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1

Variable thermal conductivity in micropolar thermoelastic medium without energy dissipation possessing cubic symmetry

Ailawalia Praveen, Priyanka

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 1

1--10

EN

This investigation deals with the effect of variable thermal conductivity in a micropolar thermoelastic medium without energy dissipation with cubic symmetry. The normal mode technique is employed for obtaining components of physical quantities such as displacement, stress, temperature distribution and microrotation.

2

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.

3

Bidirectionally stretched flow of Jeffrey liquid with nanoparticles, Rosseland radiation and variable thermal conductivity

Archana M., Gireesha B. J., Rashidi M. M., Prasannakumara B. C., Gorla R. S. R.

Archives of Thermodynamics

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2018

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Vol. 39, no 4

33–-57

EN

Heat and mass transfer stretched flow of an incompressible, electrically conducting Jeffrey fluid has been studied numerically. Nanoparticles are suspended in the base fluid and it has many applications such as cooling of engines, thermal absorption systems, lubricants fuel cell, nanodrug delivery system and so on. Temperature dependent variable thermal conductivity with Rosseland approximation is taken into account and suction effect is employed in the boundary conditions. The governing partial differential equations are first transformed into set of ordinary differential equations using selected similarity transformations, which are then solved numerically using Runge-Kutta-Felhberg fourth-fifth order method along with shooting technique. The flow, heat and mass transfer characteristics with local Nusselt number for various physical parameters are presented graphically and a detailed discussion regarding the effect of flow parameters on velocity and temperature profiles are provided. It is found that, increase of variable thermal conductivity, radiation, Brownian motion and thermophoresis parameter increases the rate of heat transfer. Local Nusselt number has been computed for various parameters and it is observed that, in the presence of variable thermal conductivity and Rosseland approximation, heat transfer characteristics are higher as compared to the constant thermal conductivity and linear thermal radiation.

4

Thermoelastic Interactions in a Rotating Infinite Orthotropic Elastic Body with a Cylindrical Hole and Variable Thermal Conductivity

Mashat D. S., Zenkour A. M., Abouelregal A. E.

Archive of Mechanical Engineering

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2017

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Vol. LXIV, nr 4

481--498

EN

In the present article, we introduced a new model of the equations of generalized thermoelasticity for unbounded orthotropic body containing a cylindrical cavity. We applied this model in the context of generalized thermoelasticity with phase-lags under the effect of rotation. In this case, the thermal conductivity of the material is considered to be variable. In addition, the cylinder surface is traction free and subjected to a uniform unit step temperature. Using the Laplace transform technique, the distributions of the temperature, displacement, radial stress and hoop stress are determined. A detailed analysis of the effects of rotation, phase-lags and the variability thermal conductivity parameters on the studied fields is discussed. Numerical results for the studied fields are illustrated graphically in the presence and absence of rotation.

5

Effect of heat transfer on thermal stresses in an annular hyperbolic fin: an approximate analytical solution

Mallick A., Ranjan R., Sarkar P. K.

Journal of Theoretical and Applied Mechanics

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2016

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Vol. 54 nr 2

437--448

EN

An approximate analytical solution is presented for thermal stresses in an annular convectiveconductive fin of a hyperbolic profile with temperature dependent thermal conductivity. The classical thermo-elasticity theory coupled with the ADM based polynomial form of temperature field is employed for an approximate analytical solution of thermal stresses. The influence of thermal parameters, i.e. variable thermal conductivity, the thermo-geometric parameter and the non-dimensional coefficient of thermal expansion on temperature and sttress fields are investigated. The results for the stress field obtained from the ADM based solution are compared with those available in literature and found to be in close agreement.

6

Effects of phase-lags in a thermoviscoelastic orthotropic continuum with a cylindrical hole and variable thermal conductivity

Zenkour A. M., Abouelregal A. E.

Archives of Mechanics

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2015

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Vol. 67, nr 6

457--475

EN

This article presents an analytical solution for the effect of phase-lags on a generalized plane strain thermoviscoelastic orthotropic medium with a cylindrical cavity subjected to a thermal shock from varying heat. It is assumed that the cylindrical cavity is made of Kelvin–Vogt type material. The general solutions for field quantities are obtained using the method of Laplace transforms. The results are graphically presented to illustrate the effect of phase-lags, viscoelasticity and variability of thermal conductivity on the studied fields. Comparisons are also presented with those in the absence of viscosity and variability of thermal conductivity.

7

Numerical study of non-Darcy forced convective heat transfer in a power law fluid over a stretching sheet

Prasad K. V., Datti P. S.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 2

473-488

EN

An analysis has been carried out to study the non-Darcy flow behavior and heat transfer characteristics of a non-Newtonian power law fluid over a non-isothermal stretching sheet with variable thermal conductivity and internal heat generation/absorption. Thermal conductivity is assumed to vary as a linear function of temperature. The partial differential equations governing the flow and heat transfer are converted into ordinary differential equations by a similarity transformation. The presence of non-Darcy forced convection and power law index leads to coupling and non-linearity in the boundary value problem. Because of the coupling and non-linearity, the problem has been solved numerically by the Keller box method. The computed values of horizontal velocity and temperature, boundary layer thickness are shown graphically in tables and figures. Several reported works on the problem are obtained as limiting cases of the present study. The results of the study have implications in extrusion processes and in other applications with porous media.

8

Heat transfer in MHD viscoelastic boundary layer flow over a stretching sheet with space and temperature dependent heat source

Abel M. S., Nandeppanavar M. M.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 2

293-309

EN

This paper presents the influences of space and temperature dependent fluid properties on the hydromagnetic boundary layer flow of a viscoelastic liquid and heat transfer over a continuously stretching sheet, with variable thermal conductivity, in the presence of a space and temperature dependent heat source/sink. The thermal conductivity is assumed to vary as a linear function of temperature. A suitable similarity transformation is used in order to convert the flow and heat transfer governing partial differential equations into a set of highly non-linear ordinary differential equations. Solutions of heat transfer equation are obtained numerically, by the shooting technique with fourth order Runge Kutta method. The parametric analysis has been presented to study the effect of various parameters like the magnetic parameter, non-Newtonian Prandtl number, non-uniform heat source/sink parameters, temperature parameter and the variable thermal conductivity parameters for two different surface conditions namely, i) a surface with a prescribed wall temperature ii) a surface with a prescribed wall heat flux. The findings are shown graphically and are discussed. The heat transfer coefficients are also tabulated for various values of the said parameters.

9

Heat and mass transfer flow with variable thermal conductivity and variable mass diffusivity in an MHD visco-elastic fluid over a non-isothermal stretching sheet

Veena P. H., Pravin V. K., Shahjahan S. M.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 2

515-541

EN

In this paper we present a mathematical analysis of heat and mass transfer phenomena in a visco-elastic fluid flow over a non-isothermal stretching sheet with variable thermal conductivity and variable mass diffusivity. Similarity transformation are used to convert highly non-linear partial differential equations into ordinary differential equations. Several closed form analytical solutions for non-dimensional temperature, concentration, heat flux and mass flux are obtained in the form of confluent hypergeometric functions for two different types of the boundary conditions, namely: (i) wall with prescribed second-order power law temperature and second-order power law concentration (PST) and (ii)wall with prescribed second-order power law heat flux and second-order power law mass flux (PHF). The effect of various physical parameters such as the suction/blowing parameter , heat source/sink parameter [...], Prandtl number Pr, Schmidt number Sc, visco-elastic parameter and permeability parameter on the temperature and concentration profiles are analyzed.

10

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.

11

Mathematical Model for Thermal Shock Problem of a Generalized Thermoelastic Layered Composite Material with Variable Thermal Conductivity

Youssef H., El-Bary A.

Computational Methods in Science and Technology

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2006

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Vol. 12, nr 2

165-171

EN

One-dimensional generalized thermoelastic mathematical model with variable thermal conductivity for heat conduction problem is constructed for a layered thin plate. The basic equations are transformed by Laplace transform and solved by a direct method. The solution was applied to a plate of sandwich structure, which is thermally shocked, and traction free in the outer sides. The inverses of Laplace transforms are obtained numerically. The temperature, the stress and the displacement distributions are represented graphically.