Heatline visualization of natural convection in a trapezoidal cavity partly filled with nanofluid porous layer and partly with non-Newtonian fluid layer

2015 ◽  
Vol 26 (4) ◽  
pp. 1230-1244 ◽  
Author(s):  
A.I. Alsabery ◽  
A.J. Chamkha ◽  
S.H. Hussain ◽  
H. Saleh ◽  
I. Hashim
Keyword(s):  
Natural Convection ◽  
Porous Layer ◽  
Newtonian Fluid ◽  
Fluid Layer

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.

Three-Dimensional Natural Convection in a Confined Fluid Overlying a Porous Layer

1993 ◽  
Vol 115 (3) ◽  
pp. 631-638 ◽  
Author(s):  
A. K. Singh ◽  
E. Leonardi ◽  
G. R. Thorpe
Keyword(s):  
Natural Convection ◽  
Porous Layer ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Fluid Layer ◽  
Three Dimensional ◽  
Side Wall ◽  
Slip Boundary Condition ◽  
Solution Procedure ◽  
Convection Current

This paper presents a numerical study of three-dimensional, laminar natural convection in an enclosure containing a fluid layer overlying a porous layer saturated with the same fluid. The Brinkman-extended Darcy formulation is used to model fluid flow in the porous layer as this facilitates the imposition of a no-slip boundary condition at the fluid/porous layer interface. The enclosure is heated from one side wall and cooled from an opposite wall, while the remaining walls are adiabatic. The mathematical analysis is carried out in terms of a vorticity-vector potential formulation that ensures the conservation of mass. The governing equations in non-dimensional form are transformed into parabolic equations by means of a false transient method in order to facilitate a solution procedure by an alternating direction implicit method. Accuracy of the numerical solutions with respect to uniformly and nonuniformly spaced grid points has been tested by performing extensive numerical experiments. As expected, it is found that the intensity of free convection is much more profound in the fluid layer. The numerical results indicate that penetration of the fluid into the porous region depends strongly upon the Darcy and Rayleigh numbers. The effect of the ratio of thermal conductivities (porous to fluid regions) is to intensify the convection current in the fluid layer.

Stability of natural convection in a vertical non-Newtonian fluid layer with an imposed magnetic field

Meccanica ◽  
2017 ◽  
Vol 53 (4-5) ◽  
pp. 773-786 ◽  
Author(s):  
B. M. Shankar ◽  
Jai Kumar ◽  
I. S. Shivakumara ◽  
K. R. Raghunatha
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Newtonian Fluid ◽  
Fluid Layer

scholarly journals Natural Convection in Horizontal Fluid-Superposed Porous Layers Heated Locally From Below

2010 ◽  
Author(s):  
Aniruddha Bagchi ◽  
Francis A. Kulacki
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Porous Layer ◽  
Fluid Layer ◽  
Lower Surface ◽  
Length Ratio ◽  
Height Ratio ◽  
Porous Layers ◽  
Recirculating Flow ◽  
Heater Length

This paper reports numerical studies of steady two-dimensional natural convection in fluid-superposed porous layers heated locally from below. The numerical simulation is based on the Darcy-Brinkman-Forchheimer model for the porous layer and focuses on the parametric domain in which the flow is well established, i.e., the overall Rayleigh number is several orders of magnitude larger than the critical value. An emphasis is placed on revealing the effects of two dimensionless parameters on the overall Nusselt number: the porous layer-to-cavity height ratio (η = Hm/H) and the heater-to-cavity base length ratio (δ = LH/L). Calculations cover η = 0.25, 0.5, 0.75, δ = 0.25, 0.5, 1, and overall Rayleigh numbers from 103 to 106. For a fixed height ratio, overall Nusselt numbers increase with a decrease in the heater length. For a given heater length ratio, overall Nusselt number increases with an increase in the height of the overlying fluid layer. Recirculating flow is confined primarily to the overlying fluid layer with some penetration into the upper part of the porous layer. The present results represent an extension of the well studied problem of buoyant convection in superposed layers with a fully heated lower surface.

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