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1

Computer simulation of heat and mass transfer effects on nanofluid flow of blood through an inclined stenosed artery with hall effect

Mishra Nidhish Kumar

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 1

129--138

EN

The present study deals with the analysis of heat and mass transfer for nanofluid flow of blood through an inclined stenosed artery under the influence of the Hall effect. The effects of hematocrit-dependent viscosity, Joule heating, chemical reaction and viscous dissipation are taken into account in the governing equations of the physical model. Non-dimensional differential equations are solved using the finite difference method, by taking into account the no-slip boundary condition. The effects of different thermophysical parameters on the velocity, temperature, concentration, shear stress coefficient and Nusselt and Sherwood numbers of nano-biofluids are exhaustively discussed and analysed through graphs. With an increase in stenosis height, shear stress, the Nusselt number and the Sherwood number are computed, and the impacts of each are examined for different physical parameters. To better understand the numerous phenomena that arise in the artery when nanofluid is present, the data are displayed graphically and physically described. It is observed that as the Hartman number and Hall parameter increase, the velocity drops. This is as a result of the Lorentz force that the applied magnetic field has generated. Blood flow in the arteries is resisted by the Lorentz force. This study advances the knowledge of stenosis and other defects’ non-surgical treatment options and helps reduce post-operative consequences. Moreover, ongoing research holds promise in the biomedical field, specifically in magnetic resonance angiography (MRA), an imaging method for artery examination and anomaly detection.

2

Effects of variable fluid properties and mixed convection on biomagnetic fluid flow and heat transfer over a stretching sheet in the presence of magnetic dipole

Murtaza M. G., Alam Jahangir, Tzirtzilakis E. E., Shamshuddin Md., Ferdows M.

Journal of Power Technologies

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2023

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Vol. 103, nr 4

193--208

EN

This investigations covers the numerical analysis of a steady biomagnetic fluid flow (BFD) that passed through a two dimensional stretching sheet under the influence of magnetic dipole. The effect of fluid variable viscosity and thermal conductivity are also taken into consideration as assumed to vary as linear function of temperature. Our model mathematically formulated for BFD namely blood which consist of principles of magnetohydrodynamic (MHD) and ferrohydrodynamic (FHD), where blood treated as an electrically conducting fluid as well as polarization. Using similarity transformations, the governing system of partial differential equations are transferred into system of ordinary differential equations (ODE). The resulting coupled non linear ODE is numerically solved by employing bvp4c function technique available in MATLAB software. The effects of pertinent parameters namely ferromagnetic interaction parameter, magnetic field parameter, mixed convection parameter, viscosity variation parameter, Prandtl number, thermal conductivity parameter etc are plotted and discussed adequately for velocity and temperature profile as well as skin friction coefficient and rate of heat transfer. The results revels that velocity profile decreases as enhanced values of ferromagnetic number whereas temperature profile increased. Also found that skin friction coefficient reduces and rate of heat transfer increases by increasing values of thermal conductivity parameter and viscosity variation parameter. For numerical validation a comparisons has been made for some specific values with previous investigators. We hope that the present analysis will present in bio-medical and bio-engineering sciences.

3

Computational analysis of soret and dufour effects on nanofluid flow through a stenosed artery in the presence of temperature-dependent viscosity

Mishra Nidhish K.

Acta Mechanica et Automatica

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2023

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Vol. 17, no. 2

246--263

EN

In this study, the Soret and Dufour effects in a composite stenosed artery were combined with an analysis of the effect of varying viscosity on copper nanofluids in a porous medium. Blood viscosity, which changes with temperature, is taken into account using the Reynolds viscosity model. The finite difference approach is used to quantitatively solve the governing equations. For use in medical applications, the effects of the physical parameters on velocity, temperature and concentration along the radial axis have been investigated and physically interpreted. The results are graphically displayed and physically defined in order to facilitate comprehension of the various phenomena that occur in the artery when nanofluid is present. It is observed that the Soret effect increases the rate of heat transfer but decreases the rate of mass transfer. The new study enhances knowledge of non-surgical treatment options for stenosis and other abnormalities, hence reducing post-operative complications. Additionally, current research may have biomedical applications such as magnetic resonance angiography (MRA), which provide a picture of an artery and enable identification of any anomalies, and thus may be useful

4

Effect of lubricant compressibility and variable viscosity on the performance of three-lobe journal bearing

Mahdi Mushrek A., Abass Basim Ajeel

Archive of Mechanical Engineering

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2022

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LXIX, nr 2

203–-219

EN

Different configurations of journal bearings have been extensively used in turbo- machinery and power generating equipment. Three-lobe bearing is used due to its lower film temperature and stable operation. In this study, static performance of such a bearing has been investigated at different eccentricity ratios considering lubricant compressibility and variable viscosity. The effect of variable viscosity was considered by taking the viscosity as a function of the oil film thickness while Dowson model is used to consider the effect of lubricant compressibility. The effect of such parameters was considered to compute the oil film pressure, load-carrying capacity, attitude an- gle and oil side leakage for a bearing working at (ε from 0.6 to 0.8) and (viscosity coefficient from 0 to 1). The mathematical model as well as the computer program prepared to solve the governing equations were validated by comparing the pressure distribution obtained in the present work with that obtained by EL-Said et al. A good agreement between the results has been observed with maximum deviation of 3%. The obtained results indicate a decrease in oil film pressure and load-carrying capacity with the higher values of viscosity coefficient while the oil compressibility has a little effect on such parameters.

5

Mixed convective flow with variable viscosity and variable thermal conductivity in a channel in the presence of first order chemical reaction with heat generation or absorption

Shobha K. C., Biradar Mahadev, Mallikarjun B Patil

Journal of Applied Mathematics and Computational Mechanics

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2021

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Vol. 20, nr 1

91--102

EN

A study has been made on the flow and heat transfer of a viscous fluid in a vertical channel with first order chemical reaction and heat generation or absorption assuming that the viscosity and thermal conductivity are dependent on the fluid temperature. The temperature of the walls is maintained constant. Under these assumptions, the governing balance equations of mass, momentum and energy are formulated. The dimensionless forms of the governing equations are coupled and non-linear, which cannot be solved analytically and therefore require the use of the Runge-Kutta fourth order along with shooting technique. Graphs for velocity and temperature under different values of parameters involved are plotted and discussed. The skin friction and Nusselt number on the channel walls are also computed and discussed. Furthermore, the investigation found that variable viscosity and variable thermal conductivity enhance the velocity and temperature of the flow.

6

Numerical analysis of the transient and non-isothermal channel flow of a third-grade fluid with convective cooling

Chinyoka Tiri, Makinde Oluwole Daniel

Engineering Transactions

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2020

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Vol. 68, iss. 4

335--351

EN

We investigate the unsteady, non-isothermal, pressure driven channel flow of a third grade liquid subject to exothermic reactions. We assume temperature dependent fluid viscosity and also that the flow is subjected to convective cooling at the channel walls. The exothermic reactions are modelled via Arrhenius kinetics and the convective heat exchange with the ambient at the channel walls follows Newton’s law of cooling. The time-dependent, coupled, and nonlinear partial differential equations governing the flow and heat transfer problem are solved numerically using efficient, semi-implicit finite difference algorithms. The sensitivity of the fluid flow and heat transfer system to the various embedded parameters is explored.

7

Entropy analysis of a variable viscosity MHD Couette flow Between two concentric pipes with convective cooling

Makinde Oluwole Daniel, Eegunjobi Adetayo Samuel

Engineering Transactions

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2020

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Vol. 68, iss. 4

317--334

EN

This paper addresses the combined effects of the magnetic field, thermal buoyancy force, viscous dissipation, Joule heating and temperature-dependent viscosity on the Couette flow of an incompressible conducting fluid between two concentric vertical pipes. It is assumed that convective cooling occurs at the surface of the outer moving pipe while the surface of the inner fixed pipe is maintained at a constant temperature. The nonlinear equations for momentum and energy are obtained and solved numerically using a shooting method coupled with the Runge-Kutta-Fehlberg integration procedure. Relevant results depicting the effects of embedded thermophysical parameters on the velocity and temperature profiles, skin friction, the Nusselt number, entropy generation rate and the Bejan number are presented graphically and discussed. It is found that an increase in the magnetic field intensity boosts the entropy generation rate while an increase in convective cooling lessens it.

8

Simultaneous effects of heat transfer and variable viscosity on peristaltic transport of casson fluid flow in an inclined porous tube

Manjunatha G., Rajashekhar C., Vaidya H., Prasad K. V.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 2

309--328

EN

The present study investigates the combined effects of varying viscosity and heat transfer on a Casson fluid through an inclined porous axisymmetric tube in the presence of slip effects. The modeled governing equations are solved analytically by considering the long wavelength and small Reynolds number approximations. The numerical integration is employed to obtain pressure rise and frictional force. A parametric analysis has been presented to study the effects of the Darcy number, angle of inclination, varying viscosity, velocity slip, thermal slip, yield stress, amplitude ratio, Prandtl number and Eckert number on the pressure rise, pressure gradient, streamlines, frictional force and temperature. The study reveals that an increase in the angle of inclination and viscosity parameter has a proportional increase in the pressure rise. Also, an increase in the porosity causes a significant reduction in the pressure rise.

9

Eﬀects of variable viscosity on natural convection ﬂow of an optically thick gray gas past a horizontal surface in the presence of internal heat generation

Kannan T., Malleswaran A., Moorthy M. B. K.

Transactions of the Institute of Fluid-Flow Machinery

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2018

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nr 139

3--22

EN

A numerical investigation to discuss the eﬀects of radiation and variable viscosity on heat and mass transfer characteristics of natural convection over a horizontal surface embedded in a saturated porous medium in the presence of internal heat generation is carried out in this study. The working ﬂuid for the investigation is optically thick gray gas. The Dufour and Soret eﬀects are also taken into account. Similarity transformations are employed to obtain nonlinear ordinary diﬀerential equations from the governing equations of the present problem. The numerical results for the transformed governing equations are computed by using commercial boundary value problem solver for ordinary diﬀerential equations. The eﬀects are discussed by varying the parameters such as radiation, Dufour and Soret numbers, buoyancy ratio, Prandtl number, Schmidt number, and variable viscosity. Presence of internal heat generation enhances the velocity proﬁle and signiﬁcantly decreases the concentration boundary layer thickness. On increasing ﬂuid radiation, the temperature of the ﬂuid is higher than that of the surface and the concentration boundary layer thickness decreases away from the surface.

10

Effect of variable viscosity on MHD inclined arterial blood flow with chemical reaction

Tripathi B., Sharma B. K.

International Journal of Applied Mechanics and Engineering

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2018

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Vol. 23, no. 3

767--785

EN

In this paper, we present the mathematical study of heat and mass transfer effects on an arterial blood flow under the influence of an applied magnetic field with chemical reaction. A case of mild stenosis is considered in a non-tapered artery which is inclined at an angle γ from the axis. The variable viscosity of the blood is considered varying with the hematocrit ratio. Governing non-linear differential equations have been solved by using an analytical scheme, homotopy perturbation method to obtain the solution for the velocity, temperature and concentration profiles of the blood flow. For having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted for wall shear stress, velocity, temperature and concentration profiles with varying values of the applied magnetic field, chemical reaction parameter and porosity parameter. The results show that in an inclined artery, the magnitude of the wall shear stress at stenosis throat increases as values of the applied magnetic field increase while it reduces as the values of both the chemical reaction and porosity parameters increase. Contour plots have been plotted to show the variations of the velocity profile of blood flow as the values of the height of the stenosis as well as the influence of the applied magnetic field increase.

11

Flow behavior in weakly permeable micro-tube with varying viscosity near the wall

Gupta R. R., Kumar V., Chand S.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 4

16--21

EN

Weakly permeable micro-tubes are employed in many applications involving heat and/or mass transfer. During these processes, either solute concentration builds up (mass transfer) or steep change in temperature (heat transfer) takes place near the permeable wall causing a change in the viscosity of the fluid. Results of the present work suggest that such change in viscosity leads to a considerable alteration in the flow behavior, and the commonly assumed parabolic velocity profile no longer exists. To solve the problem numerically, the equation of motion was simplified to represent permeation of incompressible, Newtonian fluid with changing viscosity through a micro-tube. Even after considerable simplification, the accuracy of the results was the same as that obtained by previously reported results for some specific cases using rigorous formulation. The algorithm developed in the present work is found to be numerically robust and simple so that it can be easily integrated with other simulations.

12

Hypothetical analysis for peristaltic transport of metallic nanoparticles in an inclined annulus with variable viscosity

Nadeem S., Sadaf H.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 2

447--454

EN

The main objective of this article is to present a mathematical model for peristaltic transport in an inclined annulus. In this analysis, two-dimensional flow of a viscous nanofluid is observed in an inclined annulus with variable viscosity. Copper as nanoparticle with blood as its base fluid has been considered. The inner tube is unifom or rigid, while the outer tube takes a sinusoidal wave. Governing equations are solved under the well-known assumptions of low Reynolds number and long-wavelength. Exact solutions have been established for both velocity and nanoparticle temperature. The features of the peristaltic motion are explored by plotting graphs and discussed in detail.

13

Effect of variable viscosity on free flow of non-Newtonian power-law fluids along a vertical surface with thermal stratification

Moorthy M., Senthilvadivu K.

Archives of Thermodynamics

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2012

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Vol. 33, no. 4

109-121

EN

The aim of this paper is to investigate the effect of thermal stratification together with variable viscosity on free convection flow of non-Newtonian fluids along a nonisothermal semi infinite vertical plate embedded in a saturated porous medium. The governing equations of continuity, momentum and energy are transformed into nonlinear ordinary differential equations using similarity transformations and then solved by using the Runge-Kutta-Gill method along with shooting technique. Governing parameters for the problem under study are the variable viscosity, thermal stratification parameter, non-Newtonian parameter and the power-law index parameter.The velocity and temperature distributions are presented and discussed. The Nusselt number is also derived and discussed numerically.

14

Asymptotic solution for laminar flow of an incompressible fluid with variable viscosity and thermal conductivity between rotating surfaces of revolution

Walicka A.

International Journal of Applied Mechanics and Engineering

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2007

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Vol. 12, no 3

831-848

EN

A steady laminar flow of an incompressible Newtonian fluid with variable viscosity and thermal conductivity is considered, in a narrow space between two surfaces of revolution, rotating with generally different angular velocities about a common axis of symmetry. The problem statement for two classes of throughflow, with full and rotational inertia, is fonnulated. A procedure for perturbing a creeping flow solution and an iteration scheme are developed to produce a solution for higher approximations. The solution depends on eight or seven parameters and is asymptotic in the sense of its good convergence in the second approximation for both classes of throughflow. Results for second class of throughflow are presented for the velocity components, the pressure and the temperature distributions for typical shapes of surfaces as disks and spherical surfaces.

15

The effect of variable viscosity on MHD natural convection in micropolar fluids

El-Hakiem M. A., Modather M., Abdou M.

International Journal of Applied Mechanics and Engineering

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2006

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Vol. 11, no 2

301-320

EN

The influence of variable viscosity and a transverse magnetic field on natural convection in micropolar fluids is examined. The fluid viscosity is assumed to vary as an inverse linear function of temperature. Four different vertical flows have been analyzed, those adjacent to an isothermal surface and uniform heat flux surface, a plane plume and flow generated from a horizontal line energy source on a vertical adiabatic surface, or wall plume. By means of similarity solutions and deviation of the velocity, temperature and micro-rotation fields as well as the skin friction, heat transfer and wall couple stress results from their constant values are determined.

16

A class of exact solutions to equations governing the steady plane flows of an incompressible fluid of variable viscosity via von Mises variables

Naeem R. K., Ali S. A.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 2

395-436

EN

A class to exact solutions of equations governing the steady plane flows of an incompressible fluid of variable viscosity are determined using von ? Mises variables. Applications of some of the solutions to the boundary value problems are also indicated.

17

Effects of temperature-dependent viscosity and heterogeneous chemical reaction on unsteady convective diffusion in a non-isothermal plane-Poiseuille flow

Siddheshwar P. G., Manjunath S.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 3

471-494

EN

A closed-form solution is obtained for the problem of dispersion of solute in a non-isothermal flow of a Newtonian fluid with temperature-dependent viscosity. The effect of wall-catalysed reaction on dispersion is investigated against the background of the no-reaction problem. The analytical result on dispersion of solute with wall catalysed reaction at long times is compared with the analytical solution when reaction is absent. The Taylor (1953) and Aris (1956) regimes of dispersion for the present problem are obtained as limiting cases from the study. The graphical results of the study serve as a jury on any numerical study that might be undertaken considering non-asymptotic all-time analysis. The results of the study indicate that heating from above is an effective means of controlling dispersion in variable-viscosity liquids.