Search for: flow-of-fluids
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    Herschel-Bulkley rheological parameters of lightweight colloidal gas aphron (CGA) based fluids

    , Article Chemical Engineering Research and Design ; Volume 93 , 2015 , Pages 21-29 ; 02638762 (ISSN) Ziaee, H ; Arabloo, M ; Ghazanfari, M. H ; Rashtchian, D ; Sharif University of Technology
    Institution of Chemical Engineers  2015
    The proper understanding of rheological characteristics of CGA based fluids is of crucial importance in determining the performance of the fluid, in order to maintain the most effective fluid properties for safe, efficient, and economical drilling operation. This paper presents a concise investigation on the effect of concentration of the three main components of a novel environmentally friendly lightweight CGA based drilling fluid, i.e., xanthan gum biopolymer, starch, and biosurfactant, to the Herschel-Bulkley rheological model parameters. The three parameters of Herschel-Bulkley model, i.e., yield stress, fluid consistency, and fluid flow index were calculated by fitting the experimental... 

    Efficient back analysis of multiphysics processes of gas hydrate production through artificial intelligence

    , Article Fuel ; Volume 323 , 2022 ; 00162361 (ISSN) Zhou, M ; Shadabfar, M ; Huang, H ; Leung, Y. F ; Uchida, S ; Sharif University of Technology
    Elsevier Ltd  2022
    Natural gas hydrate, a crystalline solid existing under high-pressure and low-temperature conditions, has been regarded as a potential alternative energy resource. It is globally widespread and occurs mainly inside the pores of deepwater sediments and sediments under permafrost area. Hydrate production via well depressurization is deemed well-suited to existing technology, in which the pore pressure is lowered, the natural gas hydrate is dissociated into water and gas, and the water and gas are produced from well. This method triggers multiphysics processes such as fluid flow, heat transfer, energy adsorption, chemical reaction and sediment deformation, all of which are dependent on the... 

    Recovery of drop in heat transfer rate for a rotating system by nanofluids

    , Article Journal of Molecular Liquids ; Volume 220 , 2016 , Pages 961-969 ; 01677322 (ISSN) Zeibi Shirejini, S. R ; Rashidi, S ; Abolfazli Esfahani, J ; Sharif University of Technology
    This paper simulates Al2O3-water nanofluid flow and forced convection around a rotating circular cylinder. The governing parameters are Reynolds number (1 ≤ Re ≤ 100), solid volume fraction of nanoparticles (0 ≤ φ ≤ 0.05) and non-dimensional rotation rate (0 ≤ α ≤ 3). The simulations are performed to study the effects of mentioned parameters on the heat transfer rate and fluid flow characteristics. The governing equations including the continuity, momentum, and energy equations are solved with a finite volume method. It is observed that the reduction of heat transfer with increase in rotation rate is in the vicinity of 6.9% and 32% for Re = 5 and 100, respectively at φ = 0.05. Furthermore,... 

    Neural network prediction model of three-phase fluids flow in heterogeneous porous media using scaling analysis

    , Article Journal of Petroleum Science and Engineering ; Volume 138 , 2016 , Pages 122-137 ; 09204105 (ISSN) Zarringhalam, A ; Alizadeh, M ; Rafiee, J ; Moshirfarahi, M. M ; Sharif University of Technology
    Scaling analysis of fluid displacement in porous media is a reliable, fast method to evaluate the displacement performance of different oil production processes under various conditions. This paper presents the scaling studies of multiphase fluid flow through permeable media with a special attention to the three-phase immiscible water alternating gas (WAG) flooding under conditions prevailing in many oil reservoirs. The investigations are performed on a heterogeneous reservoir to study in detail the sensitivity of the displacement process to the scaling groups using various combinations of the process controlling parameters. The procedure of Inspectional analysis (IA) was utilized to... 

    Conceptual duct shape design for horizontal-axis hydrokinetic turbines

    , Article Scientia Iranica ; Volume 23, Issue 5 , 2016 , Pages 2113-2124 ; 10263098 (ISSN) Zahedinejad, A ; Rad, M ; Khayat, M ; Sharif University of Technology
    Sharif University of Technology  2016
    In the present paper, conceptual duct shape design for kinetic energy extraction with hydrokinetic turbines is discussed. The goal is to find a single-passage axisymmetric geometry that holds stable flow with maximum kinetic energy flux at duct throat. For finding the optimum duct shape, the fluid flow was numerically simulated in a wedge shaped space with Flow-Simulation Software. In a multi-stage conceptual design, tabulated configurations were employed to study each geometrical characteristic separately. These include curvature of profile camber, trailing edge shape, profile tip shape, and duct exit cross sectional area. The revolved profile of each duct consists of a well constrained... 

    Compatible numerical schemes for coupled flow and transport in porous media

    , Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) Zade, A. Q ; Manzari, M. T ; Hannani, S. K ; Sharif University of Technology
    American Society of Mechanical Engineers  2006
    In this paper, the compatibility of various combinations of numerical schemes for the solution of flow and transport equations in porous media is studied and the possible loss of accuracy and global mass conservation are investigated. Here, the flow equations are solved using three popular finite element methods including the Standard Galerkin (SG), Discontinuous Galerkin (DG) and Mixed Finite Element (MFE) methods among which only the DG method possesses the local conservation property. Besides, the transport of a scalar variable which is governed by a convection-diffusion equation is studied in conjunction with the flow equations. The transport equation is solved using both the Streamline... 

    Modeling of Non-Darcy flow through anisotropic porous media: Role of pore space profiles

    , Article Chemical Engineering Science ; Volume 151 , 2016 , Pages 93-104 ; 00092509 (ISSN) Veyskarami, M ; Hassani, A. H ; Ghazanfari, M. H ; Sharif University of Technology
    Elsevier Ltd 
    Excess pressure drop induced by inertial effects limits the applicability of Darcy's law for modeling of fluid flow through porous media at high velocities. It is expected such additional pressure drop is influenced by pore/morphology of porous media. This work concerns with fundamental understanding of how throat curvature affects intrinsic properties of porous media at non-Darcy flow conditions using network modeling. Conical, parabolic, hyperbolic, and sinusoidal capillary ducts with three types of imposed anisotropy are used to construct the network in a more realistic manner. Solutions of one dimensional Navier-Stokes equation for incompressible fluid flow through converging/diverging... 

    Recommendations on enhancing the efficiency of algebraic multigrid preconditioned GMRES in solving coupled fluid flow equations

    , Article Numerical Heat Transfer, Part B: Fundamentals ; Volume 55, Issue 3 , 2009 , Pages 232-256 ; 10407790 (ISSN) Vakili, S ; Darbandi, M ; Sharif University of Technology
    The algebraic multigrid (AMG) algorithm as a preconditioner to the Krylov subspace methods has drawn the attention of many researchers in solving fluid flow and heat transfer problems. However, the efficient employment of this solver needs experience, because users have to quantify several important parameters. In this work, we choose a hybrid finite-volume element method and quantify the optimum magnitudes for those parameters. To generalize our results, two sets of fluid flow governing equations, the thermobuoyant flow and confined diffusion flame, are studied and the optimum values are determined. The results indicate that the AMG can be very effective if a proper storage method is chosen... 

    Modelling of power-law fluid flow through porous media using smoothed particle hydrodynamics

    , Article Transport in Porous Media ; Volume 74, Issue 3 , 2008 , Pages 331-346 ; 01693913 (ISSN) Vakilha, M ; Manzari, M. T ; Sharif University of Technology
    The flow of non-Newtonian fluids through two-dimensional porous media is analyzed at the pore scale using the smoothed particle hydrodynamics (SPH) method. A fully explicit projection method is used to simulate incompressible flow. This study focuses on a shear-thinning power-law model (n < 1), though the method is sufficiently general to include other stress-shear rate relationships. The capabilities of the proposed method are demonstrated by analyzing a Poiseuille problem at low Reynolds numbers. Two test cases are also solved to evaluate validity of Darcy's law for power-law fluids and to investigate the effect of anisotropy at the pore scale. Results show that the proposed algorithm can... 

    An X-FEM implementation of hydro-fracture growth in naturally fractured saturated porous media

    , Article Poromechanics 2017 - Proceedings of the 6th Biot Conference on Poromechanics, 9 July 2017 through 13 July 2017 ; 2017 , Pages 2027-2034 ; 9780784480779 (ISBN) Vahab, M ; Khoei, A. R ; Khalili, N ; Sharif University of Technology
    In this paper, a coupled hydro-mechanical formulation is developed for the simulation of interaction between hydraulic fractures and natural discontinuities within saturated porous media. The momentum balance equation of the bulk together with the momentum balance and continuity equations of the fluid phase are employed to obtain the fully coupled set of governing equations. The hydro-fracture is modeled for fluid flow using the Darcy law. The natural discontinuity on the other hand is modeled for both opening and closing modes which induce fluid flow and/or contact behavior along the crack edges. The discontinuity in the displacement field is incorporated by using the Heaviside enrichment... 

    Igniter jet dynamics in solid fuel ramjets

    , Article Acta Astronautica ; Volume 64, Issue 2-3 , 2009 , Pages 166-175 ; 00945765 (ISSN) Tahsini, A. M ; Farshchi, M ; Sharif University of Technology
    The dynamics of a two dimensional plane jet injected at the base of a step, parallel to the wall, in backward facing step flow geometry is numerically studied. The objective of this work is to gain insight into the dynamics of the igniter flow field in solid fuel ramjet motors. Solid fuel ramjets operate by ingestion of air and subsequent combustion with a solid fuel grain such as polyethylene. The system of governing equations is solved with a finite volume approach using a structured grid in which the AUSM+ scheme is used to calculate the convective fluxes. The Spalart and Allmaras turbulence model is used in these simulations. Experimental data have been used to validate the flow solver... 

    Rheology, stability and filtration characteristics of colloidal gas aphron fluids: role of surfactant and polymer type

    , Article Journal of Natural Gas Science and Engineering ; Volume 26 , September , 2015 , Pages 895-906 ; 18755100 (ISSN) Tabzar, A ; Arabloo, M ; Ghazanfari, M. H ; Sharif University of Technology
    Elsevier  2015
    Colloidal Gas Aphron (CGA) are finding increasing application in fields of science and engineering because of their distinctive characteristic. As interest in the application of CGA based fluids grows and in order to select the best procedure for using them in successful petroleum engineering operations, there is a need to gain a better understanding of the factors that affect their properties and behavior. This article discusses the rheological characterization, stability analysis and filtration properties of CGA based fluids for three bio-polymers and two ionic surfactant. The stability and filtration analysis were investigated with the static drain rate technique and API filtration tests,... 

    Induced soap-film flow by non-uniform alternating electric field

    , Article Journal of Electrostatics ; Volume 73 , February , 2015 , Pages 112-116 ; 03043886 (ISSN) Shirsavar, R ; Ramos, A ; Amjadi, A ; Taherinia, J ; Mashhadi, M ; Nejati, A ; Sharif University of Technology
    Elsevier  2015
    Fluid flows generated on soap films by non-uniform alternating electric fields are studied. Two parallel metal rods subjected to an AC voltage are placed perpendicular to the soap film, which is anchored in a dielectric frame. The fluid flow is generated by electrohydrodynamic induction. At very low signal frequencies there is induced surface charge, but there is no tangential electric field at the surface, so there is no force and no flow. Fluid flow is observed increasing the frequency, when there are both surface charge and tangential electric field. The flow velocity increases with decreasing thickness of the soap film  

    Impact of temperature and etching methods on surface roughness, topography, and composition of glass micromodels

    , Article Energy and Fuels ; Volume 36, Issue 23 , 2022 , Pages 14066-14078 ; 08870624 (ISSN) Shirazi, M ; Masihi, M ; Mahani, H ; Tamsilian, Y ; Sharif University of Technology
    American Chemical Society  2022
    Fluid flow in porous media is affected by surface characteristics such as roughness and topography. In this work, to simulate the surface of natural porous structures in transparent interconnected media like micromodels, various degrees of roughness have been artificially created on flat glass substrates via different methods of laser ablation, cream etching, combination of laser ablation and cream etching, and hydrofluoric acid (HF) etching. The obtained surfaces by each method were characterized in detail via field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX/EDS), and surface profilometry. The impact of high... 

    Optimization of the pem fuel cell cooling system by entropy generation minimization

    , Article 3rd International Conference on Fuel Cell Science, Engineering, and Technology, 2005, Ypsilanti, MI, 23 May 2005 through 25 May 2005 ; 2005 , Pages 441-448 ; 0791837645 (ISBN); 9780791837641 (ISBN) Sharifian, L ; Saidi, M. H ; Sharif University of Technology
    American Society of Mechanical Engineers  2005
    Cooling system is essential for high power fuel cells to maintain cells temperature in an acceptable limit. In this paper a suitable cooling system for the PEM fuel cell has been designed and optimized. The design includes the number of the cooling plates, the proper circuit of the cooling channels in the plates, the channel dimensions, the flow rate of the cooling fluid and its temperature. The optimization technique is minimization of the entropy generation through the cooling plates. The design of the cooling channels and plates is such that the plate temperature doesn't exceed from a desired temperature and the temperature variation in the plate becomes minimized. In this design, the... 

    Numerical modeling of ureagenesis in a microfluidic channel mimicking a liver lobule

    , Article 2015 22nd Iranian Conference on Biomedical Engineering, ICBME 2015, 25 November 2015 through 28 November 2015 ; 2015 , Pages 54-59 ; 9781467393515 (ISBN) Sharifi, F ; Firoozabadi, B ; Saidi, M. S ; Firoozbakhsh, K ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2015
    Ammonia detoxification is one of the main functions of the liver results in production of urea. In this study ammonia elimination and urea production was simulated in a microchannel mimicking the hepatic porto central axis. Navier- Stockes equations along with convection equations were solved for the related species in the entire domain. Since the Reynolds number was small (~1) the fluid flow regime was laminar. Urea cycle was modeled regarding its four main enzymes. Twelve rate equations were also solved in order to obtain the concentration of each metabolites participating in urea cycle. Concentration of the urea reached its maximum ca. 1.2e-5 M at the end of the channel which is in good... 

    The characteristics of serrated flow in superalloy IN738LC

    , Article Materials Science and Engineering A ; Volume 486, Issue 1-2 , 2008 , Pages 376-380 ; 09215093 (ISSN) Sharghi Moshtaghin, R ; Asgari, S ; Sharif University of Technology
    Serrated flow was investigated in superalloy IN738LC, a nickel-base γ′ age-hardened alloy. In this material serrated flow appeared between 350 and 450 °C and strain rate of (8.77 × 10-5 to 8.77 × 10-3) s-1. Activation energy for this process was calculated to be 0.69-0.86 eV which is in good agreement with the values reported for similar alloys. Results show that the diffusion rate of substitutional solute atoms at this temperature range is too low to cause this effect. This suggests that the interaction of solute atoms and moving dislocation is responsible for the observed serrated flow in this alloy. © 2007 Elsevier B.V. All rights reserved  

    Fluid flow and heat transfer in microchannel with and without porous medium under constant heat flux

    , Article Sadhana - Academy Proceedings in Engineering Sciences ; Volume 47, Issue 2 , 2022 ; 02562499 (ISSN) Shamsoddini Lori, M ; Sharif University of Technology
    Springer  2022
    In this study, the heat transfer and fluid flow characteristics of a three-dimensional microchannel that is partially filled with a layer of porous medium at its bottom solid wall is investigated. The microchannel is consisted of a clear fluid flow region, solid walls and a porous layer that is attached to its solid bottom wall. A constant heat flux is applied to the bottom wall of the microchannel. Darcy-Brinkman-Forchheimer model is used to simulate the fluid flow inside the porous medium. The novelty of this work is to investigate thoroughly and precisely the effect of using of porous layer configuration in MCHSs on hydraulic and thermal performances. The effect of porous layer thickness,... 

    Numerical simulation of heat transfer in mixed electroosmotic pressure-driven flow in straight microchannels

    , Article Journal of Thermal Science and Engineering Applications ; Volume 8, Issue 2 , 2016 ; 19485085 (ISSN) Shamloo, A ; Merdasi, A ; Vatankhah, P ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2016
    This paper investigates two-dimensional, time-independent elecroosmotic pressuredriven flow generated by a direct current electric potential with asymmetrical and symmetrical zeta potential distributions along the microchannel walls. Fluid flow through the horizontal microchannel is simulated using a numerical method. Two different cases are proposed to study the effect of electric potential on the flow field. First, negative electric potential is applied on the microchannel walls. In this case, large segments with negative electric potential are initially placed on the first half of the microchannel walls with two different arrangements. Afterward, smaller segments with negative electric... 

    Numerical optimization and inverse study of a microfluidic device for blood plasma separation

    , Article European Journal of Mechanics, B/Fluids ; Volume 57 , 2016 , Pages 31-39 ; 09977546 (ISSN) Shamloo, A ; Vatankhah, P ; Bijarchi, M. A ; Sharif University of Technology
    Elsevier Ltd  2016
    In this paper, a passive microfluidic device for continuous real time blood plasma separation has been studied and optimized. A numerical model is used to solve both the fluid flow and the particles confined within it. Red blood cells are considered as particles with diameter of 7μm. A parametric study is performed in order to characterize the effect of different parameters on separation and purity efficiency. In this study, four different variables were introduced to design the microfluidic device for blood plasma separation including: the angle between the daughter channels and the main channel, the widths, the diffuse angle and the number of daughter channels. Results show that the...