Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
16
8
2013
ASSESSMENT OF X-RAY MICRO-CT MEASUREMENTS OF POROSITY AND SOLUTE CONCENTRATION DISTRIBUTIONS DURING DIFFUSION IN POROUS GEOLOGIC MEDIA
Using x-ray micro-computed tomography (micro-CT) for quantitative measurements in porous media is inherently challenged by uncertainties, which need to be identified and quantified to enable meaningful interpretation of measurements. For this purpose, we present results of experiments using micro-CT to measure the three-dimensional distribution of diffusion-accessible porosity and time-variant iodide tracer concentration within dolostone and sandstone samples. The precision, detection limits and spatial resolution of measurements were determined. Using a 0.6 M iodide tracer, the
precision of attenuation coefficient measurement was approximately ±4%, in both the dolostone and sandstone samples. The precision for diffusion-accessible porosity and solute concentration measurements were ±7% and ±0.04 M, with detection limits of 20% and 0.12 M, respectively. The spatial resolution of measurement was 40 μm, representing the minimum size of features that can be distinctively resolved in a reconstructed image with 18.23 μm voxel size.
H. M. D.
Agbogun
Department of Earth Sciences, University of New Brunswick; Laboratory for Threat Material Detection, Department of Mechanical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3
Esam M. A.
Hussein
Laboratory for Threat Material Detection, Department of Mechanical Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada E3B 5A3
Tom A.
Al
Department of Earth Sciences, University of Ottawa
683-694
EXPERIMENTAL INVESTIGATION OF TWO-PHASE MIST FLOWAND HEAT TRANSFER IN POROUS MEDIA
An experimental investigation was conducted to examine steady, air-water mist flow in a porous material. The aim
was to quantify the effects of various operating and design parameters on the cooling effectiveness. Parameters tested included the porous material type, porous material porosity and permeability, diameter and thermal conductivity, carrier gas velocity, and channel characteristics on the heat transfer rate and pressure drop. The results are compared with the single-phase flow where no mist was used. A fully instrumented experimental test facility that included a cylindrical and a rectangular electrically heated test section was used. Water was used as the mist liquid, with air as the carrier
gas. Local heat transfer coefficients, defined based on the temperature difference between the heated surface and the bulk gas, were obtained along the channels for a wide range of operating conditions. The data indicate that mist cooling can increase the heat transfer coefficient by more than an order of magnitude compared to forced convection using only the carrier gas in porous media.
Mohammad
Nikian
Mechanical and Aerospace Engineering Faculty, Science and Research Branch, Islamic Azad University (IAU), Pounak Square, Tehran, Iran
Hossein
Shokouhmand
University of Tehran
M.
Khayat
Mechanical and Aerospace Engineering Faculty, Science and Research Branch, Islamic Azad University (IAU), Pounak Square, Tehran, Iran
A.
Mohammadzadeh
Mechanical and Aerospace Engineering Faculty, Science and Research Branch, Islamic Azad University (IAU), Pounak Square, Tehran, Iran
695-707
EFFECT OF POROSITY AND FLR CORRECTIONS ON JEANS INSTABILITY OF SELF-GRAVITATING RADIATIVE THERMALLY CONDUCTING VISCOUS PLASMA
The effects of porosity, radiative heat-loss function, and finite ion Larmor radius (FLR) corrections on the selfgravitational instability of infinite homogeneous viscous plasma have been investigated incorporating the effects of thermal conductivity, finite electrical resistivity, and permeability. A general dispersion relation is derived using the normal mode analysis method with the help of relevant linearized perturbation equations of the problem. The wave propagation along and perpendicular to the direction of magnetic field has been discussed. The condition of stability of the medium is discussed by applying the Routh-Hurwitz criterion. We find that the presence of porosity, FLR corrections,
radiative heat-loss function, and thermal conductivity modifies the fundamental Jeans criterion of gravitational
instability. Analytical and numerical calculations are carried out to show the effect of various physical parameters on the growth rate of the self-gravitational instability. From the curves we find that temperature dependent heat-loss function, medium porosity, and FLR corrections have a stabilizing effect, while density dependent heat-loss function has a destabilizing effect on the growth rate of self-gravitational instability in the present medium.
Sachin
Kaothekar
Department of Engineering Physics, Mahakal Institute of Technology, Ujjain (M. P.) 456664, India
Rajendra K.
Chhajlani
School of Studies in Physics, Vikram University Ujjain (M.P.)-456010, India
709-724
EFFECTS OF POROUS INTERNAL COMPONENTS ON LIQUID SLOSH DYNAMICS
Internal submerged components strongly influence the slosh dynamics of liquid storage tanks and submersed baffles are used for slosh suppression over a long period of time. The effect of a circumferential baffle on dynamic behavior has been analyzed experimentally as well as numerically by various methods. The baffles constrict the flow and modify flow pattern in the tank. These baffles are found to be more effective near the surface than at the bottom. However, use of a solid baffle attaches considerable weight penalty which is substantial when considered in the context of spacecraft and mass liquid carriage vessels. To reduce the weight penalty as well as to ensure uniform velocity distribution in the tank and to smooth out peaks and valleys in the damping due to series of baffles, perforated baffles are widely used as slosh suppression devices. Several experimental studies are performed to understand the effect of perforated baffles but very few numerical studies are reported. The purpose of this study is to understand and examine numerically the effect of perforation in horizontal baffles on the slosh dynamics of a partially filled rectangular liquid tank. The sloshing is studied using a weak-form Galerkin finite element model.
Arun
Kumar
Department of Aerospace Engineering, IIT Kharagpur Kharagpur-721302, West Bengal, India
K. P.
Sinhamahapatra
Aerospace Engineering Department, Indian Institute of Technology Kharagpur, Kharagpur-721302, West Bengal, India
725-747
TIME-DEPENDENT FLOW IN A COMPOSITE CHANNEL WITH HEAT TRANSFER
In this article, unsteady oscillatory flow and heat transfer in a horizontal composite porous channel is discussed. The Darcy-Brinkman model is used to develop the governing equations for the flow in a porous medium. The upper plate is oscillating with the constant amplitude while the lower plate is stationary. The viscous and Darcian dissipation terms are included in the energy equation. At the interface of both regions the velocity, shear stress, and temperature profiles are assumed to be continuous. The governing equations for momentum and heat transfer are solved analytically using the series solution in terms of harmonic and nonharmonic functions in both regions of the channel. The effects of various physical parameters on the velocity and the temperature profiles are analyzed with the help of graphs and tables.
Muhammad
Nasir
Department of Mathematics Quaid-i-Azam University, Islamabad, Pakistan 44000
Sufian
Munawar
Quaid-i-Azam University Islamabad
Asif
Ali
Department of Mathematics, Quaid-i-Azam University 45320, Islamabad 44000, Pakistan
749-756
EFFECT OF RADIATION ON MIXED CONVECTION ALONG VERTICAL CYLINDER WITH UNIFORM SURFACE HEAT FLUX IN A POROUS MEDIUM
In this study, the effect of radiation on mixed convection along a vertical cylinder with uniform surface heat flux in a porous medium is investigated numerically using an implicit finite-difference method. Similar and nonsimilar solutions are obtained for combined radiation and mixed convection regime. Nusselt numbers are obtained for various values of different parameters. Several values of the power-law variation in surface heat flux, buoyancy, curvature, and mixed convection parameters are considered to study their effects on heat transfer rates. The Rosseland approximation is used to describe the radiative heat flux in energy equation.
Waqar A.
Khan
Department of Engineering Sciences, PN Engineering College, National University of Sciences and Technology, Karachi; CHASHMA Nuclear Power Plant, Pakistan Atomic Energy Commission, Mianwai, Pakistan
Malik M.
Imran
Department of Engineering Sciences, PN Engineering College, National University of Science and Technology, Karachi 75350, Pakistan
Qaisar
Ali
Department of Engineering Sciences, PN Engineering College, National University of Science and Technology, Karachi 75350, Pakistan
757-765
EFFECTS OF SLIP ON PULSATING FLOW OF AN INCOMPRESSIBLE MICROPOLAR FLUID THROUGH A POROUS MEDIUM BETWEEN TWO PARALLEL PLATES
This paper deals with the pulsating flow of an incompressible micropolar fluid through a porous medium bounded by two horizontal parallel plates. The flow is assumed to be governed by Eringen's micropolar fluid flow equations. Navier's slip condition at the boundary is used instead of the usual no-slip condition. The analytical expressions for velocity and microrotation fields are obtained. The effects of the slip parameter, Darcy number, and micropolar parameters are studied. The results are presented and discussed through graphs. As the slip parameter tends to zero, the solution of the problem with the usual no-slip condition can be recovered.
Punnamchandar
Bitla
Dept of Mathematics, Amrita School of Engineering, Coimbatore, Amrita Vishwa Vidyapeetham, Amrita University, India, 641112
T. K. V.
Iyengar
Department of Mathematics, National Institute of Technology, Warangal-506004, Andhra Pradesh, India
769-775