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Title: Electro-osmotically Assisted Peristaltic Transport in Microchannels
Authors: Waheed, Sadia
Keywords: Physical Sciences
Issue Date: 2021
Publisher: COMSATS University, Islamabad.
Abstract: Electro-osmotically Assisted Peristaltic Transport in Microchannels The core objective of this thesis is to examine the judicious combination of electroosmotic and peristaltic mechanisms in micro-channels. The effects of various parameters of physical importance on the peristaltic flow augmented with electroosmosis in Newtonian, non-Newtonian and nanofluids over different geometries (symmetric/asymmetric/curved) is emphasized. This thesis deals with the application of mathematics in peristaltic fluid flow augmented with electroosmosis; the formulation and modeling of the problem, development of appropriate analytical/numerical solution and interpretations of the results highlighting the effects of the proposed parameters remain in focus. The transport model comprises the continuity, momentum, energy, concentration and electric potential equations with appropriate boundary conditions. The consideration of the physical parameters is justified with appropriate application from biosciences, biomicrofluidics and technology. Mathematical modeling of the considered problems is based on realistic assumptions and approximations. Furthermore, entropy analysis will also be addressed in the said flows. The results obtained are compared with the existing literature and are explained physically. It is believed that the inclusion of the proposed additional parameters will improve the basic understanding of electroosmosis and lay a framework to improve the technological and biological aspects through the analytical analysis. A peristaltic flow is created by wave propagation along the channel walls. It is an inherent characteristic of numerous biological and biomedical systems. The physics significantly changes with the length scale from macro to micro level. Electroosmosis is one of the important electrokinetic phenomena of microfluidics which primarily depends on the emergence of an electric double layer (EDL) and applied electric field. The peristaltic (natural phenomena) flow augmented with electroosmosis (chemical phenomena) is of dynamic importance in improving/controlling the physiological transport. The significance of this judicious combination is applicable in designing the electro-osmotically actuated bio-micro xi fluidic devices/systems. Mathematical simulations of peristaltic transport in microfluidic devices have recently attracted some attention. Most of the studies on EOF are based on the Newtonian fluids because most of the electrolytes or buffer solutions used in microfluidic devices are Newtonian fluids. We feel that some important links are missing in the development of the peristalsis with electroosmosis in the microchannel, which needs to be addressed. The existing observations were without consideration of non-newtonian fluids, nanofluids, viscous dissipation, Joule heating, MHD, porosity, heat and mass transfer under certain conditions. We further notice that the concept of entropy generation is not attended in peristalsis. We intend to incorporate these concepts here. We will elucidate the physics of the electroosmosis and peristalsis mechanisms and the underlying concepts which will help to understand the phenomena of electroosmosis in the presence of such physically important factors. Generally, close form exact solutions of non-linear differential equations are not possible. Therefore, analytical and numerical solutions are presented. Thesis is organized as follows: Chapter one is based on literature review, fundamentals equations and basic definitions involved in the subsequent chapters. In chapter two, we present the heat and electroosmotic characteristics in the flow of a third-order fluid regulated by peristaltic pumping. Here, symmetric microchannel is considered. The emerging non-linear mathematical model is solved analytically and compared numerically by the built-in scheme of working software. The results presented here are published in “Journal of Biological Physics, 1-21” Thermal analysis of the electroosmotic flow of Williamson fluid in the presence of peristaltic propulsion and asymmetric zeta potential at the walls is presented in chapter three. The normalized governing equations are subjected to reliable approximations. The emerging non-linearized boundary value problem is solved analytically and numerically. The influence of various dominant parameters is discussed for various physical quantities. To verify the accuracy of results, the comparison of solutions is also shown. This work has been published in “Alexandria Engineering Journal” xii In chapter four, electrokinetic peristaltic slip transport in an asymmetric porous microchannel is presented to explore the entropy production in steady magnetohydrodynamic Jeffery fluid under Debye and long wavelength approximations. The emerging two-dimensional bounded problem with electrokinetic body forces is solved numerically. The content of this paper is published in “Journal of the Brazilian Society of Mechanical Sciences and Engineering, 42(295), 295” Heat and transport characteristics of electroosmotic flow augmented with peristaltic transport of incompressible Carreau fluid is presented in chapter five. To determine the energy distribution, viscous dissipation is reckoned. Debye Huckel 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 work has been published in “Applied Sciences, 9(20), 4359” Chapter six investigates the electrokinetic peristaltic transportation of Sisko fluid in tapered microchannel under the action of an axial electrical and transverse magnetic field. Heat transfer characteristics of flow are simulated with viscous and porous dissipation. Emerging non-linear electrokinetic system is solved using numerical scheme. Accuracy of results is verified by comparison with special cases of existing literature. The results of this chapter are submitted for publication in “Numerical Methods for Partial Differential Equations Editorial Office” In chapter seven, a mathematical scrutiny is introduced for the flow of magneto hydrodynamic nanofluid through an asymmetric microfluidic channel under an applied axial electric field. The impacts of wall flexibility, Joule heating and upper/lower wall zeta potentials are considered. Electric potential expressions can be modeled in terms of an ionic Nernst-Planck equation, Poisson-Boltzmann equation and Debye length approximation. The content of this paper is published in “Boundary Value Problems, 2019(1), 12” Entropy generation in double-diffusive convection in an Electro-osmotic flow of nanofluids via a peristaltic microchannel is presented in chapter eight. Buoyancy effects due to change in temperature, solute concentration and nanoparticle volume fraction are also considered. This study was performed under lubrication and Debye- xiii Huckel linearization approximation. The governing equations are solved exactly. This work has been published in “Entropy, 21(10), 986” Chapter nine investigates the analysis of electrokinetic peristaltic transportation of blood flow in a curved microchannel. Heat transfer analysis is also considered under the viscous dissipation effect. Lubrication scheme and Debye-Huckel estimate lead to simplify the governing equations. Suitable boundary conditions have been exploited to arising nonlinear coupled PDEs. The coupled and non-linear system is solved numerically. The content of this chapter is submitted for publication in “International Communications in Heat and Mass transfer” In chapter ten, we present mathematical study on the thermal mechanism of electroosmotic peristaltic flow of Jeffery fluid through the microtube. The walls are patterned with periodic oscillations in the longitudinal direction. The electric potential, velocity and temperature field are determined numerically under lubrication and Debye-Huckel approximations. The results obtained from here are published in “Bionanoscience” Future recommendations are given in chapter eleven. In chapter twelve, list of references is provided.
Gov't Doc #: 24675
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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