Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
16
10
2013
HEATLINE VISUALIZATION OF NATURAL CONVECTION IN AN INCLINED SQUARE POROUS ENCLOSURE WITH SINUSOIDAL BOUNDARY CONDITIONS
Convection in an inclined square porous enclosure with sinusoidally varying wall temperatures is visualized and analyzed by the heatline concept. The Darcy model is used in the mathematical formulation for the porous layer and the COMSOL Multiphysics software is applied to solve the dimensionless governing equations. The governing parameters considered are the amplitude ratio, 0.0 ≤ ε ≤ 1.0, the phase deviation, 0 ≤ Φ ≤ π, the inclination angle of the enclosure, 0° ≤ φ ≤ 90°, and the Rayleigh number, 50 ≤ Ra ≤ 1000. Generally, decreasing the inclination angle was found to increase the number of cells in the enclosure and decrease the heat transfer rate. Combination of the sinusoidal and cosinusoidal temperature profiles on the vertical walls produced the highest heat transfer rate.
Habibis
Saleh
School of Mathematical Sciences, Universiti Kebangsaan Malaysia, 43600 UKM Bangi Selangor, Malaysia
I
Hashim
875-885
THE STUDY OF FLUID FLOWS AND HEAT TRANSFER OF TWO IMMISCIBLE INCOMPRESSIBLE FLUIDS IN NATURALLY PERMEABLE CHANNELS USING THE BRINKMAN−DARCY MODEL
Laminar flows of two immiscible, incompressible fluids past permeable channels have been studied for the three cases of plane Couette flow, generalized Couette flow, and Poiseuille flow. The free-flow channel has two layers of immiscible fluids, while the porous region has been divided into a Brinkman layer and a Darcy layer. The Beavers−Joseph condition has been used to match velocities at the Brinkman−Darcy interface, while the continuity of velocities and stresses have been used at the interface of the free-fluid and Brinkman regions. Momentum and energy equations are solved analytically, yielding corresponding velocity and temperature profiles. Nusselt numbers are calculated for variations in viscosity ratios and Darcy numbers. We observe that modifications in these parameters lead to variations in Nusselt numbers and alterations in velocity and temperature profiles.
Dayle C.
Jogie
Department of Mathematics and Statistics, St. Augustine, Trinidad and Tobago, West Indies
Balswaroop
Bhatt
The University of the West Indies, St. Augustine
887-902
NUMERICAL SOLUTION OF DOUBLE-DIFFUSIVE NATURAL CONVECTION IN A POROUS CAVITY PARTIALLY HEATED FROM BELOW AND PARTIALLY SALTED FROM THE SIDE
Double-diffusive natural convection in a square porous enclosure is studied numerically when the bottom and right walls are partially heated and partially salted, respectively. The top wall is maintained at a constant cold temperature and the left wall is fully salted at a lower concentration than the right. The Darcy model is used in the mathematical formulation. The finite volume method is used to solve the governing equations. The governing parameters of the present study are Rayleigh number (Ra), Lewis number (Le), buoyancy ratio (N), heating segment length (lh) heating segment position (xh), concentration segment length (ls), and concentration segment position (ys). The results were discussed in the effect of these parameters on streamlines, isotherms, isoconcentration lines, and the heat- and mass-transfer processes, and presented graphically. Generally, there is a direct relation between buoyancy ratio and heat- and mass-transfer processes. The results show a significant effect of the heating and concentration segment's length and position on the heat- and mass-transfer processes. The minimum value of average Nusselt number occurs with N > 0 for all the positions of the heating segment except the positions xh > 0.1 and 0.9, where the minimum value occurs with N > 1 and − 1, respectively.
Anas
Altawallbeh
assistant Professor
Nawaf
Saeid
Mechanical Engineering Programme, Faculty of Engineering
I
Hashim
903-919
MIXED CONVECTION FLOW AND HEAT TRANSFER IN A VENTED ENCLOSURE FILLED PARTIALLY WITH A POROUS MEDIUM
Mixed convection flow and heat transfer in a vented enclosure filled partially with a porous medium was studied in this investigation for various pertinent parameters. The effects of solid-to-fluid thermal conductivity ratio, Darcy number, Richardson number, location of the porous layer, and width of the porous layer on the streamlines, isotherms, and temperature and velocity profiles at midsections of the enclosure were analyzed in this study. The generalized model of the momentum equation, which is also known as the Forchheimer−Brinkman extended Darcy model, was utilized in modeling the fluid motion inside the porous layer. The results of this investigation illustrated that the location and width of the porous layer have a significant effect on the streamlines and isotherm patterns within the enclosure. Moreover, flow- and heat-transfer activities within the enclosure were found to depreciate as the width of the porous layer increases. Finally, the results showed that as the conductivity ratio of the porous layer increases, the porous layer becomes more conductive.
Bader
Alshriaan
Mechanical Engineering Department, Kuwait University, Al-Safat 13060, Kuwait
921-932
NUMERICAL STUDY OF THERMOELECTRIC GENERATION WITHIN A CONTINUOUS FLOW POROUS MEDIA BURNER
A numerical study based on direct thermal to electric energy conversion was performed in a continuous flow porous media burner. The optimal lengths and placements of thermoelectric elements for a set of operational variables (filtration velocity and composition of gas mixture) were sought in order to maximize the system overall efficiency. A two-temperature resistance model for finite time thermodynamics was developed for the thermoelectric elements energy fluxes. Different operational variable sets that allowed wave stabilization inside the reactor were employed, giving rise to different thermal gradients and total power output. Results indicate an optimal thermoelements length and region for its placement inside the steep thermal gradients for maximum power production.
Luis
Henriquez-Vargas
Department of Chemical Engineering, Universidad de Santiago de Chile, 3363 B. O'Higgins, Santiago, Chile
M.
Maiza
Chemical Engineering Department, Universidad de Santiago de Chile, B. O'Higgins 3363, Chile
Pablo
Donoso-Garcia
Department of Chemical Engineering, Universidad de Santiago de Chile, B. O'Higgins 3363, Chile
933-944
REFLECTION OF PLANE WAVES FROM A FREE SURFACE OF A POROTHERMOELASTIC SOLID HALF-SPACE
In the present paper, the reflection of plane waves from a free surface of a generalized porothermoelastic solid half-space is studied. The appropriate solutions in the generalized porothermoelastic solid half-space are obtained which satisfy the required boundary conditions at the free surface of the half-space to obtain the relations between the reflection coefficients of reflected waves for an obliquely incident plane wave. The paper also discusses the energy partitioning during reflection of plane waves. The reflection coefficients and energy ratios are computed for a relevant material data for a certain range of the angle of incidence. The effects of thermal fields are shown graphically on the reflected waves.
Baljeet
Singh
Department of Mathematics, Post Graduate Government College, Sector-11, Chandigarh-160 011, India
945-957
3-D SIMULATION OF ACID INJECTION INTO A CARBONATE POROUS MEDIA: NONLINEAR CHEMISTRY
Formation damage reduces well production or injection capacity, and the removal of damage is one of the major goals of petroleum engineers. Matrix acidizing can significantly enhance the productivity of a well when near-wellbore formation damage is present. In this treatment, acidic solution is injected to the well at pressures below the rock failure pressure. Acid can dissolve minerals in the formation and consequently recover or increase the permeability in the near-wellbore region. In successful carbonate acidization, acid can create empty channels called wormholes. During production, wormholes become pathways for the reservoir fluid to reach the well and hence improve production. In this work, matrix acidization in the multilayer carbonate reservoirs has been simulated in 3-D radial flow. The model includes nonlinear chemistry at the solid−fluid interface, depending on the reservoir temperature. The effect of rock composition in each layer and reservoir temperature on the final skin factor and dissolution patterns has been investigated. Also, the effects of temperature and concentration on acid viscosity and density have been considered. A good agreement is found between the simulated and field data.
Fereshteh
Samadi
School of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
Feridun
Esmaeilzadeh
Department of Chemical and Petroleum Engineering, Shiraz University, Shiraz, Iran
Dariush
Mowla
Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz 71345
959-966