scholarly journals Numerical Simulation of Transient Free Convection Flow and Heat Transfer in a Porous Medium

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Rajesh Sharma ◽  
Anuar Ishak
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Darcy Number ◽  
Convection Flow ◽  
Force Model ◽  
Moving Plate ◽  
Drag Forces ◽  
Flow And Heat Transfer ◽  
Momentum And Heat Transfer

The coupled momentum and heat transfer in unsteady, incompressible flow along a semi-infinite vertical porous moving plate adjacent to an isotropic porous medium with viscous dissipation effect are investigated. The Darcy-Forchheimer nonlinear drag force model which includes the effects of inertia drag forces is employed. The governing differential equations of the problem are transformed into a system of nondimensional differential equations which are solved numerically by the finite element method (FEM). The non-dimensional velocity and temperature profiles are presented for the influence of Darcy number, Forchheimer number, Grashof number, Eckert number, Prandtl number, plate velocity, and time. The Nusselt number is also evaluated and compared with finite difference method (FDM), which shows excellent agreement.

scholarly journals Hydromagnetic flow and heat transfer adjacent to a stretching vertical sheet in a micropolar fluid

2013 ◽  
Vol 17 (2) ◽  
pp. 525-532
Author(s):  
Nor Yacob ◽  
Anuar Ishak ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Micropolar Fluid ◽  
Leading Edge ◽  
Skin Friction Coefficient ◽  
Convection Flow ◽  
Electrically Conducting ◽  
Keller Box Method ◽  
Flow And Heat Transfer ◽  
The Magnetic Field

An analysis is carried out for the steady two-dimensional mixed convection flow adjacent to a stretching vertical sheet immersed in an incompressible electrically conducting micropolar fluid. The stretching velocity and the surface temperature are assumed to vary linearly with the distance from the leading edge. The governing partial differential equations are transformed into a system of ordinary differential equations, which is then solved numerically using a finite difference scheme known as the Keller box method. The effects of magnetic and material parameters on the flow and heat transfer characteristics are discussed. It is found that the magnetic field reduces both the skin friction coefficient and the heat transfer rate at the surface for any given K and ?. Conversely, both of them increase as the material parameter increases for fixed values of M and ?.

Unsteady mixed convection flow at a three-dimensional stagnation point

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amin Noor ◽  
Roslinda Nazar ◽  
Kohilavani Naganthran ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Mixed Convection ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Unsteady Mixed Convection

Purpose This paper aims to probe the problem of an unsteady mixed convection stagnation point flow and heat transfer past a stationary surface in an incompressible viscous fluid numerically. Design/methodology/approach The governing nonlinear partial differential equations are transformed into a system of ordinary differential equations by a similarity transformation, which is then solved numerically by a Runge – Kutta – Fehlberg method with shooting technique and a collocation method, namely, the bvp4c function. Findings The effects of the governing parameters on the fluid flow and heat transfer characteristics are illustrated in tables and figures. It is found that dual (upper and lower branch) solutions exist for both the cases of assisting and opposing flow situations. A stability analysis has also been conducted to determine the physical meaning and stability of the dual solutions. Practical implications This theoretical study is significantly relevant to the applications of the heat exchangers placed in a low-velocity environment and electronic devices cooled by fans. Originality/value The case of suction on unsteady mixed convection flow at a three-dimensional stagnation point has not been studied before; hence, all generated numerical results are claimed to be novel.

Natural Convection Flow and Heat Transfer Between a Fluid Layer and a Porous Layer Inside a Rectangular Enclosure

1987 ◽  
Vol 109 (2) ◽  
pp. 363-370 ◽  
Author(s):  
C. Beckermann ◽  
S. Ramadhyani ◽  
R. Viskanta
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Numerical Model ◽  
Porous Layer ◽  
Fluid Layer ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Rectangular Enclosure ◽  
Flow And Heat Transfer

A numerical and experimental study is performed to analyze the steady-state natural convection fluid flow and heat transfer in a vertical rectangular enclosure that is partially filled with a vertical layer of a fluid-saturated porous medium. The flow in the porous layer is modeled utilizing the Brinkman–Forchheimer–extended Darcy equations. The numerical model is verified by conducting a number of experiments, with spherical glass beads as the porous medium and water and glycerin as the fluids, in rectangular test cells. The agreement between the flow visualization results and temperature measurements and the numerical model is, in general, good. It is found that the amount of fluid penetrating from the fluid region into the porous layer depends strongly on the Darcy (Da) and Rayleigh (Ra) numbers. For a relatively low product of Ra × Da, the flow takes place primarily in the fluid layer, and heat transfer in the porous layer is by conduction only. On other hand, fluid penetrating into a relatively highly permeable porous layer has a significant impact on the natural convection flow patterns in the entire enclosure.

Pseudoplastic natural convection flow and heat transfer in a cylindrical vertical cavity partially filled with a porous layer

2019 ◽  
Vol 30 (3) ◽  
pp. 1096-1114 ◽  
Author(s):  
Kasra Ayoubi Ayoubloo ◽  
Mohammad Ghalambaz ◽  
Taher Armaghani ◽  
Aminreza Noghrehabadi ◽  
Ali J. Chamkha
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Free Convection ◽  
Porous Layer ◽  
Power Law ◽  
Convection Flow ◽  
Governing Equations ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Vertical Cavity

Purpose This paper aims to theoritically investigate the free convection flow and heat transfer of a non-Newtonian fluid with pseudoplastic behavior in a cylindrical vertical cavity partially filled with a layer of a porous medium. Design/methodology/approach The non-Newtonian behavior of the pseudoplastic liquid is described by using a power-law non-Newtonian model. There is a temperature difference between the internal and external cylinders. The porous layer is attached to the internal cylinder and has a thickness of D. Upper and lower walls of the cavity are well insulated. The governing equations are transformed into a non-dimensional form to generalize the solution. The finite element method is used to solve the governing equations numerically. The results are compared with the literature results in several cases and found in good agreement. Findings The influence of the thickness of the porous layer, Rayleigh number and non-Newtonian index on the heat transfer behavior of a non-Newtonian pseudoplastic fluid is addressed. The increase of pseudoplastic behavior and increase of the thickness of the porous layer enhances the heat transfer. By increase of the porous layer from 0.6 to 0.8, the average Nusselt number increased from 0.15 to 0.25. The increase of non-Newtonian effects (decrease of the non-Newtonian power-law index) enhances the heat transfer rate. Originality/value The free convection behavior of a pseudoplastic-non-Newtonian fluid in a cylindrical enclosure partially filled by a layer of a porous medium is addressed for the first time.

Effect of Apex Angle, Porosity, and Permeability on Flow and Heat Transfer in Triangular Porous Ducts

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
S. Negin Mortazavi ◽  
Fatemeh Hassanipour
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Temperature Distribution ◽  
Apex Angle ◽  
Convection Flow ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Wide Range ◽  
Porosity And Permeability ◽  
Forced Convection Flow

This paper presents an analysis of forced convection flow and heat transfer in triangular ducts containing a porous medium. The porous medium is isotropic and the flow is laminar, fully developed with constant properties. Numerical results for velocity and temperature distribution (in dimensionless format) in the channel are presented for a wide range of porosity, permeability, and apex angles. The effects of apex angle and porous media properties (porosity and permeability) are demonstrated on the velocity and temperature distribution, as well as the friction factor (fRe) and Nusselt numbers in the channel for both Isoflux (NuH) and Isothermal (NuT) boundary conditions. The consistency of our findings has been verified with earlier results in the literature on empty triangular ducts, when the porosity in our models is made to approach one.

scholarly journals MHD Flow of a Viscous Fluid over an Exponentially Stretching Sheet in a Porous Medium

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Muhmmad Sajid ◽  
Wasim Awan ◽  
Muhammad Rafique ◽  
Wajid Aziz ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Differential Equations ◽  
Stretching Sheet ◽  
Transfer Problem ◽  
Heat Transfer Analysis ◽  
Physical Parameters ◽  
Exponentially Stretching Sheet ◽  
Flow And Heat Transfer ◽  
Exponentially Stretching

Radiation effects on magnetohydrodynamic (MHD) boundary-layer flow and heat transfer characteristic through a porous medium due to an exponentially stretching sheet have been studied. Formulation of the problem is based upon the variable thermal conductivity. The heat transfer analysis is carried out for both prescribed surface temperature (PST) and prescribed heat flux (PHF) cases. The developed system of nonlinear coupled partial differential equations is transformed to nonlinear coupled ordinary differential equations by using similarity transformations. The series solutions for the transformed of the transformed flow and heat transfer problem were constructed by homotopy analysis method (HAM). The obtained results are analyzed under the influence of various physical parameters.

scholarly journals Unsteady Boundary Layer Stagnation Point Flow and Heat Transfer over a Stretching Sheet in a Porous Medium with Slip Effects

CFD letters ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 52-61
Author(s):  
Haliza Rosali ◽  
Mohd Noor Badlilshah ◽  
Mohamat Aidil Mohamat Johari ◽  
Norfifah Bachok
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Differential Equations ◽  
Stretching Sheet ◽  
Thermal Slip ◽  
Slip Effect ◽  
Unsteady Boundary Layer ◽  
Flow And Heat Transfer ◽  
Slip Effects

Boundary layer flow and heat transfer over a stretching sheet in a porous medium has many applications in industrial processes. The effect of porosity plays a significant role in determining the behaviour of the fluid flow. Based on that, we analyzed the unsteady boundary layer stagnation point flow and heat transfer towards a stretching sheet by considering the porosity. The velocity and thermal slip effects are taken into consideration in the present analysis. The governing non-linear partial differential equations were transformed into a system of nonlinear ordinary differential equations using similarity transformation. The resulting ordinary differential equations were solved numerically using the shooting method in Maple software. Numerical results for the dimensionless velocity profile, temperature profile, skin friction coefficients and the local Nusselt number are presented for various parameters. The effect of dimensionless material parameter, thermal slip effect and velocity slip effect on the flow field is also discussed. It is found that the skin friction coefficients decrease whereas the local Nusselt number increases with the increase in permeability parameter.

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