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porous-materials
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Experimental Investigation of Heat Transfer Coefficient of Porous Materials in Various Air Pressures
, M.Sc. Thesis Sharif University of Technology ; Nouri Broujerdi, Ali (Supervisor)
Abstract
Heat transfer in porous media has recently become an important subject in mechanical engineering. Heat transfer in porous media is central in many applications involving industrial devices (chemical engineering, heat exchangers, nuclear reactor, etc...) as well as complex geological formations (in situ combustion and pyrolysis, geothermal sites, etc...). On track to achieve heat transfer methods and heat transfer coefficients of porous materials, this investigation describes the design process of fabrication and experimental analysis of calculation the conduction heat transfer coefficient of the uniform porous materials. We report on thermal conductivity measurements performed on uniform...
Numerical Study of the Effect of Permeability in Single-Phase Flow in Porous Media
, M.Sc. Thesis Sharif University of Technology ; Sadrhosseini, Hani (Supervisor) ; Ashjari, Mohammad Ali (Supervisor)
Abstract
Present study is to simulate laminar flow in a channel exposed to heat flux from the walls and filled with porous media by software ANSYS CFX in finite volume method. The analysis is based on the Naviere-Stokes equations in the flow field which are modified to Brinkman-Forchheimer equations to be applicable for porous media. Effect of Reynolds number and permeability on seepage velocity, temperature distribution, heat transfer and pressure drop are investigated.Simulations are performed for two cases: fully developed flow at the entrance of the porous media and developing flow, which are corresponding to the Reynolds numbers of Re=77.6 and Re=1553 respectively (U= 0.01 m/s and U= 0.2 m/s)....
Analytical Solution to Partial Differential Equations Derived from Thermo-Hydro-Mechanical Analysis
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
In this research an analytical and semi analytical solution to the differential eqautions derived from coupled analysis of heat transfer, moisture transfer and solid deformation in porous materials is presented. In first section, differential equations derived from Hydro-mechanical analysis of an unsaturated soil layer with limited thickness was considered and it is assumed that pore air pressure is equal to atmospheric pressure. To solve the system of equations laplace transform is used.In second section, the effect of daily changes in temperature on transient heat and moisture transfer in semi infinite layer is studied in three dimension. Energy conservation equation and pore liquid mass...
Hierarchical Multi-scale Analysis using Nonlinear Finite Element & its Application to Porous Media
, M.Sc. Thesis Sharif University of Technology ; Naghdabadi, Reza (Supervisor) ; Sohrabpour, Saeed (Supervisor)
Abstract
Porous materials, with diverse applications in engineering branches, are categorized as multi-scale. A multi-scale material is one which shows different structure and/or behavior in two or more different length scales. There are physical models which can calculate the macroscopic properties of such materials by using both the properties and volume fractions of the ingredients. However, the number of such theories which can handle problems in the fields of elasticity and hydrodynamics is much less; the fields in which the tensor orders of the properties are more than one. Fortunately, in recent years, a new method named "Computational Multi-scale Homogenization" has been offered to homogenize...
Phase behavior and interfacial tension evaluation of a newly designed surfactant on heavy oil displacement efficiency; effects of salinity, wettability, and capillary pressure
, Article Fluid Phase Equilibria ; Vol. 396, issue , June , 2015 , p. 20-27 ; ISSN: 03783812 ; Masihi, M ; Ayatollahi, S ; Sharif University of Technology
Abstract
This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized....
Random walk-percolation-based modeling of two-phase flow in porous media: Breakthrough time and net to gross ratio estimation
, Article Physica A: Statistical Mechanics and its Applications ; Vol. 406, issue , July , 2014 , p. 214-221 ; ISSN: 03784371 ; Masihi, M ; Ghaedi, M ; Sharif University of Technology
Abstract
Fluid flow modeling in porous media has many applications in waste treatment, hydrology and petroleum engineering. In any geological model, flow behavior is controlled by multiple properties. These properties must be known in advance of common flow simulations. When uncertainties are present, deterministic modeling often produces poor results. Percolation and Random Walk (RW) methods have recently been used in flow modeling. Their stochastic basis is useful in dealing with uncertainty problems. They are also useful in finding the relationship between porous media descriptions and flow behavior. This paper employs a simple methodology based on random walk and percolation techniques. The...
An approach for the estimation of dynamic imbibition capillary pressure curves
, Article Energy Sources, Part A: Recovery, Utilization and Environmental Effects ; Vol. 36, issue. 9 , Dec , 2010 , p. 1007-1017 ; ISSN: 15567036 ; Shadizadeh, S.R ; Masihi, M ; Kharrat, R ; Ghazanfari, M. H ; Sharif University of Technology
Abstract
Capillary pressure is one of the most important parameters for reservoir engineering studies. Although different experimental methods are devised to measure capillary pressure, these methods do not represent the physics of fluid flow, which happens at reservoir conditions. Thus, it is attempted to extract the capillary pressure from spontaneous imbibition data, the common mechanism of oil production in water wet porous media. In this work, a new approach is developed to obtain the imbibition capillary pressure curve by using spontaneous water imbibition data in oil-water-rock systems. Comparison of calculated imbibition capillary pressure curves by the new approach with experimental values...
Lattice Boltzmann method on quadtree grids for simulating fluid flow through porous media: A new automatic algorithm
, Article Physica A: Statistical Mechanics and its Applications ; Vol. 392, issue. 20 , May , 2013 , p. 4772-4786 ; ISSN: 03784371 ; Jamshidi, S ; Masihi, M ; Sharif University of Technology
Abstract
During the past two decades, the lattice Boltzmann (LB) method has been introduced as a class of computational fluid dynamic methods for fluid flow simulations. In this method, instead of solving the Navier Stocks equation, the Boltzmann equation is solved to simulate the flow of a fluid. This method was originally developed based on uniform grids. However, in order to model complex geometries such as porous media, it can be very slow in comparison with other techniques such as finite differences and finite elements. To eliminate this limitation, a number of studies have aimed to formulate the lattice Boltzmann on the unstructured grids. This paper deals with simulating fluid flow through a...
Scaling equations for oil/gas recovery from fractured porous media by counter-current spontaneous imbibition: From development to application
, Article Energy and Fuels ; Vol. 27, issue. 8 , July , 2013 , p. 4662-4676 ; ISSN: 08870624 ; Masihi, M ; Sharif University of Technology
Abstract
Spontaneous imbibition, the capillary-driven process of displacing the nonwetting phase by the wetting phase in porous media, is of great importance in oil/gas recovery from matrix blocks of fractured reservoirs. The question of how properly scaling up the recovery by counter-current spontaneous imbibition has been the subject of extensive research over decades, and numerous scaling equations have been proposed. As a convention, the scaling equations are usually defined analytically by relating the early time squared recovery to squared pore volume. We show this convention does not apply to common scaling practices and, if used, causes nontrivial scatter in the scaling plots. We explain that...
Non-equilibrium model of gravity drainage in a single block
, Article Journal of Porous Media ; Vol. 16, issue. 6 , 2013 , p. 559-571 ; ISSN: 1091028X ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
Abstract
This work concerns with developing a non-equilibrium model of gravity drainage in a single block. The proposed model which considers both non-equilibrium effects of capillary pressure and relative permeabilities is used for prediction of oil recovery by gravity drainage from a single block. Close agreement observed between the model results and experimental data disclosed that the non-equilibrium assumption is completely reliable for modeling of gravity drainage. The results revealed that when the characteristic time of the saturation variation is comparable with the time required to establish capillary equilibrium, the non-equilibrium effects in gravity drainage must be considered. The...
Permeability reduction of membranes during particulate suspension flow; analytical micro model of size exclusion mechanism
, Article Journal of Membrane Science ; Vol. 435, issue , May , 2013 , p. 155-164 ; ISSN: 3767388 ; Ayatollahi, S ; Habibi, A ; Masihi, M ; Sharif University of Technology
Abstract
Particle capture at porous media in cross-flow microfiltration is studied to investigate permeability reduction as a function of membrane pore size and particle size distribution. A new model in pore scale and its pertinent mathematical expressions, which consider pore and particle size distribution, are provided. Permeability reduction of the membrane because of size exclusion during particulate suspension flow was predicted using the developed model. It is assumed that the size exclusion is the dominant mechanism of particle retention causes pore blocking and permeability reduction in the porous media.The exact analytical solution of the stochastic model for size exclusion is used to...
Non-equilibrium model of three-phase flow in porous media in presence of capillary and gravity forces
, Article Journal of Hydrology ; Vol. 478, issue , November , 2013 , p. 119-131 ; ISSN: 00221694 ; Ghazanfari, M. H ; Masihi, M ; Sharif University of Technology
Abstract
In this work a generalized non-equilibrium model of three-phase flow in porous media including gravity as well as capillary terms is developed and used for analysis of Riemann's problem in several three-phase systems. The proposed model uses the extension of Barenblatt model to three-phase systems considering dynamic effects in both relative permeability and capillary pressure functions. We compare the solution of the Riemann's problem when non-equilibrium effects are included. While equilibrium formulation develops unstable oscillatory solution in the elliptic region, non-equilibrium solution is smooth and stable. The results of this work might be helpful to better understanding the...
Monitoring wettability alteration by silica nanoparticles during water flooding to heavy oils in five-spot systems: A pore-level investigation
, Article Experimental Thermal and Fluid Science ; Vol. 40, issue , July , 2012 , p. 168-176 ; ISSN: 08941777 ; Mohammadi, S ; Ghazanfari, M. H ; Kharrat, R ; Masihi, M ; Sharif University of Technology
Abstract
It is well known that the displacement efficiency of EOR processes is mainly affected by wettability of porous medium; however, the role of nanoparticles on wettability alteration of pores surfaces remains a topic of debate in the literature. Furthermore, a little is known about how the dispersed silica nanoparticles affect the microscopic/macroscopic recovery efficiency of heavy oils during common immiscible EOR processes such as water flooding. In this study, a series of injection experiments was performed on five-spot glass micromodel which is initially saturated with the heavy oil. Distilled water and dispersed silica nanoparticles in water (DSNW) at different values of weight percent...
Study on non-equilibrium effects during spontaneous imbibition
, Article Energy and Fuels ; Vol. 25, issue. 7 , June , 2011 , p. 3053-3059 ; ISSN: 08870624 ; Masihi, M ; Standnes, D. C ; Sharif University of Technology
Abstract
Spontaneous imbibition of water into the matrix blocks because of capillary forces is an important recovery mechanism for oil recovery from naturally fractured reservoirs. In modeling this process, it has been assumed classically that local equilibrium is reached and, therefore, capillary pressure and relative permeability functions are only a function of water saturation, resulting in the appearance of the self-similarity condition. In some works published in the last 2 decades, it has, however, been claimed that local equilibrium is not reached in porous media, and therefore, opposite the classical local-equilibrium/self-similar approach, non-equilibrium effects should be taken into...
Scaling, multifractality, and long-range correlations in well log data of large-scale porous media
, Article Physica A: Statistical Mechanics and its Applications ; Vol. 390, issue. 11 , June , 2011 , p. 2096-2111 ; ISSN: 03784371 ; Jafari, G. R ; Sahimi, M ; Masihi, M ; Sharif University of Technology
Abstract
Three distinct methods, namely, the spectral density, the multifractal random walk approach, and the multifractal detrended fluctuation analysis are utilized to study the properties of four distinct types of well logs from three oil and gas fields, namely, the natural gamma ray emission, neutron porosity, bulk density, and the sonic transient time logs. Such well logs have never been analyzed by the methods that we utilize in the present study. The results indicate that the well logs exhibit multifractal characteristics, and the estimated Hurst exponents by the three methods are close to each other. Using multifractal detrended fluctuation analysis and the shuffled and surrogated data, we...
Iterative coupled experimental-numerical evaluation of dispersivity in fractured porous media using micromodel system
, Article 73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 ; Vol. 4, issue , 2011 , p. 2461-2466 ; Ghazanfari, M. H ; Masihi, M ; Kharrat, R ; Kianinejad, A ; Sharif University of Technology
Abstract
In this study a new iterative algorithm is developed to evaluate dispersivity in fracture and matrix, distinctly. The novelty of proposed algorithm is using mathematical model of solute transport in fractured porous media coupled with experimental data iteratively. A fractured glass micromodel has been designed to visualize the interaction between fracture and matrix during displacement of n-Decane by n-Octane at constant rate. The similarity between numerical and experimental model has been enhanced by reducing the assumptions which were applied in previous related studies. The iteration is performed on velocity components of solute transport and longitudinal as well as transversal...
An automated simple algorithm for realistic pore network extraction from micro-tomography images
, Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 ; Jamshidi, S ; Salehi, S
Abstract
Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images...
A new model based on multilayer kinetic adsorption mechanism for asphaltenes adsorption in porous media during dynamic condition
, Article Fluid Phase Equilibria ; Vol. 375, issue , 2014 , Pages 236-245 ; ISSN: 03783812 ; Ghotbi, C ; Taghikhani, V ; Shahrabadi, A ; Sharif University of Technology
Abstract
In this work, a new model based on multilayer kinetic adsorption mechanism has been proposed to account asphaltene adsorption in porous media under dynamic condition and the model was verified using experimental data obtained in this work and also with those reported in the literature. In the proposed model two steps are considered for asphaltene adsorption. The first step is taken as adsorption of asphaltenes on the surface of the porous media and the second step is taken as adsorption of asphaltenes on the asphaltenes already adsorbed on the porous media. The Crank-Nicholson method, central difference in space and trapezoidal rule in time, giving second order convergence in time was...
Porosity variation below a fluid-porous interface
, Article Chemical Engineering Science ; Vol. 107 , April , 2014 , pp. 311-316 ; ISSN: 00092509 ; Morad, M. R ; Matyka, M ; Liu, B ; Malekmohammadi, R ; Weise, J ; Kuypers, M. M. M ; Sharif University of Technology
Abstract
The correct quantification of porosity is essential in all studies pertaining to porous media. A host of existing works employs a constant, bulk value for porosity, even when the porous sample is attached to a free fluid. Since the volume fraction of the solid matrix near the interface region differs from that in the core, the porosity undergoes a spatial variation. Here we present a novel relation for the porosity as a function of depth below the interface, using the concept of surface roughness applied on the classical definition of open porosity. This relation has been verified by computational modeling as well as non-invasive laser experiments. It has been shown that this depth-dependent...
Investigation of membrane preparation condition effect on the PSD and porosity of the membranes using a novel image processing technique
, Article Journal of Applied Polymer Science ; Volume 131, Issue 4 , 15 February , 2014 ; ISSN: 00218995 ; Samimi, A ; Mousavi, S. A ; Bozarjamhari, R. B ; Sharif University of Technology
Abstract
A totally computerized image processing program package is developed to analyze the SEM images of membrane surface and cross-section. Pore size distribution and porosity of the fabricated membranes are determined using the proposed image processing procedure. Furthermore, effect of coagulation bath temperature on the morphology and mechanical properties (such as tensile strength, strain break, tensile energy absorbent, and tensile stiffness) of Polysulfone (PSf) membranes are investigated. The results reveal that the mechanical properties are higher when N-methyl-2-pyrrolidone (NMP) is used as solvent. Also, an increase in the coagulation bath temperature caused a monotonous increase in the...