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.

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.

Analysis of a Viscoelastic Fluid Flow in a Microchannel With Asymmetric Zeta Potentials Under a Combination of Electroosmotic and Magnetohydrodynamic Driven Forces

2014 ◽  
Author(s):  
Juan P. Escandón ◽  
Oscar E. Bautista ◽  
Federico Méndez
Keyword(s):  
Fluid Flow ◽  
Electric Fields ◽  
Viscoelastic Fluid ◽  
Flow Rate ◽  
Electroosmotic Flow ◽  
Future Application ◽  
Buffer Solution ◽  
Viscoelastic Parameter ◽  
Zeta Potentials ◽  
Fluid Field

In this paper an analytical solution to describe the velocity profiles and flow rate of combined electroosmotic and magnetohydrodynamic flows in a microchannel is obtained. A fully-developed flow is considered and the fluid obeys a constitutive relation based in a simplified Phan-Thien-Tanner model. Asymmetric boundary conditions with different zeta potentials at the walls are specified to provide a perturbation to the fluid flow. The effect of the dimensionless parameters on the flow field as viscoelastic parameter, the Hartmann number, the ratio of applied electric fields on the fluid field and the ratio of the wall zeta potentials is predicted. The analysis permits to establish the conditions for which the flow rate is increased respect to a purely electroosmotic flow, therefore, in the limit of small Hartmann numbers and low electrical conductivity in the buffer solution correspond to the range where the electric and magnetic effects can be used to move a charged solution in the flow control and sample handling in biomedical and chemical analysis. In addition, we determine the conditions that must be met to prevent the undesirable lateral electroosmotic flow, which is present in this kind of applications. Finally, the combined effect of asymmetric zeta potentials and electro-magnetic fields on viscoelastic fluid flows in microchannels is discussed as future application of mixed in microfluidics devices.

Electrokinetics of polymeric fluids in narrow rectangular confinements

Soft Matter ◽  
2021 ◽  
Author(s):  
Aditya Natu ◽  
Uddipta Ghosh
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Double Layers ◽  
Polymeric Fluids ◽  
Polymeric Liquids ◽  
Electrical Double Layers

Flow of polymeric liquids in narrow confinements of rectangular cross section, in the presence of electrical double layers is analyzed here. Our analysis is motivated by the fact that many...

Molecular solvent models of electrical double layers

1991 ◽  
Vol 36 (11-12) ◽  
pp. 1677-1684 ◽  
Author(s):  
G.M. Torrie ◽  
G.N. Patey
Keyword(s):  
Double Layers ◽  
Electrical Double Layers ◽  
Solvent Models

scholarly journals Asymptotic Behavior of a Viscoelastic Fluid in a Closed Loop Thermosyphon: Physical Derivation, Asymptotic Analysis, and Numerical Experiments

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
Justine Yasappan ◽  
Ángela Jiménez-Casas ◽  
Mario Castro
Keyword(s):  
Asymptotic Behavior ◽  
Viscoelastic Fluid ◽  
Closed Loop ◽  
Theoretical Study ◽  
Equations Of Motion ◽  
Asymptotic Properties ◽  
Inertial Manifold ◽  
Thermal Gradients ◽  
External Temperature ◽  
First Time

Fluids subject to thermal gradients produce complex behaviors that arise from the competition with gravitational effects. Although such sort of systems have been widely studied in the literature for simple (Newtonian) fluids, the behavior of viscoelastic fluids has not been explored thus far. We present a theoretical study of the dynamics of a Maxwell viscoelastic fluid in a closed-loop thermosyphon. This sort of fluid presents elastic-like behavior and memory effects. We study the asymptotic properties of the fluid inside the thermosyphon and the exact equations of motion in the inertial manifold that characterizes the asymptotic behavior. We derive, for the first time, the mathematical derivations of the motion of a viscoelastic fluid in the interior of a closed-loop thermosyphon under the effects of natural convection and a given external temperature gradient.

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