Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
16
6
2013
MIXED CONVECTION IN VISCOELASTIC FLOW DUE TO A STRETCHING SHEET IN A POROUS MEDIUM
We present an analysis of mixed convection boundary layer flow of an incompressible and electrically conducting viscoelastic fluid over a linearly stretching surface embedded in a porous medium. The momentum equation includes the effect of the buoyancy force due to free convection. The thermal equation includes the effects of thermal radiation and viscous dissipation. We consider two general types of nonisothermal boundary conditions, namely, prescribed surface temperature and prescribed heat flux. The governing partial differential equations for the fluid flow and temperature are reduced to a nonlinear system of ordinary differential equations which are solved analytically using the homotopy analysis method (HAM). Convergence of the HAM solutions is discussed in detail. The effects of various parameters on the skin friction coefficient and wall heat transfer are presented along with plots of the velocity and temperature profiles.
Antonio
Mastroberardino
Penn State Erie, The Behrend College
Ulavathi S.
Mahabaleswar
Faculty of Mathematics, Government First Grade College for Women, Hassan 573 201, India
483-500
SIMILARITY SOLUTIONS FOR BOUNDARY LAYER FLOW OF A DUSTY FLUID THROUGH A POROUS MEDIUM OVER A STRETCHING SURFACE WITH INTERNAL HEAT GENERATION/ABSORPTION
An analysis is made for an unsteady two-dimensional boundary layer flow of a viscous, incompressible electrically conducting dusty fluid in the vicinity of a stagnation point on a stretching sheet. Fluid flow is considered in a porous medium under the influence of transverse magnetic field in the presence of internal heat generation/absorption. Using a time-dependent stream function, the governing partial differential equations corresponding to the momentum and energy transfer are converted into a set of nonlinear ordinary differential equations by applying the suitable similarity variables. Numerical solutions of these equations are obtained by the Runge−Kutta−Fehlberg-45 method. The effect of the strength of the uniform magnetic field, unsteadiness parameter, the ratio of free stream velocity parameter and stretching parameter, Prandtl number, dust interaction parameter, suction parameter, Eckert number, and the heat generation/absorption coefficients on both the fluid flow and heat transfer are presented.
Siddapura S.
Manjunatha
Department of Studies and Research in Mathematics, Kuvempu University, Shankaraghatta-577 451, Shimoga, Karnataka, India
Bijjanal Jayanna
Gireesha
Cleveland State University
Kunabevu M.
Eshwarappa
Department of Physics, Govt. First Grade College, Hassan-573201, Karnataka, India
Channabasappa S.
Bagewadi
Department of Studies and Research in Mathematics, Kuvempu University, Shankaraghatta-577 451, Shimoga, Karnataka, India
501-514
EXPERIMENTAL SORPTION DYNAMIC IN PACKED BED OF SILICA GEL
This paper studies both numerically and experimentally the phenomenon of heat and mass transfer occurring in an adsorptive fixed bed. The experiment consists of a cylindrical column filled with uniform grain silica gel subjected to humid airflow. The computer code developed for this work simulates the influence of some physical and geometrical parameters derived from the adsorptive and regenerative processes that occur in packed beds during dehumidification. It was used as a one-dimensional, transient, and nonisothermal model. The equations were discretized via finite volume method, fully implicit formulation, and colocated arrangement. Linear systems have been solved by the Thomas algorithm. The experimental and numerical results are described as temperature profiles along three different speeds observed during regeneration and under various conditions of relative humidity at the adsorptive bed outlet. These results are consistent with the physical conditions of the desired outlet.
Joselma A.
Amorim
Department of Mechanical Engineering, Federal University of Paraiba, Joao Pessoa, Paraiba, Brazil
H. M.
Vieira
Department of Mechanical Engineering, Federal University of Paraiba, Joao Pessoa, Paraiba, Brazil
Cicero H. T.
Andrade
Department of Mechanical Engineering, Federal University of Paraiba, Joao Pessoa, Paraiba, Brazil
J. M.
Medeiros
Federal Institute of Education, Science, and Technology of Paraiba, Joao Pessoa, Paraiba, Brazil
J. C.
Santos
Department of Production Engineering, Regional University of Cariri, Juazeiro do Norte, Ceara, Brazil
Jose Mauricio
Gurgel
Mechanical Technology Department, Federal University of Paraíba, P.O. Box 5115, 58051-970 João Pessoa, Brazil
515-525
BOUNDS FOR THE GROWTH RATE OF PERTURBATION IN A COUPLE-STRESS FLUID IN THE PRESENCE OF ROTATION AND MAGNETIC FIELD IN A POROUS MEDIUM
A layer of couple-stress fluid heated from below in a porous medium is considered in the presence of uniform vertical magnetic field and rotation. Following the linearized stability theory and normal mode analysis, the paper, through mathematical analysis of the governing equations of couple-stress fluid convection with a uniform vertical magnetic field and rotation in porous medium, for any combination of perfectly conducting free and rigid boundaries of infinite horizontal extension at the top and bottom of the fluid, established that the complex growth rate Ð¾ of oscillatory perturbations, neutral or unstable for all wave numbers, must lie inside a semi-ring enclosed by the two semi-circles of radii, ε/2 { Q − √(Q2 + 4TA )} and ε/2 { Q + √(Q2 + 4TA )}, in the right half of the σr−σi plane whose centers are at the origin, where TA is the Taylor number, Q is the Chandrasekhar number, and ε is the porosity of the porous medium. Further, it has been established that the sufficient condition for the validity of the "principle of exchange of stability" in magneto-rotatory thermal convection in a couple-stress fluid in a porous medium is that Q/√(Q2 + 4TA) ≤ 1, and that the existence of oscillatory motions of growing amplitude in the present configuration depends crucially upon the magnitude of the nondimensional number Q/√(Q2 + 4TA), in the sense so long as 0<Q/(√(Q2 +4TA)) ≤ 1, no such motions are possible, and in particular principle of exhange of stability (PES) is valid.
Ajaib S.
Banyal
Department of Mathematics, Govt. College Nadaun, Dist. Hamirpur, (HP) India 177033
Monika
Khanna
Department of Mathematics, Govt. College Dehri, Dist. Kangra, (HP) India 176022
527-536
CHARACTERIZATION (TWO-DIMENSIONAL−THREE-DIMENSIONAL) OF CERAMIC MICROFILTRATION MEMBRANE BY SYNCHROTRON RADIATION: NEW AND ABRADED MEMBRANES
Membranes are used in many industrial fields and, when performances of these processes decrease, the issue of modifying the porous structure is often raised. Many optical or microscopic techniques allow us to perfectly characterize the membrane's surface but very few allow the characterization of its depth. Through the comparison between a new and an abraded membrane, this paper presents the post-processing of images obtained by radiation synchrotron and associated dimensions that can be obtained by three-dimensional (3D) reconstruction. Thus, the whole thickness of the membrane is obtained from the skin to the permeate exit and a morphological analysis of the solid and pore phase is proposed at the heart of the membrane. The two-dimensional characterization allows one to perfectly define the mapping of the pores and to quantify by different comparisons the modification of the skin of a membrane after usage. The 3D characterization by X-ray tomography at the scale of the thickness of the membrane allows us to obtain the granulometric distribution of the different phases of the porous matrix. This ability to characterize both the solid and the pores is relevant to the study of membranes, showing not only the modification of the solid matrix but also highlighting pore fouling.
Jerome
Vicente
lnstitut Universitaire des Systemes Thermiques Industriels (IUSTI-CNRS-UMR 6595), Aix-Marseille Universite Technopole de Chateau-Gombert
Y.
Wyart
Laboratoire de Mecanique, Modelisation et Procedes Propres (M2P2-CNRS-UMR 7340), Aix Marseille Universite, Europole de l'Arbois, BP 80, Bat. Laennec, Hall C, 13545 Aix en Provence cedex 04, France
Philippe
Moulin
Laboratoire de Mecanique, Modelisation et Procedes Propres (M2P2-CNRS-UMR 7340), Aix Marseille Universite, Europole de l'Arbois, BP 80, Bat. Laennec, Hall C, 13545 Aix en Provence cedex 04, France
537-545
PREDICTION OF THE RETENTION VOLUME OF SEDIMENT DURING WATER-BASED SEDIMENT INJECTION
The aim of this study is to propose a model for describing the pressure changes due to the retention of sediment (organic matter adsorbed on fines, diameter range 1−100 µm) inside saturated sand beds. Such model makes it possible to predict the retention volume of sediment, which is useful for considering the biodiversity of tidal flats. On the basis of Poiseuille's law and the hydraulic radius concepts, two models could theoretically be proposed to predict the pressure drop in the absence or presence of sediment retention. From one of the proposed models, the retention volume of sediment is determined, and is verified by comparing the predictions with experimental data. It was found that the friction coefficient determined based on the proposed model was in good agreement with that determined from the measured pressure drop, suggesting that the measured pressure drop can be reproduced by the proposed model. Moreover, the retention volume predicted by the proposed model well matches the measured retention weight. It was found that the properties of organic matter bonded onto sediment particles strongly affected the retention behavior of sediment. Sediment that is absorbed by decomposed organic matter travels more easily through sand beds, resulting in a low reduction of permeability.
Narong
Touch
Department of Civil and Environmental Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima City, Hiroshima 739-8527, Japan
Tadashi
Hibino
Department of Civil and Environmental Engineering, Hiroshima University, Kagamiyama 1-4-1, Higashi-Hiroshima City, Hiroshima 739-8527, Japan
547-557
NON-EQUILIBRIUM MODEL OF GRAVITY DRAINAGE IN A SINGLE BLOCK
This work concerns with developing a non-equilibrium model of gravity drainage in a single block. The proposed model which considers both non-equilibrium effects of capillary pressure and relative permeabilities is used for prediction of oil recovery by gravity drainage from a single block. Close agreement observed between the model results and experimental data disclosed that the non-equilibrium assumption is completely reliable for modeling of gravity drainage. The results revealed that when the characteristic time of the saturation variation is comparable with the time required to establish capillary equilibrium, the non-equilibrium effects in gravity drainage must be considered. The results of this work can be potentially helpful for developing new simulation models to be used for predicting oil recovery by gravity drainage mechanism.
S.
Jahanbakhshi
Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran
Mohammad Hossein
Ghazanfari
Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
Mohsen
Masihi
Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran
559-571
SLIP AND BUOYANCY LIFT EFFECTS ON THE MIXED CONVECTION FLOW AND RADIATION HEAT TRANSFER OF A MICROPOLAR FLUID TOWARD VERTICAL PERMEABLE PLATE
We present an investigation for mixed convection flow and radiation heat transfer of a micropolar fluid toward vertical permeable plate with slip and buoyancy lift effects. The coupled partial differential governing equations are reduced to a set of nonlinear ordinary differential equations by applying a suitable similarity transformation. Analytic approximate solutions are obtained for velocity and temperature fields by employing the homotopy analysis method. The effects of slip parameter, permeable parameter, the Prandtl number, the radiation parameter, the material parameter, the magnetic parameter, and the buoyancy parameter on the velocity and temperature fields are analyzed and discussed in detail.
Liancun
Zheng
School of Mathematics and Physics, University of Science and Technology Beĳing, Beĳing 100083,
China
Ning
Liu
School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083, China
Jiajia
Niu
School of Mathematics and Physics, School of Mechanical Engineering, University of Science and Technology Beijing, Beijing 100083, China
Xinxin
Zhang
School of Energy and Environmental Engineering, University of Science and Technology Beĳing,
Beĳing 100083, China
575-583