Begell House Inc.
Journal of Porous Media
JPM
1091-028X
18
12
2015
BUOYANCY-DRIVEN HEAT TRANSFER OF WATER−BASED NANOFLUID IN A PERMEABLE CYLINDRICAL PIPE WITH NAVIER SLIP THROUGH A SATURATED POROUS MEDIUM
1169-1180
10.1615/JPorMedia.v18.i12.10
Sara
Khamis
The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha- Tanzania
Oluwole Daniel
Makinde
Faculty of Military Science, Stellenbosch University, Private Bag X2, Saldanha 7395, South
Africa
Yaw
Nkansah-Gyekye
The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha- Tanzania
semi-discretization
buoyancy force
nanofluids
Navier slip
porous medium
The combined effect of buoyancy-driven force, variable viscosity and Navier slip on heat transfer of unsteady water−based nanofluid flow containing copper and alumina nanoparticles in a permeable cylinder through saturated porous medium is investigated numerically. The Darcy-Brinkman-Forchheimer model was adopted to describe the flow. The non-linear partial differential equations governing the problem were obtained and solved numerically using a semi-discretization finite difference method together with Runge-Kutta-Fehlberg integration scheme. The numerical solutions for velocity, temperature, skin friction and Nusselt number have been presented graphically and discussed quantitatively. The results reveal that both nanofluid temperature and velocity are enhanced with increasing nanoparticle volume fraction and Grashof number and reduced with the increasing viscosity; Navier slip parameter; porous media resistance parameter and porous media shape factor parameter.
MODELING CONTAMINANT TRANSPORT IN SATURATED SOIL COLUMN WITH THE CONTINUOUS TIME RANDOM WALK
1181-1186
10.1615/JPorMedia.v18.i12.20
Shahram
Shahmohammadi-Kalalagh
Department of Water Sciences and Engineering, Tabriz Branch, Islamic Azad University, Tabriz, Iran
advection-dispersion
continuous time random walk
breakthrough curve
Fickian
non-Fickian
In this paper, we evaluate the continuous time random walk (CTRW) theory for its capability to characterize solute and contaminant transport in one-dimensional saturated homogeneous soil column at the experiments conducted by Shiozawa (cited in Toride, N., Leij, F., and van Genuchten, M. Th., The CXTFIT Code for Estimating Transport Parameters from Laboratory or Field Tracer Experiments, Version 2.1, Research Rep. 137, US Salinity Lab, Riverside, CA, 1999). The transport process was also simulated by using the advection-dispersion equation (ADE) for comparison. The non-Fickian behavior is found at distances less than 11 cm with β value of 1.909, and Fickian form transport is obtained at distances larger than 11 cm with β values larger than 2. Comparing to ADE the CTRW gives better fits to the breakthrough curves (BTCs), with lower values of root mean square error (RMSE) and higher values of determination coefficient (r2). The CTRW captures the full evolution of BTCs, and especially at the early part of the breakthrough curves. Therefore, it seems that the CTRW can be used as an appropriate approach to simulate the solute transport in a saturated homogeneous soil column.
COMPUTATIONAL INVESTIGATION OF HYDROMAGNETIC THERMO-SOLUTAL NANOFLUID SLIP FLOW IN A DARCIAN POROUS MEDIUM WITH ZERO MASS FLUX BOUNDARY CONDITION USING STRETCHING GROUP TRANSFORMATIONS
1187-1200
10.1615/JPorMedia.v18.i12.30
M. Jashim
Uddin
USM
Muhammad Nomani
Kabir
Faculty of Computer Systems and Software Engineering, University Malaysia Pahang, 26300 Gambang, Pahang, Malaysia
Yasser
Alginahi
Deanship of Academic Services, Department of Computer Science, Taibah University, P.O. Box 344, Madinah, Saudi Arabia
Darcy porous medium
velocity and thermal slip
zero mass flux
stretching group transformations
In this paper, hydromagnetic thermo-solutal nanofluid flow past a flat plate embedded in a Darcy porous medium has been investigated considering zero mass flux with velocity and thermal slips boundary conditions. The nanofluid flow is considered as 2D, steady state, incompressible, and laminar. We used a generalized stretching group of transformations to develop the similarity solutions of the model. Using these transformations, the transport equations of the nanofluid flow model are reduced to a system of nonlinear ordinary differential equations (ODEs). Finally, the transformed ODEs are computationally solved using MATLAB nonlinear equation solver "fsolve" and ODE solver "ode15s". Solutions are compared with previously available results and the comparison shows good correlation. Furthermore, the computational results are provided to demonstrate the influence of the dimensionless velocity slip parameter, thermal slip parameter, magnetic field parameter, Brownian motion parameter, thermophoresis parameter, and Darcy number on the dimensionless velocity, temperature, and nanoparticle volume fraction (concentration) fields, as well as on the heat transfer rate and skin friction. It was found that the skin friction factor decreases (increases) while the heat transfer rate increases (decreases) with the velocity (thermal) slip parameter. Both the heat transfer rate and the friction factor increase with the magnetic field and Darcy number.
HEAT TRANSFER ENHANCEMENT IN AN ASYMMETRICALLY HEATED CHANNEL PARTIALLY FILLED WITH FIBROUS POROUS MEDIA−A LBM APPROACH
1201-1220
10.1615/JPorMedia.v18.i12.40
Mohammad
Abbaszadeh
Shiraz University, Mechanical Engineering Department, Shiraz, Iran
Alireza
Salehi
Mechanical Engineering Department, Amirkabir University of Technology, Hafez Ave., Tehran, Iran; Isfahan University of Technology, Mechanical Engineering Department, Isfahan, Iran
Abbas
Abbassi
Department of Mechanical Engineering, Amirkabir University of Technology (Tehran
Polytechnic), 424 Hafez Ave., P.O. Box 15875-4413, Tehran, Iran
fibrous porous media
conjugate heat transfer
lattice Boltzmann method
partially filled channel
asymmetrical heated channel
regular arrangements
In this study, conjugate heat transfer in a 2D planar channel partially filled with fibrous porous media is numerically investigated using the lattice Boltzmann method. The considered porous media is formed by a regular matrix of solid fibers, modeled as square obstacles and located in a cross flow. Asymmetrical thermal boundary conditions are implemented to the channel walls. Pore scale simulation combined with a local thermal nonequilibrium assumption are applied to the solid phase. Average Nusselt number on the constant temperature wall is reported as the criterion for heat transfer enhancement. Effects of geometrical parameters such as blockage ratio, porous block eccentricity, porosity, and some thermophysical parameters such as Reynolds and Prandtl numbers are investigated. Apart from confirming the efficiency of the partially filled channel over the fully filled one, obtained results demonstrate the existence of optimum values for the blockage ratio and porous block eccentricity. Also, heat transfer and pressure drop are increased as the size of the fibers increases. Moreover, decreasing the porosity, by adding number of fibers in the porous block, can increase the value of the average Nusselt number.
DISTRIBUTION OF ELEMENTAL MERCURY IN SATURATED POROUS MEDIA
1221-1229
10.1615/JPorMedia.v18.i12.50
M.
Devasena
Environmental and Water Resources Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai − 600036 India; Department of Civil Engineering, Sri Krishna College of Technology, Kovaipudur, Coimbatore − 641042 India
Indumathi M.
Nambi
Environmental and Water Resources Engineering Division, Department of Civil Engineering, Indian Institute of Technology Madras, Chennai-600 036, Tamil Nadu, India
mercury
residual saturation
micromodel
interfacial area
capillary number
Elemental mercury (Hg0) is often found in the vicinity of industrial facilities such as chlor alkali plants, thermometer manufacturing units, and pharmaceutical industries. During accidental land spills or improper disposals of used Hg0, it penetrates into the subsurface and gets entrapped in the available pore spaces. Once Hg0 is entrapped in the subsurface as residual blobs, it would be subjected to biochemical transformations and be converted to other toxic forms of mercury. A significant lacuna prevails in addressing Hg0 contamination and remediation which is dominated by pore scale processes in the subsurface. In this study, a series of experiments was performed to characterize the morphological distribution of Hg0 at its residual saturation as a function of capillary number (NC). An initially water-saturated micromodel was flooded with Hg0 at a prescribed rate to simulate the migration of Hg0 into the saturated zone. Then Hg0 was displaced by water flooding and finally residual Hg0 was established at different NC. Images taken during the experiment were processed to generate residual Hg0 saturation, size, shape, and interfacial area. Residual Hg0 ranged from small spherical blobs to large complex blobs and was found to have an inverse relationship with NC. The results obtained in this study would serve as fundamental parameters for evaluating relationship amongst residual mercury saturation, interfacial area, and ground water flow in mercury-contaminated sites.
INVESTIGATING THE EFFECT OF MEDIAN PORE-THROAT DIAMETER ON SPONTANEOUS IMBIBITION
1231-1238
10.1615/JPorMedia.v18.i12.60
Zhiye
Gao
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum,
Beijing 102249, China; Unconventional Natural Gas Institute, China University of Petroleum, Beijing, 102249, China
Qinhong
Hu
Department of Earth and Environmental Sciences, University of Texas at Arlington, Arlington, Texas 76019, USA
spontaneous imbibition
scaling
median pore-throat diameter
wettability
Spontaneous imbibition (SI) plays an important role in the process of oil/gas recovery from fractured reservoirs. Scaling of SI data is a good way to investigate the factors controlling imbibition process and several classic scaling equations have been proposed. However, the effect of pore structure on SI process is insufficiently considered in these scaling equations. This work investigated the effect of median pore-throat diameter (D50) on SI process and proposed new scaling equations to compensate the effect of D50 on SI process. Three types of rocks, including Barnett shale, dolomite, and Indiana sandstone, were used in this study. Our results show that the wettability conditions of these three types of rocks could be determined by comparing scaled water and n-decane imbibition curves. Also, the imbibition curves of different rocks were better correlated after using these new scaling equations, which indicates that D50 as an index of pore structure significantly affects the process of SI.
ON DOUBLE-DIFFUSIVE HADLEY FLOW IN MAXWELL FLUIDS THROUGH A HORIZONTAL POROUS LAYER
1239-1249
10.1615/JPorMedia.v18.i12.70
Anjanna
Matta
Department of Mathematics, Faculty of Science and Technology, IFHE University, Hyderabad Telangana, India - 501203
P. A. Lakshmi
Narayana
Department of Mathematics, Indian Institute of Technology Hyderabad, Hyderabad - 502205, Telangana, India
double-diffusive convection
inclined gradients
horizontal layer
linear stability analysis
porous medium
Hadley flow
Maxwell fluids
The present study deals with the effect of stress relaxation on the mechanism of instability of the double-diffusive Hadley flow through a shallow horizontal layer of a porous medium induced by thermal and solutal gradients inclined to the vertical by means of linear stability analysis. The Hadley flow which is set up by the horizontal components of these gradients becomes unstable when vertical components are sufficiently large and this instability is analyzed using three-dimensional normal modes. The vertical thermal Rayleigh number is treated as the eigenvalue. The system that constitutes the eigenvalue problem is solved by using a two-term Galerkin approximation for various modes of instability. The detailed analysis is carried out for both the stationary and oscillatory modes. Results are presented for various values of the governing parameters of the flow. It is observed that the stress relaxation parameter has a significant role in convective instability.
ANALYSIS OF THE INFLUENCE OF THERMAL EXPANSION ON A STAGNATION-POINT FLOW ESTABLISHED IN AN INERT POROUS MEDIUM
1251-1264
10.1615/JPorMedia.v18.i12.80
M. A. Endo
Kokubun
lnstituto Nacional de Matematica Pura e Aplicada, Estrada Dona Castorina, 110, Rio de Janeiro, Rio de Janeiro 22460-320, Brazil
Fernando F.
Fachini
Grupo de Mecanica de Fluidos Reativos, Laboratorio de Combustao e Propulsao, Instituto Nacional de Pesquisas Espaciais, Cachoeira Paulista, Sao Paulo 12630-000, Brazil
stagnation-point flow
porous medium
heat transfer
thermal expansion
In the present work we analyze the influence of gas thermal expansion in the properties of a stagnation-point flow established in an inert porous medium. With the use of a semi-heuristic, non-Darcean formulation for the flow, we compare the obtained results with the results of the incompressible (constant-density) model. When thermal expansion is considered, the Darcy resistance term is proportional to the inverse of the Darcy number (dimensionless permeability), to the square of the local gas temperature and to the local mass flux. It is shown that if the Darcy number is low enough, an increase on the wall temperatures can lead to a decrease on the wall shear, a result opposed to what is observed for non-confined problems and that is not captured by incompressible models. The pressure recovery from the wall to the outside of the boundary layer is greatly affected by the Darcy number and by the thermal expansion imposed by the hot wall. For instance, if the Darcy number (wall temperature) is low (high) enough, the maximum pressure is achieved above the stagnation point. The effects of porosity, wall temperature, solid-to-gas thermal conductivities ratio, and interphase heat exchange coefficient on the wall properties are also analyzed. The results presented here are of relevance for the design of electronic devices porous coolers that have a maximum operating temperature, above which its component may be damaged.
VOLUME 18, 2015 CONTENTS
1265-1276
10.1615/JPorMedia.v18.i12.90