Search for: 3-d-numerical-simulation
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    Numerical investigation of geometric parameter effects on the aerodynamic performance of a Bladeless fan

    , Article Alexandria Engineering Journal ; Volume 55, Issue 1 , 2016 , Pages 223-233 ; 11100168 (ISSN) Jafari, M ; Afshin, H ; Farhanieh, B ; Sojoudi, A ; Sharif University of Technology
    Elsevier  2016
    Aerodynamic performance of a Bladeless fan is numerically investigated considering the effect of five geometric parameters. Airflow through this fan was analyzed by simulating a Bladeless fan within a 2 m × 2 m × 4 m room. Analysis of the flow field inside the fan and the evaluation of its performance were obtained by solving conservations of mass and momentum equations for the aerodynamic investigations. In order to design the Bladeless fan an Eppler 473 airfoil profile was used as the cross section of the fan. Five distinct parameters, namely height of cross section of the fan, outlet angle of the flow relative to the fan axis, thickness of airflow outlet slit, hydraulic diameter, and... 

    A novel method for producing unequal sized droplets in micro- and nanofluidic channels

    , Article European Physical Journal E ; Volume 38, Issue 9 , September , 2015 ; 12928941 (ISSN) Bedram, A ; Moosavi, A ; Kazemzadeh Hannani, S ; Sharif University of Technology
    Springer New York LLC  2015
    Abstract: We propose a novel method for producing unequal sized droplets through breakup of droplets. This method does not have the disadvantages of the available methods and also reduces the dependence of the droplets volume ratio on the inlet velocity of the system by up to 26 percent. The employed method for investigating the proposed system relies on 3D numerical simulation using the VOF algorithm and the results have been obtained with various valve ratios for both the micro- and nanoscale. The results indicate that the droplet length during the breakup process increases linearly with time. The droplet length at the nanoscale is smaller than that at the micro scale. It has been shown... 

    Heat transfer enhancement of ferrofluid flow within a wavy channel by applying a non-uniform magnetic field

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 139, Issue 5 , 2020 , Pages 3331-3343 Mousavi, S. M ; Biglarian, M ; Rabienataj Darzi, A. A ; Farhadi, M ; Hassanzadeh Afrouzi, H ; Toghraie, D ; Sharif University of Technology
    Springer Netherlands  2020
    This paper presents the effects of a non-uniform magnetic field on the hydrodynamic and thermal behavior of ferrofluid flow in a wavy channel by 3D numerical simulation. The wavy surfaces at the top and bottom of the channel are heated by constant heat fluxes. Moreover, the sidewalls are adiabatic. In the wavy section, in the perpendicular direction of the main flow, the magnetic field that linearly varies along the direction of the main flow is applied. The mathematical model that is consistent with the principles of ferrohydrodynamics and magnetohydrodynamics is used for the problem formulation. The results indicate that the wavy wall enhances the heat transfer rate on the bottom of the... 

    Three-dimensional numerical simulation of rising bubbles in the presence of cylindrical obstacles, using lattice boltzmann method

    , Article Journal of Molecular Liquids ; Volume 236 , 2017 , Pages 151-161 ; 01677322 (ISSN) Alizadeh, M ; Seyyedi, S. M ; Taeibi Rahni, M ; Ganji, D. D ; Sharif University of Technology
    A typical process in many industrial applications is rising bubble dynamic in viscous liquids like two-phase reactors. Examining the physical behavior of bubbles may improve the understanding of systems regarding design and operation. This study focused on the splitting of bubbles resulting from their impact on solid obstacles. Fragmentation of the bubbles appears in many applications such as lab on a chip in small scale or slug bubbly flow moving upward in a tube in large scales. Using a new index-function model in Lattice Boltzmann technique proposed by “He”, we simulated the deformation and motion of a bubble in different regimes, through which, we accurately captured a sharp interface... 

    Theoretical and experimental studies of a magnetically actuated valveless micropump

    , Article Journal of Micromechanics and Microengineering ; Volume 27, Issue 1 , 2017 ; 09601317 (ISSN) Ashouri, M ; Shafii, M. B ; Moosavi, A ; Sharif University of Technology
    Institute of Physics Publishing  2017
    This paper presents the prototype design, fabrication, and characterization of a magnetically actuated micropump. The pump body consists of three nozzle/diffuser elements and two pumping chambers connected to the ends of a flat-wall pumping cylinder. A cylindrical permanent magnet placed inside the pumping cylinder acts as a piston which reciprocates by using an external magnetic actuator driven by a motor. The magnetic piston is covered by a ferrofluid to provide self-sealing capability. A prototype composed of three bonded layers of polymethyl-methacrylate (PMMA) has been fabricated. Water has been successfully pumped at pressures of up to 750 Pa and flow rates of up to 700 μl min-1 while... 

    Newtonian and generalized Newtonian reacting flows in serpentine microchannels: pressure driven and centrifugal microfluidics

    , Article Journal of Non-Newtonian Fluid Mechanics ; Volume 251 , January , 2018 , Pages 88-96 ; 03770257 (ISSN) Madadelahi, M ; Shamloo, A ; Sharif University of Technology
    Elsevier B.V  2018
    This paper presents a comprehensive 3D numerical simulation of reacting flows in micro scale dimension through centrifugal, or Lab-On-a-CD (LOCD), and pressure-driven, or Lab-On-a-Chip (LOC) devices. Three different serpentine channel configurations (rectangular, triangular and sinusoidal) are investigated. In these configurations, two chemical species enter from two inlets and according to an irreversible chemical reaction, start yielding other species. Both Newtonian and generalized Newtonian fluids are considered in the simulations and the results are compared for both LOC and LOCD devices. Besides, the effects of different parameters such as the aspect ratio of channels’ cross section,... 

    Numerical investigation of the effects of fin shape, antifreeze and nanoparticles on the performance of compact finned-tube heat exchangers for automobile radiator

    , Article Applied Thermal Engineering ; Volume 133 , 2018 , Pages 248-260 ; 13594311 (ISSN) Habibian, S. H ; Mostafazade Abolmaali, A ; Afshin, H ; Sharif University of Technology
    Elsevier Ltd  2018
    In this paper, heat transfer and pressure drop of air in the radiator of an internal combustion engine automobile were investigated. First, three types of fins including louvered, triangular vortex generator and rectangular vortex generator were modeled and their performance were compared with a plain fin. Effects of adding antifreeze in volume ratios of 40, 50 and 60% on the performance of louvered and rectangular vortex generator fins were investigated. Finally, the effects of adding copper oxide and aluminum oxide nanoparticles on the heat transfer improvement of louvered and rectangular vortex generator fins were simulated. The results demonstrated that louvered fin had the highest heat... 

    3D finite element modeling of shear band localization via the micro-polar Cosserat continuum theory

    , Article Computational Materials Science ; Volume 49, Issue 4 , 2010 , Pages 720-733 ; 09270256 (ISSN) Khoei, A. R ; Yadegari, S ; Biabanaki, S. O. R ; Sharif University of Technology
    In this paper, a micro-polar continuum model is presented based on the Cosserat theory for 3D modeling of localization phenomena. Since the classical continuum model suffers from the pathological mesh-dependence in strain localization problem, the governing equations are regularized by adding the rotational degrees-of-freedom to conventional degrees-of-freedom. The fundamental relations in three-dimensional Cosserat continuum are presented and the internal length parameters are introduced in the elasto-plastic constitutive matrix to control the shear bandwidth. The mesh independency of Cosserat model in strain-softening problem is verified and the effect of internal parameters is...