Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
15
4
2012
NUMERICAL SIMULATION OF DRYING A POROUS MATERIAL USING THE LATTICE BOLTZMANN METHOD
In the present study, a novel method for numerical simulation of drying a porous media is proposed. The lattice Boltzmann method is employed to solve the two-dimensional hydrodynamic, heat, and mass transfer equations in the dryer section. The governing equations for a two-dimensional brick as a porous solid are derived by combining conservation laws, Fourier's law for heat conduction, and Darcy's and Fick's laws for mass diffusion in porous material. These equations are solved numerically using the conventional Computational Fluid Dynamics method, finite difference. As cases in point, the moisture content and temperature distribution, both in the porous material and dryer section, are calculated. In addition, convective heat and mass transfer coefficients along the solid surface are computed, as well as the average temperature and moisture of the porous medium in a 45-h drying period. It was observed that during the initial period of drying, the drying rate is faster than final period; the rate of evaporation in the leading edge is higher than other regions.
Hossein
Shokouhmand
University of Tehran
Salah
Hosseini
Department of Mechanical Engineering, University of Tehran, Tehran, Iran
Vahid
Abdollahi
Department of Mechanical Engineering, University of Tehran, Tehran, Iran
303-315
GAS EXPANSION-INDUCED ACCELERATION EFFECT IN HIGH-PRESSURE GAS FLOWS NEAR A WELLBORE
In a high-pressure gas well, gas acceleration increases continuously as the gas moves and expands toward the wellbore. This expansion-induced acceleration effect in the linear flow of a high-pressure gas near a wellbore is studied. It is shown that for a given bottomhole flowing pressure, gas acceleration reduces mass flow rate, and for a given mass flow rate, gas acceleration decreases bottomhole flowing pressure. Acceleration steepens the pressure profile near the wellbore. When the bottomhole flowing pressure is decreased to a critical value, the gas mass flow rate reaches a maximum and the flow becomes choked. At choking condition, the gas pressure curve forms a vertical tangent at the wellbore wall and creates an unbounded pressure gradient. A further decrease in the bottomhole flowing pressure induces expansion shocks at the wellbore wall..
Y.
Jin
College of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102200, China
K. P.
Chen
College of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102200, China ; School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, Arizona 85287-6106, USA
M.
Chen
College of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102200, China
N.
Grapsas
School for Engineering of Matter, Transport & Energy, Arizona State University, Tempe, Arizona 85287-6106, USA
317-328
HEAT AND MASS TRANSFER IN REACTIVE POROUS MEDIA WITH LOCAL NONEQUILIBRIUM CONDITIONS
A two-dimensional mathematical model is developed to simulate the coupled heat and mass transfer in porous media involving strong exothermic chemical reaction. This type of problem has received great attention due to its relevance to a wide range of engineering applications, such as storage of food waste and other products, chemical reactors, drying technologies, catalytic reactors and many others. The flow in our problem is governed by the Darcy-Brinkman-Forchheimer model, which is solved numerically with the finite volume method. The effect of pertinent parameters such as Darcy number, Biot interstitial number, Reynolds number, solid-to-fluid conductivity ratio, and Frank-Kamenetskii number are analyzed. The influence of the exothermic chemical reaction on both heat and mass transfers is discussed. Both quantitative and qualitative results are presented.
A.
Bousri
Laboratoire de Transports Polyphasique et Milieux Poreux, FGMGP, USTHB, BP 32 El Alia 16111 Algiers, Algeria
Khedidja
Bouhadef
USTHB, Faculty of Mechanical and Process Engineering (FGMGP), Laboratory of Multiphase Transport and Porous Media (LTPMP), Algeria
H.
Beji
Laboratoire des Technologies Innovantes, Université de Picardie, Jules Verne, Amiens, France
Rachid
Bennacer
L2MGC F-95000, University of Cergy-Pontoise, 95031 Cergy-Pontoise Cedex, Paris, France; ENS-Cachan Dpt GC/LMT/CNRS UMR 8535, 61 Ave. du PrĂ©sident Wilson, 94235 Cachan Cedex, France
Rachid
Nebbali
Laboratoire de Transports Polyphasique et Milieux Poreux, FGMGP, USTHB, BP 32 El Alia 16111 Algiers, Algeria
329-341
EFFECTS OF FRACTURE PROPERTIES ON THE BEHAVIOR OF FREE-FALL AND CONTROLLED GRAVITY DRAINAGE PROCESSES
Naturally fractured petroleum reservoirs (NFRs) contribute significantly to worldwide oil and gas production. The oil production from NFRs is strongly affected by the flow communication between fractures and the surrounding matrix. The flow communication makes the gravity drainage processes in porous media with a network of fractures more complex because the flux between the two elements must be stipulated in terms of easily measured parameters. This paper provides details on the effects of fracture properties such as aperture, length, spacing, orientation, and also fracture pattern on the production rate, recovery factor, matrix-to-fracture transfer rate, viscous fingering, and capillary continuity in fractured porous media for gravity drainage processes. Experimental and theoretical studies were conducted to investigate the performance of free-fall gravity drainage (FFGD) and controlled gravity drainage (CGD) processes in unconsolidated fractured media using different test fluids. A total of seven fracture configurations were fabricated in prototypes to study the drainage behavior. Numerical simulations were also performed using COMSOL software to mathematically describe the behavior of the gravity drainage process in fractured media using the experimental data to validate the simulations. A good agreement between simulation and experimental results was achieved for both FFGD and CGD modes. The flow communication between the fracture and the matrix blocks played the most significant role in the drainage of liquid from the fractured media. Upon moderate inclination angles, enhanced production performance was achieved in CGD processes as they allowed more rapid liquid withdrawal compared to the porous media with vertical fractures, and the liquid recovery factor at gas breakthrough was also higher as a result of enhanced horizontal and vertical permeabilities. It was also found that it is possible to develop an isolated liquid phase above a horizontal fracture when the fracture aperture is higher than the value required to sustain capillary continuity between blocks.
Sohrab
Zendehboudi
Memorial University
Nima
Rezaei
Chemical Engineering Department, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
Ioannis
Chatzis
Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario N2l 3G1, Canada
343-369
QUANTUM EFFECTS ON THE RAYLEIGH-TAYLOR INSTABILITY OF STRATIFIED FLUID/PLASMA THROUGH BRINKMAN POROUS MEDIA
Quantum effects on Rayleigh-Taylor instability of a stratified plasma layer through a Brinkman porous medium are investigated. The relation between square-normalized growth rate and square-normalized wave number in two algebraic equations is obtained and analyzed. We compare the instability of Brinkman's model with Darcy's model. The results show that Brinkmanâ€™s model is more stable than Darcy's model, in spite of the fact that the final point for stability (quantum cutoff) of Brinkman's model is the same as that of Darcy's model.
Gamal
Hoshoudy
South valley Uni.
373-381
NATURAL CONVECTION HEAT TRANSFER IN A POROUS CAVITY IN THE PRESENCE OF A BIOCHEMICAL HEAT SOURCE WHICH IS DEPENDENT ON SOLUTE CONCENTRATION GENERATION RATE
This paper is concerned with natural convection in a square cavity filled with a porous medium in the presence of an internal heat source. The transient biochemical heat source which is dependent on a solute concentration generation rate is studied completely. The Darcy model is used for the momentum equation and the source term in the energy equation is proportional to the average generation rate of solute concentration, governed by a Monod model. The effects of variable porosity on heat transfer, biochemical heat source, flow pattern, and mass transfer are investigated thoroughly. The obtained results in the case of variable porosity are compared with a constant porosity condition. Results show that the assumption of variable porosity has a significant effect on the flow pattern, temperature contours, and the value of the biochemical heat source.
Mohammad Hassan
Kayhani
Department of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran
Mohsen
Nazari
Department of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran
E.
Shakeri
Department of Mechanical Engineering, Shahrood University of Technology, Shahrood, Iran
383-392
MAGNETOHYDRODYNAMIC CASSON FLUID FLOW WITH HEAT AND MASS TRANSFER THROUGH A POROUS MEDIUM OVER A STRETCHING SHEET
The problem of the magnetohydrodynamic non-Newtonian flow with heat and mass transfer through a porous medium over a stretching sheet is studied. The non-Newtonian fluid under consideration obeys the rheological equation of state due to the Casson model. The system is stressed by a uniform transverse magnetic field. The system of nonlinear partial differential equations which controlled this flow is solved by using Kummer's functions. The velocity, temperature, and concentration distributions are obtained. The effects of various physical parameters of the problem on these distributions are discussed numerically and illustrated graphically through a set of graphs. Several limiting situations with their implications are given and discussed.
Hameda Mohammed
Shawky
Department of Mathematics, Faculty of (Girls) Al-Azhar University, Nasr City, Cairo, Egypt
393-401