Electroosmotic Flow Rate: A Semiempirical Approach

2000 ◽  
pp. 247-266 ◽  
Author(s):  
J. H. Chang ◽  
Z. Qiang ◽  
C. P. Huang ◽  
D. Cha
Keyword(s):  
Flow Rate ◽  
Electroosmotic Flow ◽  
Semiempirical Approach

Electroosmotic Flow in Hydrophobic Microchannels of General Cross Section

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Morteza Sadeghi ◽  
Arman Sadeghi ◽  
Mohammad Hassan Saidi
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Slip Length ◽  
Debye Length ◽  
Surface Hydrophobicity ◽  
Double Layers ◽  
Slip Conditions ◽  
Wall Boundary Conditions ◽  
Electroosmotic Velocity

Adopting the Navier slip conditions, we analyze the fully developed electroosmotic flow in hydrophobic microducts of general cross section under the Debye–Hückel approximation. The method of analysis includes series solutions which their coefficients are obtained by applying the wall boundary conditions using the least-squares matching method. Although the procedure is general enough to be applied to almost any arbitrary cross section, eight microgeometries including trapezoidal, double-trapezoidal, isosceles triangular, rhombic, elliptical, semi-elliptical, rectangular, and isotropically etched profiles are selected for presentation. We find that the flow rate is a linear increasing function of the slip length with thinner electric double layers (EDLs) providing higher slip effects. We also discover that, unlike the no-slip conditions, there is not a limit for the electroosmotic velocity when EDL extent is reduced. In fact, utilizing an analysis valid for very thin EDLs, it is shown that the maximum electroosmotic velocity in the presence of surface hydrophobicity is by a factor of slip length to Debye length higher than the Helmholtz–Smoluchowski velocity. This approximate procedure also provides an expression for the flow rate which is almost exact when the ratio of the channel hydraulic diameter to the Debye length is equal to or higher than 50.

scholarly journals Analytical Solution for Heat Transfer in Electroosmotic Flow of a Carreau Fluid in a Wavy Microchannel

2019 ◽  
Vol 9 (20) ◽  
pp. 4359 ◽  
Author(s):  
Saima Noreen ◽  
Sadia Waheed ◽  
Abid Hussanan ◽  
Dianchen Lu
Keyword(s):  
Fluid Flow ◽  
Flow Pattern ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Linear Problem ◽  
Perturbation Technique ◽  
Volumetric Flow Rate ◽  
Carreau Fluid ◽  
Long Wavelength ◽  
Wide Range

This article explores the heat and transport characteristics of electroosmotic flow augmented with peristaltic transport of incompressible Carreau fluid in a wavy microchannel. In order to determine the energy distribution, viscous dissipation is reckoned. Debye Hückel linearization and long wavelength assumptions are adopted. Resulting non-linear problem is analytically solved to examine the distribution and variation in velocity, temperature and volumetric flow rate within the Carreau fluid flow pattern through perturbation technique. This model is also suitable for a wide range of biological microfluidic applications and variation in velocity, temperature and volumetric flow rate within the Carreau fluid flow pattern.

Basic Study for Micro Pump Using Electroosmotic Flow

2003 ◽  
Author(s):  
Tamio Fujiwara ◽  
Akinori Kamiya ◽  
Osami Kitoh ◽  
Tatsuo Ushijima
Keyword(s):  
Pressure Gradient ◽  
Flow Rate ◽  
Applied Voltage ◽  
Electroosmotic Flow ◽  
Great Influence ◽  
Smoluchowski Equation ◽  
Flow Meter ◽  
Flow Rates ◽  
Micro Pump ◽  
Gap Width

The characteristic features of electroosmotic flow have been studied to obtain important information for applying the flow to a micro pump as a driving device. Here, an electroosmotic flow of water was generated in a donut channel constructed by a gap between two parallel donut-shaped glass plates. The flow rate was measured in relation to the applied voltage, the gap width of the channel, the pressure gradient and the properties of the fluid. The experimental results were compared with a theoretical equation of electroosmosis, the Helmholtz-Smoluchowski equation, which predicts that the electroosmotic flow rate is proportional to the applied voltage as well as to the gap width. The Electroosmotic flow rate increased linearly with the applied voltage. however, there appeared some particular voltage ranges of nonlinear relation unlike the Helmholtz-Smoluchowski equation. The water properties (the conductivity and the kinds of impurities included) had a great influence on the electroosmotic flow rate characteristics including the degree of non-linearity and even the flow direction. The cause of these phenomena has not been clarified. It is conjectured that the zeta potential of the glass-water interface was altered by the applied electric field. It is confirmed that the electroosmotic flow rate is proportional to the gap size of the channel. When a pressure gradient existed in the direction of the electroosmotic flow, the total flow rate was given as a sum of the flow rates of the electroosmotic and Poiseuille flows. These findings provide important information for micro pumps. For measuring the electroosmotic flow rate, we developed a micro flow meter consisting of a capillary and two fine wires. This flow meter makes it possible to measure a flow rate the order of 1×10−3 mm3/sec (= 1 nl/sec) and has a potential ability to measure even much smaller flow rates.

scholarly journals Electroosmotic Flow of Viscoelastic Fluid in a Nanochannel Connecting Two Reservoirs

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 747 ◽  
Author(s):  
Mei ◽  
Qian
Keyword(s):  
Constitutive Model ◽  
Viscoelastic Fluid ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Double Layers ◽  
Ionic Conductance ◽  
Electrical Double Layers ◽  
Interconnect System ◽  
First Time ◽  
Thinning Effect

: Electroosmotic flow (EOF) of viscoelastic fluid with Linear Phan-Thien–Tanner (LPTT) constitutive model in a nanochannel connecting two reservoirs is numerically studied. For the first time, the influence of viscoelasticity on the EOF and the ionic conductance in the micro-nanofluidic interconnect system, with consideration of the electrical double layers (EDLs), is investigated. Regardless of the bulk salt concentration, significant enhancement of the flow rate is observed for viscoelastic fluid compared to the Newtonian fluid, due to the shear thinning effect. An increase in the ionic conductance of the nanochannel occurs for the viscoelastic fluid. The enhancement of the ionic conductance is significant under the overlapping EDLs condition.

scholarly journals Electroosmotic Flow of Non-Newtonian Fluid in Porous Polymer Membrane at High Zeta Potentials

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1046
Author(s):  
Shuyan Deng ◽  
Yukun Zeng ◽  
Mingying Li ◽  
Cuixiang Liang
Keyword(s):  
Zeta Potential ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Applied Voltage ◽  
Electroosmotic Flow ◽  
Polymer Membrane ◽  
Porous Polymer ◽  
Total Flow ◽  
Total Flow Rate ◽  
Zeta Potentials

To help in the efficient design of fluid flow in electroosmotic pumps, electroosmotic flow of non-Newtonian fluid through porous polymer membrane at high zeta potentials is studied by mainly evaluating the total flow rate at different physical parameters. Non-Newtonian fluid is represented by the power-law model and the porous polymer membrane is considered as arrays of straight cylindrical pores. The electroosmotic flow of non-Newtonian fluid through a single pore is studied by solving the complete Poisson–Boltzmann equation and the modified Cauchy momentum equation. Then assuming the pore size distribution on porous polymer membrane obeys Gaussian distribution, the performance of electroosmotic pump operating non-Newtonian fluid is evaluated by computing the total flow rate of electroosmotic flow through porous polymer membrane as a function of flow behavior index, geometric parameters of porous membrane, electrolyte concentration, applied voltage, and zeta potential. It is found that enhancing zeta potential and bulk concentration rather than the applied voltage can also significantly improve the total flow rate in porous polymer membrane, especially in the case of shear thinning fluid.

Unsteady Rotating Electroosmotic Flow Through a Slit Microchannel

2016 ◽  
Vol 32 (5) ◽  
pp. 603-611 ◽  
Author(s):  
D.-Q. Si ◽  
Y.-J. Jian ◽  
L. Chang ◽  
Q.-S. Liu
Keyword(s):  
Flow Rate ◽  
Electroosmotic Flow ◽  
Volume Flow Rate ◽  
Electrical Potential ◽  
Velocity Fields ◽  
Volume Flow ◽  
Half Height ◽  
Poisson Boltzmann ◽  
Flow Through ◽  
Poisson Boltzmann Equation

AbstractUsing the method of Laplace transform, an analytical solution of unsteady rotating electroosmotic flow (EOF) through a parallel plate microchannel is presented. The analysis is based upon the linearized Poisson-Boltzmann equation describing electrical potential distribution and the Navies Stokes equation representing flow field in the rotating coordinate system. The discrepancy of present problem from classical EOF is that the velocity fields are two-dimensional. The rotating EOF velocity profile and flow rate greatly depend on time t, rotating parameter ω and the electrokinetic width K (ratio of half height of microchannel to thickness of electric double layer). The influence of the above dimensionless parameters on transient EOF velocity, volume flow rate and EO spiral is investigated.

Electroosmotic Flow Pump on Transparent Polyimide Substrate Fabricated Using Hot Embossing

2013 ◽  
Vol 300-301 ◽  
pp. 1356-1359 ◽  
Author(s):  
Hirofumi Saito ◽  
Hiroki Komatsuzaki ◽  
Ryuta Ikoma ◽  
Takayuki Komori ◽  
Keigo Kuroda ◽  
...  
Keyword(s):  
Flow Rate ◽  
Electroosmotic Flow ◽  
Hot Embossing ◽  
Ozone Treatment ◽  
Capping Layer ◽  
Polyimide Substrate ◽  
Uv Ozone ◽  
Flow Pump

Improved fabrication processes of an all-polyimide micro electroosmotic flow pump using hot embossing are described. Microchannels in the micropump were fabricated by hot embossing on a transparent polyimide substrate. A silicon micromachined mold was pressed into the transparent polyimide substrate at a temperature of 300 oC to form microchannel patterns on the substrate. The depth and width of the microchannels were 25 μm and 50 μm, respectively. A UV ozone treatment was performed to improve adhesion between the transparent polyimide substrate and film capping layer. This UV ozone treatment enhanced adhesion and resulted in the reduction of the adhesion temperature as low as 100 oC, and nearly no deformation of the microchannels was observed. As a result, the electroosmotic flow pump exhibited the flow rate of 0.7 μl/min when a voltage of 50 V was given between the electrodes separated 20 mm each other.

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