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flow-behavior
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Relative permeability estimation of porous media: Comparison of implicit and explicit approaches
, Article CHISA 2006 - 17th International Congress of Chemical and Process Engineering, Prague, 27 August 2006 through 31 August 2006 ; 2006 ; 8086059456 (ISBN); 9788086059457 (ISBN) ; Rashtchian, D ; Kharrat, R ; Vossoughi, S ; Khodabakhsh, M ; Taheri, S ; Sharif University of Technology
2006
Abstract
Relative permeability is used to describe quantitatively simultaneous transport of two or more immiscible phases through a porous medium. Accurate estimates of relative permeability curves depend on the method of estimation and are desired to obtain reliable predictions of flow behavior. To compare the accuracy of relative permeability estimation of implicit and explicit methods, primary drainage experiments of water by a sample oil fluid have been studied. The experiments performed on a horizontal glass type micromodel as a model of porous media sample under different fixed high flow rates condition to negate capillary pressure effects. The relative permeability of oil and water phases is...
Simulation and experimental analyses of dynamic strain aging of a supersaturated age hardenable aluminum alloy
, Article Materials Science and Engineering A ; Volume 585 , 2013 , Pages 165-173 ; 09215093 (ISSN) ; Karimi Taheri, A ; Kim, H. S ; Sharif University of Technology
2013
Abstract
In this paper, dynamic strain aging (DSA) behavior in a temperature range of (25-235°C) and strain rate range of (10-4-5×10-2s-1) was investigated using a supersaturated age hardenable aluminum alloy. It was found that two mechanisms consisted of pinning of solute atoms to mobile dislocations and dynamic precipitation, were responsible for DSA in the testing conditions. The effects of both mechanisms on the macroscopic flow curve were studied using experimental and improved physically based material modeling approaches. It was shown that both phenomena lead to a negative strain rate hardening in the alloy. Dynamic precipitation acting at high temperature results in considerable work...
Modeling the Microstructure Evolution and Mechanical Properties of Al-Mg-Si alloys During Thermomechanical Treatment
, Ph.D. Dissertation Sharif University of Technology ; Karimi Taheri, Ali (Supervisor)
Abstract
The Al-Mg-Si alloys are an important group of industrial materials used extensively in the automotive and aerospace industry, due to their high strength to weight ratio, good corrosion resistance and the recycle ability. In order to achieve a combination of optimized microstructure and properties during the production processes, the study of deformation behavior and heat treatment of these alloys is necessary. Therefore, the prediction of microstructural evolution and mechanical properties as a function of alloy chemical composition and thermomechanical treatment is important for these alloys, from both the scientific and industrial aspects. In the present research, the flow behavior of this...
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...
Constitutive modeling of hot deformation behavior of the AA6063 alloy with different precipitates
, Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; Volume 44, Issue 13 , December , 2013 , Pages 5853-5860 ; 10735623 (ISSN) ; Taheri, A. K ; Kim, H. S ; Sharif University of Technology
2013
Abstract
The current study proposes a simple constitutive model that integrates the kinetics of precipitation during static aging and the kinetics of precipitate dissolution during preheating to deformation temperature to predict the hot flow behavior of AA6063 alloy. The model relates the flow behavior of the age-hardenable alloy to the alloy chemistry, thermal history as well as deformation temperature, strain, and strain rate by means of a physically based model. Different aging conditions, including supersaturated solid solution and overaging conditions with different deformation parameters, were assessed. Each part of the model was in good agreement with those of experimental and other model...
Flow behavior and mechanical properties of a high silicon steel associated with dynamic strain aging
, Article Journal of Materials Engineering and Performance ; Volume 21, Issue 9 , September , 2012 , Pages 1919-1923 ; 10599495 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
Springer
2012
Abstract
Flow behavior of two grades of steel including a high silicon (HS) steel and a plain low carbon steel as the reference were considered in this work. Tensile testing at temperatures varying between 25 and 550 °C and different strain rates in the range of 4×10-5 to 0.1 s-1 were conducted and the mechanical properties, such as elongation at fracture point and strain rate sensitivity were then determined. It is observed that for both steels, dynamic strain aging occurs in the employed deformation conditions, however, the region of serrated flow and the type of the serration were somehow different. For the case of the HS steel, the serrated flow region is shifted to the higher temperatures and...
Analysis and modeling time headway distributions under heavy traffic flow conditions in the urban highways: Case of Isfahan
, Article Transport ; Volume 26, Issue 4 , 2011 , Pages 375-382 ; 16484142 (ISSN) ; Tamannaei, M ; Haghshenash, H ; Sharif University of Technology
Abstract
The time headway of vehicles is an importan microscopic traffic flow parameter which affects the safety and capacity of highway facilities such as freeways and multi-lane highways. The present paper intends to provide a report on the results of a study aimed at investigating the effect of the lane position on time headway distributions within the high levels of traffic flow. The main issue of this study is to assess the driver's behavior at different highway lanes based on a headway distribution analysis. The study was conducted in the city of Isfahan, Iran. Shahid Kharrazi six-lane highway was selected for collecting the field headway data. The under-study lanes consisted of passing and...
Stress relaxation and flow behavior of ultrafine grained AA 1050
, Article Mechanics of Materials ; Volume 89 , 2015 , Pages 23-34 ; 01676636 (ISSN) ; Akbarzadeh, A ; Yoon, Y. O ; Kim, S. K ; Sharif University of Technology
Elsevier
2015
Abstract
Abstract Flow behavior of ultrafine grained (UFG) AA 1050 sheets processed by Accumulative Roll-Bonding (ARB) and its viscous nature are investigated by plane strain compression test (PSC) along with stress relaxation. Occurrence of dynamic recovery is validated by TEM observations as the microstructural explanation of the flow softening at the start of deformation of the 8-cycles specimen. Significant recovery of the UFG specimens during the stress relaxation test is also disclosed. It is discussed that neither the internal stress (σi ) nor the density of mobile dislocations are constant during the test. The possible effects of these two factors as well as contribution of the...
Carbon-based nanocomposites: Distinguishing between deep-bed filtration and external filter cake by coupling core-scale mud-flow tests with computed tomography imaging
, Article Journal of Natural Gas Science and Engineering ; Volume 105 , 2022 ; 18755100 (ISSN) ; Fouji, M ; Ghorbani Heidarabad, R ; Aghaei, H ; Hajiabadi, S. H ; Bedrikovetsky, P ; Mahani, H ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Although Multi-Walled Carbon NanoTubes (MWCNTs) are found to influence the rheological behavior of drilling fluids, there are yet some controversies regarding their performance towards reducing formation damage induced by the invasion of water-based drilling fluids (WBFs). To address this important question, we synthesized novel nanocomposite materials via modifying the MWCNT via varying the proportion of carboxylated MWCNTs to PolyVinyl Alcohol (PVA). These nanocomposites were then used to make nano-based drilling-fluids (NDFs). The performance of the NDFs was evaluated by a set of rheological behavior tests, filtration experiments, and core-scale mud flow tests. To distinguish between the...
Modeling and Vibration Analysis of Laminated Composite Beam with Magneto-Rheological Fluid Segments
, Ph.D. Dissertation Sharif University of Technology ; Behzad, Mehdi (Supervisor) ; Zabihollah, Abolghasem (Supervisor) ; Shamloo, Amir (Co-Advisor)
Abstract
Magnetorheological (MR) materials show variations in their rheological properties when subjected to varying magnetic fields. They have quick time response, in the order of milliseconds, and thus are potentially applicable to structures and devices when a tunable system response is required. When integrated with a structural system, they can produce higher variations in the dynamic response of the structure. In this thesis, vibration behavior of laminated-composite beam with MR Fluid is investigated.In most studies, shear strain across the thickness of MR layer has been considered as a constant value which does not precisely describe the actual shear strain field. Shear modulus of MR layer in...
Experimental Study on the Effect of Surfactant and Brine Salinity on Stability and Flow Behavior of Foam in the Presence of Oil
, M.Sc. Thesis Sharif University of Technology ; Fatemi, Mobeen (Supervisor) ; Ghazanfari, Mohammad Hossein (Supervisor)
Abstract
Gas injection is one of the most common methods to enhance oil recovery. But due to the low viscosity and density of gas, viscous fingering and gravity over ride usually happens which lead to reduction of gas injection performance to oil production. Foam injection is one of the techniques that has the potential to improve oil production by increasing. Foam apparent viscosity is higher than gas and its liquid which is made from it. So it can increase sweep efficiency and enhance oil recovery. However, presence of oil can destabilize foam. Beside, salinity has different effects on foamability and foam stability. Foam stability in high saline environment is a challenge. Therefore, the stability...
Pressure effects on electroosmotic flow of power-law fluids in rectangular microchannels
, Article Theoretical and Computational Fluid Dynamics ; Vol. 28, issue. 4 , 2014 , pp. 409-426 ; ISSN: 09354964 ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
Abstract
In this paper, the fully developed electroosmotic flow of power-law fluids in rectangular microchannels in the presence of pressure gradient is analyzed. The electrical potential and momentum equations are numerically solved through a finite difference procedure for a non-uniform grid. A complete parametric study reveals that the pressure effects are more pronounced at higher values of the channel aspect ratio and smaller values of the flow behavior index. The Poiseuille number is found to be an increasing function of the channel aspect ratio for pressure assisted flow and a decreasing function of this parameter for pressure opposed flow. It is also observed that the Poiseuille number is...
An approximate analytical solution for electro-osmotic flow of power-law fluids in a planar microchannel
, Article Journal of Heat Transfer ; Volume 133, Issue 9 , July , 2011 ; 00221481 (ISSN) ; Fattahi, M ; Hassan Saidi, M ; Sharif University of Technology
2011
Abstract
The present investigation considers the fully developed electro-osmotic flow of power-law fluids in a planar microchannel subject to constant wall heat fluxes. Using an approximate velocity distribution, closed form expressions are obtained for the transverse distribution of temperature and Nusselt number. The approximate solution is found to be quite accurate, especially for the values of higher than ten for the dimensionless Debye-Huckel parameter where the exact values of Nusselt number are predicted. The results demonstrate that a higher value of the dimensionless Debye-Huckel parameter is accompanied by a higher Nusselt number for wall cooling, whereas the opposite is true for wall...
Identification of flow units using methods of testerman statistical zonation, flow zone index, and cluster analysis in tabnaak gas field
, Article Journal of Petroleum Exploration and Production Technology ; Volume 6, Issue 4 , 2016 , Pages 577-592 ; 21900558 (ISSN) ; Ghasem Al Askari, M. K ; Masihi, M ; Sharif University of Technology
Springer Verlag
Abstract
The relation between porosity and permeability parameters in carbonated rocks is complicated and indistinct. Flow units are defined with aim of better understanding reservoir unit flow behavior and relation between porosity and permeability. Flow units reflect a group of rocks with same geological and physical properties which affect fluid flow, but they do not necessarily coincide with boundary of facies. In each flow unit homogeneity of data is preserved and this homogeneity fades in the boundaries. Here, in this study, three methods are used for identification of flow units and estimation of average porosity and permeability in three wells of Tabnaak gas field located in south of Iran....
Modeling of viscoelastic fluid flow behavior in the circular die using the leonov-like conformational rheological constitutive equations
, Article Macromolecular Symposia ; Volume 274, Issue 1 , 2008 , Pages 6-10 ; 10221360 (ISSN) ; Kanvisi, M ; Sharif University of Technology
2008
Abstract
In this paper, the flow behavior of Leonov-Like conformational rheological model, which has root in the generalized Poisson bracket formalism based on the conformation tensor, have been studied in the circular die flow. Prediction of the normal stress differences during the flow of these fluids lets us to follow and calculate relaxation dependent phenomena such as die swell. The model predictions have been compared for the four families of mobility expressions. The Study of the model prediction sensitivity to its mobility term shows that model predictions can cover a wide range of rheological behaviors generally observed for polymer melts and solutions in the circular die flow. Copyright ©...
Flow visualization around a non-circular tube
, Article International Journal of Engineering, Transactions B: Applications ; Volume 19, Issue 1 , 2006 , Pages 73-82 ; 1728-144X (ISSN) ; Lavasani, A. M ; Sharif University of Technology
Materials and Energy Research Center
2006
Abstract
The flow behavior around a cam shaped tube in a cross flow has been investigated experimentally using flow visualization and pressure distribution measurements. The range of attack angle and Reynolds number based on an equivalent circular diameter are within 0 < α < 360° and 2×104Reeq <3.4×104, respectively. The pressure drag features are clarified in relation to the flow behavior around the tube. It is found that the highest pressure drag coefficient occurs at α = 90° and 270° over the whole range of Reynolds number. Results show that the pressure drag coefficient of the cam - shaped tube is lower than that of a circular tube with the same surface area for more of the attack angles
Thermal transport characteristics pertinent to electrokinetic flow of power-law fluids in rectangular microchannels
, Article International Journal of Thermal Sciences ; Vol. 79, issue , 2014 , p. 76-89 ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
Abstract
In the present study, the thermal characteristics of electroosmotic flow of power-law fluids in rectangular microchannels in the presence of pressure gradient are investigated. The governing equations for fully developed flow under H1 thermal boundary conditions are first made dimensionless and subsequently solved through a finite difference procedure for a non-uniform grid. The influence of the major parameters on thermal features of the flow such as the temperature distribution and Nusselt number is discussed by a complete parametric study. The results reveal that the channel aspect ratio and the non-Newtonian characteristic of the fluid can affect the thermal behavior of the flow. It is...
Investigation on the importance of the diffusion process during lean gas injection into a simple synthetic depleted naturally fractured gas condensate reservoir
, Article Petroleum Science and Technology ; Volume 30, Issue 7 , Feb , 2012 , Pages 655-671 ; 10916466 (ISSN) ; Gerami, S ; Ghotbi, C ; Hashemi, A ; Sharif University of Technology
2012
Abstract
A depleted naturally fractured gas condensate reservoir with extremely tight matrix permeability in the center of Iran is used for gas storage. Due to the tightness of the matrix, simulation of this process may present a unique challenge in terms of the importance of diffusion process in flow behavior of the injected gas in matrix blocks. This article presents a multimechanistic (Darcian-type flow and Fickian-type flow) mathematical model to investigate the importance of diffusion process as a function of important rock and fluid parameters. The authors' approach consists of the following steps: (a) development of a 1-D governing equations for a single matrix block consists of a gas...
Combined electroosmotically and pressure driven flow of power-law fluids in a slit microchannel
, Article Journal of Non-Newtonian Fluid Mechanics ; Volume 166, Issue 14-15 , August , 2011 , Pages 792-798 ; 03770257 (ISSN) ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
2011
Abstract
Electroosmotic flow of power-law fluids in the presence of pressure gradient through a slit is analyzed. After numerically solving the Poisson-Boltzmann equation, the momentum equation with electroosmotic body force is solved through an iterative numerical procedure for both favorable and adverse pressure gradients. The results reveal that, in case of pressure assisted flow, shear-thinning fluids reach higher velocity magnitudes compared with shear-thickening fluids, whereas the opposite is true when an adverse pressure gradient is applied. The Poiseuille number is found to be an increasing function of the dimensionless Debye-Hückel parameter, the wall zeta potential, and the flow behavior...
Physically based material model for evolution of stress-strain behavior of heat treatable aluminum alloys during solution heat treatment
, Article Materials and Design ; Volume 31, Issue 1 , 2010 , Pages 433-437 ; 02641275 (ISSN) ; Karimi Taheri, A ; Sharif University of Technology
2010
Abstract
A mathematical model based on Kocks-Mecking-Bergstrom model, has been proposed to predict the flow behavior of age hardenable aluminum alloys, under different conditions of solution heat treatment and hot deformation. Considering the published literature, most researchers have taken into account the precipitation and solution strengthening contribution to the flow stress by a constant and some others have ignored these effects. So these available descriptions cannot be applicable directly to different conditions of solution heat treatment. In order to enable these constitutive descriptions to take into account the effects of soaking time and temperature, we introduce in this research a...