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two-phase-flow
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Experimental Modeling of Gas-liquid Two-phase Flow in a Tapered Upriser Pipe
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor)
Abstract
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...
Numerical Simulation of Two-dimensional Sonoluminescence Phenomenon, Using Front Tracking/Ghost Fluid Method
, M.Sc. Thesis Sharif University of Technology ; Tayyebi Rahni, Mohammad (Supervisor)
Abstract
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...
Effect of variable Geometry on a Vertical Two Phase Flow
, M.Sc. Thesis Sharif University of Technology ; Nouri Borujerdi, Ali (Supervisor)
Abstract
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...
Compositional Simulation of 1-D Oil Reservoirs Flow Using a High-Resolution Central Scheme
, M.Sc. Thesis Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
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...
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...
Investigation on the Effect of air Inlet on the Behavior of Air-Water two Phase Flow in a Large Diameter Vertical Tube
, M.Sc. Thesis Sharif University of Technology ; Saidi, Hassan (Supervisor)
Abstract
Knowledge of Air-water two phase flows is significant to different engineering systems such as chemical reactors and power plant and petrochemical and petroleum industry. One of the most industrial cases of two phase flow is two phase flow in vertical large pipes. Because of gravity, two phase flow in Vertical pipes is different from horizontal pipes. Considering these flows can play a significant role in long-term reliability and safety of industrial systems. There are many parameters that effect on flow characteristics such as length and diameter of pipe and shape and condition of air inlet. Effect of air inlet is on the shape of bubbles and this can effects on flow pattern and another...
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...
Two Phase Flow in Micro-channel with Liquid Injection From Wall
, M.Sc. Thesis Sharif University of Technology ; Nouri Borujerdi, Ali (Supervisor)
Abstract
In this thesis, two-phase flow modeling in two-dimensional micro channel with liquid injection from wall is studied. Two models as "separated flow model" and "two-phase mixture flow" is developed. The separated flow model considers gas and liquid flow in separated films of flow with an interface between the phases. The two-phase mixture flow considers equivalent fluid mixture from gas and liquid with local modification in density and viscosity. Governing equations include continuity and momentum solved with control volume method. SIMPLE algorithm's been used to pressure-velocity linked equations. Velocity and pressure profiles plotted for mentioned models at a given situations. By comparing...
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...
Investigation of Flow Formed by two Impinging Jets
, M.Sc. Thesis Sharif University of Technology ; Kebriaei, Azadeh (Supervisor)
Abstract
Due to importance of designing geometry and working condition of injector it is necessary that by testing cold flow, we gain better understanding of atomization characteristics and in particular initial atomization close to injector which defines the spray characteristics. Up to today experimental measurements in the high density zone close to injector has been difficult to to optical limitations and also analytical solutions of atomization process is limited due to complexity and highly nonlinear equations. Numerical solutions are also under development and researchers have recently done researches and simulations. In this field the modeling of liquid sheet collapse has challenged numerical...
Experimental Study of Pressure Fluctuation in Two Phase Slug Flow In a Tunnel with Rectangular Cross Section with an Expansion Transition and Horizontal Slope
, M.Sc. Thesis Sharif University of Technology ; Borghie, Mahmood (Supervisor)
Abstract
Air enterance in to flowing water is something that is commonly seen in the water conveyance systems. The mixture of Air and water that flow together create a kind of flow that is called two phase flow. This kind of flow is often seen in culverts and water conveyance systems. There are different flow patterns in two phase flow. Considering pressure fluctuation, pressure drop and pressure recovery, slug flow pattern is the most complicated pattern among all.
Sometimes a singularity is used in a tunnel; one of the singularities that are frequently used in water conveyance system is expansion transition. In this study an experimental setup is used to model two phase slug flow, which passes...
Sometimes a singularity is used in a tunnel; one of the singularities that are frequently used in water conveyance system is expansion transition. In this study an experimental setup is used to model two phase slug flow, which passes...
Investigation of Flooding Phenomena in Gas-liquid Flow
, M.Sc. Thesis Sharif University of Technology ; Nouri-Broujerdi, Ali (Supervisor)
Abstract
In a counter current two phase flow systems that liquid flows downward due to gravity on the pipe wall and gas flows upward due to pressure gradient in the pipe core, Flooding and reversal Flooding are important phenomena. Flooding is beginning of velocity direction change of liquid from downward to upward that with zero axial velocity of liquid in interface, liquid is on verge of moving upward. When mass flow rate of liquid or gas increase, some part of liquid film are separated and enter the gas stream. With further increase in mass flow rate of liquid or gas in flooding point, reversal flooding occurs that cause to all liquid film flows upward. Flooding and reversal flooding phenomena are...
Numerical Investigation of Surface Wettability Effect on Liquid-Liquid Two-Phase Flow Heat Transfer in Microchannels
, Ph.D. Dissertation Sharif University of Technology ; Kazemzadeh Hannani, Siamak (Supervisor) ; Farhanieh, Bijan (Co-Supervisor)
Abstract
It is aimed in this study to numerically investigate the effect of contact angle on the heat transfer coefficient in oil-water two-phase flow. For this purpose, the finite element method (FEM) is used to solve the unsteady Navier-Stokes and energy equations. The level set method is also used to capture the interface between the phases. In the first part of the study, two-phase flow of the water and calibration oil is considered in a T-junction geometry at contact angles of 5°, 40°, and 75°. It is observed that the flow patterns formed in the microchannel depend on the initial flow condition which results in the hysteresis phenomenon. Investigating the effect of wall contact angle on the...
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....
A Finite Volume Method for Simulation of 2D Two-Phase Flow in Porous Medium with Anisotropic PermeabilityTensor on Unstructured Cell CenterTriangular Grid
,
M.Sc. Thesis
Sharif University of Technology
;
Taghi Zadeh Manzari, Mehrdad
(Supervisor)
;
Kazemzadeh Hannani, Siamak
(Supervisor)
Abstract
Rapid variation in permeability with strong anisotropy are common features in subsurface reservoirs. When formulating a finite-volume pressure equation scheme, continuous normal flux and pressure are key physical constraints that must be imposed at control-volume interfaces, across which strong discontinuities in permeability can occur.
The derivation of algebraic flux continuity conditions for full-tensor discretization operators has lead to families of efficient locally conservative flux-continuous control-volume distributed (CVD) finite- volume schemes for determining the discrete pressure and elocity fields in subsurface reservoirs [5, 9, 11, 13].
When applying these...
The derivation of algebraic flux continuity conditions for full-tensor discretization operators has lead to families of efficient locally conservative flux-continuous control-volume distributed (CVD) finite- volume schemes for determining the discrete pressure and elocity fields in subsurface reservoirs [5, 9, 11, 13].
When applying these...
Multirate Transfer Functions in Dual Porosity-Dual Permeability Models in Simulation of Naturally Fractured Reservoirs in 2D Two Phase Water-Oil System
, M.Sc. Thesis Sharif University of Technology ; Taghi Zade Manzari, Meherdad (Supervisor) ; Afshin, Hossein (Co-Advisor) ; Kazemzadeh Hannani, Siamak (Co-Advisor)
Abstract
Naturally Fractured Reservoirs (NFRs) play an important role in petroleum industry and the global economy.. The reservoirs of the most complex geological structures in petroleum engineering science, on the other hand the largest sources of hydrocarbons are considered throughout the world and especially in our country. Therefore, characterization and modeling them frst step to develop best practices for hydraulic fracturing gap, optimal design of production Method and evaluate potential reservoirs. Physics of the present work is 2D two-phase immiscible flow under gravittational effect through fractured porous media and the most practical formulas for transfer function in dual porosity-dual...
Dynamics and Heat transfer of Two-phase Non-Newtonian Fluids in Superhydrophobic Channels
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor)
Abstract
When the fluid passes through the microchannel, some energy is lost due to drag force and pressure drop. One of the methods used in the last few decades to optimize energy consumption is creating superhydrophobic surfaces in microchannels. These surfaces, with their features such as increasing the contact angle and reducing the contact angle hysteresis, can reduce energy loss, which is due to the presence of unevenness on the surface, and by trapping air and creating a two-phase flow, they reduce the drag force. On the other hand, the air trapped inside these irregularities will also affect the heat transfer of the passing fluid in the microchannel, which by creating resistance in the...
Numerical Investigation of Ambient Pressure and Electric Potential on the Heat Transfer Rate of an Electrospray
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, Kaveh (Supervisor)
Abstract
Electrospray is a process in which the charged liquid is subjected to the effect of an electric field and after passing through an emitter, it will propagate in the form of jets or small droplets. This process is used in applications such as electric thrusters, cooling or mass spectrometry. In the electronics industry, cooling high-temperature microprocessors is a challenge. In this regard, air-based cooling systems are not well able to discharge heat from electrical and electronic components. Electrospray cooling technology is one of the new and promising methods. In this research, the two-dimensional simulation of electrospray cooling is performed by using COMSOL commercial software as a...
Modeling of two-phase flow in porous media with heat generation
, Article International Journal of Multiphase Flow ; Volume 69 , March , 2015 , Pages 115-127 ; 03019322 (ISSN) ; Saidi, M. S ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
The main purpose of this work is investigation of coolability of a boiling debris bed. The main governing equations are derived using volume averaging technique. From this technique some specific interfacial areas between phases are appeared and proper relations for modeling these areas are proposed. Using these specific areas, a modification for the Tung/Dhir model in the annular flow regime is proposed. The proposed modification is validated and the agreements with experimental data are good. Finally, governing equations and relations are implemented in the THERMOUS program to model two-phase flow in the debris bed in the axisymmetric cylindrical coordinate. Two typical configurations...
Simulation of multi-component multi-phase fluid flow in two-dimensional anisotropic heterogeneous porous media using high-order control volume distributed methods
, Article Computers and Mathematics with Applications ; Volume 78, Issue 10 , 2019 , Pages 3303-3328 ; 08981221 (ISSN) ; Taghizadeh Manzari, M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In this paper, flow of multi-component two-phase fluids in highly heterogeneous anisotropic two-dimensional porous media is studied using computational methods suitable for unstructured triangular and/or quadrilateral grids. The physical model accounts for miscibility and compressibility of fluids while gravity and capillary effects are neglected. The governing equations consist of a pressure equation together with a system of mass conservation equations. For solving pressure equation, a new method called Control Volume Distributed Finite Element Method (CVDFEM) is introduced which uses Control Volume Distributed (CVD) vertex-centered grids. It is shown that the proposed method is able to...