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Simulation of Heat and Mass Balance in Rotary Kiln of Iron Pellets Induration
, M.Sc. Thesis Sharif University of Technology ; Yuzbashizadeh, Hossein (Supervisor)
Abstract
In this study, the heat and mass balance of rotary kiln of iron pellets induration was simulated. Due to large amount of heat transfer calculations, a quasi three-dimensional model has been used in this study. First, the freeboard heat condition was simulated via fluent program and the average temperature of freeboard was stablished. Then, a one-dimensional heat transfer model was developed using heat transfer equations. In this model, the heat transfer via conduction, convection and radiation in different parts of the kiln was included. Also, the bed reactions and their effect on bed temperature were evaluated. Finally, transversal movement and velocity of particles was studied. Transversal...
Investigation of the Effect of Particulate Emissions From Steel Complex on Adjacent Urban Areas Using Source and Receptor Modeling Approaches
, M.Sc. Thesis Sharif University of Technology ; Torkian, Ayoob (Supervisor)
Abstract
Expansion of city boundaries as a result of increased population has reduced the distance from industrial complexes and health effects of industrial air pollution have been intensified. As such, studies are needed to determine appropriate methodologies for quantifying the effect of these industries on the concentration of air pollutants in urban areas. In this study, particulate emissions from a steel mill complex was modeled using ADMS4 and the predicted results were compared with actual measurements made in the adjacent urban area. A receptor model (CMB8.2) was also used to quantify the share of the steel mill on the heavy metals' concentrations in the city by considering other sources...
Assessment of Sources and Components of Fine PM and Effect of Different Parameters on them in Tehran
, Ph.D. Dissertation Sharif University of Technology ; Arhami, Mohammad (Supervisor)
Abstract
Currently PM2.5 is a major air pollution concern in Tehran, Iran due to frequent high levels and possible adverse impacts. In this study, which is the first of its kind to take place in Tehran, composition and sources of PM2.5 and carbonaceous aerosol were determined, and their seasonal trends were studied. In this regard, fine PM samples were collected every six days at four station for two years from February 2014 to February 2015 (first phase) and March 2015 to February 2016 (second phase). The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The source apportionment was performed using...
Assessing Major Sources and Components of Fine Particulate Matter (PM2.5) In Tehran
, M.Sc. Thesis Sharif University of Technology ; Arhami, Mohammad (Supervisor)
Abstract
Due to their adverse effects on human health and the environment, PM2.5 has been identified as one of the most important pollutants in Tehran. Considering the heterogeneous land use of this city, insufficient information on the amount and chemical components of these particles in its various regions, as well as lack of accurate information about the contribution of each source in the production of pollutants, this research investigates the concentration of fine particulate matter and its constituents in four stations of Tehransar, Sharif University of Technology, Shahid Mahallati and Shahriyar and studies their sources. Initially, the pollutant mass concentration and concentration of its...
Source Apportionment of Air Particulate Matter (PM2.5)in Tehran Using CMB Model
, M.Sc. Thesis Sharif University of Technology ; Erhami, Mohammad (Supervisor)
Abstract
In recent years, one of the most important air pollution in Tehran in terms of creating unhealthy air quality is particulate matter and especially PM2.5. Particulate matter in Tehran is released from various sources. Identification of components and estimating the contribution of each emission sources, helps governers to find air pollution control strategies. To find out major components of PM2.5 in Tehran, a one year sampling to collect PM2.5 was conducted from February 2014 through February 2015 in AQM station at Sharif University of Technology located west of Tehran. 24-hour integrated samples collected on a 1-in-6 day schedule on both Teflon and quartz filters. TOT analysis was done for...
CFD-aided simulation of frost growth inside a narrow duct with uniform wall temperature variation
, Article ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2014, Collocated with the ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting ; 2014 ; ISBN: 9780791846278 ; Asgari, E ; Hajikaram, M ; Schneider, G. E ; Sharif University of Technology
Abstract
In this paper, we study the frost formation and growth at the walls of a duct with uniform wall temperature variation. The simulation is performed for laminar flow regime considering suitable semi-empirical models incorporated with computational fluid dynamics (CFD) method. The frost growth is considered to be normal to the duct surface. Since the duct aspect ratio is high, we perform our simulations in two-dimensional zones. To simulate the frost layer properly, we solve both the energy and mass balance equations implementing some semi-empirical correlations on the frost side. At this stage, we suitably predict the required heat flux value at the solid boundary and the heat transfer...
Estimation of naturally fractured oil reservoir properties using the material balance method
, Article Scientia Iranica ; Volume 21, Issue 3 , 2014 , Pages 781-791 ; ISSN: 10263098 ; Jamshidi, S ; Gholinezhad, S ; Sharif University of Technology
Abstract
In fractured reservoirs, a large variation of permeability due to the presence of fractures leads to changes in the production mechanism compared to conventional reservoirs. Hence, an appropriate model with the ability to describe the reservoir properly can provide a more confident prediction of its future performance. One of the features of a representative model is the number and height of the matrix blocks. The determination of these two parameters is one of the decisive steps in the calculation of an accurate amount of oil production from these reservoirs. In fact, matrix height shows its effect as a gravity force, which is one of the driving mechanisms. If the matrix height is less than...
An experimental investigation of permeability impairment under dynamic flow conditions due to natural depletion in an Iranian oilfield
, Article Petroleum Science and Technology ; Volume 31, Issue 3 , 2013 , Pages 250-261 ; 10916466 (ISSN) ; Bagherzadeh, H ; Bolouri, H ; Sharif University of Technology
2013
Abstract
Asphaltene deposition is an issue that has received much attention since it has been shown to be the cause of major production problems. It leads to permeability reduction under the processes of natural depletion as well as hydrocarbon gas/CO2 injection. Though a great deal of researches have focused on studying permeability impairment in reservoir rocks, little is known about the asphaltene deposition mechanisms that control the permeability reduction for Iranian reservoirs. In this work, an experimental effort is made to investigate the permeability impairment of core samples of Iranian oil reservoirs. The experiments are performed on both sandstone and carbonate rock types at reservoir...
Optimization assisted asphaltene deposition modeling in porous media during a natural depletion scheme
, Article Petroleum Science and Technology ; Volume 30, Issue 9 , Mar , 2012 , Pages 958-965 ; 10916466 (ISSN) ; Bagheri, M ; Kharrat, R ; Ghazanfari, M ; Ghotbi, C ; Sharif University of Technology
2012
Abstract
Changes in thermodynamic properties such as pressure, temperature, and composition may result in asphaltene precipitation and deposition in porous media. In addition, asphaltene deposition can cause wettability alteration, permeability reduction, and ultimately a decrease in the productivity of a reservoir. Natural depletion is one of the most common processes of asphaltene deposition in which pressure changes destabilize the dissolved asphaltene in the oil and settle them onto the rock surface. In this work, natural depletion experiments in consolidated core samples were performed under simulated reservoir conditions to obtain reliable data and analyze the asphaltene deposition mechanisms....
Hydro-mechanical modeling of two-phase fluid flow in deforming, partially saturated porous media with propagating cohesive cracks using the extended finite element method
, Article Computational Plasticity XI - Fundamentals and Applications, COMPLAS XI, 7 September 2011 through 9 September 2011 ; September , 2011 , Pages 1516-1527 ; 9788489925731 (ISBN) ; Khoei, A. R ; Sharif University of Technology
Abstract
In the present paper, a fully coupled numerical model is developed for the hydromechanical analysis of deforming, progressively fracturing porous media interacting with the flow of two immiscible, compressible wetting and non-wetting pore fluids. The governing equations involving the coupled two-phase fluid flow and deformation processes in partially saturated porous media containing cohesive cracks are derived within the framework of the generalized Biot theory. The displacement of the solid phase, the pressure of the wetting phase and the capillary pressure are taken as the primary unknowns of the three-phase formulation. A softening cohesive law is employed to describe the nonlinear...
Numerical model for estimation of corrosion location in nuclear power plant steam generators
, Article Nuclear Engineering and Design ; Volume 241, Issue 1 , 2011 , Pages 95-100 ; 00295493 (ISSN) ; Jahanfarnia, G ; Kebriaee, A ; Sharif University of Technology
Abstract
Deposition of dissolved impurities and corrosion in steam generators is a significant problem in the operation of nuclear power plants. Impurities and corrosion products usually accumulate in the secondary sides of steam generators (SG) and form deposits on the SG surfaces. A high level of impurity concentration close to the SG heating surface causes the corrosion process to occur with more intensity. The aim of this study is to estimate the most probable locations of impurity concentration and deposition in a SG. Equations representing the convection and diffusion in the liquid phase close to the heated surface (the viscous sub layer) are derived. Based on the mass balance of impurities in...
A comparison of finite volume formulations and coupling strategies for two-phase flow in deforming porous media
, Article Computers and Geotechnics ; Volume 67 , 2015 , Pages 17-32 ; 0266352X (ISSN) ; Ataie Ashtiani, B ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In this paper a locally mass conservative finite volume method is employed to model the one-dimensional, two-phase immiscible flow in a poroelastic media. Since, an appropriate choice of primary variables is critical in simulating multiphase subsurface flow, depending on such a choice, the governing equations can be expressed in different forms. By implementing Picard iteration to a highly nonlinear system of equations, three numerical models including pressure form, mixed form and mixed form with a modified Picard linearization are developed in this study. These models have been evaluated in terms of stability, convergence and mass conservation in various one-dimensional test cases....
Modeling and optimization of asphaltene deposition in porous media using genetic algorithm technique
, Article Society of Petroleum Engineers - International Oil and Gas Conference and Exhibition in China 2010, IOGCEC, 8 June 2010 through 10 June 2010 ; Volume 1 , June , 2010 , Pages 479-491 ; 9781617388866 (ISBN) ; Kharrat, R ; Ghazanfari, M. H ; Bagheri, M. B ; Sharif University of Technology
2010
Abstract
Different models have been proposed for deposition of asphaltene on reservoir rocks that due to complexity of asphaltene nature, most of them have not been productive. Here, a reliable model is proposed which despite of previous models, considers the change in asphaltene saturation in the core. The obtained experimental data in the laboratory was used for model validation. In this work, a series of core flooding tests was carried out in presence of connate water at different solvent-oil volume ratios. Pressure drop was measured at three different terminals along the core. The obtained experimental data as well as mass balance equations, momentum equation, asphaltene deposition and...
Organic compound characterization and source apportionment of indoor and outdoor quasi-ultrafine particulate matter in retirement homes of the Los Angeles Basin
, Article Indoor Air ; Volume 20, Issue 1 , 2010 , Pages 17-30 ; 09056947 (ISSN) ; Minguillón, M. C ; Polidori, A ; Schauer, J. J ; Delfino, R. J ; Sioutas, C ; Sharif University of Technology
2010
Abstract
Quasi-ultrafine (quasi-UF) particulate matter (PM0.25) and its components were measured in indoor and outdoor environments at four retirement communities in Los Angeles Basin, California, as part of the Cardiovascular Health and Air Pollution Study (CHAPS). The present paper focuses on the characterization of the sources, organic constituents and indoor and outdoor relationships of quasi-UF PM. The average indoor/outdoor ratios of most of the measured polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes were close to or slightly lower than 1, and the corresponding indoor-outdoor correlation coefficients (R) were always positive and, for the most part, moderately strong (median R...
Dynamic modeling and optimization of asphaltene deposition in reservoir rocks using genetic algorithm
, Article 72nd European Association of Geoscientists and Engineers Conference and Exhibition 2010: A New Spring for Geoscience. Incorporating SPE EUROPEC 2010 ; Volume 6 , 2010 , Pages 4291-4295 ; 9781617386671 (ISBN) ; Kharrat, R ; Hemmatfar, V ; Ghotbi, C ; Sharif University of Technology
Society of Petroleum Engineers
2010
Abstract
Asphaltene deposition is a problematic challenge for oil production. Changes in key parameters like pressure and fluid composition during natural depletion and different gas injection scenarios may result in asphaltene precipitation and deposition. In this work, a model is developed by application of mass balance equations, momentum equation, asphaltene deposition and permeability reduction models. An algorithm is developed to perform iterative procedure to solve the numerical equations that contains highly coupled variables. Indeed, an equation is introduced to calculate the saturation of the precipitated asphaltene phase. Model parameters were determined by genetic algorithm which is a...
Conceptualization of karstic aquifer with multiple outlets using a dual porosity model
, Article Groundwater ; Volume 55, Issue 4 , 2017 , Pages 558-564 ; 0017467X (ISSN) ; Ataie Ashtiani, B ; Sharif University of Technology
Abstract
In this study, two conceptual models, the classic reservoir (CR) model and exchange reservoirs model embedded by dual porosity approach (DPR) are developed for simulation of karst aquifer functioning drained by multiple outlets. The performances of two developed models are demonstrated at a less developed karstic aquifer with three spring outlets located in Zagros Mountain in the south-west of Iran using 22-years of daily data. During the surface recharge, a production function based on water mass balance is implemented for computing the time series of surface recharge to the karst formations. The efficiency of both models has been assessed for simulation of daily spring discharge during the...
A Mechanobiological model for damage-induced growth in arterial tissue with application to in-stent restenosis
, Article Journal of the Mechanics and Physics of Solids ; Volume 101 , 2017 , Pages 311-327 ; 00225096 (ISSN) ; Naghdabadi, R ; Sohrabpour, S ; Holzapfel, G. A ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
In-stent restenosis (ISR) is one of the main drawbacks of stent implementation which limits the long-term success of the procedure. Morphological changes occurring within the arterial wall due to stent-induced mechanical injury are a major cause for activation of vascular smooth muscle cells (VSMCs), and the subsequent development of ISR. Considering the theory of volumetric mass growth and adopting a multiplicative decomposition of the deformation gradient into an elastic part and a growth part, we present a mechanobiological model for ISR. An evolution equation is developed for mass growth of the neointima, in which the activation of VSMCs due to stent-induced damage (injury) and the...
Superheated water extraction of catechins from green tea leaves: Modeling and simulation
, Article Scientia Iranica ; Volume 16, Issue 2 C , 2009 , Pages 99-107 ; 10263098 (ISSN) ; Abdollahi Govar, A ; Sharif University of Technology
2009
Abstract
Catechins from fresh green tea leaves as potential sources of anticancer and antioxidant components were target materials in this work. Superheated water extraction, which is a kind of leaching operation, and solvent partition with chloroform and ethyl acetate were utilized to recover Catechins from tea leaves. Then, a mathematical model was developed to simulate the superheated water extraction of Catechins. The unsteady state mass balance of the solute in solid and superheated water phases led to two partial differential equations. The model was solved numerically using a linear equilibrium relationship. The model parameters were predicted applying existing experimental correlations. An...
Conceptual hydrosalinity model for prediction of salt load from wastewater flows into soil and ground water
, Article International Journal of Environmental Science and Technology ; Volume 6, Issue 3 , 2009 , Pages 359-368 ; 17351472 (ISSN) ; Mirbagheri, S. A ; Monavvari, M ; Javid, A. H ; Zarei, H ; Sharif University of Technology
2009
Abstract
Dynamic hydrosalinity models are available, but are not used extensively on a large scale soil which receives wastewater from industrial areas, partly because adequate database are expensive to be obtained. Thus, for this reason, there is an urgent need to assess the salt and other pollutant loads collected in wastewater flows into the soil and/ or ground water systems. A conceptual hydrosalinity model was used on two major underlying principals of mass balance and steady state. This model was initially tested on the 4,117 km2 plains west of the Yazd-Ardakan district in the central part of Iran. This model was used at a time when the soil and ground water salinity problem was serious due to...
Assessment of the impacts of sewerage network on groundwater quantity and nitrate contamination: case study of tehran
, Article World Environmental and Water Resources Congress 2020: Groundwater, Sustainability, Hydro-Climate/Climate Change, and Environmental Engineering, 17 May 2020 through 21 May 2020 ; 2020 , Pages 53-66 ; Kerachian, R ; Aghayi, M. M ; Zahraie, B ; Zhu, Z ; Sharif University of Technology
American Society of Civil Engineers (ASCE)
2020
Abstract
Many communities in arid and semi-Arid areas rely on groundwater for drinking water. However, anthropogenic activities such as the use of fertilizers and human waste disposal impose the risk of nitrate pollution to the aquifers. With over 8.5 million population, Tehran, the capital of Iran, has experienced rapid population growth during the past decades while the majority of the city did not have a sewerage network and the main way of wastewater disposal was individual cesspits inside houses. The long-Term discharge of raw wastewater in cesspits has increased nitrate concentration in the Tehran aquifer which serves as a source of one-Third of drinking water for the city. Although the...