Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
17
11
2014
COMPOSITIONAL EFFECTS IN LIGHT/MEDIUM OIL RECOVERY BY AIR INJECTION: VAPORIZATION VS. COMBUSTION
Combustion can be used to enhance recovery of heavy, medium, or light oil in highly heterogeneous reservoirs. Such
broad range of applicability is attained because not only do the high temperatures increase the mobility of viscous oils
but also the high thermal diffusion spreads the heat evenly and reduces heterogeneity effects. For the latter reason,
combustion is also used for the recovery of light oils. The reaction mechanisms are different for light oils, where vaporization is dominant, whereas for medium nonvolatile oils combustion is dominant. We will only consider combustion of medium and light oils. Therefore we ignore coke formation and coke combustion. It is our goal to investigate the relative importance of vaporization and combustion in a two-component mixture of volatile and nonvolatile oils in a low air injection rate regime. By changing the composition we can continuously change the character of the combustion process. We derive a simplified model for the vaporization/combustion process, and implement it in a finite element package, COMSOL. For light oil mixtures, the solution consists of a thermal wave upstream, a combined vaporization/combustion wave in the middle (with vaporization upstream of combustion) and a saturation wave downstream. For medium mixtures the vaporization/condensation sequence is reversed and vaporization moves ahead of the combustion.
Due to its low viscosity, the light oil is displaced by the gases to a region outside the reach of oxygen and therefore
less oil remains behind to reach the combustion zone. This leads to a high combustion front velocity. For oil with more
nonvolatile components, vaporization occurs downstream of the combustion zone. As more oil stays behind to feed the
combustion zone, the velocity of the combustion zone is slower, albeit the temperatures are much higher. The relative importance of vaporization/combustion depends also on the injection rate, pressure, initial temperature, and oil viscosity. Numerical calculations allow to estimate the bifurcation points where the character of the combustion changes from a vaporization-dominated to a combustion-dominated process.
Negar Khoshnevis
Gargar
Delft University of Technology, Civil Engineering and Geosciences, Stevinweg 1, 2628 CE Delft, The Netherlands
Alexei A.
Mailybaev
Instituto Nacional de Matematica Pura e Aplicada (IMPA), Estrada Dona Castorina 110, Rio de Janeiro 22460-320, Brazil
Dan
Marchesin
Instituto Nacional de Matematica Pura e Aplicada (IMPA), Estrada Dona Castorina 110, Rio de Janeiro 22460-320, Brazil
Hans
Bruining
Delft University of Technology, Civil Engineering and Geosciences, Stevinweg 1, 2628 CE Delft, The Netherlands
937-952
HYDROMAGNETIC FLOW OF A NANOFLUID IN A POROUS CHANNEL WITH EXPANDING OR CONTRACTING WALLS
The present study investigates the hydromagnetic flow of a nanofluid in a two-dimensional porous channels between
slowly expanding or contracting walls. Assuming symmetric injection (or suction) along the uniformly expanding
porous walls and using a similarity transformation, the governing flow equations are reduced to nonlinear ordinary differential equations. The resulting equations are then solved analytically by using the homotopy analysis method (HAM). The convergence of the obtained series solutions is analyzed through the minimization of the averaged square residual error. A comparison between analytical and numerical solutions is presented for the validation in both graphical and tabular forms. The results obtained by HAM are in very good agreement with numerical solutions obtained by the shooting method coupled with a Runge-Kutta scheme. The effects of various physical parameters such as wall expansion ratio, Brownian motion parameter, thermophoresis parameter, and Lewis number on flow variables are discussed.
Analysis shows that for the case of contracting walls, the temperature increases for a given increase in Brownian motion parameter, and the thermophoresis parameter. In addition, the nanoparticle concentration increases with an increase in Brownian motion parameter and Lewis number.
Suripeddi
Srinivas
Department of Mathematics, School of Advanced Sciences, VIT University, Vellore 632014,
India
A.
Vijayalakshmi
Department of Mathematics, School of Advanced Sciences, VIT-University, Vellore-632014, India
T. R.
Ramamohan
CSIR Fourth Paradigm Institute (Formerly, CSIR Center for Mathematical Modeling and Computer Simulation), Wind Tunnel Road, Bangalore-560 037, India
A. Subramanyam
Reddy
Department of Mathematics, School of Advanced Sciences, VIT University, Vellore 632014,
India
953-967
ON ACCELERATED FLOWS OF MAGNETOHYDRODYNAMIC THIRD GRADE FLUID IN A POROUS MEDIUM AND ROTATING FRAME VIA A HOMOTOPY ANALYSIS METHOD
This work generates approximate analytic solutions of the unsteady state of rotating magnetohydrodynamic (MHD) flow
of a third grade fluid past a rigid plate in a porous medium. By using the modified Darcy's law of a third grade fluid, the equations governing the flow are modeled. Employing the homotopy analysis method (HAM), the approximate analytic solutions of the modeled equations are developed for the following two problems: (i) constant accelerated flow and (ii) variable accelerated flow. The obtained solutions clearly satisfy the governing equations and all the imposed initial and boundary conditions. Finally, the influences of emerging parameters are studied through graphs which emphasize the effects of magnetic field, rotating frame, and porosity parameters.
Mojtaba
Nazari
UTM Centre for Industrial and Applied Mathematics; Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia
Zainal Abdul
Aziz
Department of Mathematics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia
Faisal
Salah
Department of Mathematics, Faculty of Science, University of Kordofan, Elobied, 51111,
Sudan
969-981
NATURAL CONVECTION IN A CAVITY FILLED WITH POROUS MEDIUM WITH PARTIALLY THERMAL ACTIVE SIDEWALLS UNDER LOCAL THERMAL NONEQUILIBRIUM CONDITIONS
Steady non-Darcian natural convection in a square cavity filled with a heat-generating porous medium is studied
numerically by adopting the local thermal nonequilibrium model. All of the walls of the enclosure are adiabatic except the left wall, which is set as the partially active thermal wall. Six different cooling zones are considered along the left vertical wall, and a two-equation model is used in consideration of the microscopic heat transfer between the solid and fluid phases. It is found that the cooling of a single wall can generate unsymmetrical distribution of streamlines, and isotherms of fluid phase in porous enclosures when Rayleigh number is high (Ra = 107). The local Nusselt number of solid phase (Nusy) presents symmetrical distribution about the center line of Y direction. The total heat transfer rate Q of case A has a higher value and its increasing rate becomes larger with the increase of porosity. Compared with other thermally active cases, the value of the total heat transfer rate Q of case E is the lowest with an increase of porosity.
Feng
Wu
School of Chemical Engineering, Northwest University, Taibai North Road 229, Xi'an 710069, China
Gang
Wang
Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, P. R. China; and School of Civil Engineering, Lanzhou University of Technology, Lanzhou 730050, P. R. China
Wenjing
Zhou
Key Laboratory of Thermo-Fluid Science and Engineering, Ministry of Education, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China
983-997
MIXED CONVECTION FLOW ALONG A VERTICAL STRETCHING PERMEABLE SHEET IN A DARCY− BRINKMAN ISOTROPIC POROUS MEDIUM
The boundary layer flow along a vertical permeable sheet embedded in a Darcy−Brinkman porous medium, has been
investigated in this paper. At the sheet either constant suction or constant injection is applied. The results are obtained with the direct numerical solution of the governing equations. The problem is similar and is governed by four nondimensional parameters which are the Prandtl number, the mixed convection parameter, the permeability parameter, and
the suction (injection) parameter. The influence of these parameters on the results is presented in tables and figures. It is found that the permeability parameter, suction parameter, and Pr number act in the same way on velocity while the mixed convection parameter and the injection parameter act in the opposite way. Concerning the temperature the permeability and the injection parameter act in the same way, whereas the Pr number, the mixed convection parameter, and the suction parameter act in the opposite way.
Asterios
Pantokratoras
School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece
999-1006
MIXED CONVECTION SLIP FLOW WITH HEAT TRANSFER AND POROUS MEDIUM
Effects of velocity and thermal slip conditions in the mixed convection flow are addressed in the presence of heat
source/sink. An incompressible fluid saturates the porous medium. Similarity transformations reduce the governing
partial differential equations into ordinary differential equations. Numerical solution of the resulting problems is discussed. The present analysis reveals that, by reducing the boundary layer thickness, the increasing velocity slip parameter makes the fluid velocity increase whereas nondimensional temperature decreases for increasing values of velocity slip parameter. The rate of heat transfer decreases with increasing values of thermal slip. The surface temperature increases when heat source/sink parameter is increased.
Swati
Mukhopadhyay
Department of Mathematics, The University of Burdwan, India
Iswar Chandra
Mandal
Department of Mathematics, The University of Burdwan, Burdwan-713104, W. B., India
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, Jeddah 21589, Saudi Arabia
1007-1017
3D NUMERICAL INVESTIGATION OF FLUID FLOW THROUGH OPEN-CELL METAL FOAMS USING MICRO-TOMOGRAPHY IMAGES
In this research, a 3D simulation of fluid flow in open-cell foams with a porosity percentage of 85, 90, 95, and 98
was performed on the basis of meshing their computed micro-tomography (μCT) images. The finite volume method
with a high-quality structured hexahedral element grid was used to discretize the equations. Results show that the
pressure gradient (dP/dx) increased by a decrease in porosity, and decreased by an increase in the inlet velocity. Also, by an increase in porosity percentage, the linear and nonlinear term coefficients of the pressure gradient equation
(−dP/dx = αu + βu2) vary between 1116 < α < 11595 (kg·m−3·s−1) and 210 < β < 3186 (kg·m−4), respectively
By comparing the results obtained from the simulation and the experimental results obtained from other studies, it was
specified that if the Reynolds number is less than 1, the flow is in the laminar (or Darcy flow) zone, and a transient
flow is attained at Reynolds numbers above. In other words, it can be concluded that the numerical results are found in
reasonable agreement with the experimental data.
Mohammad
Zafari
Department of Materials Engineering, Isfahan University of Technology, 84156-83111, Isfahan, Iran
Masoud
Panjepour
Department of Materials Engineering, Isfahan University of Technology, 84156-83111, Isfahan, Iran
Mohsen Davazdah
Emami
Department of Mechanical Engineering, Isfahan University of Technology, 84156-83111, Isfahan, Iran
Mahmood
Meratian
Department of Materials Engineering, Isfahan University of Technology, 84156-83111, Isfahan, Iran
1019-1029