Begell House
Journal of Porous Media
Journal of Porous Media
1091-028X
17
6
2014
SIMULATION OF FLOW IN POROUS MEDIA: AN EXPERIMENTAL AND MODELING STUDY
Most of the porous media in nature as well as in engineering projects are open to air and approximately all of the flows in these media have an unconfined nature. Therefore study about unconfined flow through open coarse porous media has been widely used in different branches of engineering and sciences. In this study, by introducing a special network which is called "CPFN" (coupled pressurized−free surface network), the unconfined flow through open porous media is studied. In this kind of modeling, initially the physical properties of the equivalent CPFN network must be determined and then by analyzing this network, the hydraulic parameters of flow through real porous media will be determined. In this research, a new method is introduced to analyze the mentioned network, which is discussed in detail in a separate article, and a simple method for determining the geometric parameters of this equivalent network is proposed here. Validation of these proposed models and the related equations are achieved by triggering and monitoring the flow discharge and water surface profile in seven different experimental models which have been built in the hydraulic laboratory at the Engineering School of Shiraz University. Results show good agreement between the predicted values of the network model and the experimental data obtained in the laboratory.
Seied Hosein
Afzali
Department of Civil and Environmental Engineering, School of Engineering, Shiraz University, Shiraz, Iran
Parviz
Monadjemi
Department of Civil and Environmental Engineering, School of Engineering, Shiraz University, Shiraz, Iran
469-481
FREE CONVECTION OF VISCOELASTIC WALTER'S FLUID−SATURATED POROUS MEDIUM IN A VERTICAL DOUBLE-PASSAGE WAVY CHANNEL
Fully developed laminar free convection of a Walter's fluid (model B')-saturated porous medium has been investigated in a vertical double-passage wavy channel. The considered channel has asymmetric constant wall temperatures and is divided into two passages by means of a thin plane baffle. Analytical solutions are found using the perturbation method and long wave approximation has been used to solve the perturbed part. Results are drawn for varying physical parameters such as Grashof number, wall temperature ratio, porous parameter, viscoelastic parameter, and product of wave number and space coordinate at different positions of the baffle. These results indicate that the fully developed flow could be significantly affected with buoyancy forces, wall temperature ratio, viscoelastic parameter, and wave number in the double-passage channel. The skin friction and the Nusselt numbers are given in the tables for varying the governing parameters.
J. Prathap
Kumar
Department of Mathematics, Gulbarga University, Gulbarga-585 106, Karnataka
Jawali
Umavathi
Gulbarga University
H.
Prema
Department of Mathematics, Gulbarga University, Gulbarga 585 106, Karnataka, India
483-502
PORE NETWORK MODELING FOR PREDICTION OF RESIDUAL GAS SATURATION IN WATER INVASION PROCESS
In water encroachment processes a high amount of gas is trapped behind the gas and water contact in water drive gas reservoirs as residual gas saturation (RGS). Gas and water imbibition has been experimentally studied in core scale to determine RGS in previous studies. However, modeling of the imbibition process has only been developed for oil−water systems. Core experiments could not precisely estimate the important parameters that affect RGS. Gas trapping is influenced by displacement mechanisms at the pore scale. For the first time, a three-dimensional pore network model is presented to study gas−water displacement in drainage and imbibition processes in pore scale. This study describes a new dynamic pore network algorithm for imbibition that updates pressure and saturation implicitly to study the transient nature of water film flow and snap-off occurrence and recognizes the important parameters affecting RGS at pore scale. The network model is used to study the effect of different parameters such as pore morphology, initial water saturation (IWS), temperature, pressure, and flow rate on RGS. The results indicate that pore morphology affects formation of the frontal displacement advances or the snap-off events and it is the main reason for the nonunique correlation between RGS and petrophysical properties. Temperature and pressure conditions also affect RGS, and determining RGS at room temperature and atmospheric pressure causes error. For example, the results of increasing pore cross-section angularity and increasing pore radius size are not compatible with the previous results. The increase in the flow rate and capillary number causes a reduction in the number of snap-off events and RGS for the same aspect ratio (AR), while RGS is more sensitive to flow rate at higher AR. At low capillary numbers, variation of AR strongly affects RGS and the number of snap-off events, while at high capillary numbers, RGS is nearly independent of AR. Moreover, the critical capillary number in gas−water displacement is around 10−8, while in oil-water systems it is about 10−5.
Mahnaz
Hekmatzadeh
Department of Petroleum Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran; IOR Research Institute, Research and Technology Directorate, National Iranian Oil Company, Tehran, Iran
Mitra
Dadvar
Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
Mohammadali
Emadi
IOR Research Institute, Research and Technology Directorate, National Iranian Oil Company, Tehran, Iran
503-520
MIXED CONVECTION MHD HEAT AND MASS TRANSFER OVER A NONLINEAR STRETCHING VERTICAL SURFACE IN A NON-DARCIAN POROUS MEDIUM
A numerical model is developed for the steady two-dimensional laminar mixed convection magnetohydrodynamic heat and mass transfer of an electrically conducting viscous fluid in a non-Darcian porous medium over a nonlinear stretching vertical sheet in the presence of viscous dissipation and Ohmic heating. The stretching velocity and the transverse magnetic field are assumed to vary as a power law function of the distance from the origin. The temperature-dependent fluid properties, namely, the fluid viscosity and the thermal conductivity, are assumed to vary as an inverse and linear function of the temperature, respectively. A generalized similarity transformation is introduced and the governing boundary layer equations are transformed to a set of nonlinear coupled ordinary differential equations which are then solved based on a shooting algorithm along with a Runge−Kutta integration scheme over the entire range of physical parameters with appropriate boundary conditions. The influence of various involved physical parameters on velocity, temperature, and concentration fields as well as on local skin friction, local Nusselt number, and local Sherwood number are studied using graphical and tabular forms. The analysis is carried out for both assisting and opposing flows.
Masoud Molaei
Najafabadi
Mechanical Engineering Department, Amirkabir University of Technology, No. 424, Hafez Ave., PO Box 15875-4413, Tehran, Iran
Rama Subba Reddy
Gorla
Department of Mechanical Engineering, Cleveland State University, Cleveland, OH, 44115 USA; Department of Mechanical Engineering, University of Akron, Akron, Ohio 44325, USA; Department of Mechanical & Civil Engineering, Purdue University Northwest, Westville, IN 46391, USA
521-535
FLOW SIMULATION AND MIXED CONVECTION IN A LID-DRIVEN SQUARE CAVITY WITH SATURATED POROUS MEDIA
A fluid convection flow driven by a uniformly movable lid with thermosolutal stratification in a square enclosure filled with a porous medium is studied. A wide range of Grashof numbers, 104 ≤ Gr ≤ 106, and Reynolds numbers, 500 ≤ Re ≤ 2500, have been investigated for the flow, heat, and mass transfer characteristics. The porosity inside the enclosure is chosen to be 0.4 for the Darcy number varying from 10−4 to 1.0. A detailed comparison of the flow, heat, and mass transfer is made in this article. The average rates of heat and mass transfer from the top and bottom lids on the flow parameters are also investigated.
A. K.
Nayak
Department of Mathematics, IIT, Roorkee, India
P. K.
Jena
Department of Mathematics, Ravenshaw University, Cuttack-3, Orissa, India
P. A. Lakshmi
Narayana
Department of Mathematics, Indian Institute of Technology Hyderabad, Hyderabad - 502205, Telangana, India
537-548
A NUMERICAL STUDY OF NANOFLUID FORCED CONVECTION IN A POROUS CHANNEL WITH DISCRETE HEAT SOURCES
A numerical simulation is carried out to investigate the laminar forced convection flow of Al2O3−water nanofluid in a porous parallel plates channel with discrete heat sources using a single-phase approach. The heat sources are placed on the bottom wall of the channel, and the remaining surfaces of the channel are considered adiabatic. The effects of Darcy number (Da = 10−1, 10−2, 10−4, and 10−6), particle volume fraction (φ = 0% (distilled water), 3%, 5%, and 9%), heat flux of heat sources (q = 5000,10,000, 20,000, and 30,000 W/m2), porosity (0.4, 0.6, 0.8, and 0.95), and thermal conductivity ratio (ks/kf = 1, 5,10, and 30) on the average heat transfer coefficient (h), pressure drop (ΔP), thermal-hydraulic performance (η), and wall temperature (Tw) are investigated. A remarkable decrease in wall temperature is observed, especially on the heat sources. It is founded that heat transfer and pressure drop increase for all cases as volume fraction increases. Results also reveal that in a fixed volume fraction, the average heat transfer coefficient ratio, referring to the values calculated for base fluid, increases as heat flux and porosity increase or thermal conductivity ratio decreases. No change in the average heat transfer coefficient ratio is observed with Darcy number variation. Furthermore, it is found that the pressure ratio, referring to the values calculated for base fluid, is approximately independent of all considered parameters, except volume fraction.
Payam Rahim
Mashaei
CAE Lab and CFD Center, School of Mechanical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran
Seyed Mostafa
Hosseinalipour
CAE Lab and CFD Center, School of Mechanical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran
549-561