Begell House Inc.
Journal of Porous Media
JPM
1091-028X
14
4
2011
THE EFFECT OF LOCAL THERMALNONEQUILIBRIUM ON THE ONSET OF CONVECTION IN A POROUS MEDIUM LAYER SATURATED BY A NANOFLUID: BRINKMAN MODEL
285-293
10.1615/JPorMedia.v14.i4.10
Andrey V.
Kuznetsov
Department of Mechanical and Aerospace Engineering, North Carolina State University, Campus Box 7910, Raleigh, NC 27695, USA
D. A.
Nield
Department of Engineering Science, University of Auckland, Auckland, New Zealand
local thermal nonequilibrium
LTNE
nanofluid
porous medium
instability
natural convection
The onset of convection in a horizontal layer of a porous medium saturated by a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. For the porous medium the Brinkman model is employed. Three cases of free-free, rigid-rigid, and rigid-free boundaries are considered. The effect of local thermal nonequilibrium between the particle, fluid, and solid-matrix phases is investigated using a three-temperature model. The analysis reveals that in some circumstances the effect of local thermal nonequilibrium (LTNE) can be significant, but for a typical dilute nanofluid (with large Lewis number and with small particle-to-fluid heat capacity ratio) the effect is small.
MEDIUM-POROSITY SINTERED IRON COMPACT AND THE CORRELATION BETWEEN THE PARAMETERS AFFECTING ITS POROSITY DEGREE USING EXPERIMENTAL DESIGN TECHNIQUE
295-303
10.1615/JPorMedia.v14.i4.20
Yasser M. Z.
Ahmed
Central Metallurgical Research and Development Institute, CMRDI, Helwan, Cairo, Egypt
B. A.
Iskander
Academy of Specialized Studies, Department of Technology, Development Workers University, Cairo, Egypt
F. M.
Mohamed
Central Metallurgical Research and Development Institute, CMRDI, Helwan, Cairo, Egypt
M.
Ibrahim
Central Metallurgical Research and Development Institute, CMRDI, Helwan, Cairo, Egypt
M. E. H.
Shalabi
Central Metallurgical Research and Development Institute, CMRDI, Helwan, Cairo, Egypt
porous iron compact
powder metallurgy
naphthalene
total porosity
Porous iron compacts with a porosity degree in the range of (20−70%) have received great attention as a result of their unique properties. There are various parameters controlling fabrications of such compacts using powder metallurgy techniques. Sintering temperature, sintering time, compaction pressure, as well as the amount of filler materials (naphthalene amount added as pore-forming materials) represents the most effective parameters during fabrication. With the aid of experimental design technique (full factorial design), correlation between all of these parameters and the porosity degree of the final sintered compacts is evaluated. It was found that while compaction pressure has the most positive significant effect on total porosity, the amount of naphthalene had the highest negative effect on it. On the other hand, the interaction between both naphthalene amount and compaction pressure as well as between naphthalene amount and sintering temperature is significant, affecting the total porosity of the final porous iron compacts.
THREE-DIMENSIONAL STUDY OF PERMEABILITY EFFECT ON CONVECTION IN HETEROGENEOUS POROUS MEDIUM FILLED WITH A TERNARYN HYDROCARBON MIXTURE
305-315
10.1615/JPorMedia.v14.i4.30
T. J.
Jaber
Faculty of Engineering and Applied Sciences, Alhosn University, Abu Dhabi, UAE
M. Ziad
Saghir
Department of Mechanical and Industrial Engineering, Ryerson University, 350 Victoria St., Toronto, ON M5B2K3, Canada
thermodiffusion
heterogeneous porous medium
permeability
Soret effect
molecular diffusion
In this paper the effect of permeability in the heterogeneous porous medium on fluid transport is studied with consideration of thermodiffusion (Soret effect) and molecular diffusion. A ternary mixture of n-dodecane (C12), tetrahydonaphthalene (THN), and isobutylbenzene (IBB) in a porous medium subjected to a lateral heating is numerically investigated at atmospheric pressure. Employing a single-phase model and Darcy’s law, the continuity and the energy equations are solved numerically using the finite-volume method. The permeability of the matrix (main domain, Km = 10 mD) is kept constant, while the permeability of the subdomains (Kf) is varied. Various permeability ratios (Kf = Km = 10; 100; 1000, and 10000) are examined in this study, which cover a wide range of oil reservoirs. The temperature, fluid flow, and solute fields are discussed in detail in order to show the subdomain’s effect on fluid transport, especially when thermodiffusion is taken into consideration. The results reveal that when the subdomain/matrix permeability ratio is large, the flow in the subdomain region is pronounced. This leads to a nonuniform concentration distribution of the mixture components in the subdomains region.
NUMERICAL MODELING OF TWO-DIMENSIONAL CYLINDRICAL POROUS RADIANT BURNERS WITH SIDEWALL HEAT LOSSES
317-327
10.1615/JPorMedia.v14.i4.40
Mehdi
Maerefat
Department of Mechanical Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran, Iran
M.
Khosravy el-Hossaini
Energy Research Centre, Research Institute of Petroleum Industry, P.O. Box 14665-137, Tehran, Iran
K.
Mazaheri
Department of Mechanical Engineering, Tarbiat Modares University, Iran
reduced kinetics mechanism
porous radiant burner
cylindrical
two-dimensional
numerical simulation
In this paper, numerical modeling of axisymmetric cylindrical porous radiant burners with sidewall heat loss has been studied. Nonlocal thermal equilibrium is assumed between gas and solid phases and the solid phase is considered as the thermal radiation medium in this modeling. Lateral heat loss at the experimental conditions is found to be 6% of the supplied fuel energy, which causes the highly two-dimensional characteristics and lower temperature profiles in the burner. The experienced maximum peak temperature reduction is about 150 K compared to a one-dimensional flame. The lower flame peak temperature leads to less NOX formation, which results in about 44% reduction of NO concentration at the burner outlet surface for a stoichiometric mixture. This brings about the new results very close to the experimental results. As lateral heat loss increases, the flame front moves downstream. About 6 mm of backward movement is observed when the lateral heat loss is about 23% of the firing rate. This is due to the lower flame speed at lower flame temperature. The new findings are observed for both stoichiometric as well as lean mixtures.
CONVECTION AND HEAT TRANSFER IN LAYERED SLOPING,WARM-WATER AQUIFERS
329-343
10.1615/JPorMedia.v14.i4.50
Robert
McKibbin
Institute of Information and Mathematical Sciences, Massey University at Albany, Auckland, New Zealand
Nicholas
Hale
Oxford Centre for Collaborative Applied Mathematics, Mathematical Institute, Oxford, OX1 3LB, United Kingdom
Robert W.
Style
Oxford Centre for Collaborative Applied Mathematics, Mathematical Institute, Oxford, OX1 3LB, United Kingdom
Nicole
Walters
School of Mathematics, Statistics and Operations Research, Victoria University of Wellington, New Zealand
warm water
aquifers
convection
layered systems
mass transfer
heat transfer
What convective flow is induced if a geologically-stratified groundwater aquifer is subject to a vertical temperature gradient? How strong is the flow? What is the net heat transfer? Is the flow stable? How does the convection affect the subsequent species distribution if a pollutant finds its way into the aquifer? This paper begins to address such questions. Quantitative models for buoyancy-driven fluid flow in long, sloping warm-water aquifers with both smoothly- and discretely-layered structures are formulated. The steady-state profiles are calculated for the temperature and for the fluid specific volume flux (Darcy velocity) parallel to the boundaries in a sloping system subjected to a perpendicular temperature gradient, at low Rayleigh numbers. The conducted and advected heat fluxes are compared and it is shown that the system acts somewhat like a heat pipe. The maximum possible ratio of naturally advected-to-conducted heat transfer is determined, together with the corresponding permeability and thermal conductivity profiles.
VORTICITY TRANSPORT IN VISCOELASTIC FLUID IN THE PRESENCE OF SUSPENDED MAGNETIC PARTICLES THROUGH POROUS MEDIUM
347-352
10.1615/JPorMedia.v14.i4.60
Pardeep
Kumar
Department of Mathematics, International Centre for Distance Education and Open Learning (ICDEOL), Himachal Pradesh University, Shimla-171005, India
Gursharn Jit
Singh
Satish Chand Dhawan Government College (SCD), Ludhiana, Punjab, India
Rivlin-Ericksen viscoelastic fluid
suspended particles
vorticity
porous medium
The transport of vorticity in Rivlin-Ericksen viscoelastic fluid in the presence of suspended magnetic particles in porous medium is considered. Equations governing the transport of vorticity in Rivlin-Ericksen viscoelastic fluid in the presence of suspended magnetic particles in porous medium are obtained from the equations of magnetic fluid flow proposed by Wagh and Jawandhia in their 1996 study on the transport of vorticity in magnetic fluid. A two-dimensional case is also studied.
EFFECT OF POROUS ADDITIVES ON PROPERTIES OF THE ATTAPULGITE-BASED CaCl2 COMPOSITES FOR COOLING APPLICATIONS
353-361
10.1615/JPorMedia.v14.i4.70
X. L.
Yao
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
Y.
Tang
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
Hai-Jun
Chen
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
Q.
Cui
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
L. L.
Sheng
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
K.
Zheng
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
X. J.
Chen
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
H. Q.
Yao
College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing 210009, China
adsorption refrigeration; composite adsorbent; porous additive; calcium chloride; attapulgite
The effects on the properties of composites when adding porous materials (13X zeolite, silica gel, or alumina) were investigated based on the preparation and performance testing of attapulgite-based CaCl2 composites. The adsorption performance of the composites was carried out using the static weighing method, and the desorption behavior was done through thermal analysis. Also, the composite adsorbents were characterized by x-ray diffraction. The results show that low 13X zeolite and alumina additives could yield a positive water adsorption effect and improve the dispersion of CaCl2 in composite adsorbents, thus increasing their water adsorption properties at low relative humidity. The desorption temperature of the composite adsorbents was not affected by the addition of lower than 25% of porous materials. The adsorption stability of the composites was improved for suppression of CaCl2 agglomeration due to the dispersion promoting effect of porous materials. At a relative humidity of 20%, water uptakes on the composite with 20% 13X zeolite content could reach 0.36kg/kg, which is 20% higher than the original attapulgite-based CaCl2 composite.
QUANTIFYING THE ROLE OF PORE GEOMETRY AND MEDIUM HETEROGENEITY ON HEAVY OIL RECOVERY DURING SOLVENT/CO-SOLVENT FLOODING INWATER-WET SYSTEMS
363-373
10.1615/JPorMedia.v14.i4.80
Ali Akbar
Dehghan
Tehran Petroleum Research Center, Petroleum University of Technology, Iran; and Department of Chemical and Petroleum Engineering, University of Calgary, Canada
Riyaz
Kharrat
Petroleum University of Technology, Petroleum Research Center, Tehran, Iran
Mohammad Hossein
Ghazanfari
Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran,
Iran
S.
Vossoughi
Department of Chemical and Petroleum Engineering, University of Kansas, USA
pore geometry
heterogeneity
co-solvent
micromodel
heavy oil
water wet
five spot
Porous medium characteristics (e.g., pore geometry and medium heterogeneity) as well as the chemical nature of the o-solvents crucially affect the oil displacement efficiency during solvent flooding processes. In this work, initially saturated models with heavy crude oil were used to perform a series of solvent injection experiments. Several one-quarter five-spot micromodels with pre-designed pore geometry were constructed and used. In addition, rock-look-alike flow patterns generated from thin sections of sandstone and dolomite reservoir rocks were etched onto glass plates to form micromodels mimicking the pore geometry and heterogeneity of these rocks. Four different groups of chemicals and their mixtures were used to investigate the effect of co-solvents when they were added to the main liquid hydrocarbon. Highresolution video pictures taken of the displacement process allowed microscopic analysis of the displacement mechanism at the pore level. Experimental results revealed that the displacement efficiencies of solvent mixtures greatly depend on the chemical properties of the added co-solvents. The most effective co-solvent with the greatest sweep efficiency was detected from different chemical mixtures. The experiments performed on various network patterns demonstrated that a higher coordination number along with a higher pore−throat size ratio of the flow paths improved the displacement efficiency. Media heterogeneity resulted in higher residual oil saturation by reducing the contact area, increasing the solvent bypass, and causing the oil to be trapped. The microscopic observations confirmed that the presence of connate water in strongly water-wet medium could improve the final recovery. However, the extent of this improvement greatly depends on the type of co-solvents used in the injection process.