Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
10
7
2007
Parametric Investigations of a Modified Simultaneous Water-Alternating-Gas Injection Technique
The energy of reservoirs gets depleted as production continues. The restoration of reservoir energy involves injection of gas and/or water to support reservoir pressure and to provide a sweeping mechanism. Owing to the unfavorable mobility ratio, gas injection alone results in early breakthrough and poor sweep efficiency. Water and gas might be injected alternatively or together to improve the sweep efficiency. These processes improve the sweep efficiency by stabilizing the displacement front. In this article, a reservoir simulation tool was used to study a new design of simultaneous injection process, in which water is injected at the top of the reservoir and gas is injected at the bottom. The difference in water and gas densities provides a sweeping mechanism in which water tends to sweep hydrocarbons downward and gas tends to sweep the hydrocarbons upward. It is expected that the two displacement mechanisms will work to enhance the overall sweep efficiency. The effects of several design parameters on these drive mechanisms are investigated. Such parameters include the mobility ratio between water and oil phases, the viscosity ratio between gas and oil phases, the lateral aspect ratio, the location of the water and gas injection wells, and the injection rates of water and gas.
Meshal
Algharaib
Department of Petroleum Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
Ridha B.
Gharbi
Department of Petroleum Engineering, College of Engineering & Petroleum, Kuwait University, P. O. Box 5969, Safat 13060, Kuwait
Adel
Malallah
Department of Petroleum Engineering, College of Engineering and Petroleum, Kuwait University, Safat 13060, Kuwait
Wafaa
Al-Ghanim
Kuwait Oil Company, Ahmadi, Kuwait
633-656
Simulation of Melting of Ice under a Constant Temperature Heat Source Using a Combined Transfinite Interpolation and Partial Differential Equation Methods
Within the framework of the novel numerical method, this article presents an efficient algorithm for solving multidimensional nonlinear heat problem involving phase change. A numerical study is made for melting of ice subjected to a constant temperature heat source with different initial conditions. The algorithmic design is based on two steps: Preliminary grids are first generated by an algebraic method, that is, a transfinite interpolation method, with subsequent refinement using a Partial Differential Equation (PDE) mapping (parabolic grid generation) method in the next step. Numerical examples are given for the two melting conditions: low and very low initial temperatures. The accuracy and flexibility of the presented numerical methods are verified by comparing the results with existing analytical solutions. The simulated results are also compared with the experimental results. In summary, the algorithm is able to efficiently and accurately predict the evolution of temperature distribution and deformation of an interface (melting front) with smooth grid point distribution. An important application of the present algorithm would be in the field of phase change problems.
P.
Rattanadecho
Faculty of Engineering, Thammasat University (Rangsit Campus), Pathumthani 12121
C.
Serttikul
Faculty of Engineering, Thammasat University (Rangsit Campus), Pathumthani 12121, Thailand
657-676
Photoresponse of Metal-Porous Silicon-Silicon Structure
In this article, we first review the potential applications of porous silicon (PS) in solar cell structures. Then we describe the fabrication of this material by electrochemical anodization method in hydrofluoric acid (HF) solution. The spectral responses of photovoltaic devices based on metal-PS-Si sandwich structures are presented. At room temperature, the photoresponse (photovoltage or photocurrent) of these devices has been measured by variation of the optical excitation energy. The highest photo-sensitivity (photocurrent) was found to be at a wavelength of 540 nm. The photoresponse of PS shows better results as compared to a Si solar cell. The contribution of the photovoltaic effects from the junctions of the metal-PS and from PS-Si heterojunction was observed for the visible wavelength range of light and under white light of different powers. Current-voltage (I-V) characteristics have been done in dark and room light. The results indicate that the sandwich structure has a diode barrier.
M.
Zare
Department of Physics, Alzhara University, Tehran 19938, Iran
Reza S.
Dariani
Department of Physics, Alzahra University, Tehran, 19938, Iran
Z.
Bayindir
Department of Physics, Queen's University, Kingston, Ontario K7L 3N6, Canada
K.
Robbie
Department of Physics, Queen's University, Kingston, Ontario K7L 3N6, Canada
677-686
A Mathematical Study of Hall Effects on Peristaltic Transport of Hydromagnetic Flow Through a Porous Medium
In this work a theoretical analysis is presented for the problem of peristaltic transport of a viscous electrically conducting fluid through a porous medium in a planar channel, in which the flow is induced by a sinusoidal wave traveling on the walls. This problem has numerous applications in various branches of science, including the stimulation of fluid flow in a porous medium under the effect of elastic waves and studies of blood flow dynamics in living creatures. The effect of the Hall currents and the permeability of the medium on the mean axial velocity and the reversal flow have been investigated. A perturbation solution of the stream function for zeroth, first, and second order in a small amplitude ratio for the free pumping case is obtained. The results, for smaller values of the Hall parameter, show that the axial velocity decreases by increasing the Hall parameter and permeability parameter, and the possibility of flow reversal increases by increasing the permeability parameter and decreases by increasing the Hall parameter.
Mohamed H.
Haroun
Department of Mathematics, Faculty of Education, Ain Shams University, Heliopolis, Roxy, Cairo, Egypt
687-700
Mixed Convection in a Square Cavity Filled with a Porous Medium and Different Exit Port Position
This article presents a two-dimensional finite difference numerical model of steady laminar mixed convection inside a square vented cavity filled with a fluid-saturated porous medium for different outlet port positions. It was assumed that one of the vertical walls is at constant temperature, while the remaining walls are perfectly insulated (adiabatic). Forced convection was imposed at the inlet port fixed at the bottom surface and vented through the exit port. The exit port position was allowed to vary. A powerful, accurate numerical algorithm was introduced to solve the governing equations. This method has some advantages, such as high speed of convergence, high accuracy, and simplicity. It is concluded that the maximum overall heat transfer of the cavity is achieved when the exit port is located in the upper right corner, while minimum heat transfer is observed when the outlet port is located in the both the upper right or lower left corner.
J.
Ghazanfarian
Mechanical Engineering Department, Amirkabir University of Technology, P. O. Box 15875-4413 Tehran, Iran
Abbas
Abbassi
Mechanical Engineering Department, Amirkabir University of Technology 424 Hafez Avenue, P.O. Box 15875-4413, Tehran, Iran
701-718
Identification of Viscoplastic Behavior of Metal Powders Using Pressureless Sintering Results
The phenomenological viscoplastic modeling introduced by Abouaf et al. (1988) for porous solids is used as the material constitutive law at elevated temperatures. Before applying the model, its parameters should be identified. Part of the model parameters is classically identified by hot isostatic pressing (HIP) experiments. This work presents the possibility of applying the viscoplastic modeling to the process of pressureless sintering. Therefore an expression for the material densification rate during this process is derived. This expression gives, obviously, the possibility of parameter identification by the experiments of pressureless sintering instead of by HIP experiments. This task has been done for the case of 316L stainless steel compact.
Mohammad-Hasan
Abbasi
Department of Materials Engineering, Isfahan University of Technology, 84156 Isfahan, Iran
719-726
Hiemenz Flow of a Micropolar Viscoelastic Fluid in a Hydromagnetic Saturated Porous Medium
The boundary layer equations are solved for the case of two-dimensional Hiemenz flow in hydromagnetics of a micropolar viscoelastic, incompressible, viscous, electrically conducting fluid impinging normal to a plane in the presence of a transverse magnetic field saturated porous medium. Numerical solutions are given for the governing momentum and angular momentum equations. An approximate solution is given that is simple and yet sufficiently accurate for the entire range of values of the Hartman number investigated. A discussion has been provided for the effect of micropolar, permeability, and viscoelastic parameters on Hiemenz flow in hydromagnetics.
S.M.M.
EL-Kabeir
Department of Mathematics, Salman bin Abdulaziz University, College of Science and Humanity Studies, Al-Kharj, 11942, Saudi Arabia; Department of Mathematics, Aswan University, Faculty of Science, 81528, Egypt
M. Modather M.
Abdou
Department of Mathematics, Faculty of Science Aswan, South Valley University, Aswan, Egypt; Department of Mathematics, College of Science and Humanity Studies, Salman Bin AbdulAziz University, Al-Kharj, KSA
727-737