Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
4
2
2001
Heat Transfer with Propane Evaporation from a Porous Wick of Heat Pipe
Heat transfer enhancement in the evaporator of a vapordynamic thermosyphon and loop heat pipe (LHP) filled with propane is discussed. The experimental data for heat transfer with propane pool boiling on horizontal smooth and porous tubes inside the vapordynamic thermosyphon and the LHP evaporator were recorded for saturation temperature Ts = 0−30°C and heat input q = 0.1−120 kW/m2 (q = 0.02−30 kW/m2 for LHP evaporator). Heat transfer intensification up to 3−5 times was obtained with a heat transfer coefficient up to 30 × 103 W/m2.
Leonid L.
Vasiliev, Jr.
Byelorussian Academy of Sciences; and Luikov Heat & Mass Transfer Institute, Porous Media Laboratory, P. Brovka Str. 15, 220072 Minsk, Belarus
Alexander S.
Zhuravlyov
Luikov Heat & Mass Transfer Institute, National Academy of Sciences of Belarus, Porous Media Laboratory, P. Brovka Str. 15, 220072 Minsk, Belarus
Mikhail N.
Novikov
Luikov Heat & Mass Transfer Institute, National Academy of Sciences of Belarus, Porous Media Laboratory, P. Brovka Str. 15, 220072 Minsk, Belarus
L. L.
Vasiliev, Jr
Luikov Heat & Mass Transfer Institute, National Academy of Sciences of Belarus, Porous Media Laboratory, P. Brovka Str. 15, 220072 Minsk, Belarus
10
The Performance of Miscible Enhanced Oil Recovery Displacements in Geostatistically Generated Permeable Media Using Horizontal Wells
The effect of heterogeneity on the performance of enhanced oil recovery (EOR) processes with horizontal wells was investigated using a three-dimensional, finite difference, chemical flood simulator (UTCHEM). We used the reservoir and fluid properties typical of an oil field from the Middle East region. Several three-dimensional heterogeneous permeable media, each with different permeability variation and spatial correlations, were generated geostatistically using the matrix decomposition method to cover a wide range of permeability variation and correlation lengths. Initially, simulations of miscible displacements with one horizontal injector and one horizontal producer were performed in all these heterogeneous reservoirs. The displacement performances of the two horizontal wells in each of the heterogeneous reservoirs were then compared with that obtained with two vertical wells (one injector and one producer). For all the permeable media, the effect of the amount of cross flow on the displacement behavior was also investigated. The study shows that the performance of miscible EOR processes with horizontal wells is strongly affected by the permeability variation and the spatial correlation of the reservoir heterogeneity. The combination of high permeability variation and high correlation length significantly reduces the performance of horizontal wells.
Ridha B.
Gharbi
Department of Petroleum Engineering, College of Engineering & Petroleum, Kuwait University, P. O. Box 5969, Safat 13060, Kuwait
Ali A.
Garrouch
Department of Petroleum Engineering, Faculty of Engineering & Petroleum, Kuwait University, P. O. Box 5969, Safat 13060, Kuwait
14
Nonlinear Study of Stratified Fluid Through Porous Media
An analysis is presented to describe the effects of Darcy resistance, fluid inertia, and horizontal density gradient on a heterogeneous Boussinesq fluid saturated porous medium in the presence of the vertical gravitational field using the Forchheimer-Lapwood extended Darcy (DLF) equation. The fluid is initially at rest, and sets in motion owing to two forms of the initial density gradients. One is the constant initial horizontal density gradient and the other is the piecewise constant density gradient. In the case of the uniform initial horizontal density gradient a purely horizontal motion develops satisfying the nonlinear. Forchheimer extended Darcy (FD) equation. Analytical solution of this equation is obtained and limiting solutions valid for the Darcy regime and for a nonviscous fluid in the absence of porous media are derived. A measure of the stability of the flow is discussed briefly using the Richardson number. A comparison between the nature of solutions satisfying the nonlinear and linear initial value problems is made. We found that the vertical density gradient varies continuously both with space z and time t but the horizontal density gradient remains unchanged. In the case of a piecewise constant initial density gradient with continuous distribution of density, stream function formulation is used and the solutions are obtained using time-series analysis. In this case the solution shows crowding of the density profiles in the lower half of the channel, reflecting an increase in density gradient and incipient frontogenesis there, because of the increase in circulation of the flow due to the piecewise initial density gradient.
10
Effects of Heterogeneity in Forced Convection in a Porous Medium: Parallel-Plate Channel, Asymmetric Property Variation, and Asymmetric Heating
The effects of variation (in the transverse direction) of permeability and thermal conductivity on fully developed forced convection in a parallel plate channel or circular duct filled with a saturated porous medium is investigated analytically on the basis of a Darcy model. Previous work on the case of symmetric property variation and symmetric heating is now supplemented by a study of the case of asymmetric property variation, for both symmetric and asymmetric heating, lsoflux and isotemperature boundary conditions are treated in turn. For the isofiux case, it is found that both permeability variation and conductivity variation lead to a reduction in the value of the Nusselt number Nu based on mean properties, but for the isotemperature case the situation is more complicated. For the isoflux case and permeability variation only, Nu is independent of the degree of asymmetric heating as represented by a flux ratio τ, but in the case of conductivity variation Nu is strongly dependent on τ and the degree of conductivity variation. In the case of isotemperature boundary conditions no fully developed solution exists when both the property variation and the heating are asymmetric.
Donald A.
Nield
Department of Engineering Science, University of Auckland, New Zealand
12
Analytical Solutions of Fluid Flows Through Composite Channels
Fluid flow is assumed to be steady, incompressible, with a negligible gravitational force, and is constrained in an infinite horizontal channel composed of one or more different types of porous media. The cross section of the channel is taken to be both rectangular and circular. The nondimensional Brinkman equation involves the parameter α=Γ/Da, where Da is the Darcy number which represents the type of medium in which the fluid flows and Γ is the ratio of the fluid viscosity μf to the effective viscosity μ In this article an analytical study in the fully developed section of the three-dimensional composite channel is presented for different geometrical configurations, namely, when the channel consists of (1) a single porous medium of uniform porosity; (2) two different uniform porous media; (3) three porous layers each of uniform porosity, including when assembled to produce a symmetrical situation; and finally, (4) an axisymmetric channel with two different cylindrical porous regions of uniform porosity. The analytical solutions for different cases are compared and the effect of the Darcy parameter is discussed.
A. K.
Al-Hadhrami
Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT, UK
Lionel
Elliott
Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT, UK
Derek B.
Ingham
Centre for CFD, Department of Applied Mathematical Studies, The University of Leeds, Leeds, LS2 9JT, UK
X.
Wen
Department of Applied Mathematics, University of Leeds, Leeds LS2 9JT, UK
16
Darcy's Law for a Heterogeneous Porous Medium
We consider slow viscous flow of a Newtonian fluid through a spatially varying porous medium. Applying the method of homogenization in a heterogeneous porous medium constructed by a microscopic, locally periodic structure we are able to derive an appropriate form of Darcy's law. This is a macroscopic relationship between the average fluid velocity and the overall pressure and external force mediated by a heterogeneous permeability tensor. A simple explicit example, which is amenable to analytical resolution and which exhibits part of the complexity of a general situation, is considered.
F. D. Moura
Neto
Instituto Politécnico, Universidade do Estado do Rio de Janeiro C. P. 97282, 28601-970, Nova Friburgo, RJ, Brazil
S. T.
Melo
Instituto de Matematica e Estati'stica, Universidade de Sao Paulo, Sao Paulo, SP, 05508-900, Brazil
14
Natural Convection from a Vertical Plate in a Saturated Porous Medium: Nonequilibrium Theory
6
Transient Pulsating Flow in Channels Partially Filled with a Porous Material
Analytical solutions are obtained for (he problem of transient pulsating flow in parallel-plate channels partially filled with a porous material. The investigation considers three different cases: in the first case, one porous substrate is attached at one of the channel walls; in the second, one porous substrate is inserted at the center of the channel; and in the third, one porous substrate is inserted at each of the channel walls. Also, the effect of the local macroscopic inertial term in the porous domain momentum equation is investigated. It is found that this term has significant effects at large Darcy numbers and high frequency of oscillations.
Malak
Naji
Mechanical Engineering Department, Jordan University of Science and Technology, Irbid 22110, Jordan
8
Transient Natural Convection in Differentially Heated Porous Enclosures: Corrected Abstract
The following abstract should replace the one that appeared with this article in the Journal of Porous Media, 3(2), 165 (2000).Transient natural convective flow and heal transfer in a differentially heated enclosure filled with a saturated porous medium is investigated numerically by adopting the general flow model that accounts for both the boundary and the inertial effects in porous media. The present study covers investigation of the fluid Rayleigh number (RA) between 1 × 105 and 1 × 109, the Darcy number (DA) of 1 × 10−6 to 1 × 10−2 for aspect ratio, and the inertial parameter and modified Prandtl number of unity. For DA > 1 × 10−6, it is found that if the modified Rayleigh number (Ram − Ra.Da) is greater than 100, significant differences exist between the general model and the Darcy model predictions, especially at the early transient stage. Both in the Darcy and non-Darcy regimes, the Brinkman extended model agreed well with the general model. Also, it is found that Forchheimer's term is significant in the transient stage, but it is of no importance at the steady state.
A. A.
Merrikh
Department of Mechanical Engineering, Eastern Mediterranean University, G. Magosa, T.R.N.C. Mersin 10, Turkey
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