Begell House Inc.
Journal of Porous Media
JPM
1091-028X
20
11
2017
THEMODIFFUSION EFFECTS ON MHD BOUNDARY LAYER SLIP FLOW OF NANOFLUID OVER A NONLINEAR STRETCHING SHEET THROUGH A POROUS MEDIUM
961-970
10.1615/JPorMedia.v20.i11.10
V.
Nagendramma
Department of Applied Mathematics, SPMVV, Tirupati-517502, AP, India
R.V.M.S.S. Kiran
Kumar
Department of Mathematics, S.V. University, Tirupati-517502, AP, India
P. Durga
Prasad
Department of Mathematics, S.V. University, Tirupati-517502, AP, India
A.
Leelaratnam
Department of Applied Mathematics, SPMVV, Tirupati-517502, AP, India
S. Vijaya Kumar
Varma
Department of Mathematics, Sri Venkateswara University, Tirupati-517 502, A.P., India
MHD
velocity slip
nonlinear stretching sheet
nanofluid
thermodiffusion effects
The two-dimensional triple-diffusive boundary layer slip flow of nanofluid over a nonlinear stretching sheet embedded
in a porous medium is scrutinized in the concerned study. The model used for the nanofluid incorporates the effects of
thermophoresis, Brownian motion, cross-diffusion, and the power law stretching parameter. A uniform magnetic field
of strength B0 is applied perpendicular to the flow direction. Using suitable similarity transformations, governing partial differential equations were reduced to higher-order ordinary differential equations and are solved by using the Matlab bvp4c package. Concrete graphical analysis is carried out to study the effects of different emerging parameters on velocity, temperature, solute, and nanoparticle concentration distributions coupled with a comprehensive discussion. Furthermore, the Nusselt number, the Sherwood number, and the nanofluid Sherwood number are derived and discussed graphically.
PREPARATION AND CHARACTERIZATION OF Co-Cu BIMETALLIC SHAPED CATALYST SUPPORTED ON TiO2
971-976
10.1615/JPorMedia.v20.i11.20
Vida Nourozi
Rad
Department of Chemistry, Science and Research Branch, Islamic Azad University,
Poonak-Hesarak, Tehran, Iran
Mansoor
Anbia
Research Laboratory of Nanoporous Materials, Faculty of Chemistry, Iran University of Science
and Technology, Farjam Street, Narmak, P.O. Box 16846-13114, Tehran, Iran
Moayed Hossaini
Sadr
Department of Chemistry, Science and Research Branch, Islamic Azad University,
Poonak-Hesarak, Tehran, Iran
Karim
Zare
Department of Chemistry, Science and Research Branch, Islamic Azad University,
Poonak-Hesarak, Tehran, Iran
anatase-TiO2
binder
bimetallic catalyst
extrude
Bimetallic Co-Cu/TiO2 catalyst was prepared through a co-impregnation method with anatase-TiO2 as support. The catalyst powder was shaped by three different binders (bentonite, polyvinyl alcohol, and polyethylene glycol) into extrudes. Samples were characterized using X-ray powder diffraction, temperature-programmed reduction (TPR), Brunauer–Emmett–Teller analysis, Barrett–Joyner–Halenda analysis, scanning electron microscopy (SEM), and energy dispersive X-ray techniques. Among the catalysts prepared, an optimal catalyst with the composition 65% TiO2 and a mixture of 1% polyvinyl alcohol, 2% PEG-1000, and 25% bentonite was selected with suitable properties. The specific surface area of the catalyst was found to be 127 m2·g-1 with a pore diameter of 9.28 nm. TPR results reveal that the presence of Cu lowers the reduction temperature of Co. The TPR profile is in good agreement with the results shown by SEM that the metal species were well dispersed over the TiO2 support.
HYDROMAGNETIC CONVECTION FLOW IN TWO IMMISCIBLE FLUIDS THROUGH A POROUS MEDIUM IN AN INCLINED ANNULUS
977-987
10.1615/JPorMedia.v20.i11.30
Jafar
Hasnain
Bahria University, Islamabad
Zaheer
Abbas
Department of Mathematics, The Islamia University of Bahawalpur, Bahawalpur 63100, Pakistan
two-phase flow
non-Newtonian third-grade fluid
porous medium
inclined annulus
numerical
solution
In this article, a fully developed steady hydromagnetic flow and mixed convection of two immiscible fluids driven
by a constant pressure gradient through a porous medium in an inclined annulus at angle φ with a horizontal axis
are carried out numerically. The fluids streaming in the annular space between two concentric cylinders are non-
Newtonian third-grade and viscous fluids. A uniform external magnetic field is exerted perpendicularly to the flow
direction, and both fluids are electrically conducting. Darcy's law for viscous fluids and modified Darcy's law for third-grade fluids are employed to obtain the governing flow equations. The numerical solutions of transformed nonlinear
ordinary differential equations are obtained via shooting method and are presented graphically in the form of velocity
and temperature and discussed under the influence of associated flow parameters. The study reveals that the shear
thickening property of the third-grade parameter has a decreasing effect on fluid velocity. Heat-generating parameters enhance fluid temperature; however, heat-absorbing parameters curtail the temperature of fluid.
INTERACTION OF CONVECTIVE AND NIELD–KUZNETSOV'S CONDITIONS IN HYDROMAGNETIC FLOW OF NANOFLUID SUBJECT TO DARCY–FORCHHEIMER EFFECTS
989-998
10.1615/JPorMedia.v20.i11.40
Muhammad Kamran
Siddiq
Department of CASPAM, Bahauddin Zakariya University, Multan 63000, Pakistan
Amar
Rauf
Department of Mathematics, The Islamia University of Bahawalpur, Bahawalpur, 63100,
Pakistan; Department of Mathematics, COMSATS University Islamabad, Sahiwal Campus 57000,
Pakistan
Sabir Ali
Shehzad
Department of Mathematics, COMSATS Institute of Information Technology, Sahiwal 57000,
Pakistan
Ahmed
Alsaedi
Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Department of Mathematics, Faculty of Science, King Abdulaziz University, P. O. Box. 80257,
Jeddah 21589, Saudi Arabia
Tasawar
Hayat
Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000, Pakistan; Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science,
King Abdulaziz University, P.O. Box 80257, Jeddah 21589, Saudi Arabia
viscous nanofluid
stretchable sheet
MHD
non-Darcy porous medium
A numerical study of two-dimensional magnetohydrodynamic (MHD) boundary layer flow of viscous nanofluid over a
stretching sheet is developed. Fluid-saturating porous space is bounded by a stretching surface. The Darcy–Forchheimer
model is employed to characterize the porous medium. A uniform transverse magnetic field is applied perpendicular
to the surface of the sheet. Appropriate transformations are employed in obtaining the nonlinear ordinary differential
equations. Convective boundary condition and normal flux of the nanoparticles are implemented at the surface of
the sheet. Numerical solutions for the velocity, temperature, and concentration fields are constructed. The results are
presented and discussed through graphical and tabular forms.
UNSTEADY FREE CONVECTION IN A SQUARE POROUS CAVITY SATURATED WITH NANOFLUID: THE CASE OF LOCAL THERMAL NONEQUILIBRIUM AND BUONGIORNO'S MATHEMATICAL MODELS
999-1016
10.1615/JPorMedia.v20.i11.50
H.
Zargartalebi
Department of Mechanical Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran
Mohammad
Ghalambaz
Department for Management of Science and Technology Development, Ton Duc Thang University
Mikhail A.
Sheremet
Department of Theoretical Mechanics, Tomsk State University, 634050, Tomsk, Russia; Institute of Power Engineering, Tomsk Polytechnic University, 634050, Tomsk, Russia
Ioan
Pop
Department of Applied Mathematics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
unsteady free convection
porous media
thermal nonequilibrium model
nanofluids
Buongiorno's model
Considering Buongiorno's model, the unsteady free convection in a porous enclosure filled with a nanofluid is studied
while the nanoparticles, the base fluid, and the solid porous matrix are in local thermal nonequilibrium. It is assumed that the left and right vertical walls are suddenly heated and cooled. Moreover, the movement of the nanoparticles is affected by Brownian and thermophoresis forces. The influence of multifarious thermophysical variables, such as solid–fluid and nanoparticle–fluid interaction heat transfer parameters, buoyancy ratio parameter, and Rayleigh number, on the transient average Nusselt number for the solid matrix, the base fluid, and the nanoparticles is investigated. It is found that the increase of solid–fluid and nanoparticle–fluid interaction heat transfer parameters would majorly augment the solid and nanoparticle average Nusselt numbers, respectively. Furthermore, the decrease of the buoyancy ratio
and the increase of Rayleigh number would boost the average Nusselt number for all of the three phases. Eventually,
the period of reaching to steady state shows a direct proportion to buoyancy ratio and a reverse proportion to Rayleigh number.
MECHANICAL INSTABILITY OF SILTY SAND POROUS MEDIA UNDER MONOTONIC LOADINGS
1017-1029
10.1615/JPorMedia.v20.i11.60
Mohammed
Bousmaha
Department of Civil Engineering and Architecture, University Abdelhamid Ibn Badis of
Mostaganem, Algeria
Hanifi
Missoum
LCTPE Laboratory, Faculty of Science and Technology, University Abdelhamid Ibn Badis,
Mostaganem, Algeria
Karim
Bendani
Department of Civil Engineering and Architecture, University Abdelhamid Ibn Badis of
Mostaganem, Algeria; Laboratory of Construction, Transports, and Environment Protection, University Abdelhamid
Ibn Badis of Mostaganem, Algeria
Mohammed
Derkaoui
Department of Civil Engineering and Architecture, University Abdelhamid Ibn Badis of
Mostaganem, Algeria
Fethi
Belhouari
Department of Civil Engineering and Architecture, University Abdelhamid Ibn Badis of
Mostaganem, Algeria
silty sand
density state
instability
shear strength
void ratio
In recent years, understanding the mechanisms of mechanical instability of sandy soils as porous media has been
continuously revised to include new parameters that may control the mechanical behavior under static or dynamic
loadings. Such instability may be manifested by severe damage of structures, leading to catastrophic failure in many cases. The accurate determination of critical or residual shear strength for soil susceptible to liquefaction phenomena has been a major challenge in geotechnical engineering. Consequently, it is essential to determine the main parameters that may control substantially the shear resistance and to provide a broad understanding on contractive and dilative phases of soil behavior in undrained conditions. In this work, an experimental program on reconstituted loose and medium dense specimens of terrigenous silica sands with different specified fine contents was conducted with the main goal to analyze its mechanical behavior under undrained conditions. The present article is an attempt to describe experimentally the mechanical behavior of low plastic silty sand soils and to represent the variation of the critical shear
strength via the fine content, the density state, and the equivalent void ratio. The last characteristic seems to represent rightly the vulnerability of the material to instability.
STUDY OF DOLOMITE SURFACE STABILITY BY DFT APPROACH CONSIDERING DEFECTS
1031-1041
10.1615/JPorMedia.v20.i11.70
Raiza
Hernandez-Bravo
Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas, Mexico City, Mexico
dolomite
DFT
surface energy
defects
The stability of dolomite surfaces has been studied in the present work through a nonparameterized density functional
theory (DFT) with the aim to build a molecular model of a rock surface in contact with oil in a carbonate reservoir. The rock surface was studied in its pristine form by considering defects such as cationic substitution and anionic vacancies. Therefore a systematic molecular study was performed by the substitution of Ca+2 by Mg+2 and their influence in the generation of vacancies at the CO2-3 and cationic sites. The molecular simulations showed that Mg+2 presented the highest probability for spontaneous creation of vacancies; that is, the reactions where the substitution of Ca by Mg took place are favored. Therefore the stability is higher when Ca is substituted by Mg. Surface energy results showed that the most stable pristine surface is the one corresponding to the [104] plane of the conventional dolomite cell. The developed model can be used to favor the dolomitization to improve the reservoir quality by the generation of vacancies and stability by the substitution of Ca by Mg incrementing the reservoir porosity in the order of 13%.
EFFECT OF CHEMICAL REACTION ON MIXED CONVECTIVE FLOW IN A VERTICAL CHANNEL CONTAINING POROUS AND FLUID LAYERS
1043-1058
10.1615/JPorMedia.v20.i11.80
J. Prathap
Kumar
Department of Mathematics, Gulbarga University, Gulbarga, Karnataka, India
Jawali C.
Umavathi
Department of Mathematics, Gulbarga University, Kalaburgi-585106, Karnataka, India
Shreeedevi
Kalyan
Department of Mathematics, Gulbarga University, Gulbarga, Karnataka, India
chemical reaction parameter
viscous dissipation
porous medium
regular perturbation method
finite difference method
We analyze the free convection flow through a vertical channel filled with a composite porous medium in the presence of a first-order chemical reaction. The flow is modeled using a Darcy–Lapwood–Brinkman equation model. The viscous and Darcy dissipation terms are also included in the energy equation. Analytical and numerical solutions for the
governing coupled nonlinear ordinary differential equations are obtained by perturbation series method and by finite
difference method, respectively. Separate solutions are matched at the interface by using suitable matching conditions. The approximate solutions have been obtained for velocity, temperature, and concentration distributions in the two regions of the composite channel. The effects of various parameters, such as thermal Grashof number, mass Grashof number, porous parameter, viscosity ratio, width ratio, conductivity ratio, and chemical reaction parameter, on the flow field are presented graphically and discussed. The volumetric flow rate, total species rate, total heat rate added to the flow, and Nusselt number are also evaluated. It is found that the thermal Grashof number and mass Grashof number enhance the flow in both regions in the presence or in the absence of a first-order chemical reaction. It is also found that the Nusselt number at the left wall is enhanced and at the right wall is reduced for large values of mass Grashof number. The values obtained by finite difference method are justified by comparing with the values obtained by perturbation method, and these values agree to the order of 10-4 in the absence of Brinkman number.