Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
13
6
2010
COCURRENT GAS-LIQUID FLOW IN METAL FOAM: AN EXPERIMENTAL INVESTIGATION OF PRESSURE GRADIENT
Metal foams have a relatively large "fluid/solid" contact area (m2 m−3) as well as small pressure drops due to their open structure. They may be used for many applications, such as in chemical reactors for the deposition of a catalyst. Gas and liquid cocurrent flows through this solid foam packing are investigated. Sample pore sizes are in the range of 400−2500 μm. The influence of pore size and gas and liquid mass flow rate density on the pressure gradient is experimentally investigated, and flow regimes are observed (bubbly, pulsating, and trickle flow). The reduced pressure gradient, defined as the two-phase multiplier by Lockhart and Martinelli formalism, allows the gathering and comparing of results obtained for all samples. Although the pore size range is very wide, the two-phase multiplier does not reveal any significant discrepancy between all the tested samples. Moreover, a correlation with glass-packed beds may reasonably be used to predict the pressure drop in metal foam (±25%).
Jean-Philippe
Bonnet
M2P2 UMR CNRS 6181, Université Paul Cézanne, Europôle de l'Arbois, Bátiment Laennec, Hall C,13545 Aix en Provence Cedex 4, France
Frederic
Topin
Polytech Marseille, Laboratoire IUSTI, UMR CNRS 7343, Technopole de Chateau Gombert, 5 rue Enrico Fermi, 13453 Marseille Cedex 13, France
Jerome
Vicente
lnstitut Universitaire des Systemes Thermiques Industriels (IUSTI-CNRS-UMR 6595), Aix-Marseille Universite Technopole de Chateau-Gombert
Lounes
Tadrist
Aix-Marseille Universite, CNRS, Laboratoire IUSTI, UMR 7343, Marseille 13453, France
497-510
NUMERICAL INSPECTION OF TURBULENT/LAMINAR NONREACTIVE AND LAMINAR COMBUSTIVE REACTIVE FLOWS IN POROUS MEDIA
In this study, the two-dimensional (2D) axisymmetric models of the turbulent/laminar nonreactive and the laminar combustive reactive flows in porous media are simulated numerically by the finite volume method along with the SIMPLE algorithm. The turbulence is simulated by a k − ε model adapted to the porous structure due to the additional source terms. The premixed combustion of methane-air is simulated by applying the single step chemical reaction mechanism. The obtained results for the flow simulation in porous media show that the turbulent kinetic energy is amplified within the foam and separated flow regions do not form or penetrate inside the porous material in the turbulent flow model. The simulation of the premixed laminar submerged flames indicates the super adiabatic combustion in the lean mixtures and implies the flame acceleration which results in higher thermal loads in these flames. Furthermore, the stabilization process and the position of flame within the foam are examined through using different methods for convergence of the numerical code and the acquired predictions are compared to the previous results of the similar research.
A.
Yarahmadi
Mechanical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., P.O. Box 15875-4413, Tehran, Iran
Reza
Hosseini
School of Mechanical Engineering, Amirkabir University of Technology (Tehran Polytechnic), 424 Hafez Avenue, Tehran, Iran
M. R. H.
Nobari
Mechanical Engineering Department, Amirkabir University of Technology, 424 Hafez Ave., P.O. Box 15875-4413, Tehran, Iran
511-528
THERMAL EQUILIBRIUM ASSUMPTION OF FLUID FLOW IN POROUS CHANNEL AS DESCRIBED BY A HYPERBOLIC HEAT-CONDUCTION MODEL
The transient thermal behavior of a homogeneous composite domain described by the hyperbolic heat-conduction model is investigated semianalytically. The composite domain consists of a matrix (fluid domain) and inserts (solid domain), each of which is made of different materials. Two cases are considered. In the first case, the conduction in the solid domain is included and, in the second, the conduction in the fluid domain. The range of parameters, within which the use of the thermal equilibrium assumption in transient flow in porous channel as described by a hyperbolic heat-conduction model, is determined. The effect of different parameters that affect the local thermal equilibrium assumption under the effect of the hyperbolic heat conduction model is also investigated.
Abed F.
khadrawi
Mechanical Engineering Department, Al-Balqa' Applied University, Al-Huson University College, Jordan
Moh'd Ahmad
Al-Nimr
Jordan University of Science and Technology
Montasir A.
Hader
Mechanical Engineering Department, Jordan University of Science and Technology, Irbid 22110, Jordan
529-535
NON-DARCY MIXED CONVECTION IN A FLUID-SATURATED SQUARE POROUS ENCLOSURE UNDER SUCTION EFFECT: PART I
In this study, volume-averaged equations governing the steady mixed convection flow in a vertical square enclosure filled with a non-Darcian fluid-saturated homogeneous porous medium are investigated numerically by the Galerkin finite element method. The forced flow conditions are imposed by providing an inlet at the bottom wall and an outlet with suction on the top wall. The free convection is induced by introducing a hot but isothermal temperature on the left vertical wall together with Boussinesq approximation on density. Detailed numerical simulations are carried out for a wide range of governing parameters such as Grashof Number (Gr*), Rayleigh Number (Ra), suction/injection velocity (a), and suction/injection width (D/H) as a fraction of the length of the square enclosure.
B. V. Rathish
Kumar
Department of Mathematics and Statistics, Indian Institute of Technology Kanpur,
Kanpur-208016, India
Somanchi V S S N V G
Krishna Murthy
Department of Applied Mathematics, Defence Institute of Advanced Technology, Gririnagar, Pune 411025, India
Vivek
Sangwan
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India
Mohit
Nigam
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India
Peeyush
Chandra
Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur 208016, India
537-554
AN EFFICIENT AND RELIABLE TWO-DIMENSIONAL PATTERNING OF POROUS SILICON
An efficient and reliable method for patterning a two-dimensional porous Si (PS) is presented in this work. The Cr/Au (50/200 nm) layer is used as a mask for electrochemical prosification of Si to form a two-dimensional pattern of porous Si. Quality of the formed 8 × 8 pads of porous Si is analyzed using statistical image analysis, an atomic force microscope, a scanning electron microscope, and also images from an optical microscope. It is shown that a combination of photoresist patterning and Cr/Au deposition can be used to generate arrays of silicon nanoporous in selected surface regions. Our results indicate that using the Cr/Au layer as a mask during prosification of Si results in sharper patterns with higher resolution in comparison to conventionally used photoresist masks such as Shipley and SU8 photoresists. The sharpness of the formed patterns is also investigated by calculating the correlation coefficient using image processing of the formed pattern with the ideal pattern. The correlation coefficient of the patterns made by the Cr/Au mask is 0.99 and the maximum deviation of the formed pattern from the original Cr/Au pattern is 3.44 μm, which shows an almost perfect correlation of the generated array with the ideal pattern.
Hassan
Hajghassem
Electrical Engineering Department, Shahid Beheshti University, Tehran, Iran
A.
Erfanian
Electrical Engineering Department, K. N. Toosi University, Tehran, Iran
M.
Mohtashamifar
Electronic Research Center, Tehran, Iran
M.
Aliahmadi
Electronic Research Center, Tehran, Iran
S. Morteza
Alehashemi
Electronic Research Center, Tehran, Iran
S. Maryam
Banihashemian
Islamic Azad University, Qom Branch, Qom, Iran
557-563
MAGNETOHYDRODYNAMIC THIN FILM FLOW OF A SISKO FLUID IN A POROUS SPACE
This investigation provides an analytical study of magnetohydrodynamic thin film flow of a Sisko fluid on a moving belt. The flow modeling in a porous space is given by means of a modified Darcy's law. Analytical expression of velocity is derived by homotopy analysis method. Graphs are sketched, and variations of emerging flow parameters are analyzed.
M. Usman
Ashraf
Department of Mathematics, Quaid-i-Azam University, 45320 Islamabad, Pakistan
565-571
UNSTEADY MAGNETOHYDRODYNAMIC OSCILLATORY FLOW AND HEAT TRANSFER ANALYSIS OF A VISCOUS FLUID IN A POROUS CHANNEL FILLED WITH A SATURATED POROUS MEDIUM
In this article, unsteady oscillatory flow of a magnetohydrodynamic fluid and heat transfer analysis with nonuniform wall temperature through a planar channel filled with a saturated porous medium are studied. It is assumed that the walls of the channel are porous so that suction/injection may take place. The exact analytic closed-form solution is obtained for velocity and temperature fields. The mathematical results are then plotted to see the effect of different parameters on the flow phenomenon.
Ahmer
Mehmood
Department of Mathematics, International Islamic University, Islamabad, Pakistan
Asif
Ali
Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan
Tahir
Mahmood
Department of Mathematics, The Islamia University of Bahawalpur, Pakistan
573-577
VARIABLE VISCOSITY AND CHEMICAL REACTION EFFECTS ON NON-DARCY MAGNETOHYDRODYNAMIC MIXED CONVECTIVE HEAT AND MASS TRANSFER PAST A POROUS WEDGE IN THE PRESENCE OF SUCTION OR INJECTION
An analysis is presented to investigate the effects of variable viscosity on non-Darcy magnetohydrodynamic mixed convective heat and mass transfer of a viscous, incompressible, and electrically conducting fluid past a porous wedge in the presence of a chemical reaction. The wall of the wedge is embedded in a uniform non-Darcian porous medium to allow for possible fluid wall suction or injection. The governing partial differential equations of the problem, subjected to their boundary conditions, are solved numerically by applying an efficient solution scheme for local nonsimilarity boundary layer analysis. Numerical calculations, up to a third-order level of truncation, are carried out for different values of dimensionless parameters in the problem, and an analysis of the results obtained shows that the flow field is influenced appreciably by the applied magnetic field. The results are compared with those known from the literature, and excellent agreement between the results is obtained.
Ramasamy
Kandasamy
Centre for Science Studies, Universiti Tun Hussein Onn Malaysia
Muhaimin
Nordin
Centre for Science Studies, Universiti Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat Johor, Malaysia
Azme B
Khamis
Centre for Science Studies, Universiti Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat Johor, Malaysia
579-590