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    Geometry optimization of a fibrous scaffold based on mathematical modelling and CFD simulation of a dynamic cell culture

    , Article Computer Aided Chemical Engineering ; Volume 38 , 2016 , Pages 1413-1418 ; 15707946 (ISSN); 9780444634283 (ISBN) Tajsoleiman, T ; Abdekhodaie, M. J ; Gernaey, K. V ; Krühne, U ; Kravanja, Z ; Bogataj, M ; Sharif University of Technology
    Elsevier B.V  2016
    In tissue engineering, the development of a tissue essentially depends on supply of an adequate amount of nutrients and the design of a proper biophysical micro-environment for cells. The limitation of the available initial number of cells, expensive substances and time consuming experiments are the main bottlenecks in this type of processes. In this regard, mathematical modelling and computational fluid dynamics simulation (CFD) are powerful tools to identify an efficient and optimized design by providing reliable insights of the process. This study presents a mathematical model and CFD simulation of cartilage cell culture under a perfusion flow, which allows not only to characterize the... 

    An investigation of empirical formulation and design optimisation of co-flow fluidic thrust vectoring nozzles

    , Article Aeronautical Journal ; Volume 121, Issue 1236 , 2017 , Pages 213-236 ; 00019240 (ISSN) Banazadeh, A ; Saghafi, F ; Sharif University of Technology
    Cambridge University Press  2017
    The purpose of this paper is to design and develop an advanced co-flow fluidic nozzle, based on the Coanda effect concept, for multi-directional thrust vectoring of small jet engines. Recent progress on finding an optimal geometry with a fixed momentum ratio to achieve maximum thrust deflection angle is discussed here. The efficiency of the system is found to be a weakly nonlinear function of the secondary to primary flow momentum as well as three geometric parameters. A useful empirical formulation is derived for thrust vectoring angle, based on a series of tests carried out on different nozzles. An accurate computational fluid dynamics model is also developed and evaluated against the... 

    Efficient computational design of a scaffold for cartilage cell regeneration

    , Article Bioengineering ; Volume 5, Issue 2 , 24 April , 2018 ; 23065354 (ISSN) Tajsoleiman, T ; Abdekhodaie, M. J ; Gernaey, K. V ; Kruhne, U ; Sharif University of Technology
    MDPI AG  2018
    Due to the sensitivity of mammalian cell cultures, understanding the influence of operating conditions during a tissue generation procedure is crucial. In this regard, a detailed study of scaffold based cell culture under a perfusion flow is presented with the aid of mathematical modelling and computational fluid dynamics (CFD). With respect to the complexity of the case study, this work focuses solely on the effect of nutrient and metabolite concentrations, and the possible influence of fluid-induced shear stress on a targeted cell (cartilage) culture. The simulation set up gives the possibility of predicting the cell culture behavior under various operating conditions and scaffold designs.... 

    Comprehensive modeling and CFD simulation of absorption of CO2 and H2S by MEA solution in hollow fiber membrane reactors

    , Article AIChE Journal ; Vol. 60, issue. 2 , 2014 , pp. 657-672 ; ISSN: 00011541 Amrei, S. M. H. H ; Memardoost, S ; Dehkordi, A. M ; Sharif University of Technology
    A comprehensive mathematical model has been developed for the simulation of simultaneous chemical absorption of carbon dioxide and hydrogen sulfide by means of Monoethanolamine (MEA) aqueous solution in hollow fiber membrane reactors is described. In this regard, a perfect model considering the entrance regions of momentum, energy, and mass transfers was developed. Computational Fluid Dynamics (CFD) techniques were applied to solve governing equations, and the model predictions were validated against experimental data reported in the literature and excellent agreement was found. Effects of different disturbances on the dynamic behavior of the reactor were investigated. Moreover, effects of... 

    Experiments and CFD simulation of ferrous biooxidation in a bubble column bioreactor

    , Article Computers and Chemical Engineering ; Volume 32, Issue 8 , 22 August , 2008 , Pages 1681-1688 ; 00981354 (ISSN) Mousavi, S. M ; Jafari, A ; Yaghmaei, S ; Vossoughi, M ; Turunen, I ; Sharif University of Technology
    In the present attempt a set of experiments and a 3D simulation using a commercially available computational fluid dynamics package (FLUENT) were adopted to investigate complex behavior involving hydrodynamics and ferrous biological oxidation in a gas-liquid bubble column reactor. By combining the hydrodynamics and chemical species transport equations, the velocity field, air volume fraction and ferrous biooxidation rate in the column were simulated. The kinetic model proposed by Nemati and Webb [Nemati, M., & Webb, C. (1997). A kinetic model for biological oxidation of ferrous iron by Thiobacillus ferrooxidans. Biotechnology and Bioengineering, 53, 478-486] was used to simulate the... 

    Numerical investigation of the effects of a copper foam filled with phase change materials in a water-cooled photovoltaic/thermal system

    , Article Energy Conversion and Management ; Volume 163 , 2018 , Pages 187-195 ; 01968904 (ISSN) Mousavi, S ; Kasaeian, A ; Shafii, M. B ; Jahangir, M. H ; Sharif University of Technology
    Elsevier Ltd  2018
    The purpose of the present study is to investigate the thermal performance of a photovoltaic/thermal system, integrated with phase change materials in porous medium. For this purpose, a metal foam was employed as porous medium and the performance of five different PCMs, as organic and inorganic, were examined as well. Moreover, the effects of different key parameters such as the mass flow rate, solar irradiance, inlet water temperature and inclination were studied. Finally, the simulation results were compared with a water-cooled photovoltaic/thermal without incorporating PCMs and porous medium, and thermal performance of the three PV/T cases were reported. The highest thermal efficiency of... 

    CFD simulation of natural draught cooling tower wind-covering

    , Article Applied Mechanics and Materials, Dubai ; Volume 307 , 2013 , Pages 279-284 ; 16609336 (ISSN) ; 9783037856598 (ISBN) Darbandi, M ; Salemkar, H ; Behrouzifar, A ; Abrar, B ; Sharif University of Technology
    Past experiences have shown that a local wind can considerably affect the performances of powerplant cooling towers and factory chimneys. In thermal powerplants, the performance of Rankin cycles would reduce if the temperature of its condenser increases. This issue is very important to powerplants located in countries with strong local winds. To remedy the malperformance of a natural cooling tower in windy conditions, it is required to understand the physics of flow around cooling towers more clearly. One adverse physics is known as the wind covering problem which can drastically affect the natural draught through a cooling tower in windy conditions. In this paper, we focus on wind-covering... 

    CFD simulation of airflow in the side-platform stations

    , Article MATEC Web of Conferences, 20 July 2015 through 21 July 2015 ; Volume 28 , 2015 ; 2261236X (ISSN) Adibi, O ; Farhanieh, B ; Afshin, H ; Wei-Hsin L ; Zhihua G ; Sharif University of Technology
    EDP Sciences  2015
    Design of an appropriate ventilation system is one of the main concerns in the construction of subways. In this paper, thermal comforts of side-platform stations are investigated by numerical methods. For the numerical simulation, grids are generated by structured methods and governing equations are discretized by finite volume methods. In the numerical simulation, second order upwind and second order central difference scheme are used to consider the convection and diffusion terms of momentum and energy equations, respectively. Results of this study show that in term of thermal comfort, region next to the hallway and the middle part of the platform is the worst zones of the station. In... 

    Experimental study on cavitation behavior of propellers in the uniform flow and in the wake field

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 38, Issue 6 , 2016 , Pages 1585-1592 ; 16785878 (ISSN) Alimirzazadeh, S ; Roshan, S. Z ; Seif, M. S ; Sharif University of Technology
    Springer Verlag 
    Cavitation behavior of fully submerged propellers is an important issue in the marine engineering field. Cavitation tunnel is usually used for studying hydrodynamic performances and cavitation behavior of a propeller. In the present study, the cavitation behavior of the DTMB P4119 propeller was studied both in a uniform flow and in the wake field of a specific vessel. Considering the dimensions of the test section of K23 cavitation tunnel of Sharif University of Technology and related blockage effects, the propeller was scaled so that the model was 0.195 (m) in diameter. A wake screen was used to generate the desired wake field, which itself was primarily determined by CFD simulations around... 

    A new developed semi-full-scale approach to facilitate the CFD simulation of shell and tube heat exchangers

    , Article Chemical Engineering Science ; Volume 245 , 2021 ; 00092509 (ISSN) Darbandi, M ; Abdollahpour, M. S ; Hasanpour Matkolaei, M ; Sharif University of Technology
    Elsevier Ltd  2021
    The full-scale CFD simulations may not be recommended in preliminary steps of STHEs’ design and sensitivity analyses because of heavy computations. This work benefits from the sequential geometry repetitions in STHEs and presents a new semi-full-scale approach, which alleviates the need for full-scale simulation of STHEs. This approach first isolates the smallest zone, say block, which is sequentially repeated in the STHE domain. Second, this block is carefully simulated considering various thermal and flow working conditions. Third, the data collected from these CFD simulations are used to generate the required thermal and flow correlations for the chosen block at various working... 

    Marangoni instabilities for convective mobile interfaces during drop exchange: Experimental study and CFD simulation

    , Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Vol. 441, issue , 2014 , pp. 846-854 ; ISSN: 09277757 Javadi, A ; Karbaschi, M ; Bastani, D ; Ferri, J. K ; Kovalchuk, V. I ; Kovalchuk, N. M ; Javadi, K ; Miller, R ; Sharif University of Technology
    The inflow pattern of liquid into a droplet is studied experimentally using a surface active dye and compared with results of CFD simulations. The results show visual agreement between experiments and simulations. The CFD simulations show also good agreement with the surface tension measured by drop profile analysis tensiometry (PAT). The inflow of the surfactant induces a Marangoni instability caused by the local arrival of the surfactant at the drop surface. The onset of this Marangoni instability observed experimentally has a delay of about 10. s when compared with the simulation results. Different scenarios are discussed, including a boundary layer barrier, a kinetic-controlled... 

    Modeling and simulation of barite deposition in an annulus space of a well using CFD

    , Article Journal of Petroleum Science and Engineering ; Volume 161 , 2018 , Pages 476-496 ; 09204105 (ISSN) Movahedi, H ; Shad, S ; Beagom Mokhtari Hosseini, Z ; Sharif University of Technology
    Elsevier B.V  2018
    In drilling industry, barite particles settling and barite sag as a major problem can potentially impose significant operational issues. Static conditions, in which well undergoes an extended shut-in period, could occur during different drilling and completion operations such fishing operation, tripping, and logging. Despite its importance, such phenomenon is not well understood yet. To avoid issues related to barite settlement and barite sag, a good understanding of the impact of different drilling parameters on barite settlement and sag phenomenon is required. Recently, the mathematical formulation and modeling of settlement and sag processes have gained more attention. In order to better... 

    Dynamics of liquid interfaces under various types of external perturbations

    , Article Current Opinion in Colloid and Interface Science ; Vol. 19, issue. 4 , Aug , 2014 , p. 309-319 Lotfi, M ; Karbaschi, M ; Javadi, A ; Mucic, N ; Kragel, J ; Kovalchuk, V. I ; Rubio, R. G ; Fainerman, V. B ; Miller, R ; Sharif University of Technology
    Dynamic interfacial parameters are the key properties of interfaces in many modern technologies and can be studied in various ways. For applications like foams and emulsions, the dynamics of adsorption and the dilational and shear rheology of liquid-fluid interfaces are investigated most frequently. This work gives an insight into recently developed new experimental approaches, such as fast capillary pressure tensiometry for growing and oscillating drops. These experiments are presented in comparison to more classical techniques like drop profile tensiometry and capillary wave damping. Progress in these experiments based on generated interfacial perturbations can be expected only by a close... 

    Optimization of the angle of attack of delta-winglet vortex generators over a bank of elliptical-tubes heat exchanger

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 8 A , 2013 ; 9780791856345 (ISBN) Godazandeh, K ; Godazandeh, B ; Ansari, M. H ; Ashjaee, M ; ASME ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2013
    In order to reach a more efficient and compact heat exchanger, it is essential to optimize the design, having in mind the impact of different geometrical parameters. Many of the previously cited studies in the area of heat transfer enhancement using vortex generators were confined only to defined points in the possible design space. Thus, a multiobjective optimization study is particularly suitable in order to cover this space entirely. A CFD simulation along with Pareto method were used to simulate the air flow and heat transfer and optimize the design parameters. The angle of attack of a pair of delta-winglets mounted behind each tube is varied between β = -90° and ß = +90°. Three... 

    CFD simulation of melting process of phase change materials (PCMs) in a spherical capsule

    , Article International Journal of Refrigeration ; Volume 73 , 2017 , Pages 209-218 ; 01407007 (ISSN) Sattari, H ; Mohebbi, A ; Afsahi, M. M ; Azimi Yancheshme, A ; Sharif University of Technology
    Elsevier Ltd  2017
    The present study is focused on CFD simulation of constrained melting of Phase Change Materials (PCMs) in a spherical container. To investigate the melting process of the PCM, its melting fraction was analyzed at different times. The results indicated the existence of thermally stable layers on the top of the sphere. Moreover, inspection of the calculated temperatures at different points along the vertical axis indicates the existence of some disturbances at the bottom of the sphere due to the natural convection. After the validation of the results, the effects of different parameters such as the surface temperature of the capsule, the initial temperature and the size of the spherical... 

    Using CFD simulations to improve the air-cooled steam condenser performance in severe windy conditions via proper tuning of blades pitch angles

    , Article ASME 2018 5th Joint US-European Fluids Engineering Division Summer Meeting, FEDSM 2018, 15 July 2018 through 20 July 2018 ; Volume 2 , 2018 ; 08888116 (ISSN); 9780791851562 (ISBN) Darbandi, M ; Farhangmehr, V ; Khorshidi Behzadi, H. R ; Schneider, G. E ; Fluids Engineering Division ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2018
    The use of air-cooled steam condenser (ACSC) in thermal power plants has become so normal since a few decades ago. It is because there are so many valuable advantages with the ACSC implementation, e.g., little dependency on water consumption and benefiting from the forced convection heat transfer instead of the natural one to condense the steam. However, the thermal performance of an ACSC can be readily defected by the ambient wind; specifically, when the ambient temperature is high. This research work benefits from the computational fluid dynamics tool to study the details of ACSC's thermal performance in such undesirable ambient windy conditions. Furthermore, this work suggests an... 

    Vortex shedding modes around oscillating non-uniform double heave plates

    , Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; 2020 Abazari, A ; Alvandi, M ; Behzad, M ; Thiagarajan, K. P ; Sharif University of Technology
    SAGE Publications Ltd  2020
    Multiple co-axial heave plates of uniform geometry are attached to offshore platforms for inducing damping and added mass. These effects generally decrease the magnitude of the dynamic response of the platform under applied environmental excitation forces. When spacing between heave plates is decreased the damping and added mass performance are altered due to their strong vortex interaction. A new non-uniform plate configuration is proposed that may create different hydrodynamic characteristics. The modes of vortex shedding around plate edges in a non-uniform arrangement under forced harmonic oscillation are investigated via the CFD method. Furthermore, a new simplified formula for the total... 

    Brine composition effect on the oil recovery in carbonate oil reservoirs: A comprehensive experimental and CFD simulation study

    , Article Journal of Petroleum Science and Engineering ; Volume 191 , August , 2020 Fattahi Mehraban, M ; Rostami, P ; Afzali, S ; Ahmadi, Z ; Sharifi, M ; Ayatollahi, S ; Sharif University of Technology
    Elsevier B. V  2020
    In order to understand the potential role of divalent ions involved in smart water, fluid-fluid and rock-fluid interactions are studied through contact angle and interfacial tension (IFT) measurements. Then, the suitable brines in changing contact angle and IFT are brought into measurement with spontaneous imbibition experiments to evaluate the co-impact of fluid-fluid and rock-fluid interactions. The results show the importance of SO42− ions during smart water injection as removing them from the injection water leads to a sharp drop in ultimate oil recovery. Accordingly, when the concentration of SO42− within the injection water increases four times, 10% ultimate oil recovery is recovered.... 

    Parametric study of droplet formation and characteristics within microfluidic devices - A case study

    , Article International Journal of Applied Mechanics ; Volume 12, Issue 7 , 2020 Salehi, S. S ; Shamloo, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
    World Scientific  2020
    Droplet-based microfluidics technologies hold great attention in a wide range of applications, including chemical analysis, drug screening, and food industries. This work aimed to describe the effects of different physical properties of the two immiscible phases on droplet formation in a flow-focusing microfluidic device and determining proper flow rates to form a droplet within the desired size range. A numerical model was developed to solve the governing equations of two-phase flow and the results were validated with previous experimental results. The results demonstrate different types of droplet formation regimes from dripping to jetting and different production rates of droplets as a...