Loading...
Search for:
flow-modeling
0.007 seconds
Total 102 records
Investigating Sediment Transport in Deep Reservoirs Using the 3D Numerical Model MIKE3
, M.Sc. Thesis Sharif University of Technology ; Shamsai, Abolfazl (Supervisor) ; Ghaemial, Mohsen (Supervisor)
Abstract
Nowadays, in the world and our country, Iran, sediment transport and the phenomenon of sedimentation are of great importance. The entry of water flow with suspended sediments into the dam reservoir by floods with different return periods during the initial period of dam construction causes a considerable part of the helpful volume of the reservoir to be filled with sediments. As a result, the discharge of these sediments and the methods that exist in this field should be studied so that a large volume of reservoir water is not wasted during the discharge of these sediments. In this research, the opening time and extent of the bottom outlets of Qeshlaq Dam when the flood enters the reservoir...
Gorgan Bay Water Salinity Modeling under the Scenario of Water Transfer from Caspian Sea by Pipeline
, M.Sc. Thesis Sharif University of Technology ; Raie, Mohamad (Supervisor)
Abstract
Gorgan Bay and Miankaleh Wetland have been exposed to various environmental risks in the past years due to the decrease in the Caspian water level and the subsequent decrease in the water level of these water bodies. 2 channels, Chapgoli and Ashuradeh, are the only ways connecting the Gulf with the Caspian Sea. If the water level of the Caspian Sea and the Gulf continue to decrease, these 2 channels will be completely blocked and the connection between the Gulf and the sea will be completely closed. Due to the low depth of the bay and high evaporation on this water body, the blockage of these 2 channels will eventually lead to drying up of the bay or changing the flora and fauna of the area....
Numerical Simulation of Oil Spill in Gheshm Channel
, M.Sc. Thesis Sharif University of Technology ; Raie, Mohammad (Supervisor) ; Ataie Ashtiani, Behzad (Supervisor)
Abstract
To meet the growing energy demand worldwide, oil and gas exploration and production activities have increased rapidly both in onshore and offshore areas. The produced oil from the ocean bed is transported onshore either by ship or pipeline. This has increased the risk of oil spill in the coastal areas. In order to prepare an emergency preparedness plan and to assess the magnitude of risk involved in transporting and offloading oil, oil spill simulation studies play an important role. This research describes a simulation of oil spill in coastal area of Persian Gulf, near Hormoz Strait which is called Gheshm Channel (Khouran Strait), using MIKE 21 model. The Gheshm Channel contains huge...
Field Scale Characterization of Geological Formations Using Percolation Theory
, Article Transport in Porous Media ; Vol. 92, issue. 2 , March , 2012 , p. 357-372 ; ISSN: 1693913 ; Masihi, M ; Shojaei, A ; Pishvaie, M ; King, P. R ; Sharif University of Technology
Abstract
The connectivity of high conductivity pathways in geological formations depend on the spatial distribution of geological heterogeneities that may appear on various length scales. Appropriate modeling of this is crucial within in hydrology and petroleum systems. The approach taken in this study is to use percolation theory to quantify the connectivity, hydraulic conductivity, and breakthrough time behavior between an injector and a producer within such systems. In particular, a three-dimensional overlapping sandbody model is considered which assumes that the geological formation can be split into either conductive flow units (i. e., good sands) or non-conductive units (i. e., poor sands). The...
The unsteady behavior of subsonic wind tunnel wall pressure during pitching motion of the model
, Article Scientia Iranica ; Vol.21, issue.1 , 2014 , p. 192-202 ; 10263098 ; Soltani, M. R ; Ghaeminasab, M ; Sharif University of Technology
Abstract
Extensive low speed wind tunnel experiments have been undertaken to measure the test section, oor wall pressure distribution, in the presence of a 2D wing inside the test section. The experiments were performed for both the static and dynamic pitching motion of the model under difierent conditions. In these measurements, the efiects of the existence and oscillations of a 2D wing on the oor wall pressure at various locations were studied. According to the results, as the oscillation parameters, such as mean angle of attack and frequency, change, wall pressures at the points located in the front part of the test section, in the upstream region, exhibit difierent behavior from those in the...
Discharge coefficient of a rectangular labyrinth weir
, Article Proceedings of the Institution of Civil Engineers: Water Management ; Volume 166, Issue 8 , September , 2013 , Pages 443-451 ; 17417589 (ISSN) ; Javaheri, A ; Borghei, S. M ; Sharif University of Technology
2013
Abstract
A rectangular labyrinth weir has a very good flood release capacity as well as strong economical and structural advantages. In this study, combined analytical and experimental investigations were undertaken for a rectangular labyrinth weir. The analytical model is based on the synthesis of general weir equations and spatially varied flow dynamic equations. A comprehensive set of experiments led to characterisation of the flow behaviour for low and high heads over the weir and indicated the influences of weir geometry on the release capacity. The results show that this type of weir represents an effective weir alternative and could be five times more efficient than a corresponding traditional...
A novel two-parameter relative permeability model
, Article Journal of Porous Media ; Volume 15, Issue 11 , 2012 , Pages 1061-1066 ; 1091028X (ISSN) ; Bolouri, S. H ; Sharif University of Technology
B. House
2012
Abstract
The relative permeability curves are key factors for assessment of reservoir performance by numerical simulators. The widely used one-parameter models are not sufficiently flexible for fitting laboratory measured relative permeability data. These models only show a concave upward trend and cannot represent the S-shape behavior of relative permeability. The other three-parameter models are too complex to use in practical reservoir engineering calculations. In this paper, a novel two-parameter model is proposed that maintains the simplicity of previous models while having great flexibility over a full range of saturation. The two parameters L and U control the shape of the lower and upper part...
Experimental investigation of baffle effect on the flow in a rectangular primary sedimentation tank
, Article Scientia Iranica ; Volume 17, Issue 4 B , 2010 , Pages 241-252 ; 10263098 (ISSN) ; Firoozabadi, B ; Sharif University of Technology
2010
Abstract
In primary sedimentation tanks, short-circuiting enlargement of dead zones and high flow mixing problems are caused by circulation regions (dead zones), which can reduce the optimal sedimentation of particles. For proper design of such tanks, the formation of recirculation zones should be avoided. The provision of a baffle as a geometrical modification of a tank may influence the flow field for better sedimentation. Thus, in this study, velocity measurements were performed by a three-dimensional Acoustic Doppler Velocimeter (ADV) to investigate baffle effects on the velocity distribution in a primary rectangular sedimentation tank, quantitatively. Effects of baffle positioning were also...
Generation of Voronoi grid based on vorticity for coarse-scale modeling of flow in heterogeneous formations
, Article Transport in Porous Media ; Volume 83, Issue 3 , Oct , 2010 , Pages 541-572 ; 01693913 (ISSN) ; Mahani, H ; Sharif University of Technology
2010
Abstract
We present a novel unstructured coarse grid generation technique based on vorticity for upscaling two-phase flow in permeable media. In the technique, the fineness of the gridblocks throughout the domain is determined by vorticity distribution such that where the larger is the vorticity at a region, the finer are the gridblocks at that region. Vorticity is obtained from single-phase flow on original fine grid, and is utilized to generate a background grid which stores spacing parameter, and is used to steer generation of triangular and finally Voronoi grids. This technique is applied to two channelized and heterogeneous models and two-phase flow simulations are performed on the generated...
Duct design in subsonic and supersonic flow regimes with and without normal shock waves using Flexible String Algorithm
, Article Scientia Iranica ; Volume 17, Issue 3 B , MAY-JUNE , 2010 , Pages 179-193 ; 10263098 (ISSN) ; Durali, M ; Hajilouy Benisi, A ; Ghadak, F ; Sharif University of Technology
2010
Abstract
In this investigation, the Flexible String Algorithm (FSA) used before for the inverse design of 2D subsonic ducts is developed and applied for the inverse design of subsonic and supersonic ducts with and without normal shock waves. In this method, the duct wall shape is changed under a novel algorithm based on the deformation of a virtual flexible string in a flow. Deformation of the string due to the local fl.ow conditions resulting from changes in the wall geometry is performed until the target shape satisfying the. prescribed walls pressure distribution is achieved. The flow field at each shape modification step is analyzed using an Euler equation solution by the. A USM method. Some...
Improvement of airlift pump performance based on the exergy analysis
, Article Proceedings of the 23rd International Conference on Efficiency, Cost, Optimization, Simulation, and Environmental Impact of Energy Systems, ECOS 2010, 14 June 2010 through 17 June 2010, Lausanne ; Volume 1 , 2010 , Pages 489-497 ; 9781456303006 (ISBN) ; Hanafizadeh, P ; Gholampour, P ; Shams, H ; Saidi, M. H ; Sharif University of Technology
Aabo Akademi University
2010
Abstract
Airlift systems (ALS) are widely used in various fields such as petroleum and oil extracting industries. As gas-liquid two phase flow is the main part of the flow through these systems, the analysis of such systems accompanies with problems of two phase flow modeling. However, exergy analysis could be a simple method for modeling of airlift systems. In the present study, an analytical model based on thermodynamic principles has been implemented on each phase to analyze the performance of airlift systems. The experimental data were collected at a large scale multiphase flow test rig for the airlift pump with 6m height and diameter of 50 mm. Finally, irreversibility terms, energy destruction,...
Numerical study of AN ion injection EHD micropump
, Article Proceedings of the 7th International Conference on Nanochannels, Microchannels, and Minichannels 2009, ICNMM2009, 22 June 2009 through 24 June 2009 ; Issue PART A , 2009 , Pages 179-185 ; 9780791843499 (ISBN) ; Saidi, M. S ; Saidi, M. H ; Sharif University of Technology
Abstract
The purpose of this study is to carry out a numerical investigation of injection type EHD pumps. To this end, the flow is considered laminar, steady and incompressible flow. The flow model is based on the assumptions that the fluid is Newtonian and the fluid properties are constant. The results show that all of the ions emitted from emitter are not collected by next collector electrode, but some of this injected ions move to the previous one, which causes back flow. Although this back flow is smaller than net pumping flow but it would reduce the net flow. Because of existence of this back flow, finding the optimum distance of electrodes from each other is necessary. This study shows that...
Effect of active feather length on aerodynamic performance of airfoils at low reynolds number flow
, Article AIAA AVIATION 2020 FORUM, 15 June 2020 through 19 June 2020 ; Volume 1 PartF , 2020 ; Darbandi, M ; Schneider, G. E ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc, AIAA
2020
Abstract
To increase the flight endurance of a Micro air vehicle (MAVs), which operates at low Reynolds number flow, one way is to harvest energy during its flight. By inspiring from the nature when all the birds use their feathers to control and distribute their power along the flying time, a solution might be design of a piezoelectric plate as feathers, which scavenges energy directly from the fluid flow. Cantilevered beam with piezo-ceramic layer undergoing vortex-induced vibrations can convert the mechanical energy available from the ambient environment to a usable electrical power. Since a flow-driven piezoelectric composite beam takes a form of natural three-way coupling of the turbulent fluid...
Model based compressor fault identification using stage stacking technique and nonlinear diagnostic systems
, Article Proceedings of the ASME Turbo Expo, 9 June 2008 through 13 June 2008, Berlin ; Volume 2 , 2008 , Pages 213-221 ; 9780791843123 (ISBN) ; Khaledi, H ; Ghofrani, M. B ; International Gas Turbine Institute ; Sharif University of Technology
2008
Abstract
Compressor fault identification is an important part of gas turbine diagnostic systems. Model based techniques have been used widely in this field. In this paper the performance of two compressors has been simulated using stage stacking method. One of them is the NASA 10 stage constant tip diameter compressor. The other one is the Siemens V94.2 engine's compressor. Then a new and more real compressor fault model is introduced and the effect of different faults on compressor performance has been studied. In this paper an intelligent fault diagnostic system has been developed which is able to detect different faults of the compressor. In all of the cases of faults, degradation in inlet flow...
Using vorticity as an indicator for the generation of optimal coarse grid distribution
, Article Transport in Porous Media ; Volume 75, Issue 2 , 2008 , Pages 167-201 ; 01693913 (ISSN) ; Firoozabadi, B ; Mahani, H ; Sharif University of Technology
2008
Abstract
An improved vorticity-based gridding technique is presented and applied to create optimal non-uniform Cartesian coarse grid for numerical simulation of two-phase flow. The optimal coarse grid distribution (OCGD) is obtained in a manner to capture variations in both permeability and fluid velocity of the fine grid using a single physical quantity called "vorticity". Only single-phase flow simulation on the fine grid is required to extract the vorticity. Based on the fine-scale vorticity information, several coarse grid models are generated for a given fine grid model. Then the vorticity map preservation error is used to predict how well each coarse grid model reproduces the fine-scale...
Onset of convection in a horizontal porous channel with uniform heat generation using a thermal nonequilibrium model
, Article Transport in Porous Media ; Volume 69, Issue 3 , 2007 , Pages 343-357 ; 01693913 (ISSN) ; Noghrehabadi, A. R ; Rees, D. A. S ; Sharif University of Technology
2007
Abstract
This paper considers the onset of free convection in a horizontal fluid-saturated porous layer with uniform heat generation. Attention is focused on cases where the fluid and solid phases are not in local thermal equilibrium, and where two energy equations describe the evolution of the temperature of each phase. Standard linearized stability theory is used to determine how the criterion for the onset of convection varies with the inter-phase heat transfer coefficient, H, and the porosity-modified thermal conductivity ratio, γ. We also present asymptotic solutions for small values of H. Excellent agreement is obtained between the asymptotic and the numerical results. © Springer...
Reservoir flow simulation using combined vorticity-based gridding and multi-scale upscaling
, Article Society of Petroleum Engineers - SPE Asia Pacific Oil and Gas Conference and Exhibition 2007 ""Resources, Professionalism, Technology: Time to Deliver"", Jakarta, 30 October 2007 through 1 November 2007 ; Volume 2 , 2007 , Pages 927-946 ; 9781604238594 (ISBN) ; Ashjari, M. A ; Firoozabadi, B ; Sharif University of Technology
Society of Petroleum Engineers (SPE)
2007
Abstract
A novel technique for upscaling of detailed geological reservoir descriptions is presented. The technique aims at reducing both numerical dispersion and homogenization error, generated due to incorporating a coarse computational grid and assigning effective permeability to coarse grid blocks respectively. In particular we consider implicit-pressure explicit-saturation (IMPES) scheme where homogenization error impacts the accuracy of the coarse grid solution of the pressure equation. To reduce the homogenization error, we employ the new vorticity-based gridding that generates a non-uniform coarse grid with high resolution at high vorticity zones. In addition, to control numerical dispersion,...
A model for prediction of flow behavior and temperature distribution during warm rolling of a low carbon steel
, Article Materials and Design ; Volume 27, Issue 7 , 2006 , Pages 529-534 ; 02641275 (ISSN) ; Sharif University of Technology
2006
Abstract
A two-dimensional finite element analysis is coupled with dynamic recovery and dynamic strain aging models to achieve metal flow during warm deformation of a low carbon steel. In order to assess metal behavior, compression experiments are utilized under warm deformation conditions and the results are used in the model and temperature and velocity fields are predicted with regard to the effects of dynamic recovery and dynamic strain aging. In addition, warm rolling tests are performed to verify the modelling results. Comparison between the predicted and measured roll forces shows reliability of the employed model. © 2005 Elsevier Ltd. All rights reserved
Experimental and modelling study of gravity drainage in a three-block system
, Article Transport in Porous Media ; Volume 136, Issue 2 , 2021 , Pages 471-494 ; 01693913 (ISSN) ; Karimi Malekabadi, A ; Ghazanfari, M. H ; Rostami, B ; Sharif University of Technology
Springer Science and Business Media B.V
2021
Abstract
Gravity drainage is known as the controlling mechanism of oil recovery in naturally fractured reservoirs. The efficiency of this mechanism is controlled by block-to-block interactions through capillary continuity and/or reinfiltration processes. In this study, at first, several free-fall gravity drainage experiments were conducted on a well-designed three-block apparatus and the role of tilt angle, spacers’ permeability, wettability and effective contact area (representing a different status of the block-to-block interactions between matrix blocks) on the recovery efficiency were investigated. Then, an experimental-based numerical model of free-fall gravity drainage process was developed,...
A new multiscale modeling framework for investigating thermally-induced flow maldistribution in multi-stream plate-fin heat exchangers
, Article International Journal of Heat and Mass Transfer ; Volume 180 , 2021 ; 00179310 (ISSN) ; Saidi, M. H ; Hannani, S. K ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Multi-stream Plate-fin heat exchangers (MSPFHEs) are among the most efficient heat exchangers in energy-based industries. They should be carefully designed to have maximum effectiveness and to avoid wasting energy. Flow maldistribution could significantly degrade the performance of heat exchangers. This study presents a novel modeling framework to capture the thermally-induced maldistribution in two-phase MSPFHEs. The developed model is used to show how thermally-induced flow maldistribution affects the performance of the heat exchanger, and some possible modifications are investigated to reduce its consequences. Our case study results show that thermally-induced maldistribution decreases...