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fluid-flow
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Fully implicit compositional thermal simulator using rigorous multiphase calculations
, Article Scientia Iranica ; Volume 18, Issue 3 C , June , 2011 , Pages 509-517 ; 10263098 (ISSN) ; Bozorgmehry Boozarjomehry, R ; Pishvaie, M. R ; Sharif University of Technology
2011
Abstract
Simulation of the in-situ combustion process is one of the most complex simulations amongst other reservoir flow simulations. Accurate simulation of the process is critical to obtain a successful implementation of the in-situ combustion process. Several factors impact performance of the simulation of this process. First are all the numerical models used for different sub-processes, such as reactions, fluid phase behavior, heat loss to surrounding formations and fluid physical properties. In the previous numerical models of the in-situ combustion process, very simplified models were used for the phase behavior of the fluid. Recent studies show that the fluid phase behavior model has a great...
Wettability alteration in carbonates during "Smart Waterflood": Underling mechanisms and the effect of individual ions
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 487 , 2015 , Pages 142-153 ; 09277757 (ISSN) ; Mousapour, M. S ; Ayatollahi, S ; Vossoughi, M ; Beigy, A. H ; Sharif University of Technology
Elsevier
2015
Abstract
There are increasing evidences that adjusting the chemistry of the injecting water improves the oil recovery efficiency. However, the underlying mechanisms for this technique which is referred to as "smart waterflood" have not yet been thoroughly understood. It is needed to explore the role of individual ions through set of different tests, to find the right mechanisms behind "smart waterflood". This study is focused on the fluid/solid (carbonate) interactions through systematic wettability measurement. Contact angle measurements accompanied by spontaneous imbibition tests were employed to determine the role of individual monovalent and divalent ions in wettability alteration process by...
Pore-scale simulation of fluid flow passing over a porously covered square cylinder located at the middle of a channel, using a hybrid MRT-LBM–FVM approach
, Article Theoretical and Computational Fluid Dynamics ; Volume 29, Issue 3 , 2015 , Pages 171-191 ; 09354964 (ISSN) ; Taeibi Rahni, M ; Jam, F ; Sharif University of Technology
Springer New York LLC
2015
Abstract
A comprehensive study was performed to analyze the unsteady laminar flow characteristics around a porously covered, a fully porous, and a solid squared section cylinder located in the middle of a plane channel. In order to simulate fluid flow inside porous media and porous–fluid interface accurately (minimizing modeling error), the porous region was analyzed in pore scale, using LBM. Additionally, to minimize the LBM-related compressibility error through the porous region, a multi-block multiple relaxation time lattice Boltzmann method (MRT-LBM) was used. Also, to decrease CPU time, a Navier–Stokes flow solver, based on finite volume method and SIMPLE algorithm, was coupled with MRT-LBM to...
A fluid-structure interaction model for stability analysis of shells conveying fluid
, Article Journal of Fluids and Structures ; Volume 26, Issue 5 , July , 2010 , Pages 747-763 ; 08899746 (ISSN) ; Noorian, M. A ; Haddadpour, H ; Sharif University of Technology
2010
Abstract
In this paper, a fluid-structure interaction model for stability analysis of shells conveying fluid is developed. This model is developed for shells of arbitrary geometry and structure and is based on incompressible potential flow. The boundary element method is applied to model the potential flow. The fluid dynamics model is derived by using an inflow/outflow model along with the impermeability condition at the fluid-shell interface. This model is applied to obtain the flow modes and eigenvalues, which are used for the modal representation of the flow field in the shell. Based on the mode shapes and natural frequencies of the shell obtained from an FEM model, the modal analysis technique is...
Pore-level investigation of heavy oil recovery during water alternating solvent injection process
, Article Transport in Porous Media ; Volume 83, Issue 3 , July , 2010 , Pages 653-666 ; 01693913 (ISSN) ; Farzaneh, S. A ; Kharrat, R ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
2010
Abstract
This study concerns with the microscopic and macroscopic fluid distribution and flow behavior during water alternating solvent (WAS) injection process to heavy oil using micromodel generated from thin section of a real rock which has rarely attended in the available literature. In this study, a one-quarter five-spot glass micromodel was deployed to examine the effect of flow media topology on microscopic displacements as well as macroscopic efficiency of WAS process. The micromodel was initially saturated with the heavy oil, and then the hydrocarbon solvent and water were injected alternately into it. The observations confirmed that WAS injection scheme is an effective method for the...
A numerical analysis of thermal conductivity, thermal dispersion, and structural effects in the injection part of the resin transfer molding process
, Article Journal of Porous Media ; Volume 13, Issue 4 , 2010 , Pages 375-385 ; 1091028X (ISSN) ; Karimi, M ; Seyf, H. R ; Sharif University of Technology
2010
Abstract
Thermal conductivity, thermal dispersion, and structural effects in resin transfer molding (RTM) process are studied numerically. The injection part of the RTM process is modeled as a transport of resin flow through a fibrous porous medium in a long rectangular channel. The fluid flow is modeled using the Darcy-Brinkman-Forchheimer model and the heat transfer process using the energy equation based on local thermal equilibrium assumption. Both isotropic and anisotropic heat transfer in porous media are investigated. The governing equations are solved numerically for the isotropic heat transfer case and analytically for the anisotropic case. The numerical results are fitted to the available...
Analysis of laminar flow in the entrance region of parallel plate microchannels for slip flow
, Article Proceedings of the 7th International Conference on Nanochannels, Microchannels, and Minichannels 2009, ICNMM2009, 22 June 2009 through 24 June 2009, Pohang ; Issue PART A , 2009 , Pages 345-352 ; 9780791843499 (ISBN) ; Asgarshamsi, A ; Saidi, M. H ; Sharif University of Technology
Abstract
Microscale fluid dynamics has received intensive interest due to the emergence of microelectromechanical systems (MEMS) technology. Fluid flow in microdevices has some characteristics which one of them is rarefaction effect related with gas flow. In this work, the steady state laminar rarefied gas flow in the entrance region of parallel plate microchannels is investigated by the integral method with slip flow conditions at solid surface. The effects of Knudsen number on friction factor and Nusselt number are presented in graphical form as well as analytical form. Also the effect of Knudsen number on hydrodynamic entry length is presented. The results show that as Knudsen number increases the...
Heat transfer and entropy generation analysis of hybrid graphene/Fe3O4 ferro-nanofluid flow under the influence of a magnetic field
, Article Powder Technology ; Volume 308 , 2017 , Pages 149-157 ; 00325910 (ISSN) ; Sadeghinezhad, E ; Akhiani, A. R ; Tahan Latibari, S ; Metselaar, H. S. C ; Kherbeet, A. S ; Mehrali, M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
The heat transfer characteristics and entropy generation rate of hybrid graphene-magnetite nanofluids under forced laminar flow that subjected to the permanent magnetic fields were investigated. For this purpose, a nanoscale reduced graphene oxide-Fe3O4 hybrid was synthesized by using graphene oxide, iron salts and tannic acid as the reductant and stabilizer. The thermophysical and magnetic properties of the hybrid nanofluid have been widely characterized and thermal conductivity has shown an enhancement of 11%. The experimental results indicated that the heat transfer enhancement of hybrid magnetite nanofluid compared to the case of distilled was negligible when no magnetic field was...
A numerical model for transient simulation of borehole heat exchangers
, Article Renewable Energy ; Volume 104 , 2017 , Pages 224-237 ; 09601481 (ISSN) ; Abbaspour, M ; Saidi, M. H ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A numerical model is developed to simulate the borehole heat exchanger both in the short and long time. In this regard, the computational domain is divided into the inside and outside borehole regions. A two-dimensional finite volume method is implemented in a cylindrical coordinate system for modeling of the outside borehole. Also, a thermal resistance-capacity model is presented for the borehole cross section. This model is extended to take into account the fluid transport through the U-tube and the temperature variation of the borehole components with depth. The governing equations of the two regions are solved iteratively in each time step. The proposed model is verified with the...
A sequential implicit discrete fracture model for three-dimensional coupled flow-geomechanics problems in naturally fractured porous media
, Article Journal of Petroleum Science and Engineering ; Volume 150 , 2017 , Pages 312-322 ; 09204105 (ISSN) ; Shamloo, A ; Dezfuli, A. D ; Sharif University of Technology
Abstract
A sequential implicit numerical method based on discrete-fracture model and the Galerkin Finite Element method, for time-dependent coupled fluid flow and geomechanics problems in fractured subsurface formations is presented. Discrete-fracture model has been used to explicitly represent the fracture network inside porous media. The Galerkin Finite Element method with adaptive unstructured gridding is implemented to numerically solve the spatially three-dimensional and time-dependent problem. The presented method is validated with previously obtained solutions. Two problems are numerically solved by applying the presented methodology in a three-dimensional fractured petroleum reservoir under...
Electrokinetic properties of asphaltene colloidal particles: determining the electric charge using micro electrophoresis technique
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 541 , 2018 , Pages 68-77 ; 09277757 (ISSN) ; Abolghasemi, E ; Hosseini, A ; Ayatollahi, S ; Dehghani, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this work, the electrokinetic properties of asphaltene particles have been investigated. Micro-electrophoresis method by applying DC electric field, was utilized to different mixtures containing asphaltene to determine its electric charge. It was observed that in the case of using n-heptane and its mixture with toluene (heptol), the asphaltene particles were showed to be positively charged however for toluene itself, they expressed no tendency toward the electrodes. While it is expected that larger asphaltene aggregates carry higher electric charge, the results contradictorily showed that they are mainly governed by gravity rather than electro-static force and that “aggregation” reduces...
Igniter jet dynamics in solid fuel ramjets
, Article Acta Astronautica ; Volume 64, Issue 2-3 , 2009 , Pages 166-175 ; 00945765 (ISSN) ; Farshchi, M ; Sharif University of Technology
2009
Abstract
The dynamics of a two dimensional plane jet injected at the base of a step, parallel to the wall, in backward facing step flow geometry is numerically studied. The objective of this work is to gain insight into the dynamics of the igniter flow field in solid fuel ramjet motors. Solid fuel ramjets operate by ingestion of air and subsequent combustion with a solid fuel grain such as polyethylene. The system of governing equations is solved with a finite volume approach using a structured grid in which the AUSM+ scheme is used to calculate the convective fluxes. The Spalart and Allmaras turbulence model is used in these simulations. Experimental data have been used to validate the flow solver...
Theoretical and experimental study of microstructures and weld pool geometry during GTAW of 304 stainless steel
, Article International Journal of Advanced Manufacturing Technology ; Volume 42, Issue 11-12 , 2009 , Pages 1043-1051 ; 02683768 (ISSN) ; Farzadi, A ; Serajzadeh, S ; Kokabi, A. H ; Sharif University of Technology
2009
Abstract
In this work, temperature field and weld pool geometry during gas tungsten arc welding of 304 stainless steel are predicted by solving the governing equations of heat transfer and fluid flow under quasi-steady state conditions. The model is based on numerical solution of the equations of conservation of mass, momentum, and energy in the weld pool. Weld pool geometry, weld thermal cycles, and various solidification parameters are then calculated by means of the model predictions. The model considers the effects of various process parameters including welding speed and heat input. It is found that the weld pool geometry, predicted by the proposed model, is in reasonable agreement with the...
An exact analytical model for fluid flow through finite rock matrix block with special saturation function
, Article Journal of Hydrology ; Volume 577 , 2019 ; 00221694 (ISSN) ; Abbasi, M ; Ghazanfari, M. H ; Sharifi, M ; Kazemi, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
An exact analytical solution for one-dimensional fluid flow through rock matrix block is presented. The nonlinearity induced from flow functions makes the governing equations describing this mechanism difficult to be analytically solved. In this paper, an analytical solution to the infiltration problems considering non-linear relative permeability functions is presented for finite depth, despite its profound and fundamental importance. Elimination of the nonlinear terms in the equation, as a complex and tedious task, is done by applying several successive mathematical manipulations including: Hopf-Cole transformation to obtain a diffusive type PDE; an exponential type transformation to get a...
A multiphysics model for analysis of droplet formation in electrohydrodynamic 3D printing process
, Article Journal of Aerosol Science ; Volume 135 , 2019 , Pages 72-85 ; 00218502 (ISSN) ; Movahhedy, M. R ; Khodaygan, S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Electrohydrodynamic (EHD) printing is a novel technology used for fabricating high-resolution part features from a wide range of materials. Due to the multiphysics dynamics and the multiphase nature of the microdroplet formation in the EHD printers, modeling of this phenomenon is complicated. In this paper, the formation of a droplet in an EHD printer—under a pulsed electrical field—is simulated using a new numerical model which couples the fluid flow, the electric field distribution and the movement of the electric charges under dynamic and transient conditions. The level-set method is applied to the entire multiphysics domain in order to study the formation of the droplet. The presented...
A mechanobiological mathematical model of liver metabolism
, Article Biotechnology and Bioengineering ; Volume 117, Issue 9 , 5 June , 2020 , Pages 2861-2874 ; Firoozabadi, B ; Munn, L. L ; Sharif University of Technology
John Wiley and Sons Inc
2020
Abstract
The liver plays a complex role in metabolism and detoxification, and better tools are needed to understand its function and to develop liver-targeted therapies. In this study, we establish a mechanobiological model of liver transport and hepatocyte biology to elucidate the metabolism of urea and albumin, the production/detoxification of ammonia, and consumption of oxygen and nutrients. Since hepatocellular shear stress (SS) can influence the enzymatic activities of liver, the effect of SS on the urea and albumin synthesis are empirically modeled through the mechanotransduction mechanisms. The results demonstrate that the rheology and dynamics of the sinusoid flow can significantly affect...
Comprehensive simulation of the effects of process conditions on plasma enhanced chemical vapor deposition of silicon nitride
, Article Semiconductor Science and Technology ; Volume 23, Issue 9 , 22 August , 2008 ; 02681242 (ISSN) ; Ilati, H ; Rashidian, B ; Sharif University of Technology
2008
Abstract
A numerical model for the deposition of silicon nitride using silane and ammonia mixture in a radio frequency plasma reactor has been developed. Plasma enhanced chemical vapor deposition process is simulated by combined analysis for the glow discharge, fluid flow and chemical reactions. The main goal is to investigate the effect of variations of the process parameters on the deposition rate, and uniformity of the resulting layer. The approach used is based on the theoretical partial differential equation models, without any empirical approximation of the critical data being used. Owing to the fact that the relevant equations are highly nonlinear, the discretization method is of great...
Characterization of fracture dynamic parameters to simulate naturally fractured reservoirs
, Article International Petroleum Technology Conference, IPTC 2008, Kuala Lumpur, 3 December 2008 through 5 December 2008 ; Volume 1 , 2008 , Pages 473-485 ; 9781605609546 (ISBN) ; Siavoshi, J ; Parvizi, H ; Esmaili, S ; Karimi, M. H ; Nasiri, A ; Sharif University of Technology
2008
Abstract
Fractures identification is essential during exploration, drilling and well completion of naturally fractured reservoirs since they have a significant impact on flow contribution. There are different methods to characterize these systems based on formation properties and fluid flow behaviour such as logging and testing. Pressure-transient testing has long been recognized as a reservoir characterization tool. Although welltest analysis is a recommended technique for fracture evaluation, but its use is still not well understood. Analysis of pressure transient data provides dynamic reservoir properties such as average permeability, fracture storativity and fracture conductivity.An infusion of...
Hydrodynamics analysis of Density currents
, Article International Journal of Engineering, Transactions B: Applications ; Volume 21, Issue 3 , 2008 , Pages 211-226 ; 1728-144X (ISSN) ; Firoozabadi, B ; Rad, M ; Sharif University of Technology
Materials and Energy Research Center
2008
Abstract
Density Current is formed when a fluid with heavier density than the surrounding fluid flows down an inclined bed. These types of flows are common in nature and can be produced by; salinity, temperature inhomogeneities, or suspended particles of silt and clay. Driven by the density difference between inflow and clear water in reservoirs, density current plunges clear water and moves towards a dam, while density current flows on a sloping bed. The vertical spreading due to water entrainment has an important role in determining the propagation rate in the longitudinal direction. In this work, two-dimensional steady-state salt solutions' density currents were investigated by means of...
Active queue management of TCP/IP networks using rule-based predictive control
, Article 2007 IEEE International Symposium on Industrial Electronics, ISIE 2007, Caixanova - Vigo, 4 June 2007 through 7 June 2007 ; 2007 , Pages 77-82 ; 1424407559 (ISBN); 9781424407552 (ISBN) ; Bigdeli, N ; Haeri, M ; Sharif University of Technology
2007
Abstract
Model predictive controllers, due to their capability to control the time variant and delayed systems, are considered for congestion control in computer networks. To extend the application of these controllers as an active queue management (AQM) system in dynamic TCP/IP networks, a new rule-based predictive controller is proposed. This controller uses the small signal linearized fluid-flow model of the TCP/IP networks and simulates the future behavior of control system by applying few candidate control sequences. Using the extremes of the resulted predicted output sequences, optimal control signal is determined based on some appropriate rules. This approach benefits from the mentioned...