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Air Pollution Modeling, Using AERMOD Model Coupled with OpenFOAM Software
, M.Sc. Thesis Sharif University of Technology ; Tayyebi Rahni, Mohammad (Supervisor) ; Rashidi, Yousef (Supervisor)
Abstract
Over the course of past decade, air pollution has been placed among the top issues chocking capital Tehran. Stationary source of air pollution is among the most important, but, less treated facors. On the year, 2014, Tehran’s air quality company addressed a number of projects in this very field could gain further governmental supports. This announcement could be a sign, showing the importance of this research. These researches in fact, have the potentioal to increase the authority’s decision making abilities in critical situations. As the models prognosticates future with acceptble accuracy, it leads to highly efficient dicissions. The results could also be used in demographic studies as...
The Effect of Radiation Pressure on Dust and Gas Dynamics in Accretion Disks
, M.Sc. Thesis Sharif University of Technology ; Rahvar, Sohrab (Supervisor)
Abstract
The purpose of this study is to investigate the effect of radiation pressure on accretion disks. The radiation density causes the separation of electrons from ions which leads to the creation of an internal electric dipole. In this study Radiation density is calculated using the Eddington limit. Afterwards radiation pressure is calculated with the use of collisions between photons and electrons in the plasma. Collisions are assumed to happen only between photons and electrons, due to the larger cross section of electrons compared to protons. The mentioned assumption causes the creation of an electric dipole and with it an internal electric field. The separation of the charges is assumed to...
Simulation of elasto-plastic deformations in composites by flow rules
, Article Indian Journal of Science and Technology ; Vol. 7, issue. 2 , 2014 , pp. 180-184 ; ISSN: 09746846 ; Fazaeli, D ; Daneshmand, S ; Shafaghatian, N ; Sharif University of Technology
Abstract
In this paper, a novel model is proposed to predict stress behavior in the fibrous polymer composites under an applied tensile axial loading. Tangential stress is obtained by simulating between polymeric matrix flow (polyester) and fluid flow. In the other words, creep behavior of the petrochemical material or polymeric resin (matrix) is modeled using fluid flow theory. Furthermore, behavior of the shear stress is predicted by suitable mathematical functions. Finally, important relation is extracted by combining the solid and fluid mechanics formulations
Details study of ambient wind effect on heat dissipation capacity of thermal-powerplant dry cooling-towers
, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Volume 1A , August 3–7 , 2014 , pp. V01AT03A017 ; ISSN: 08888116 ; ISBN: 9780791846216 ; Behrouzifar, A ; Mirhashemi, A ; Salemkar, H ; Schneider, G. E ; Sharif University of Technology
Abstract
Thermal powerplants report a reduction in their dry cooling tower performances due to surrounding wind drafts. Therefore, it is very important to consider the influence of wind velocity in cooling tower design; especially in geographical points with high wind conditions. In this regard, we use the computational fluid dynamics (CFD) tool and simulate a dry cooling tower in different wind velocities of 0, 5 and 10 m/s. To extend our calculations; we also consider the temperature variation of circulating water through the tower heat exchanger or deltas one-by-one. We show that some heat exchangers around the tower cannot reduce the circulating water temperature sufficiently. This causes an...
Reacting turbulent flow simulation to improve the mixing process in an oil refinery incinerator
, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Vol. 1C, issue , August , 2014 ; ISBN: 9780791846230 ; Abrar, B ; Barezban, M. B ; Faridvand, A ; Schneider, G. E ; Sharif University of Technology
Abstract
Combustion emission is one of the most important issues in the design of industries. Todays' strict environmental standards have limited the productions of CO, NOx, SOx, and other hazardous pollutants from the related industries. In this work, we study a typical oil refinery incinerator, which is used to burn waste gases residue produced during bitumen production process. The waste gas mainly includes a mixture including N2, H2O-vapor, and O2 species. Additionally, there are significant amounts of CO species and CxHy droplets in the waste gas composition. The measurements show that the CO emission becomes so crucial in high flow rate of feeding waste gas to the incinerator. Here, we...
Theoretical-experimental investigation of Co emission from an oil refinery incinerator
, Article American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM ; Vol. 1C, issue , 2014 ; Abrar, B ; Yazdi, M. K ; Zeinali, M ; Schneider, G. E ; Sharif University of Technology
Abstract
In this paper, we investigate the CO emission from an oil refinery gas incinerator both theoretically and experimentally. At the beginning of this research, our collected data from this incinerator showed that the CO contamination would be far exceeding the permissible environmental standards at the stack exhaust. Therefore, we decided to perform a combined theoretical-experimental study to find a reasonable solution to reduce the CO pollution suitably. Our theoretical study showed that a reliable solution would be to increase the incinerator operating temperature. However, we needed to collect some data from this incinerator to examine if our achieved analytical solution would work...
Experimental analysis of secondary gas injection strategies
, Article Petroleum Science and Technology ; Volume 31, Issue 8 , 2013 , Pages 797-802 ; 10916466 (ISSN) ; Alizadeh, N ; Kharrat, R ; Ghazanfari, M. H ; Laki, A. S ; Sharif University of Technology
2013
Abstract
CO2 injection is a potentially viable method of enhanced oil recovery for medium oil reservoirs. The authors compare the effect of gas injection strategy (simultaneous water-alternating gas [SWAG], water-alternating gas [WAG], and continuous gas injection [CGI]) on recovery in immiscible, near-miscible, and miscible modes of injection. It has been proved that CGI is not the most efficient injection scenario in oil-wet reservoirs. Miscible and near-miscible core flood tests demonstrated high oil recoveries in all injection strategies due to high capillary numbers achieved as a result of miscibility. The fluid mechanics of floods were discussed using pressure drop data, different mechanics was...
Effect of varying aspect ratio on relative stability for graphene nanoribbon interconnects
, Article Applied Mechanics and Materials, 24 July 2012 through 26 July 2012 ; Volume 229-231 , November , 2012 , Pages 205-209 ; 16609336 (ISSN) ; 9783037855102 (ISBN) ; Faez, R ; Nasiri, S. H ; Davoodi, B ; Sharif University of Technology
2012
Abstract
Achieving dense off-chip interconnection with satisfactory electrical performance is emerging as a major challenge in advanced system engineering. Graphene nanoribbons (GNRs) have been recently proposed as one of the potential candidate materials for both transistors and interconnect. In addition, development is still underway for alternative materials and processes for high aspect ratio (AR) contacts. Studding the effect of varying aspect ratio on relative stability of graphene nanoribbon interconnects is an important viewpoint in performance evaluation of system. In this paper, Nyquist stability analysis based on transmission line modeling (TLM) for GNR interconnects is investigated. In...
Proposal of a new design for valveless micropumps
, Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1261-1266 ; 10263098 (ISSN) ; Movahhedy, M. R ; Assempour, A ; Sharif University of Technology
2011
Abstract
A new design for a valveless micropumping device has been proposed that integrates two existing pumping technologies, namely, the wall induced traveling wave and the obstacle-type valveless micropump. The liquid in the microchannel is transported by generating a traveling wave on the channel, while the placing of two asymmetric trapezoid obstacles, along the centerline of the channel inlet and outlet, leads to a significant (up to seven times) increase of the net flow rate of the device. The effectiveness of this innovative design has been proved through a verified three-dimensional finite element model. FluidStructure Interaction (FSI) analysis is performed in the framework of an Arbitrary...
Two phase modal analysis of nonlinear sloshing in a rectangular container
, Article Ocean Engineering ; Volume 38, Issue 11-12 , August , 2011 , Pages 1277-1282 ; 00298018 (ISSN) ; Firouz Abadi, R. D ; Ghasemi, M ; Sharif University of Technology
2011
Abstract
Sloshing, or liquid free surface oscillation, in containers has many important applications in a variety of engineering fields. The modal method can be used to solve linear sloshing problems and is the most efficient reduced order method that has been used during the previous decade. In the present article, the modal method is used to solve a nonlinear sloshing problem. The method is based on a potential flow solution that implements a two-phase analysis on sloshing in a rectangular container. According to this method, the solution to the mass conservation equation, with a nonpenetration condition at the tank walls, results in velocity potential expansion; this is similar to the mode shapes...
Hydrodynamic and electrochemical modeling of vanadium redox flow battery
, Article Mechanics and Industry ; Volume 16, Issue 2 , 2015 ; 22577777 (ISSN) ; Elyasi, S ; Mollazadeh, M ; Sharif University of Technology
EDP Sciences
2015
Abstract
Two and three dimensional modeling of a single cell of vanadium redox flow battery has been done thoroughly according to electrochemical and fluid mechanic equations in this study. The modeling has been done in stationary state and its results have been presented in three chemical, electrical and mechanical sub models. The parametric analysis on some of important factors in cell operation demonstrated that increase in electrode and membrane conductivity and electrode porosity contributes to electric potential increase in cells. Also operational temperature increase leads to decrease in cells' voltage. Better fluid distribution on the electrode surface area results in better cell operation,...
Numerical investigation of thermo fluid mechanics of differentially heated rotating tubes
, Article Heat Transfer Engineering ; Volume 31, Issue 3 , 2010 , Pages 201-211 ; 01457632 (ISSN) ; Farhanieh, B ; Sharif University of Technology
2010
Abstract
Three-dimensional simulation of incompressible flow in rotating tubes for both laminar and turbulent flows has been performed using a finite-volume method for elliptic flows. The influence of Reynolds number on the velocity field and the effects of temperature gradient on temperature profiles have been presented by numerical simulations. Also the effects of velocity field, flow regime, and temperature distribution along the tube have been studied from different points of view. The results have been calculated for rotational Reynolds numbers ranging from 1000 to 320,000. The comparisons between numerically calculated velocity field and the Nusselt number have shown satisfactory agreement with...
Entropy minimization in turbine cascade using continuous adjoint formulation
, Article Engineering Optimization ; Volume 48, Issue 2 , 2016 , Pages 213-230 ; 0305215X (ISSN) ; Mazaheri, K ; Sharif University of Technology
Taylor and Francis Ltd
Abstract
A complete continuous adjoint formulation is presented here for the optimization of the turbulent flow entropy generation rate through a turbine cascade. The adjoint method allows one to have many design variables, but still afford to compute the objective function gradient. The new adjoint system can be applied to different structured and unstructured grids as well as mixed subsonic and supersonic flows. For turbulent flow simulation, the k-ω shear-stress transport turbulence model and Roe's flux function are used. To ensure all possible shape models, a mesh-point method is used for design parameters, and an implicit smoothing function is implemented to avoid the generation of non-smoothed...
Numerical analysis of coherent structures in bidirectional swirl combustion chamber
, Article Computational Thermal Sciences ; Volume 8, Issue 3 , 2016 , Pages 265-289 ; 19402503 (ISSN) ; Keshavarz, P. M ; Saidi, M. H ; Sharif University of Technology
Begell House Inc
Abstract
Analysis and identification of vortex structures and their formation, particularly in swirl flows, have received widespread interest among researchers in the field of fluid mechanics. Due to the importance of vortex structures and their applications in combustion chambers, a special type of combustion chamber, which is called a “bidirectional swirl combustor,” has been investigated in this work. The dependence of vortex structures on the combustion chamber geometry and fuel injection location in cold flow, the effect of hot flow on coherent structures, and the difference between vortex structures in hot and cold flows have been studied as well. A common characteristic which is in combustion...
Discharge capacity of conventional side weirs in supercritical conditions
, Article 4th European Congress of the International Association of Hydroenvironment engineering and Research, IAHR 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 658-664 ; 9781138029774 (ISBN) ; Jalili Ghazizadeh, M. R ; Kabiri Samani, A ; Nekooie, M. A ; Sharif University of Technology
CRC Press/Balkema
2016
Abstract
Side weirs are widely used for level control and flow regulation in hydraulic engineering applications such as irrigation, land drainage, and sewer systems. These hydraulic structures allow a part of the flow to spill laterally when the surface of the flow in the main channel rises above the weir crest. The supercritical flow over a side-weir is a typical case of spatially varied flow with decreasing discharge. This study is aimed at investigating the variations of specific energy along the side-weir using experimental results. Some diagrams have been presented in terms of dimensionless ratio of diverted discharge to total discharge. These diagrams which can be used in the design of side...
Two-dimensional symmetric double contacts of elastically similar materials
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 230, Issue 10 , 2016 , Pages 1626-1633 ; 09544062 (ISSN) ; Adibnazari, S ; Sharif University of Technology
SAGE Publications Ltd
2016
Abstract
The two-dimensional contact problem for an elastic body indenting an elastically similar half plane resulting in double contacts is important for various applications. In this paper, a generic quasi-static two-dimensional symmetric double contact problem with nonsingular end points between two elastically similar half planes, under the constant normal and oscillatory tangential loading, is analyzed. The classical singular integral equations approach is utilized to extract the pressure and shear functions in the contact zones; subsequently boundary conditions at end points are applied and a new side condition is derived and titled "the consistency condition" for symmetric double contacts....
Sea-level rise impacts on seawater intrusion in coastal aquifers: review and integration
, Article Journal of Hydrology ; Volume 535 , 2016 , Pages 235-255 ; 00221694 (ISSN) ; Mahmoodzadeh, D ; Ataie Ashtiani, B ; Simmons, C. T ; Sharif University of Technology
Abstract
Sea-level rise (SLR) influences groundwater hydraulics and in particular seawater intrusion (SWI) in many coastal aquifers. The quantification of the combined and relative impacts of influential factors on SWI has not previously been considered in coastal aquifers. In the present study, a systematic review of the available literature on this topic is first provided. Then, the potential remaining challenges are scrutinized. Open questions on the effects of more realistic complexities such as gradual SLR, parameter uncertainties, and the associated influences in decision-making models are issues requiring further investigation.We assess and quantify the seawater toe location under the impacts...
Evaluation of seepage problem under a concrete dam with finite volume method
, Article Proceedings of the 7th IASME / WSEAS International Conference on Fluid Mechanics and Aerodynamics, FMA '09, 20 August 2009 through 22 August 2009 ; 2009 , Pages 34-40 ; 9789604741069 (ISBN) ; Abdi Dezfuli, E ; Zebardast, A ; Sharif University of Technology
Abstract
In most of countries, underground waters are the most important sources to provide drinking water. So it is necessary to make scheme and to do high protection of to achieve maximum beneficiary. Necessity of this management is going to be felt by developing these sources and human's interference. However, in the past overtopping phenomenon was the first reason of dam's destruction, but nowadays by increasing of spate design's period, the significant problem that researchers are interfere with, is seepage problem. The purpose of solving the underground problems is to procure height of water as a function of coordinate and time. In observation of practical industries, we can use the...
General framework for dynamic large deformation contact problems based on phantom-node X-FEM
, Article Computational Mechanics ; 2017 , Pages 1-21 ; 01787675 (ISSN) ; Khoei, A. R ; Sharif University of Technology
Abstract
This paper presents a general framework for modeling dynamic large deformation contact-impact problems based on the phantom-node extended finite element method. The large sliding penalty contact formulation is presented based on a master-slave approach which is implemented within the phantom-node X-FEM and an explicit central difference scheme is used to model the inertial effects. The method is compared with conventional contact X-FEM; advantages, limitations and implementational aspects are also addressed. Several numerical examples are presented to show the robustness and accuracy of the proposed method. © 2017 Springer-Verlag GmbH Germany
Experimental works on dynamic behavior of laminated composite beam incorporated with magneto-rheological fluid under random excitation
, Article ACM International Conference Proceeding Series, 8 February 2017 through 12 February 2017 ; Volume Part F128050 , 2017 , Pages 156-161 ; 9781450352802 (ISBN) ; Zabihollah, A ; Behzad, M ; Sharif University of Technology
Association for Computing Machinery
2017
Abstract
Laminated composite structures are widely being used in modern industries particularly robot arms, aerospace and wind turbine blades where the structures mainly exposed to harsh random vibration and in turn, leads to unpredicted failure. Adding Magneto-rheological (MR) fluids in such structures may significantly improve their dynamic response. In the present work, the vibration response of laminated composite beams filled with MR fluids (MR laminated beam) under random loading has been investigated using experimental as well as simulation approaches. Finite Element Model (FEM) has been utilized to simulate the vibration response under random loading. An in-house set-up has been designed to...