Sharif Digital Repository

Today due to increasing demand of using energy and petroleum products, finding optimum ways to produce more oil and gas in a way which petroleum reservoirs faces less pressure drop is very necessary. Therefore, petroleum engineers face multiphase flow proportionally more than other issues. So, they have to comprehend this issue in a complete manner in order to discover the best practical ways for maximum utilization. Researchers in different ways tried to model multiphase flow, but many of provided models are so complicated and sometimes have low accuracy. In this project we tried to present a model that in simplicity has high accuracy and works in a way that apperceiving it, is very... 

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... 

A new experimental setup was fabricated; equipped with an adjustable chamber’s length, with air tangentially flowing through the wall of vortex engine. In a vortex combustion chamber, the tangential inlet fuel or oxidizer creates both inner and outer vortices which are rotating in the same angular direction. Indeed, inner vortex moves from head to the end of engine in the axial direction; however, outer vortex moves in the opposite direction. This setup was fabricated to see the effect of fuel nozzle characteristics on the wall temperature of the chamber. In a vortex engine, vortices affect spray droplets and force them to have a spiral path. Moreover, relative velocity of droplets and flow... 

Air entering in to the water supply systems and occurrence of two-phase flow makes several problems in design and operation of these systems by damaging the structures and making indefinite and complicated conditions. Existence of some singularities like contractions in pipelines makes the conditions more indefinite. So an experimental study is performed in order to investigate the two-phase flow hydraulic properties in a rectangular channel in presence of an area contraction. The contraction ratio is σ=0.44, whereby the test section is included two different rectangular channels from 60 × 100 mm to 40 × 67 mm. Four series of experiments are performed using four types of transitions with... 

Entrance of air to close water conduits occurs in many ways. This phenomenon makes displeasing effects on water transport structures. Two-phase flows in closed conduits are studied experimentally, numerically and theoretically. Even after decades, due to the complexity of the subject, these studies still require development and reformation. Numerical and theoretical two-phase models are often limited to a special regime of flow."Volume Of Fluid"(VOF) is a model for non-mixing two-phase flows. "Fluent" software uses this model in this field of flows. Volume of fluid is used successfully in some problems like dam break or rising bubbles. Main disadvantage of this model is distribution of the... 

In this project، the immiscible two phase flow of oil-water in the absence of gravity in the two dimensional domain is investigated. The uncertainty quantification of pressure and saturation of fluid in the reservoir are calculated by the methods of statistical moment equation (presented by Tchelepi) and probabilistic collocation method combined with Karhunen Loeve expansion (presented by Heng Lee). Then the results are compared with Monte Carlo simulation. Matlab Reservoir Simulation Toolbox is used for flow simulation. The main problem based on Tchelepi’s work[56[ ، is a horizontal two dimensional problem that there is two injection and production wells at the two end point grids (a... 

Porous media have many applications including heat exchangers, single-phase flow and multi-phase flow packed beds and reactors with different flow patterns, aquifers, and oil and gas reservoirs. To evaluate the behavior of porous media there is need to understand transport phenomena. In this work, we focused on metal foam porous media as an advanced porous media. The effective thermal conductivity of solid matrix, heat transfer in the presence of fluid flow, and pressure drop were investigated using CFD techniques in micro-scale supposing that the solid foam structure consisted of connected kelvin cells. The comparison of simulation results with experimental data reported in literature shows... 

There are different flow regimes in multiphase flows through the pipes, which affect the flow structure and other important fluid parameters. Each of these flow regimes are considered to be suitable or not in different industries. So it is needed to provide the situation of suitable flow regimes formation and to prevent the others from development. One of the main parameters affecting the flow regimes development is considered to be the passing flow’s channel section are or the pipe diameter. This project is defined to investigate the effect of changing pipe diameter on the formation of flow regimes in an air-water upward two-phase flow, experimentally. Therefore, a vertical pipe of 6 meters... 

Sonoluminescence is a unique phenomenon in physics, which is known as the process of converting sound into light. By applying sound to a volume of liquid, with a specific geometrical shape (such as sphere) and forming standing waves around an existing bubble, the bubble first expands to a maximum radius and then gets extremely small leading to its supersonic collapse. During the collapse, the resulting shock wave approches the center of the bubble, causing extreme increase in the pressure and temperature at the center of the bubble. This causes flashing of light during small time scales (pico-seconds). This phenomenon is used in many fields, such as treatment of cancer. Also, the energy... 

The aim of this research is to consider the effect of geometric changes on pumping performance of two phase gas-fluid flow in a vertical pipe. The idea is to inject a light gas to the bottom of a tube full of fluid so we will obtain an upward flow due to density differences. Potential benefits of this device are numerous such as dredging of river estuaries and harbors, sludge extraction in sewage treatment plant, water treatment and many others. There are almost four distinct flow patterns which occurs in the rise pipe, bubbly flow, slug flow, churn flow and annular flow that each of them require special conditions. heat transfer between two phases, phase changes, mass and volume rate... 

Airlift pumps are widely used in numerous industries for different applications such as transmission of viscous fluids (heavy hydrocarbons of oil), pumping of corrosive liquids and so on. In general, parameters which affect the efficiency of an airlift pump can be classified into two major groups. The first group is the designing parameters such as the diameter of the upriser pipe or the submergence ratio. The second group is the operation parameters such as diameter of the bubble, inlet pressure of the gas and so on. One of the designing parameters which can have an effective influence on the performance of an airlift pump is the non-constant diameter of the upriser pipe, which can be... 

Liquid-liquid extraction is one of the most important processes of chemical industries. So determination of operatiol condition in extraction columns is important. In this study, in various regimes of jet flow mass transfer coefficient during jet formation was measured and predicted experimentally. Results shown turbulent flow regime has higher mass transfer coefficient and axisymmetric jetting flow has lower mass transfer coefficient. Whereas studies related to mass transfer in liquid-liquid system are afew, numericall study was performed in this project. In this study system was simulated in unsteady state.Front-tracking method was used for simulating two phase flow and finite-volume... 

Cyclones are efficient devices in order to separate suspended particles and droplets from gas media and this effieciency is mainely because of spiral flow nature affecting the particles and droplets and taking them towards the wall. Therefore, particles and droplets move downwards toward down outlet by the gravity force. In consequence, they are being separated of the gas flow and relatively pure gas flow exits the cyclone. In this project, GAMBIT software has been used to produce three dimensional meshes including coarse, medium and fine sizes for two different geometries of cyclone. After simulation, little differences between the obtained results were revealed, showing that modeling is... 

Wide and varied aspects of droplet motion due to its increasing application in various fields has attracted much attention. Analysis of mass transfer from the liquid drop into the other fluid, such as complex and intriguing problems in fluid mechanics, which is very important. Many experimental and numerical studies have been carried out in this case that the evelopment of laboratory equipment and software, are rapidly growing.
In this study, given the importance of this issue, experimental study on mass transfer in fluid systems solution droplet liquid - liquid extraction, have been considered. Different methods have been discussed to date. In the present study, using image processing... 

For observing the beauties of the sea, underwater vehicles are of the most appropriate equipment. In an optimized design of a vehicle, one should consider all applied forces and moments at all positions of the vehicle. Moving near the free surface is one of the positions of underwater vehicles. So, study on flow around a body moving near free surface is the subject of extensive research in marine hydrodynamic.
The aim of the current investigation is a scrutiny of the influence of free surface effect on the flow around underwater vehicles. For this purpose, finite volume method is used to simulate flow around an axisymmetric body near free surface. In this simulation, volume of fluid... 

A numerical simulation of fluid flow in gas condensate wellbore, which annular flow is dominant, is performed. A three fluid model is used for annular two phase flow. The model is based on conservation equations of mass, momentum and energy for gas phase, dispersed phase (droplets) and the film. The friction between phases and with wellbore wall and also mass transfer between phases, which conservation equations rely on them, are considered. Computer programming of obtained system of equations is performed in Matlab. The Reimann method is used for solving our system of hyperbolic equations and simulation is performed for both steady and unsteady state. Transforming system of nonlinear... 

In recent years, oil and gas reservoirs are one of the most valuable natural resources and are the main economical basis of the country. Therefore any research which can help to optimize the efficiency and enhance their recovery is of great importance. In the past 30 years, reservoir simulation has evolved from a research field to one of the most flexible tools in reservoir engineering. Simulation is usually more quick, cost effective and reliable than other methods in predicting reservoir performance. Because of complexity of the great amount of computations, research in oil reservoirs field is usually done by mathematical/computer programs, named as simulators. For this reason, various... 

If the reservoir temperature lies between the critical temperature and cricondentherm of the reservoir fluid, the reservoir is classified as a retrograde gas-condensate reservoir. When the pressure is decreased on these mixtures, instead of expanding or vaporizing as might be expected, they vaporize instead of condensing. If the reservoir pressure is above the upper dew-point pressure, the hydrocarbon system exists as a single phase in the reservoir (region 3). As the reservoir pressure declines isothermally during production from the initial pressure to the upper dew-point pressure, the attraction between the molecules of the light and heavy components move further apart. As this occurs,... 

In this study, the green element method is used to model petroleum problems such as oil production due to expansion mechanism, one and two dimensional spontaneous imbibition and water flooding. Despite of boundary element method that its applications in reservoir engineering are limited to simulation of single phase fluid flow in homogenous media, green element method can solve multi-phase flow in heterogamous media. In this thesis, by this method the governing partial differential equation for these processes are modeled and then solved. In one dimensional medium, green element method can successfully simulate the oil production from heterogamous reservoir due to expansion mechanism. The... 

In this study, single-phase and two-phase, incompressible flow in a non-deformable porous media was modeled and also simulated. The Reynolds numbers have been considered high enough to justify the use of the model including inertial terms. Afterwards, the mass conservative equations were discretized. Then, the numerical model has been developed for heterogeneous porous media. The heterogeneous porous media was comprised by several specified homogeneous regions, each having isotropic transport properties or permeability distribution with applying stochastic methods. The developed numerical model was used for predicting of saturation profile in water flooding process in one, two and...