Sharif Digital Repository

An experimental study was conducted to investigate the reduction of relative permeability caused by salt precipitation. Series of isothermal sand pack flood experiments were conducted on a sand pack composed of several minerals and relative permeability of the involved phases were determined. This compose was taken south of Iranian reservoir properties. A stainless steel sand-pack of 2.5cm internal diameter and 19.2 cm long was designed and built for experimental procedure. There are is different methods to determine relative permeability of porous media, According to available facilities in the lab and objective of this study unsteady state have been chosen to determine relative... 

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).... 

This thesis is concerned with the synthesis and characterization of high porous Ti based on thin films and the effect of polymer agents on their photocatalytic properties. Ti films can demonstrate different properties like self -cleaning and treatment of broad range of aqueous pollutants when it is exposed to light of wavelength less than 400 nm. This is due to photocatalytic reaction occurring on film surface which results in film superhydrophilicity and the active oxygen species production. This active sites and radicals will cause oxidize organic pollutants and microbe adherent to the material surface.
In this study Ti thin films have been prepared by the sol-gel method from... 

Determining the porosity, water saturation and permeability values in the reservoir rock, are major steps in the petroleum engineering and formation evaluation. Today in the oil industry, these parameters are obtained using Helium gas injection technique on core (Plug) samples. However, the coring operation is difficult and costly. In addition, there isn't the possibility of coring in some of wells, such as horizontal wells. In fact, the present research is the modelling of artificial neural networks to estimate permeability in one of the Iranian oil field reservoirs by using oil well logging data. In this research, MLP neural network has been used and for network training, the evolutionary... 

The main focus of this project is the fabrication of surface engineering scaffolds based on polyurethane and titanium dioxide. The research's aim is the creation of the synergistic properties of TiO2 and PU as a new strategy for engineering artificial autologous blood vessels. In the first section, PU-TiO2 nanocomposites were synthesized by co-insitu synthesis of nanoparticles and polymer. The nanocomposite films were prepared by solvent casting and thermally induced phase separation methods. Mechanical and biological properties of films were compared with pure PU film. In solvent casting method, the outcomes revealed that the rate of endothelialization of the nanocomposite scaffold after 7... 

Today the hydrocarbon materials rank in the list of requirements of the modern societies. The increased growth of the human population, their industrial economic activities, transportation etc. requires sufficient supplies of our resources. Therefore, the hydrocarbon resources need to be discovered and evaluated accurately. There are different methods that are used to measure underground hydrocarbon resources such as well logging. In this method, a measuring device is lowered into a well to evaluate several parameter of the surrounding soil. Nuclear well logging is a sub category of well logging that uses nuclear rays to do this measurement. This method has different types of sondes which... 

In this study, a numerical investigation of propagation of sound through a fluid-saturated porous column has been proposed so that we can analyze the effects of porous media parameters on decreasing sound amplitude. The mathematical model applied for our simulation is based on Biot equations solved by an explicit finite difference method. Since Biot model is exclusively applicable to porous solids saturated with single fluid phase, in order to simulate a porous solid saturated with two immiscible fluids, we exploited the general Eulerian model instead of Biot model. Efficiency of porous sound absorbers is directly influenced by four major parameters which are porosity, rigidity and thickness... 

Transonic speed is one of the most important flight regimes. There are two main significances related to it. First, all of the supersonic air vehicles should pass through this regime to reach to their final speed. Second, nowadays most of the commercial airplanes fly in nearsonic speeds. According to nonlinear nature of the flow through the speeds, the related researchers haven’t been successful in development of a comprehensive theory as well as subsonic and supersonic ones. So, transonic flow is one of the most critical regimes in wind tunnel testing. In order to eliminate the shock-boundary layer interaction and wave cancellation, perforated walls and side suction are used in test section... 

Many natural and engineering materials have a heterogeneous structure at a certain level of observation. These materials are often referred to as composite materials or multi-phase materials or heterogeneous materials. It has been widely recognized that many macroscopic phenomena originate from the mechanics of the microstructural constituents, such as inclusions, cracks, voids, etc. The size, shape, spatial distribution, volume fraction and properties of the microstructural constituents have a significant impact on the behavior of the material observed at the macroscale. The nature of hydrocarbon reservoirs as multi-phase porous media are known for heterogeneous media at various multiple... 

In the present research, a new material model utilizing anisotropic conduction and track-scale heat input model is used to predict the melt pool geometry, material state and thermal history during the selective laser melting process of SS316L in a large range of laser parameters. The model takes into account the phase transition of the material during the process. Furthermore, the phase transition problem in the track-scale model has been analyzed and a solution has been presented. The simulated melt pools in beam-scale and track-scale simulations are compared with experimental measurements in different laser parameters. It is found that the proposed material model is able to maintain... 

Access to potable water with standard quality is an inevitable component of human’s lives. Freeze desalination, by consuming lower energy compared to other techniques, relies on the exertion of a cold source which is then accompanied by simultaneous rejection of impurities from water. Regarding this, a numerical study on freeze desalination a hollow cylinder is carried out to determine the effects of the design variables such as heat flux, hydraulic diameter, initial salt concentration, and freezing time on the ice mass, ice salinity, ice generation speed, and Nusselt number on a cold surface of the inner tube. Results show that increasing the value of heat flux from -250 W/m^2 to -1000... 

Shape Memory alloys are a kind of intelligent materials developed in recent years due to their comprehensive use in medical, robotics, and other advanced sciences. Two main characteristics of them are shape memory effect and superelasticity put these materials in the category of advanced materials. Recently, the new branch of them attracted many studies which is the porous shape memory alloys. The importance of this class of material is related to their properties such as bio-compatibility, superelasticity and shape memory effect. Since shape memory alloys are usually expensive, a new field is developed known as functionally graded porosity distribution. This method is performed by... 

Physics of present work is 2D and two phase immiscible flow under gravity and capillary effect through fractured porous media. Rock properties such as porosity and permeability are homogenous. Discrete fracture model and dual porosity-dual permeability model are used to simulate this problem. Governing equations for such reservoirs are conservation of mass and conservation of momentum. Evaluations are performed in two seperate parts. in the first part, geometry, boundary conditions and initial conditions which important models of transfer functions were calculated are provided by using discrete fracture model and results are compared with results of corresponding reference. Following... 

In this thesis, two types of two-phase flow are studied in one dimension. The first type is oil-gas two-phase flow which is miscible and compressible. The second one is oil-water two-phase flow which is immiscible and incompressible. Oil wet and water wet conditions are studied in the second type of flow. Two approaches, i.e. double porosity and double porosity-double permeability, are used to study naturally fractured reservoirs. In these approaches, the matrix and fracture are modeled as two separate media that exchange mass via a transfer function. Black oil model is applied to simulate the fluid system. The governing equations consist of the conservation of mass equations for each... 

In this study, simulation of two-phase water-oil compressible flow in naturally fractured reservoirs is studied. The studied reservoir has a 1D and horizontal ge-ometry that its properties such as porosity and permeability are homogeneous.Dual Porosity and Dual Porosity-Dual Permeability models are employed for simulation of reservoir. Reservoir descriptive equations are conservation of mass and momentum. Conservation of momentum equation is simplified by Darcy law and two-phase fluid flow is simulated with Black-oil model. Discretization of equations is done by finite volume method. In order to solve the equations of two-phase compressible fluid flow, the so-called IMPES (Implicit Pressure... 

In this work, simulation of 3D three-phase naturally fractured reservoirs is studied. Both Dual Porosity and Dual Porosity-Dual Permeability models which are commonly used in commercial softwares such as ECLIPSE and CMG, are utilized. The governing equations include the mass (in Black-oil model) and linear momentum (in Darcy law form) equations, which are converted into pressure equations and a set of transport equations for the saturations and mole fractions of phases. These equations are solved once for the matrix domain and subsequently for the fracture domain. These two set of equations are coupled through transfer functions. The accuracy of computations significantly depends on how... 

Fractured reservoirs show a different behavior from common reservoirs because of the existence of a broad network of fractures. This phenomenon makes it necessary to apply special methods for fractured reservoirs in the procedure of reservoir simulation. Since twenty percent of petroleum content in the world is buried in fractured reservoirs, investigating these reservoirs is of great importance.
The first step in simulation of these kinds of reservoirs is to come up with a geometrical model which can be used to take the fracture network influence into account. In the course for reaching such an objective, various models have been developed which are based on specific assumptions and in... 

In This work, the performance of a finite volume (FV) numerical method is examined for simulating naturally fractured hydrocarbon reservoir. The dual-porosity approach applied for fracture modeling, and the flow transfer formulated based on a generalized black oil model which is based on matrix formulation, leading to a system of equations prone to degeneracy. This FV high-resolution central scheme numerical method is not sensitive to the choice of CFL number like some of other central schemes and can conveniently handle degenerate equations appearing in the reservoir simulation governing equation. In this effort, one dimension multi phase flow simulated in naturally fractured reservoir and... 

In this research to solve the problems related to titanium implants, a new type of dental implant was designed and fabricated by using shape memory and pseudoelasticity properties of porous nitinol alloys. The elastic modulus of this implant (equal to 0.8 GPa) is similar to the cancellous jaw bone (equal to 0.3-1 GPa) which causes a normal distribution of stress and prevents bone resorption. The current approach is use of radius variation to facilitate implant surgery. These radial changes are created by using one way shape memory effect. First, the implant enters the jaw cavity by decreasing the radius and after reaching the body temperature and restoring the initial shape, the radius of... 

In this study, the influence of eutectic modification, grain refining and cooling rate on amount of shrinkage porosity in aluminium A356 alloy were investigated. Modification process for changing the morphology of eutectic silicon from needle like to fibrous like, use in aluminium – silicon alloys. This process often leads to increasing porosity in melt and affect harmfully on mechanical properties. For studying shrinkage porosity, the melt degassed completely to minimizing amount of gas in the melt. For modification, strontium in Al-10Sr master alloy and sodium in NaF salt used and for grain refining Al-10Ti and Al-5Ti-1B master alloys used. To study the effect of cooling rate, three mold...