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This paper aims to investigate the coupled effects of electrohydrodynamic and gravity forces on the circulation effectiveness of working fluid in an inclined micro heat pipe driven by electroosmotic flow. The effects of the three competing forces, namely, the capillary, the gravitational and the electrohydrodyanamic forces, on the circulation effectiveness of a micro heat pipe are compared and delineated.

The numerical model is developed based on the conservations of mass, momentum and energy with the incorporation of the Young–Laplace equation for electroosmotic flow in an inclined micro heat pipe incorporating the gravity effects.

By inducing electroosmotic flow in a micro heat pipe, a significant increase in heat transport capacity can be attained at a reasonably low applied voltage, leading to a small temperature drop and a high thermal conductance. However, the favorably applied gravity forces pull the liquid toward the evaporator section where the onset of flooding occurs within the condenser section, generating a throat that shrinks the vapor flow passage and may lead to a complete failure on the operation of micro heat pipe. Therefore, the balance between the electrohydrodyanamic and the gravitational forces is of vital importance.

This study provides a detailed insight into the gravitational and electroosmotic effects on the thermal performance of an inclined micro heat pipe driven by electroosmotic flow and paves the way for the feasible practical application of electrohydrodynamic forces in a micro-scale two-phase cooling device.

A convection‐diffusion‐reaction scheme is proposed in this study to simulate the high gradient electroosmotic flow behavior in microchannels. The equations governing the total electric field include the Laplace equation for the effective electrical potential and the Poisson‐Boltzmann equation for the electrical potential in the electric double layer.

Mixed electroosmotic/pressure‐driven flow in a straight microchannel is studied with the emphasis on the Joule heat in the equations of motion. The nonlinear behaviors resulting from the hydrodynamic, thermal and electrical three‐field coupling and the temperature‐dependent fluid viscosity, thermal conductivity, electrical permittivity, and conductivity of the investigated buffer solution are analyzed.

The solutions computed from the employed flux discretization scheme for the hydrodynamic, thermal and electric field equations have been verified to have good agreement with the analytical solution. Parametric studies have been carried out by varying the electrical conductivity at the fixed zeta potential and varying the zeta potential at the fixed electrical conductivity.

Investigation is also addressed on the predicted velocity boundary layer and the electric double layer near the negatively charged channel wall.

In this paper aims to investigate the numerical simulation of the electroosmotic flow of the Carreau-Yasuda model in the rectangular microchannel. Electromagnetic current is generated by applying an effective electric field in the direction of the current.

The non-Newtonian model used is the five-constant Carreau-Yasuda model which the non-Newtonian properties of the fluid can be well modeled. Using the finite difference method, the potential values at all points in the domain are obtained. Then, the governing equations (momentum conservation) and the energy equation are segregated and solved using a finite difference method.

In this paper, the effect of various parameters such as Weisenberg number, electrokinetic diameter, exponential power number on the velocity field and Brinkman and Pecklet dimensionless numbers on temperature distribution are investigated. The results show that increasing the Weissenberg dimensionless number and exponential power and diameter parameters reduces the maximum velocity field in the microchannel.

To the best of the authors’ knowledge, this study is reported for the first time.

Joule heating effect is a pervasive phenomenon in electro-osmotic flow because of the applied electric field and fluid electrical resistivity across the microchannels. Its effect in electro-osmotic flow field is an important mechanism to control the flow inside the microchannels and it includes numerous applications.

This research article details the numerical investigation on alterations in the profile of stream wise velocity of simple Couette-electroosmotic flow and pressure driven electro-osmotic Couette flow by the dynamic viscosity variations happened due to the Joule heating effect throughout the dielectric fluid usually observed in various microfluidic devices.

The advantages of the Joule heating effect are not only to control the velocity in microchannels but also to act as an active method to enhance the mixing efficiency. The results of numerical investigations reveal that the thermal field due to Joule heating effect causes considerable variation of dynamic viscosity across the microchannel to initiate a shear flow when EDL (Electrical Double Layer) thickness is increased and is being varied across the channel.

This research work suggest how joule heating can be used as en effective mechanism for flow control in microfluidic devices.

The purpose of this study is to investigate heat transfer and electrokinetic non-Newtonian flow in a rectangular microchannel in the developed and transient states.

The Carreau–Yasuda model was considered to capture the non-Newtonian behavior of the fluid. The dimensionless forms of governing equations, including the continuity equation for the Carreau–Yasuda fluid, are numerically solved by considering the volumetric force term of electric current (DC).

The impact of pertinent parameters such as electrokinetic diameter (R), Brinkman number and Peclet number is examined graphically. It is observed that for increasing R, the bulk velocity decreases. The velocity of the bulk fluid reaches from the minimum to the maximum state across the microchannel over time. At the electrokinetic diameter of 400, the maximum velocity was obtained. Temperature graphs are plotted with changes in the various Brinkman number (0.1 < Br < 0.7) at different times, and local Nusselt are compared against changes in the Peclet number (0.1 < ℘e < 0.5). The results of this study show that by increasing the Brinkman number from 0.25 to 0.7, the temperature along the microchannel doubles. It was observed that increasing the Peclet number from 0.3 to 0.5 leads to 200% increment of the Nusselt number along the microchannel in some areas along the microchannel. The maximum temperature occurs at Brinkman number of 0.7 and the maximum value of the local Nusselt number is related to Peclet number 0.5. Over time in the transient mode, the Nusselt number also decreases along the microchannel. By the increasing of time, the temperature increases at given value of Brinkman, which is insignificant at Brinkman number of 0.1. The simulation results have been verified by Newtonian and non-Newtonian flows with adequate accuracy.

This study contributes to discovering the effects of transient flow of electroosmotic flow for non-Newtonian Carreau–Yasuda fluid and transient heat transfer through rectangular microchannel. To the authors’ knowledge, the said investigation is yet not available in existing literature.

The purpose of this paper is to describe the development of an electroosmotic dynamic model to simulate the transport phenomena in association with the electric therapy in modern medicine.

The present study builds a new model by employing SUPG finite element method to solve the electroosmotic transport equation in microchannels of human body.

The present electroosmotic finite element analysis demonstrated that the electric treatment has a better curative effect.

The governing electric field equations for tissue fluids in microchannel include the Laplace equation for the effective electrical potential and the Helmholtz equation for the electrical potential established in the electric double layer (EDL). The transport equations governing the hydrodynamic field variables include the mass conservation equation for the electrolyte and the equations of motion for the incompressible charged fluids subject to an electroosmotic body force.

The phenomena of microchannels are dominated by elliptic equations, Laplace, Helmholtz and diffusion equations (Navier Stokes equations at Re=0.0259). These governing equations explain why the reaction of electric treatment is very fast, even immediate.

The analysis of the coupled hydrodynamic and electrical fields, the externally applied electric potential has been shown to be an aid to accelerate the tissue fluid due to the formation of an EDL. Interaction of plasma and tissue fluids in human body is also revealed.

The study of the electro-osmotic forces (EOF) in the flow of the boundary layer has been a topic of interest in biomedical engineering and other engineering fields. The purpose of this paper is to develop an innovative mathematical model for electro-osmotic boundary layer flow. This type of fluid flow requires sophisticated mathematical models and numerical simulations.

The effect of EOF on the boundary layer Williamson fluid model containing a gyrotactic microorganism through a non-Darcian flow (Forchheimer model) is investigated. The problem is formulated mathematically by a system of non-linear partial differential equations (PDEs). By using suitable transformations, the PDEs system is transformed into a system of non-linear ordinary differential equations subjected to the appropriate boundary conditions. Those equations are solved numerically using the finite difference method.

The boundary layer velocity is lower in the case of non-Newtonian fluid when it is compared with that for a Newtonian fluid. The electro-osmotic parameter makes an increase in the velocity of the boundary layer. The boundary layer velocity is lower in the case of non-Darcian fluid when it is compared with Darcian fluid and as the Forchheimer parameter increases the behavior of the velocity becomes more closely. Entropy generation decays speedily far away from the wall and an opposite effect occurs on the Bejan number behavior.

The present outcomes are enriched to give valuable information for the research scientists in the field of biomedical engineering and other engineering fields. Also, the proposed outcomes are hopefully beneficial for the experimental investigation of the electroosmotic forces on flows with non-Newtonian models and containing a gyrotactic microorganism.

The purpose of this paper is to study the mixing performance of the electrokinetically-driven power-law fluids in a zigzag microchannel.

The Poisson-Boltzmann equation, the Laplace equation, the modified Cauchy momentum equation, and the convection-diffusion equation are solved to describe the flow characteristics and mixing performance of power-law fluids in the zigzag microchannel. A body-fitted grid system and a generalized coordinate transformation method are used to model the grid system and transform the governing equations, respectively. The transformed governing equations are solved numerically using the finite-volume method.

The mixing efficiency of dilatant fluids is higher than that of pseudoplastic fluids. In addition, the mixing efficiency can be improved by increasing the width of the zigzag blocks or extending the total length of the zigzag block region.

The results presented in this study provide a useful insight into potential strategies for enhancing the mixing performance of the power-law fluids in a zigzag microchannel. The results of this study also provide a useful source of reference for the development of efficient and accurate microfluidic systems.

The purpose of this paper is to investigate the immiscible two-layer heat fluid flows in the presence of the electric double layer (EDL) and magnetic field. The effects of EDL, magnetic field and the viscous dissipative term on fluid velocity and temperature, as well as the important physical quantities, are examined and discussed.

The upper and lower regions in a horizontal microchannel with one layer being filled with a nanofluid and the other with a viscous Newtonian fluid. The nanofluid flow in the lower layer is described by the Buongiorno’s nanofluid model with passively controlled model at the boundaries. An appropriate set of non-dimensional quantities are used to simplify the nonlinear systems. The resulting coupled nonlinear equations are solved by using homotopy analysis method.

The present work demonstrates that increasing the EDL thickness and Hartmann number can restrain the fluid flow. The Brinkmann number has a significant role in the enhancement of heat transfer. It is also identified that the influence of EDL effects on microflow cannot be ignored.

The effects of viscous dissipation involved in the heat transfer process and the body force because of the EDL and the magnetic field are considered in the thermal energy and momentum equations for both regions. The detailed derivation procedure of the analytical solution for electrostatic potential is provided. The analytical solutions can lead to improved understanding of the complex microfluidic systems.

This paper seeks to numerically model electro‐osmotic flow (EOF) through microchannels using a finite element‐based unstructured mesh solution methodology.

The finite element method (FEM) combined with the characteristic‐based split (CBS) algorithm is used to solve the coupled Navier‐Stokes equations in order to simulate EOFs. The Laplace and Poisson‐Boltzmann equations are solved explicitly a priori to the solution of the fluid dynamic equations. The external electric field and internal potential values are then used to construct the source terms of the fluid dynamics equations.

Proposed methodology works excellently on unstructured meshes for both two‐ and three‐dimensional flow problems. The results obtained for benchmark channel flow problems show an excellent agreement with analytical and experimental data.

The idea of using the FEM and the CBS algorithm to solve the governing equations of EOFs is proposed. This particular method of solving these equations is unprecedented. In addition to benchmark examples, a problem of practical importance is also solved in this paper.