The influence of side wall heat transfer on convection in a confined saturated porous medium

1986 ◽  
Vol 29 (2) ◽  
pp. 349 ◽  
Author(s):  
P. D. Weidman ◽  
D. R. Kassoy
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Saturated Porous Medium ◽  
Side Wall ◽  
Wall Heat Transfer

BUOYANCY-DRIVEN HEAT TRANSFER OF WATER-BASED NANOFLUID IN A PERMEABLE CYLINDRICAL PIPE WITH NAVIER SLIP THROUGH A SATURATED POROUS MEDIUM

2015 ◽  
Vol 18 (12) ◽  
pp. 1169-1180 ◽  
Author(s):  
Sara Khamis ◽  
Oluwole Daniel Makinde ◽  
Yaw Nkansah-Gyekye
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Saturated Porous Medium ◽  
Cylindrical Pipe ◽  
Navier Slip ◽  
Water Based

scholarly journals Heat Transfer to MHD Oscillatory Viscoelastic Flow in a Channel Filled with Porous Medium

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Rita Choudhury ◽  
Utpal Jyoti Das
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Porous Medium ◽  
Radiative Heat ◽  
Saturated Porous Medium ◽  
Transverse Magnetic ◽  
Viscoelastic Flow ◽  
Viscoelastic Parameter ◽  
Flow Parameters ◽  
The Magnetic Field

The combined effect of a transverse magnetic field and radiative heat transfer on unsteady flow of a conducting optically thin viscoelastic fluid through a channel filled with saturated porous medium and nonuniform walls temperature has been discussed. It is assumed that the fluid has small electrical conductivity and the electromagnetic force produced is very small. Closed-form analytical solutions are constructed for the problem. The effects of the radiation and the magnetic field parameters on velocity profile and shear stress for different values of the viscoelastic parameter with the combination of the other flow parameters are illustrated graphically, and physical aspects of the problem are discussed.

The Characteristics of Porous Solar Wall Heating System with Localized UFAD

2012 ◽  
Vol 178-181 ◽  
pp. 237-243
Author(s):  
Li Ouyang ◽  
Wei Liu
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Saturated Porous Medium ◽  
Flow Characteristics ◽  
Heating System ◽  
Physical Models ◽  
Air Distribution ◽  
Cable System ◽  
Wall Heating ◽  
Solar Wall

In this paper, the physical models of the porous solar wall heating system with localized underfloor air distribution (UFAD) are established. Based on Brinkman-Forchheimer Extended Darcy and energy two-equation models for saturated porous medium, the influences of the structure of underfloor space on the heat transfer and flow characteristics of the system are simulated, analyzed and compared.The results show that the underfloor space with rational partition is good for improving the heat transfer and flow characteristics of system, and maintaining the cable system in the underfloor space.

scholarly journals Mixed Convective Flow of Micropolar Nanofluid across a Horizontal Cylinder in Saturated Porous Medium

2019 ◽  
Vol 9 (23) ◽  
pp. 5241 ◽  
Author(s):  
Ahmed M. Rashad ◽  
Waqar A. Khan ◽  
Saber M. M. EL-Kabeir ◽  
Amal M. A. EL-Hakiem
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Convective Flow ◽  
Volume Fraction ◽  
Saturated Porous Medium ◽  
Titania Nanoparticles ◽  
Flow And Heat Transfer ◽  
Micropolar Nanofluid ◽  
Mixed Convective Flow ◽  
The Impact

The micropolar nanofluids are the potential liquids that enhance the thermophysical features and ability of heat transportation instead of base liquids. Alumina and Titania nanoparticles are mixed in a micropolar fluid. The impact of convective boundary condition is also examined with assisting and opposing flows of both nanofluids. The main objective of this study is to investigate mixed convective flow and heat transfer of micropolar nanofluids across a cylinder in a saturated porous medium. Non-similar variables are used to make the governing equations dimensionless. The local similar and non-similar solutions are obtained by using the Runge-Kutta-Fehlberg method of seventh order. The impacts of various embedded variables on the flow and heat transfer of micropolar nanofluids are investigated and interpreted graphically. It is demonstrated that the skin friction and heat transfer rates depend on solid volume fraction of nanoparticles, Biot number, mixed convection, and material parameters.

Free convection of a hybrid nanofluid past a vertical plate embedded in a porous medium with anisotropic permeability

2019 ◽  
Vol 30 (8) ◽  
pp. 4083-4101 ◽  
Author(s):  
Aneela Bibi ◽  
Hang Xu ◽  
Qiang Sun ◽  
Ioan Pop ◽  
Qingkai Zhao
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Stability Analysis ◽  
Flat Surface ◽  
Saturated Porous Medium ◽  
Heat Energy ◽  
Hybrid Nanofluid ◽  
Anisotropic Permeability ◽  
Content Type ◽  
Hybrid Nanofluids

Purpose This study aims to carry out an analysis for flow and heat transfer of a new hybrid nanofluid over a vertical flat surface embedded in a saturated porous medium with anisotropic permeability at high Rayleigh number. Here the hybrid nanofluid is considered as the working fluid, with different kinds of small particles in nanoscale being suspended. Design/methodology/approach The generalized homogenous model is introduced to describe the behaviors of hybrid nanofluid. Within the framework of the boundary layer approximations, the governing equations embodying the conservation equations of total mass, momentum and thermal energy are reduced to a set of fully coupled ordinary differential equations via relevant scaling transformations. A flow stability analysis is performed to examine the behavior of convective heat energy. Accurate solutions are obtained by means of a very efficient homotopy-based package BVPh 2.0. Findings Results show that the linear correlations of physical quantities among the base fluid and its suspended nanoparticles are adequate to give accurate results for simulation of behaviors of hybrid nanofluids. Heat enhancement can be also fulfilled by hybrid nanofluids. A flow stability analysis suggests the heat-related power index m > −1/3 for satisfying the increasing behavior of convective heat energy. Originality/value Free convection of a hybrid nanofluid near a vertical flat surface embedded in a saturated porous medium with anisotropic permeability is investigated for the first time. The simplified hybrid nanofluid model is proposed for describing nanofluid behaviors. The results of this proposed approach agree well with those given by the traditional hybrid nanofluid model and experiment. It is expected that, by using different combinations of various kinds of nanoparticles, the new generation of heat transfer fluids can be fabricated, which possess similar thermal-physical properties as regular nanofluids but with lower cost.

Natural convective heat transfer in a hemispherical cavity filled with ZnO–H2O nanofluid saturated porous medium

2018 ◽  
Vol 29 (10) ◽  
pp. 1850097 ◽  
Author(s):  
Abderrahmane Baïri ◽  
Najib Laraqi
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Rayleigh Number ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Volume Fraction ◽  
Saturated Porous Medium ◽  
Physical Parameters ◽  
Numerical Work

This three-dimensional (3D) numerical work based on the volume control method quantifies the convective heat transfer occurring in a hemispherical cavity filled with a ZnO–H2O nanofluid saturated porous medium. Its main objective is to improve the cooling of an electronic component contained in this enclosure. The volume fraction of the considered monophasic nanofluid varies between 0% (pure water) and 10%, while the cupola is maintained isothermal at cold temperature. During operation, the active device generates a heat flux leading to high Rayleigh number reaching [Formula: see text] and may be inclined with respect to the horizontal plane at an angle ranging from 0[Formula: see text] to 180[Formula: see text] (horizontal position with cupola facing upwards and downwards, respectively) by steps of 15[Formula: see text]. The natural convective heat transfer represented by the average Nusselt number has been quantified for many configurations obtained by combining the tilt angle, the Rayleigh number, the nanofluid volume fraction and the ratio between the thermal conductivity of the porous medium’s solid matrix and that of the base fluid. This ratio has a significant influence on the free convective heat transfer and ranges from 0 (without porous media) to 70 in this work. The influence of the four physical parameters is analyzed and commented. An empirical correlation between the Nusselt number and these parameters is proposed, allowing determination of the average natural convective heat transfer occurring in the hemispherical cavity.

Mixed Convective Heat Transfer From a Heated Horizontal Plate in a Porous Medium Near an Impermeable Surface

1988 ◽  
Vol 110 (2) ◽  
pp. 390-394 ◽  
Author(s):  
P. H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Saturated Porous Medium ◽  
Forced Flow ◽  
Horizontal Plate ◽  
Flowing Fluid ◽  
Buoyancy Forces ◽  
Two Dimensional Flow

Two-dimensional flow over a horizontal plate in a saturated porous medium mounted near an impervious adiabatic horizontal surface and subjected to a horizontal forced flow has been numerically investigated. The plate is heated to a uniform temperature that is higher than the temperature of the flowing fluid. The conditions considered are such that the buoyancy forces have an effect on the flow and, therefore, on the heat transfer rate from the plate. The full governing equations, written in dimensionless form, have been solved for a range of values of the governing parameters using the finite element method. The heat transfer rate from the plate is influenced both by the dimensionless depth of the plate below the surface and the importance of the buoyancy forces, the latter having been characterized by a parameter which is equal to the ratio of the Darcy–Rayleigh number to Peclet number. The conditions under which these parameters have a negligible effect on the heat transfer rate are discussed.

Influence of Surface Heat Flux Ratio on Heat Transfer Augmentation in Square Channels With Parallel, Crossed and V-Shaped Angled Ribs

1991 ◽  
Author(s):  
J. C. Han ◽  
Y. M. Zhang ◽  
C. P. Lee
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Flux Ratio ◽  
Side Wall ◽  
Reynolds Numbers ◽  
Diameter Ratio ◽  
Wall Heat Flux ◽  
Wall Heat Transfer ◽  
Square Channel ◽  
Heat Transfer Augmentation

The effect of wall heat flux ratio on the local heat transfer augmentation in a square channel with two opposite in-line ribbed walls was investigated for Reynolds numbers from 15,000 to 80,000. The square channel composed of ten isolated copper sections has a length-to-hydraulic diameter ratio (L/D) of 20. The rib height-to-hydraulic diameter ratio (e/D) is 0.0625 and the rib pitch-to-height ratio (P/e) equals 10. Six ribbed side to smooth side wall heat flux ratios (Case 1 - q″r1/q″s = q″r2/q″s = 1; Case 2 - q″r1/q″s = q″r2/q″s = 3; Case 3 - q″r1/q″s = q″r2/q″s = 6; Case 4 - q″r1/q″s = 6 and q″r2/q″s = 4; Case 5 - q″r1/q″s = q″r2/q″s = ∞ and Case 6 - q″r1/q″s = ∞ and q″r2/q″s = 0) were studied for four rib orientations (90° rib, 60° parallel rib, 60° crossed rib, and 60° ∨-shaped rib). The results show that the ribbed side wall heat transfer augmentation increases with increasing ribbed side to smooth side wall heat flux ratios, but the reverse is true for the smooth side wall heat transfer augmentation. The average heat transfer augmentation of the ribbed side and smooth side wall decreases slightly with increasing wall heat flux ratios. Two ribbed side wall heating (Case 5 - q″r1/q″s = q″r2/q″s = ∞) provides a higher ribbed-side-wall heat transfer augmentation than the four-wall uniform heating (Case 1 - q″r1/q″s = q″r2/q″s = 1). The effect of wall heat flux ratio reduces with increasing Reynolds numbers. The results also indicate that the 60° ∨-shaped rib and 60° parallel rib perform better than the 60° crossed rib and 90° rib, regardless of wall heat flux ratio and Reynolds number.

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