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two-phase-flow
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Drag Reduction Using Geometrically Structured Surfaces for Non-newtonian Multi-phase Fluids
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
With the advancement of the industry, microscale devices use due to its unique characteristics. On the other hand, it is essential to find ways to reduce drag inside microchannels because of The importance of energy. One of the methods is to optimize the contact surface using structured geometric surfaces. These hydrophobic surfaces reduce drag by trapping the air in roughness and creating a two-phase flow. The purpose of this project is to reduce the drag within the microchannel using structured geometric surfaces for non-Newtonian and multiphase flows. In most previous studies, with simplification, Newtonian and two-phase flows have been investigated. While most industrial fluids show...
Application of Multiscale methods for Modeling Spatial Heterogeneity in Complex Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Farhadpour, Farhad A (Supervisor) ; Sayf Kordi, Ali Akbar (Supervisor)
Abstract
Underground reservoirs are highly complicated due to the presence of spatial heterogeneities at length scales that span from micrometer in pore structure of the rocks to kilometer in the reservoir models. While large-scale flow units need to be characterized using seismic and well data, detailed displacements of fluids in pore space need to be modeled using thin section analysis and pore network modeling. It is therefore necessary to adopt a multi-scale approach to reservoir description to make best use of all the available data that vary over several orders of magnitude, from micro-scale in pore structure to field scale in reservoir flow models. In this thesis, an integrated framework for...
Prediction of Hydraulic Fracturing Technology in Naturally Fractured Rocks, by Considering Immiscible Two-phase Flow
, Ph.D. Dissertation Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ayatollahi, Shahab (Supervisor) ; Shad, Saeed (Supervisor) ; Ranjbaran, Abdolrasul ($item.subfieldsMap.e)
Abstract
To have a deeper understanding of Hydraulic fracturing operation, in this study four important parts in this field was developed and simulated. In the first part, continuity and momentum equations for a single phase flow in a propagating penny-shaped fracture inside an impermeable matrix was revisited based on a fixed coordinate system. Its correctness was validated against experimental data and its features were compared with the well-known lubrication theory in analytical form. The new derived continuity equation caused the fracture tip to have a positive and finite pressure while, the conventional model predicted negative infinity for that. In the second part, Finite Volume method was...
Stability of Stratified Two-Phase Flow by Chebyshev Collocation Method
, M.Sc. Thesis Sharif University of Technology ; Nouri, Ali (Supervisor)
Abstract
In this thesis fluid flow stability will be studied using Chebychev collocation spectral method. In general instability occurs between layers of a single fluid or at the interface of two different fluids. In case of an unstable flow small imposed perturbations on the flow will grow with time and their amplitudes will grow larger. Instability in most cases is an unfavorable phenomenon and therefore should be avoided.Two-phase flow processes in horizontal or vertical pipes under various conditions like natural or forced convection are of considerable importance in industrial applications. Two-phase flow can be found in many devices and industries like boilers, nuclear reactors, cooling and...
Comparison of dual Porosity-Dual Permeability Models in 2D Two-Phase Immiscible Flows under Gravitational Effect
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Advisor)
Abstract
Physics of the present work is 2D two-phase immiscible flow under gravitational effect through fractured porous media and the most practical formulas for transfer function in dual porosity-dual permeability models have been implemented for numerical simulation of naturally fractured reservoir. The models are: Kazemi et al. (1976), Gilman (1986), Sonier et al. (1988), Quandalle and Sabathier (1989), Lim and Aziz (1995), and Rangel-German and Kovscek (2006), which are compared using a benchmark problem and the effects of gravity, capillary, number of matrix block subdomains and dual continuum media model are studied. The benchmark problem was adopted from Gilman (1986) and involves water...
Comparison of Immiscible Displacement Performance for Micro Model and Core Scales Tests and Investigation of Scale up Methods
, M.Sc. Thesis Sharif University of Technology ; Masihi, Mohsen (Supervisor)
Abstract
Because of a lot of water, gas and polymer injection processes in industry, two phase flow simulation is very useful. So performing experimental work to find out fluid flow behavior in a small scale of reservoir has special importance. The results in various scales will differ because of heterogeneity and different dominant flow regimes. To see this effects, comparison of two small scales, namely core and micromodel scales, has been studied using the scale up methods. In literature review, the scale up procedure, relative permeability methods and dimensionless numbers in two phase flows has been described. Here the relative permeability and oil...
Numerical Investigation of Droplet Generation in a Microfluidic Flow-Focusing Junction Aiming High-Throughput Droplet Generation
, M.Sc. Thesis Sharif University of Technology ; Taghipoor, Mojtaba (Supervisor) ; Hosseini, Vahid (Supervisor)
Abstract
Droplet microfluidic platform generates monodisperse droplets in a desired size through immiscible multiphase flows inside microchannels. Droplets are individual reactor and can be used for bio(chemical) analyses. Also, for materials fabrication, droplet microfluidics offers a versatile platform for generation of nano- or micro-sized particles and microcapsules that are widely used in drug delivery. In addition to the monodispersity, high-throughput generation is also necessary in many applications. Therefore, droplets must be formed in stable regimes (dripping and squeezing) in the highest possible frequency. In this study, the flow-focusing geometry, which is the most common geometry in...
Numerical Investigation of the Free Surface Effect On Underwater Vehicles
,
M.Sc. Thesis
Sharif University of Technology
;
Sayyaadi, Hassan
(Supervisor)
;
Mehdigholi, Hamid
(Supervisor)
Abstract
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...
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...
Experimental Study of the Effect of Liquid Fluid Injection Conditions Inside the Evaporation Tube on its Performance
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
This reaserch is study on the performance of evaporation tubes used in mini jet engines which has been done experimentally using laboratory equipment. In this study, researchers have tried to simulate the laboratory conditions as much as possible to the real conditions inside the mini-jet engine, increase the accuracy of the results and increase the results and bring them closer to the results inside the mini-jet engine. The experiments are divided into two categories, cold and hot In cold tests, an attempt is made to study and investigate the types of two-phase flow regimes created by applying different fluid and air flow rates, and to select annular flow regimes from among them....
Numerical Modeling of Film Condensation in the Plate-Fin Heat Exchanger Used in the CO2 Capturing and Storage Process
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
Due to the wide application of plate-fin heat exchangers in various industries such as the petrochemical industry, aerospace industry, air conditioning systems, separation and liquefaction of gases, especially natural gas, boiling, condensation, and transportation industries, proper design of these heat exchangers is necessary. Most of the previous researches in the field of heat exchanger modeling has been done in single-phase mode. The two-phase modeling has been performed, often thermodynamically, and the effects of turbulence and surface tension have been ignored. Thus, in the present study, numerical modeling of the two-phase plate-fin heat exchanger is presented. In this project,...
Modeling and Numerical Simulation of Inertial Two-Phase Flow in Heterogeneous Porous Media
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
Abstract
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...
Modeling and Simulation of Multiphase Flow of Drilling Fluid in related to Drilling Cutting Transport in Horizontal Wells
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Shadizadeh, Reza (Supervisor)
Abstract
Transport of drilling cutting to the surface is the most important function of drilling fluid. Insufficient hole cleaning leads to accumulation of cuttings in the annulus especially of a Horizontal wellbore. This may cause severe drilling problems including reduction in rate of penetration, stuck pipe, premature bit wear, increase the mud lost, high drag and torque. In this research work a mathematical model is developed to simulate cutting transport process in the horizontal drilling wells. A three-layer model was used to simulate cutting transport process in horizontal wellbores: a stationary at the bottom of hole, a moving bed and a suspension layer on top of these layers. In this model,...
Modeling and Simulation of Two Phase Flow in Gas Condensate Wells
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
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...
Modeling and Performance Investigation of Airlift Pump with Conical Upriser Pipe
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
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...
Modeling the Forces Acting on NASA's Probe B Satellite, Using Space-Time Fluid Analogy
, M.Sc. Thesis Sharif University of Technology ; Taeibi Rahni, Mohamad (Supervisor)
Abstract
The purpose of this thesis is to study the analogy of space-time fluid flow around Earth and to investigate the hydrodynamic forces caused by this fluid on NASA's Probe B satellite. According to recent research, Einstein's and Navier-Stokes equations are the same. The properties of space-time fluid, including equation of state, compressibility, viscosity, flow field around Earth, and the hydrodynamic forces entering Probe B satellite, are unknown. There are two views about the viscosity of space-time fluid. Spherical mass of the three-dimensional spherical sink and the nature of the sphere located in the probe satellite without a spherical solid particle It are considered within this flow....
Multi-Scale Numerical Modeling of Two Phase Flow over Flexible Surface Micro-Structures
, Ph.D. Dissertation Sharif University of Technology ; Javadi, Khodayar (Supervisor)
Abstract
The present thesis investigates the micro-droplet dynamics in an inclined channel covered with flexible structures. For this purpose, the DPD (dissipative particle dynamics) method is used to study the behavior of particles present in the flow, including the droplet, the fluid around the droplet, and polymeric structures. This model leads to a more accurate representation of flow hydrodynamics and indicates the way for exploring and understanding complex fluid properties in real flows. The first part of the thesis deals with the dynamics of rising bubbles attached to a vertical wall under different wettability conditions. Even though bubbles rising freely in a liquid have extensively been...
Numerical Modeling of Carbon Dioxide Sequestration in Saline Aquifers with Considering the Hydrodynamic and Solubility Trapping
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor)
Abstract
One of the most important factors in global warming is greenhouse gases such as carbon dioxide. Separating carbon dioxide from industrial activities such as fossil fuel power plants and storing it in the underground water can help combat the global warming challenge. In this research, numerical modeling of carbon dioxide sequestration in the aquifers under isothermal conditions is investigated. The process of storing carbon dioxide in aquifers consists of four main stages. In the first stage, the injected carbon dioxide accumulates into the aquifers under the impermeable bed. In the second stage, some carbon dioxide is trapped by the capillary forces inside the porous media's pores. In the...
Numerical Simulation of Cold and Hot Water Injection into Naturally Fractured Reservoirs Using the Extended Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor)
Abstract
The present article studies the isothermal and non-isothermal water injection into naturally fractured oil reservoirs by numerical simulation. The fractures in naturally fractured reservoirs can possess different characteristics. In addition. a remarkable number of naturally fractured reservoirs contain relatively heavy oils that could not be extracted economically; hence. the thermal recovery methods are extensively used for these reservoirs. Hot water injection is one of the thermal recovery methods that has not been explored enough compared to its alternatives. In this study. the effectiveness of the hot water injection over the cold (isothermal) water injection in oil production is...
A Quasi-Three-Dimensional Multiscale Model for Two-Phase Simulation of Multi-Stream Plate-Fin Heat Exchangers
, Ph.D. Dissertation Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Supervisor) ; Mafi, Mostafa (Co-Supervisor)
Abstract
The present thesis aimed to develop a thermal-hydraulic model for simulation of multi-stream plate-fin heat exchangers. In this study, a multi-scale point of view was employed for three-dimensional simulation of multi-stream plate-fin heat exchangers. This is a cost-effective method that reflects the effects of complex phenomena at the micro-scale in the macro-scale model. In this model, fluid and solid matrix temperature distributions were obtained in the three-dimensional space, considering conduction heat transfer through separating plates, side plates, cap plates, and transverse conduction through fins. The modular form of the model has facilitated layer-by-layer simulation of parallel...
Modeling of Liquid-Vapor Two Phase Flow through Nozzle
, M.Sc. Thesis Sharif University of Technology ; Nouri Borujerdi, Ali (Supervisor)
Abstract
This thesis is about modeling of liquid-vapor two phase flows through nozzle. Liquid-vapor two phase flow is very applicable in industries such as boilers, expansion valves, refrigeration and sudden failures in pipelines. Two models are used for modeling of fluid flow through nozzle, transient and steady state. In Both model the solution field is considered as saturated liquid and vapor and the mass, momentum and energy equations as well as equation of state is used for describing of fluid flow properties. Homogeneous equilibrium model is used and for complete modeling of fluid flow heat transfer and friction force is also considered.
Numerical solutions are used for solving of the...
Numerical solutions are used for solving of the...