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rheological-model
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Development of a rheological model for polymeric fluids based on FENE model
, Article Polyolefins Journal ; Volume 6, Issue 1 , 2019 , Pages 95-106 ; 23222212 (ISSN) ; Ahmad Ramazani, S. A ; Davachi, S. M ; Sharif University of Technology
Iran Polymer and Petrochemical Institute
2019
Abstract
Rheological models for polymer solutions and melts based on the finitely extensible non-linear elastic (FENE) dumbbell theory are reviewed in this study. The FENE-P model that is a well-known Peterlin approximation of the FENE model, indicates noticeable deviation from original FENE predictions and also experimental results, especially in the transient flow. In addition, both FENE and FENE-P models have some shortcomings from the point of view of theory. To overcome these shortcomings, a new approximation of the FENE spring force has been established. It has been used to develop a modified constitutive rheological model for polymeric fluids. In the procedure of modeling, the effect of...
Effect of ultrasonic irradiation treatment on rheological behaviour of extra heavy crude oil: A solution method for transportation improvement
, Article Canadian Journal of Chemical Engineering ; Volume 95, Issue 1 , 2017 , Pages 83-91 ; 00084034 (ISSN) ; Ramazani S. A, A ; Alijani Alijanvand, H ; Ghazanfari, M. H ; Ghanavati, M ; Sharif University of Technology
Wiley-Liss Inc
2017
Abstract
The highly viscous property of heavy oil often causes problems in its transportation in pipelines. Mixing heavy oil with light oil as well as ultrasound treatment are viable solutions to this problem. In this study, extra heavy crude oil samples were first diluted with 0, 0.05, 0.1, and 0.15 mL/mL (0, 5, 10, and 15 vol%) of a light crude oil; then the mixture was irradiated by ultrasonic waves for 0, 5, 10, 15, and 20 min; finally the viscous shear functions of all mixtures was measured at different values of shear rate at different temperature levels. The results revealed that the minimum viscosity of the diluted extra heavy crude oil samples was obtained at 10 min of ultrasonic...
Integrated numerical study of rainfall-induced landslides from initiation to propagation using saturation-based rheological model
, Article Scientia Iranica ; Volume 29, Issue 5 B , 2022 , Pages 2304-2316 ; 10263098 (ISSN) ; Manzari, M. T ; Hajilouy Benisi, A ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
This paper presents an integrated two-dimensional numerical framework for simulating rainfall-induced landslides from instability initiation to post-failure flow. To describe the entire process, three steps are considered in this study: (1) a coupled hydrostability analysis which detects the failure plane using the Finite Element Method (FEM) (pre-failure stage); (2) computing the local rheology of the failed mass (wet sandy soil) based on the water saturation at the onset of failure using the saturation-based rheological model (transition stage); and (3) a continuum-based propagation analysis which solves the flow of the wet material employing the Smoothed Particle Hydrodynamics (SPH)...
Rheological Evaluation of Ageing Properties of Modified Bitumens
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
Bitumen ageing is one of the principal factors causing the deterioration of asphalt pavements. Ageing is a complex process that is affected by different parameters.With the rapid growth of modified binders in road paving applications over the past twodecades, it is important to study the ageing properties of these binders. A number of laboratory methods are used tosimulatethe bitumenageing at various stages of the production and service of hot mix asphalt.Recent studies have shown that Superpave testing protocol does not fully address the ageing of modified binders. To study the ageing properties of modified binders, three different types of binder modifiers, plastomer, elastomer, and ground...
Modeling of wormhole propagation in carbonate rocks by use of in-situ-gelled acids
, Article SPE Journal ; Volume 22, Issue 6 , 2017 , Pages 2032-2048 ; 1086055X (ISSN) ; Bazargan, M ; Rostami, B ; Ayatollahi, S ; Sharif University of Technology
Abstract
Diversion in heterogeneous carbonate reservoirs plays the most important role to the success of acidizing. Without the use of diversion, more acid preferentially flows into the high-permeability region and leaves the low-permeability region underreacted. But a clear understanding of diverting agents, such as polymer-based in-situ-gelled acids, can help uniformly stimulate the near-wellbore region. In this paper, we correct the rheological model that was developed by Ratnakar et al. (2013) according to experimental data from Gomaa and Nasr-El-Din (2010b) by considering shear-rate effect in a two-scale continuum model. It is found that the rheology parameters and shear rate are influential...
Numerical simulation of landslide impulsive waves by incompressible smoothed particle hydrodynamics
, Article International Journal for Numerical Methods in Fluids ; Volume 56, Issue 2 , 2008 , Pages 209-232 ; 02712091 (ISSN) ; Shobeyri, G ; Sharif University of Technology
2008
Abstract
An incompressible-smoothed particle hydrodynamics (I-SPH) formulation is presented to simulate impulsive waves generated by landslides. The governing equations, Navier-Stokes equations, are solved in a Lagrangian form using a two-step fractional method. Landslides in this paper are simulated by a submerged mass sliding along an inclined plane. During sliding, both rigid and deformable landslides mass are considered. The present numerical method is examined for a rigid wedge sliding into water along an inclined plane. In addition solitary wave generated by a heavy box falling inside water, known as Scott Russell wave generator, which is an example for simulating falling rock avalanche into...
Numerical modeling of die filling of semi-solid A356 aluminum alloy
, Article Semi-Solid Processing of Alloys and Composites 10 - Selected, peer reviewed papers from the 10th International Conference on Semi-Solid Processing of Alloy and Composites, S2P 2008, Aachen, 16 September 2008 through 18 September 2008 ; Volume 141-143 , 2008 , Pages 605-610 ; 10120394 (ISSN); 9771012039401 (ISBN) ; Aashuri, H ; Narimannezhad, A ; Khosravani, A ; Kiani, M ; Sharif University of Technology
Trans Tech Publications Ltd
2008
Abstract
Computer base and simulation technique have been applied for modeling the semi-solid die filling and part of the solidification process of aluminum A356 alloy. A fairly simple one-phase rheological model has been implemented into a fluid flow finite element software Procast, to solve the partial differential equations. This model is purely viscous nature and is implemented in the power law cut-off model of Procast. The constitutive parameters of this model were determined for a rheocast A356 alloy. Using these parameters and comparing the simulation results with experimental data showed good correlation with the model prediction. The designed die for rheocasting was applied for the...
Mesoscopic rheological modeling of drilling fluids: Effects of the electrolyte
, Article Journal of Petroleum Science and Engineering ; Volume 195 , 2020 ; Ramazani Saadatabadi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Drilling fluid is a complex fluid, including base fluid and other materials, carrying out the vital functions during drilling operation such as cutting transport and controlling formation pressure. In order to optimize performance of a drilling process, a reliable rheological model is required in the computation of fluid flow dynamics. Time-independent Generalized Newtonian formulation are the most common models for describing the rheological behavior of drilling fluids due to its simplicity and ease of use, in spite the fact that they are not able to predict the normal stresses and could not consider effects of active components on the rheological behavior of the drilling fluid and also...
Rheological modeling of water based drilling fluids containing polymer/bentonite using generalized bracket formalism
, Article Journal of Petroleum Science and Engineering ; Volume 189 , 2020 ; Ramazani Saadatabadi, A ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Drilling fluids consist of several components with different physical and structural form which can be assumed as complex fluids. Optimum performance of drilling process could be obtained through the dynamic fluid computation which requires a reliable mathematical model capable to predict transient and steady state rheological behavior of drilling fluid. Generalized Newtonian formulations are the most popular models for drilling fluids due to their simplicity in spite of their inabilities to predict transient and elastic behavior of such fluids. In this paper, we have developed a mathematical model to predict transient and steady state rheological behavior of the complex fluids on the scale...
Mesoscopic theoretical modeling and experimental study of rheological behavior of water-based drilling fluid containing associative synthetic polymer, bentonite, and limestone
, Article Journal of Molecular Liquids ; 2021 ; 01677322 (ISSN) ; Davoodi, S ; Ramazani S.A., A ; Minaev, K.M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Employing an effective rheological model for the flow of drilling fluid that can accurately predict changing conditions is of significant importance in drilling fluid optimization. Traditional generalized Newtonian models cannot predict the time change condition, viscoelastic behavior, role of each component, or microstructural behaviors within the fluid. Consequently, the present research aims to develop constitutive equations in the framework of generalized bracket formalisms and the extra tensor concept that connect the microscopic and macroscopic properties and can overcome the aforementioned problems of traditional rheological models. The developed model is applicable for drilling fluid...
Mesoscopic theoretical modeling and experimental study of rheological behavior of water-based drilling fluid containing associative synthetic polymer, bentonite, and limestone
, Article Journal of Molecular Liquids ; Volume 347 , 2022 ; 01677322 (ISSN) ; Davoodi, S ; Ramazani S. A., A ; Minaev, K. M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Employing an effective rheological model for the flow of drilling fluid that can accurately predict changing conditions is of significant importance in drilling fluid optimization. Traditional generalized Newtonian models cannot predict the time change condition, viscoelastic behavior, role of each component, or microstructural behaviors within the fluid. Consequently, the present research aims to develop constitutive equations in the framework of generalized bracket formalisms and the extra tensor concept that connect the microscopic and macroscopic properties and can overcome the aforementioned problems of traditional rheological models. The developed model is applicable for drilling fluid...
Implementation of Darcy-Brinkman-Stokes Model for Simulation of Acid, Gel Acid and Visco-Elastic-Surfactant (VES) Acid Injection into a Carbonate Core
,
M.Sc. Thesis
Sharif University of Technology
;
Fatemi, Mobeen
(Supervisor)
;
Bazargan, Mohammad
(Supervisor)
Abstract
In this work, an improved model for simulating carbonate core acidizing, with the ability of correctly modeling fluid diversion in dual-core experiments is created based on an existing two-scale continuum model. The improvements are applied on the momentum transfer equation, continuity equation, pore-scale structure-property relations and fluid rheology model. Also a more realistic injection scenario and geometry configuration are presented for simulating the diversion experiments. The Darcy-Brinkman-Stokes equation is implemented instead of Darcy’s equation and the continuity equation is modified by adding the mass source term. A global rheology model is developed capable of capturing exact...
Simulation of Rainfall-triggered Landslides with Considering the Rheology Changes in Sandy Soils
, Ph.D. Dissertation Sharif University of Technology ; Taghizadeh Manzari, Mehrdad (Supervisor) ; Hajilouy-Benisi, Ali (Co-Supervisor)
Abstract
This study presents an integrated two-dimensional numerical framework for simulating rainfall-induced landslides from instability initiation to post-failure flow. The discrete element method (DEM) is used to establish a rheological model that relates the apparent viscosity of a granular sand to shear rate, normal stress, and water saturation. A theoretical model is developed to determine water distribution and water-induced forces between particles for different saturations. The resulting forces are embedded in a 3D shear cell as a numerical rheometer and a wet sand is sheared between two walls. A power law rheological model is obtained as a function of inertia number and saturation. It was...
Shear-rate dependence modeling of gelcast slurries: Effects of dispersant content and solid loading
, Article Ceramics International ; Vol. 40, issue. 1 PART A , 2014 , pp. 123-128 ; ISSN: 02728842 ; Faghihi-Sani, M. A ; Khoshkalam, M ; Sharif University of Technology
Abstract
Gelcasting, as a ceramic forming technique, is getting worldwide attention, in that it can be used to make high-quality, complex-shaped ceramic parts with a wide range of powders. However, a model, which can appropriately describe the shear rate dependence behavior of the slurry in casting process simulation, is limited. Therefore, this study mainly sought to investigate the best model representing the behavior of as-prepared gelcast slurry. A premix solution was prepared with monomer/cross linker of AM/MBAM with ratio of 25:1. In this procedure, ammonium polyacrylate sodium (NHPANa) was used as the dispersant and the solid load included Al2O3/20 vol% ZrO2 powder mixture. Series of slurries...
Experimental investigation and theoretical prediction of extrudate swell using conformational rheological models
, Article International Polymer Processing ; Volume 27, Issue 4 , 2012 , Pages 478-485 ; 0930777X (ISSN) ; Ahmad Ramazani, S. A ; Amoli, H. H ; Kamyabi, A ; Sharif University of Technology
Hanser
2012
Abstract
In this study the extrudate swell of polymer solutions is estimated using the microstructure of polymer molecules. When a flexible polymer chain goes through a narrow die shear stress exerting on the chain will cause the polymer chain to be stretched along the flow direction. After emerging from die all external stresses vanish immediately and the chains tend to recover their previous state due to elastic recovery. This phenomenon will results in a gradual increase in extrudate diameter and this is used as the key idea for estimating swell ratio. A Giesekus based conformational model was used in order to predict polymer chains microstructure everywhere in the domain. The resulting PDE set...
The Role of Carbon Nanotubes in Improving Thermal Stability of Polymeric Fluids: Experimental and Modeling
, Article Industrial and Engineering Chemistry Research ; Volume 55, Issue 27 , 2016 , Pages 7514-7534 ; 08885885 (ISSN) ; Ghotbi, C ; Tahmasbi, K ; Ghazanfari, M. H ; Sharif University of Technology
American Chemical Society
2016
Abstract
At harsh conditions of high pressure high temperature (HPHT), polymers undergo thermal degradation leading to serious loss in fluid rheological and filtration properties. Nanoparticles are the most promising additives proposed to address this challenge. The stability of nanofluids is perused from various facets including rheological and filtration properties, shale stability, and zeta potential. The presence of nanoparticles could amazingly reduce the filtration at high temperatures even by 95%, and it also had a conspicuous effect on shale stability, thermal conductivity, and zeta potential. Experimental data were fit to rheological models to determine the best models describing the...
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 ©...
Development of a saturation-based μ(I)-rheology for wet granular materials using discrete element method
, Article Scientia Iranica ; Volume 28, Issue 5 B , 2021 , Pages 2719-2732 ; 10263098 (ISSN) ; Taghizadeh Manzari, M ; Hajilouy Benisi, A ; Sharif University of Technology
Sharif University of Technology
2021
Abstract
The present study employs Discrete Element Method (DEM) to establish a rheological model that relates the apparent viscosity of a granular material to shear rate, normal stress, and water saturation. In addition, a theoretical model was developed to determine water distribution and water-induced forces between particles for different saturations. The resulting forces were embedded in a 3D shear cell as a numerical rheometer, and a wet specimen was sheared between two walls. A power law rheological model was then obtained as a function of inertia number and saturation. It was found that up to a critical saturation, the apparent viscosity increased with saturation that was higher than that of...
Reduction of production rate in y-shaped microreactors in the presence of viscoelasticity
, Article Analytica Chimica Acta ; Volume 990 , 2017 , Pages 121-134 ; 00032670 (ISSN) ; Saidi, M. H ; Sadeghi, A ; Sharif University of Technology
Abstract
The viscoelasticity effects on the reaction-diffusion rates in a Y-shaped microreactor are studied utilizing the PTT rheological model. The flow is assumed to be fully developed and considered to be created under a combined action of electroosmotic and pressure forces. In general, finite-volume-based numerical simulations are conducted to handle the problem; however, analytical solutions based on the depthwise averaging approach are also obtained for the case for which there is no reaction between the inlet components. The analytical solutions are found to predict accurate results when the width to height ratio is at least 10 and acceptable results for lower aspect ratios. An investigation...
Insights into application of acorn shell powder in drilling fluid as environmentally friendly additive: filtration and rheology
, Article International Journal of Environmental Science and Technology ; 2020 ; Ramazani S. A, A ; Rukavishnikov, V ; Minaev, K ; Sharif University of Technology
Springer
2020
Abstract
Conventional additives used in drilling fluid may have detrimental short- and long-term impacts on the surrounding environment. The employment of biodegradable green material in drilling fluid as alternative additives will eliminate these harmful impacts. In this study, acorn shell powder is proposed as a novel biodegradable additive for application in drilling fluid. First, the acorn shell powder was prepared and then characterized in terms of chemical structure, particle size, and morphology. The acorn shell powder, with four different concentrations, was then introduced into a water-based fluid; its functionality in the fluid system was evaluated with respect to rheological and filtration...