Oscillatory electrokinetic flow is numerically examined in a rectangular annulus microtube under the influence of various wave forms. When the inner and outer walls of the capillary are oppositely charged, an instantaneous two-direction flow field is produced and consequently the resultant flow rate is relatively reduced. A zero or negative flow rate may be achieved by appropriate design of the channel geometrical characteristics (e.g., hydraulic diameter) as well as the walls charges. In the case of sufficiently low kinematic viscosity and/or high excitation frequency, a relatively thin transient frictional layer is established close to the walls while the bulk fluid lags behind the liquid motion in the electric double layer by a phase shift. If different waveforms are combined together, fascinating outcomes can be obtained depending on the frequency of each individual wave. Applied electric fields with equal- and unequal-frequency combined waves may have the advantages of a double velocity field and a net mass flow rate, respectively. Interestingly, a direct flow pattern may be achieved by appropriately combining various waveforms with unequal frequencies. The mass flow rate decreases, with the constancy of the electrokinetic diameter, with approximately the square of hydraulic diameter. The Poiseuille number exhibits various characteristics depending on the excitation frequency as well as the type of wave especially in combination.
Skip Nav Destination
Article navigation
November 2019
Research-Article
Unsteady Electrokinetic Flow in a Microcapillary: Effects of Periodic Excitation and Geometry
Ali Jabari Moghadam
Ali Jabari Moghadam
Faculty of Mechanical Engineering,
Shahrood University of Technology,
Shahrood 3619995161, Iran
e-mail: jm.ali.project@gmail.com
Shahrood University of Technology,
Shahrood 3619995161, Iran
e-mail: jm.ali.project@gmail.com
Search for other works by this author on:
Ali Jabari Moghadam
Faculty of Mechanical Engineering,
Shahrood University of Technology,
Shahrood 3619995161, Iran
e-mail: jm.ali.project@gmail.com
Shahrood University of Technology,
Shahrood 3619995161, Iran
e-mail: jm.ali.project@gmail.com
Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received December 7, 2018; final manuscript received March 22, 2019; published online May 8, 2019. Assoc. Editor: Shizhi Qian.
J. Fluids Eng. Nov 2019, 141(11): 111104 (13 pages)
Published Online: May 8, 2019
Article history
Received:
December 7, 2018
Revised:
March 22, 2019
Citation
Moghadam, A. J. (May 8, 2019). "Unsteady Electrokinetic Flow in a Microcapillary: Effects of Periodic Excitation and Geometry." ASME. J. Fluids Eng. November 2019; 141(11): 111104. https://doi.org/10.1115/1.4043337
Download citation file:
Get Email Alerts
Cited By
Effect of Power-Law Fluids Flow Structures on Germicides Disinfection Through Taylor–Couette Configuration
J. Fluids Eng (March 2024)
A Method to Determine Bubble Distribution in Liquid Using Data of Inverse Acoustical Scattering
J. Fluids Eng (March 2024)
Related Articles
Exact Solution of AC Electro-Osmotic Flow in a Microannulus
J. Fluids Eng (September,2013)
Numerical Modeling of Chaotic Mixing in Electroosmotically Stirred Continuous Flow Mixers
J. Heat Transfer (September,2009)
Electro-Osmosis Modulated Viscoelastic Embryo Transport in Uterine Hydrodynamics: Mathematical Modeling
J Biomech Eng (February,2019)
Non-Newtonian Fluid Flow and Heat Transfer in a Semicircular Microtube Induced by Electroosmosis and Pressure Gradient
J. Heat Transfer (December,2018)
Related Proceedings Papers
Related Chapters
Boundary Layer Analysis
Centrifugal Compressors: A Strategy for Aerodynamic Design and Analysis
Stability and Range
Design and Analysis of Centrifugal Compressors
Random Turbulence Excitation in Single-Phase Flow
Flow-Induced Vibration Handbook for Nuclear and Process Equipment