Inverse Linear Function Of Temperature Research Articles

Combined Effects of Thermal Radiation and Hall Current on MHD Free-Convective Flow and Mass Transfer over a Stretching Sheet with Variable Viscosity

An analysis has been carried out on the effects of thermal radiation and Hall current of a magneto hydrodynamic freeconvective flow and mass transfer over a stretching sheet with variable viscosity in the presence of heat generation/absorption. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The boundary-layer equations governing the flow problem under consideration have been reduced to a system of nonlinear ordinary differential equations by employing a similarity transformation. Using the finite difference scheme, numerical solutions to the transform ordinary differential equations have been obtained and the results are presented graphically. The numerical results obtained are in good agreement with the existing scientific literature.

Analysis of entropy generation in a variable viscosity fluid flow between two concentric pipes with a convective cooling at the surface

Entropy generation rate in a variable viscosity liquid flowing steadily through two concentric cylindrical pipes with convective cooling at the pipe surface, are studied using the second law analysis. The outer system is assumed to exchange heat with the ambient following Newton’s cooling law, and the fluid viscosity model varies as an inverse linear function of temperature. The resulting equations and the boundary conditions are solved using the fourth Order Runge-Kutta scheme and an efficient shooting technique. Numerical expressions for fluid velocity and temperature are derived and utilised to obtain expressions for volumetric entropy generation numbers, irreversibility distribution ratio and the Bejan number in the flow field. Key words: Pipe flow, variable viscosity, entropy generation, convective cooling, irreversibility analysis.

Thermal radiation and hall effect on MHD flow, heat and mass transfer over an inclined permeable stretching sheet

Of concern in this paper is an investigation of the combined effects of thermal radiation and Hall current on momentum, heat and mass transfer in laminar boundary-layer flow over an inclined permeable stretching sheet with variable viscosity. The sheet is linearly stretched in the presence of an external magnetic field and the fluid motion is subjected to a uniform porous medium. The effect of internal heat generation/absorption is also taken into account. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The boundary-layer equations that governing the flow problem have reduced to a system of non-linear ordinary differential equations with a suitable similarity transformation. Then the transformed equations are solved numerically by employing a finite difference scheme. Thus the results obtained are presented graphically for the various parameters of interest.

Effect of variable viscosity and suction/injection on thermal boundary layer of a non-newtonian power-law fluids past a power-law stretched surface

The analysis of laminar boundary layer flow and heat transfer of non-Newtonian fluids over a continuous stretched surface with suction or injection has been presented. The velocity and temperature of the sheet were assumed to vary in a power-law form, that is u = U0xm, and Tw(x)=T4+Cxb. The viscosity of the fluid is assumed to be inverse linear function of temperature. The resulting governing boundary-layer equations are highly non-linear and coupled form of partial differential equations and they have been solved numerically by using the Runge-Kutta method and Shooting technique. Velocity and temperature distributions as well as the Nusselt number where studied for two thermal boundary conditions: uniform surface temperature (b = 0) and cooled surface temperature (b = -1), for different parameters: variable viscosity parameter θ, temperature exponent b, blowing parameter d and Prandtl number. The obtained results show that the flow and heat transfer characteristics are significantly influenced by these parameters.

Nonsimilar boundary layer analysis of double-diffusive convection from a vertical truncated cone in a porous medium with variable viscosity

This work presents a boundary layer analysis about variable viscosity effects on the double-diffusive convection near a vertical truncated cone in a fluid-saturated porous medium with constant wall temperature and concentration. The viscosity of the fluid is assumed to be an inverse linear function of the temperature. A boundary layer analysis is employed to derive the nondimensional nonsimilar governing equations, and the transformed boundary layer governing equations are solved by the cubic spline collocation method to yield computationally efficient numerical solutions. The obtained results are found to be in good agreement with previous papers on special cases of the problem. Results for local Nusselt and Sherwood numbers are presented as functions of viscosity-variation parameter, buoyancy ratio, and Lewis number. For a porous medium saturated with a Newtonian fluid with viscosity proportional to an inverse linear function of temperature, higher value of viscosity-variation parameter leads to the decrease of the viscosity in fluid flow, thus increasing the fluid velocity as well as the local Nusselt number and the local Sherwood number.

Variable viscosity and thermophoresis effects on Darcy mixed convective heat and mass transfer past a porous wedge in the presence of chemical reaction

An analysis is presented to investigate the effect of thermophoresis particle deposition and variable viscosity on Darcy mixed convective heat and mass transfer of a viscous, incompressible fluid past a porous wedge in the presence of chemical reaction. The wall of the wedge is embedded in a uniform Darcian porous medium in order to allow for possible fluid wall suction or injection. The viscosity of the fluid is assumed to be a inverse linear function of temperature. The results are analyzed for the effect of different physical parameters, such as variable viscosity, magnetic, chemical reaction and thermophoresis parameters, on the flow, the heat and mass transfer characteristics.

Non-uniform double slot suction (injection) into water boundary layer flows over a cylinder

An analysis is performed to study the effect of non-uniform double slot suction (injection) into a steady two-dimensional laminar boundary layer flow when fluid properties such as viscosity and Prandtl number are inverse linear functions of temperature. Non-similar solutions have been obtained from the starting point of the streamwise co-ordinate to the exact point of separation. By applying an implicit finite difference scheme in combination with the quasi-linearization technique and an appropriate selection of the finer step sizes along the streamwise direction, the difficulties arising at the starting point of the streamwise co-ordinate, at the edges of the slot and at the point of separation have been overcome. The results indicate that the separation can be delayed by non-uniform double slot suction and also by moving the slot downstream. However, the effect of non-uniform double slot injection is just the opposite.

Thermophoresis and chemical reaction effects on non-Darcy mixed convective heat and mass transfer past a porous wedge with variable viscosity in the presence of suction or injection

The effects of variable viscosity, thermophoresis and non-Darcy mixed convection flow with heat and mass transfer over a porous wedge are presented here, taking into account the homogeneous chemical reaction of first order. The fluid viscosity is assumed to vary as an inverse linear function of temperature. Favorable comparison with previously published work is performed. The governing fundamental equations are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using the Runge Kutta Gill and shooting methods. The steady-state velocity, temperature and concentration profiles are shown graphically. It is observed that due to the presence of first-order chemical reaction the concentration decreases with increasing values of the chemical reaction parameter. The results also showed that the particle deposition rates were strongly influenced by thermophoresis and buoyancy force, particularly for opposing flow and hot surfaces. Numerical results for the skin-friction coefficient, wall heat and mass transfer are obtained and reported graphically for various parametric conditions to show interesting aspects of the solution.

The effects of temperature dependent viscosity and thermal conductivity on unsteady MHD convective heat transfer past a semi-infinite vertical porous moving plate with variable suction

In this article, we studied the effects of variable viscosity and thermal conductivity on an unsteady two-dimensional laminar flow of a viscous incompressible conducting fluid past a semi-infinite vertical porous moving plate taking into account the effect of a magnetic field in the presence of variable suction. The fluid viscosity is assumed to vary as an inverse linear function of temperature but the thermal conductivity is assumed to vary as a linear function of temperature. It is assumed that the porous plate moves with a constant velocity in the direction of fluid flow, and the free stream velocity follows the exponentially increasing small perturbation law. The governing equations for the flow are transformed into a system of nonlinear ordinary differential equations by perturbation technique and are solved numerically by using the shooting method. The effects of the various parameters on the velocity and temperature profiles as well as the surface skin-friction coefficient are presented graphically.

Effect of variable viscosity on non-Darcy free or mixed convection flow on a vertical surface in a non-Newtonian fluid saturated porous medium

The effect of variable viscosity on non-Darcy free or mixed convective heat transfer along a vertical surface embedded in a porous medium saturated with a non-Newtonian fluid has been analysed. The viscosity of the fluid is assumed to be an inverse linear function of temperature. Furthermore, the coordinates and dependent variables are transformed to yield computationally efficient numerical solutions which are compared with the existing results, for a few particular cases. The results show that the variable viscosity parameter, viscosity index, mixed convection parameter, Ergun number, Peclet number, Rayleigh number and temperature variation parameter have significant influence on the velocity and heat transfer rate at the surface.

Chebyshev finite difference method for the effects of variable viscosity and variable thermal conductivity on heat transfer to a micro-polar fluid from a non-isothermal stretching sheet with suction and blowing

Abstract The effects of variable viscosity and variable thermal conductivity on heat transfer from a stretching sheet to a micro-polar fluid are analyzed using the theory of micro-polar fluids formulated by Eringen. The fluid viscosity and the thermal conductivity are assumed to vary as inverse linear functions of temperature. By means of the similarity solutions, deviation of the velocity, micro-rotation and temperature fields from their constant values are determined numerically by using Chebyshev finite difference method.

Effect of variable viscosity on non-Darcy free or mixed convection flow on a vertical surface in a fluid saturated porous medium

This paper analyzes the variable viscosity effects on non-Darcy free or mixed convection flow on a vertical surface in a fluid saturated porous medium. The viscosity of the fluid is assumed to be a inverse linear function of temperature. Velocity and heat transfer are found to be significantly affected by the variable viscosity parameter, Ergun number, Peclet number or Rayleigh number.

Finite-element method for the effects of chemical reaction, variable viscosity, thermophoresis and heat generation/absorption on a boundary-layer hydromagnetic flow with heat and mass transfer over a heat surface

The effects of variable viscosity, thermophoresis and heat generation or absorption on hydromagnetic flow with heat and mass transfer over a heat surface are presented here, taking into account the homogeneous chemical reaction of first order. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The velocity profiles are compared with previously published works and are found to be in good agreement. The governing fundamental equations are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using the finite element method. The steady-state velocity, temperature and concentration profiles are shown graphically. It is observed that due to the presence of first-order chemical reaction the concentration decreases with increasing values of the chemical reaction parameter. The results also showed that the particle deposition rates were strongly influenced by thermophoresis and buoyancy force, particularly for opposing flow and hot surfaces. Numerical results for the skin-friction coefficient, wall heat transfer and particle deposition rate are obtained and reported graphically for various parametric conditions to show interesting aspects of the solution.

The effect of variable viscosity on mixed convection heat transfer along a vertical moving surface

The effect of temperature dependent viscosity on laminar mixed convection boundary layer flow and heat transfer on a continuously moving vertical surface is studied. The fluid viscosity is assumed to vary as an inverse linear function of temperature. Local similarity solutions are obtained for the boundary layer equations subject to isothermally moving vertical surface with uniform speed. The effect of various governing parameters, such as Prandtl number Pr, the mixed convection parameter λ = S Gr x / Re x 2 , and the viscosity/temperature parameter θ r which determine the velocity and temperature distributions, the local heat transfer coefficient, and the local shear stress coefficient at the surface are studied. Significant changes are obtained in dimensionless local heat transfer and shear stress coefficient at the surface when the magnitude of θ r has small values for each λ. Critical values of λ are obtained for predominate natural convection and buoyancy shear stress for assisting and opposing flow for various θ r .

Natural convection flow from an isothermal horizontal circular cylinder with temperature dependent viscosity

Free convection flow from an isothermal horizontal circular cylinder immersed in a fluid with viscosity proportional to an inverse linear function of temperature is studied. The governing boundary layer equations are transformed into a non-dimensional form and the resulting nonlinear system of partial differential equations is reduced to local non-similarity equations which are solved numerically by a very efficient implicit finite difference method together with Keller box scheme. Numerical results are presented by velocity and viscosity profiles of the fluid as well as heat transfer characteristics, namely the local heat transfer rate and the local skin-friction coefficients for a wide range of viscosity parameter e (= 0.0, 0.5, 1.0, 2.0, 3.0,4.0) and the Prandtl number Pr (= 1.0, 7.0, 10.0, 15.0, 20.0, 30.0).

Effects of non-Darcian on forced convection heat transfer over a flat plate in a porous medium-with temperature dependent viscosity

The non-Darcian effect on forced convection heat transfer over a flat plate in a porous medium is examined. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The effects of inertia forces and the distance from the leading edge of the plate on the velocity and temperature fields as well as on the skin friction and heat transfer coefficients in the boundary layer over a semi-infinite plate are studied. The nonlinear boundary layer equations, governing the problem under consideration, are solved numerically by applying an efficient numerical technique based on the Keller box method. The velocity profiles, temperature profiles and the skin friction components on the plate are computed and discussed in detail numerically for various values of the variable viscosity parameter, the modified Reynolds number, the stream wise coordinate and the Prandtl number.

Thermal-diffusion and diffusion-thermo effects on mixed free-forced convective flow and mass transfer over an accelerating surface with a heat source in the presence of suction and blowing in the case of variable viscosity

An analysis has been carried out to obtain the thermal-diffusion and the diffusion-thermo effects on the mixed free-forced convective and mass transfer steady laminar boundary-layer flow over an accelerating surface with a heat source in the presence of suction and blowing. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The partial differential equations governing the problem under consideration have been transformed by a similarity transformation into a system of ordinary differential equations which is solved numerically by applying the shooting method. The results for an impermeable accelerating surface are discussed. The effects of the variable viscosity parameter θr, the thermal diffusion parameter Sr, the diffusion-thermo parameter Df, suction or blowing parameter m, heat flux parameter s and Schmidt number Sc have been examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The effects of varying these parameters are studied in the case of a surface with prescribed wall temperature and a surface with prescribed wall heat flux.

Variable viscosity effect on hydromagnetic flow and heat transfer about a fluid underlying the axisymmetric spreading surface

The effect of variable viscosity on the flow and heat transfer about a fluid underlying the axisymmetric spreading surface in the presence of an axial magnetic field has been investigated. The viscosity of the fluid is assumed to vary as an inverse linear function of temperature and the magnetic field strength is inversely proportional to the radial coordinate. The partial differential equations, governing the present problem, have been transformed, by suitable similarity variables, into a system of ordinary differential equations. This system is solved numerically by the shooting technique. Numerical results are introduced in graphical form for different values of viscosity parameter, θr, and magnetic field parameter. In the presence of variable viscosity, an increase in Prandtl number leads to a rise in the velocity field. Generally, it leads to a fall in the temperature field. Both magnetic field and variable viscosity raise the heat transfer and suppress the fluid flow.

Chebyshev finite difference method for the effects of variable viscosity and variable thermal conductivity on heat transfer from moving surfaces with radiation

In this article, we studied the effects of variable viscosity and variable thermal conductivity on heat transfer from moving surfaces in a micropolar fluid through a porous medium with radiation. The fluid viscosity is assumed to vary as an inverse linear function of temperature and the thermal conductivity is assumed to vary as a linear function of temperature. The governing fundamental equations are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using Chebyshev finite difference method (ChFD). Numerical solutions are obtained for different values of variable viscosity, variable thermal conductivity, porous medium, radiation, velocity ratio and micropolar parameters. Two cases are considered, one corresponding to a plane surface moving in parallel with the free stream and the other, a surface moving in the opposite direction to the free stream. The numerical results show that, variable viscosity, variable thermal conductivity, radiation and the permeability have significant influences on the velocity, the angular velocity and temperature profiles, shear stress, couple stress and Nusselt number in the above two cases.

Chebyshev finite difference method for the effect of variable viscosity on magneto-micropolar fluid flow with radiation

An analysis is presented for heat transfer to MHD flow of a micropolar fluid from an isothermal stretching sheet with suction through a porous medium in the presence of radiation and variable viscosity. The fluid viscosity is assumed to vary as an inverse linear function of temperature. The governing fundamental equations on the assumption of small magnetic Reynolds number are approximated by a system of nonlinear ordinary differential equations and are solved numerically by using Chebyshev finite difference method (ChFD). Numerical soluations are obtained for different values of radiation, variable viscosity, magnetic and porous parameters