. Catalano ◽  
P. M. Biesheuvel
Keyword(s):  
Osmotic Flow ◽  
Electro Osmotic Flow
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