Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
6
2
2003
A Review of Terminology Pertaining to Darcy's Law and Flow through Porous Media
Flow through porous media is usually governed by Darcy's Law. This law is typically taught as part of programs in civil, chemical, mechanical, petroleum, and agricultural engineering. Soil scientists also use Darcy's Law extensively. Unfortunately, this well-known law is not taught with much consistency, even within a single program such as an undergraduate degree in civil engineering. After presenting examples that illustrate the high degree of variability that now exists with respect to the manner of presentation, it is argued that the nomenclature and terminology associated with Darcy's Law could be greatly reduced and simplified.
David
Hansen
Dalhousie University, Sexton Campus, Department of Civil Engineering P.O. Box 1000, Halifax. Nova Scoria, Canada, B3J 2Х4
15
Transient Behavior of Water-Oil Interface in an Upward Flow in Porous Media
A numerical study is performed to analyze unsteady flow of two immiscible fluids, water and oil, in a vertical cell filled with a porous medium. Injection of water from the bottom face perturbs the water-oil interface, which ceases being horizontal. The fluid motion in the porous medium is described by the transient Darcy model and continuity equation. A fully implicit, strongly coupled mathematical model is adopted to handle rapid water-oil interface changes. Effects of dimensionless parameters such as gravity-viscosity number N, dimensionless flow rate, Darcy number, and porosity are investigated and thoroughly documented. Their effects on evolution of the water-oil interface, on water breakthrough time, and on oil recovery are presented and discussed. A significant development of water-oil interface occurs, as the gravity-viscosity parameter and the porosity of the reservoir rock decrease. Results show that the breakthrough time is shorter for very dense, viscous oils (low values of N) and in the case of low Darcy number. High permeability can be beneficial in practical situations if the flow rate is maintained constant, since it permits considerable delay of water breakthrough, mainly at high values of N. A new coning correlation is presented to predict water breakthrough time and oil recovery, based on the flow equations and regression analysis using the data from numerical simulations.
Yacine
Ould-Amer
Laboratoire des Transports Polyphasiques et Milieux Poreux, Departement de Genie Mecanique, USTHB, B.P. 32, El Alia, Bab Ezzouar 16111, Algeria
Salah
Chikh
USTHB
12
Effect of Viscous Dissipation on the Darcy Forced-Convection Flow Past a Plane Surface
The uniform forced-convection flow in a fluid-saturated porous medium adjacent to a plane surface with prescribed temperature distribution Tw = Tw(x) is considered. The effect of viscous dissipation is included in the energy balance equation as a quadratic term of the Darcy velocity (see Bejan, 1984, 1995). It is shown that the usual asymptotic condition T (x, y ® Ґ) = const, єTҐ (as it was applied in some recent publications dealing with mixed-convection problems) contradicts this balance equation. In the present paper, -the appropriate asymptotic condition (a linear function of x) is specified and it is shown that this steady forced-convection problem can formally be reduced to a standard transient heat conduction problem in a homogeneous semi-infinite solid. By exploiting this analogy, several examples solvable in exact analytic form are presented.
E.
Magyari
Chair of Physics of Buildings, Institute of Building Technology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8093 Zurich, Switzerland
Ioan
Pop
Department of Applied Mathematics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
B.
Keller
Chair of Physics of Buildings, Institute of Building Technology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8093 Zurich, Switzerland
12
Double Diffusive Natural Convection in a Cylinder Filled with Moist Porous Grains and Exposed to a Constant Wall Heat Flux
Fluid flow and heat and mass transfer induced by double-diffusive natural convection within a vertical cylinder filled with a moist granular product, opened at both edges and exposed to a constant wall heat flux, is studied numerically in this paper. The innovation of this study, in addition to the fact of considering a nonconfined geometry, consists of taking into account the evaporation/condensation phenomena within grains via the drying kinetics. The resolution of the equations set is done by the finite-volume method. The numerical code validation was carried out in a previous paper. We report here the time-space evolution of temperature, pressure, velocity, vapor concentration, and water content in the medium. The effect of varying external temperature, concentration, and wall heat flux was also studied.
Leila
Zili-Ghedira
Energy and Thermal Systems Laboratory, National Engineering School of Monastir, University of Monastir, Avenue Ibn El Jazzar, 5019 Monastir, Tunisia
Khalifa
Slimi
ISTLS
Sassi Ben
Nasrallah
Laboratoire d'Études des Systèmes Thermiques et Énergétiques, Ecole Nationale d'Ingénieurs
de Monastir, Monastir 5019 Tunisie
14
Finite Amplitude Analysis of Convection in Rotating Mushy Layers during the Solidification of Binary Alloys
We consider the Solidification of a binary alloy in a mushy layer (or reactive porous layer) subject to Coriolis effects. A near-eutectic approximation and large far-field temperature is employed in order to study the dynamics of the mushy layer in the form of small deviations from the classical case of convection in a horizontal passive porous. The linear stability theory is used to investigate the Coriolis effect analytically in a rotating mushy layer for a new diffusion time scale proposed by the author. Weak nonlinear analysis provides differential equations for the amplitude, corresponding to both stationary and oscillatory convection.
Saneshan
Govender
School of Mechanical Engineering, University of Kwa-Zulu; School of Mechanical Engineering, University of Natal, Durban, South Africa; Eskom Holdings Ltd, Engineering Department (Gas Division), Eskom Enterprises Park, Simba Road, Sunninghill, Johannesburg
11