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Total 223 records

    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
    Abstract
    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... 

    Novel thermal aspects of hybrid nanofluid flow comprising of manganese zinc ferrite MnZnFe2O4, nickel zinc ferrite NiZnFe2O4 and motile microorganisms

    , Article Ain Shams Engineering Journal ; Volume 13, Issue 5 , 2022 ; 20904479 (ISSN) Ahmad, S ; Akhter, S ; Imran Shahid, M ; Ali, K ; Akhtar, M ; Ashraf, M ; Sharif University of Technology
    Ain Shams University  2022
    Abstract
    An enhancement in heat transfer due to nanofluids is essentially required in various thermal systems. Hybrid nanofluids possess high thermal conductivity and, have ability to embellish and enhance the thermal strength of common fluids. Our concern in this paper is to examine the innovative attributes of hybrid nanofluids like Manganese zinc ferrite (MnZnFe2O4) and Nickel zinc ferrite (NiZnFe2O4) in the bio-convective flow of motile gyrotactic microorganisms subject to Darcy Forchheimer medium. The effect of activation energy has also been taken into account. Mathematical treatment is carried out via MATLAB software. The use of MnZnFe2O4 - NiZnFe2O4/H2O exhibits improved thermal... 

    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
    Abstract
    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... 

    Investigation on reactive flow through porous media by quadtree Lattice Boltzmann

    , Article Journal of Natural Gas Science and Engineering ; Volume 104 , 2022 ; 18755100 (ISSN) Mahmoudi, S ; Ayatollahi, S ; Jamshidi, S ; Raoof, A ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    In this study, in order to investigate the effect of the underlying pore-scale processes on continuum scale simulations of porous media dissolution, we improve the standard Lattice Boltzmann method using Quadtree grid refinement approach to simulate fluid flow and reactive transport through large domain sizes. Our results have shown considerable computational improvements up to 80% in simulation time together with increased numerical accuracy. The results and the added value of the new approach are discussed using comparison of our model with the conventional LBM. Moreover, we have applied a systematic analysis by increasing complexity levels and starting from fluid flow and continuing with... 

    Thermal characteristics of kerosene oil-based hybrid nanofluids (Ag-MnZnFe2O4): A comprehensive study

    , Article Frontiers in Energy Research ; Volume 10 , 2022 ; 2296598X (ISSN) Ahmad, S ; Ali, K ; Haider, T ; Jamshed, W ; Tag El Din, E. S. M ; Hussain, S. M ; Sharif University of Technology
    Frontiers Media S.A  2022
    Abstract
    Hybrid nanofluids are new and most fascinating types of fluids that involve superior thermal characteristics. These fluids exhibit better heat-transfer performance as equated to conventional fluids. Our concern, in this paper, is to numerically interpret the kerosene oil-based hybrid nanofluids comprising dissimilar nanoparticles like silver (Ag) and manganese zinc ferrite (MnZnFe2O4). A numerical algorithm, which is mainly based on finite difference discretization, is developed to find the numerical solution of the problem. A numerical comparison appraises the efficiency of this algorithm. The effects of physical parameters are examined via the graphical representations in either case of... 

    Multiscale modeling of coupled thermo-hydro-mechanical analysis of heterogeneous porous media

    , Article Computer Methods in Applied Mechanics and Engineering ; Volume 391 , 2022 ; 00457825 (ISSN) Saeedmonir, S ; Khoei, A. R ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    This paper presents a numerical multiscale formulation for analysis of the transient heat and fluid flow in deformable heterogeneous porous media. Due to the heterogeneity of the media, the direct numerical simulation of the micro-structures leads to high computational costs. Hence, the multi-scale method can provide an efficient computational procedure. To this end, the first-order computational homogenization is adopted for two-scale simulation of THM problems. The governing equations of the problem contain a stress equilibrium equation, a mass continuity equation and an advection–diffusion equation in a fully coupled manner. Accordingly, the proper virtual power relations are defined as a... 

    CFD simulation of thermal performance of hybrid oil-Cu-Al2O3 nanofluid flowing through the porous receiver tube inside a finned parabolic trough solar collector

    , Article Sustainable Energy Technologies and Assessments ; Volume 50 , 2022 ; 22131388 (ISSN) Samiezadeh, S ; Khodaverdian, R ; Doranehgard, M. H ; Chehrmonavari, H ; Xiong, Q ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    In this study, we perform numerical simulations to investigate the thermal and flow characteristics of a parabolic trough solar collector equipped with a porous receiver tube and internal longitudinal fins. The heat transfer medium is a synthetic oil-Cu-Al2O3 hybrid nanofluid. We examine the thermal characteristics of the nanofluid in response to variations in several system parameters. We find that at Reynolds numbers between 5 × 103 and 5 × 105, increasing the volume fraction of Cu nanoparticles can increase the temperature gain at the exit of the receiver tube by 6.4%. Furthermore, the temperature gradient in the cross-section of the collector increases as the direct normal solar... 

    Heat transfer and fluid flow analysis of microchannel heat sinks with periodic vertical porous ribs

    , Article Applied Thermal Engineering ; Volume 205 , 2022 ; 13594311 (ISSN) Lori, M.S ; Vafai, K ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    In this study, a detailed numerical analysis of the fluid flow and heat transfer of a three-dimensional microchannel is performed to evaluate the effect of using periodic vertical porous and solid ribs with various geometrical shapes, including rectangular, elliptical, isosceles triangular, backward triangular and forward triangular on the walls of this microchannel. Darcy-Brinkman-Forchheimer equations are used to model transport through the porous medium. The results for microchannels with solid ribs and with porous ribs are compared to each other. It is found that at the lowest studied inlet velocity (uin=0.25m/s), for the rib heights of Hr=0.025mm,0.05mmand0.07mm, the average Nusselt... 

    Simulation of proppant transport at intersection of hydraulic fracture and natural fracture of wellbores using CFD-DEM

    , Article Particuology ; Volume 63 , 2022 , Pages 112-124 ; 16742001 (ISSN) Akhshik, S ; Rajabi, M ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    Proppants transport is an advanced technique to improve the hydraulic fracture phenomenon, in order to promote the versatility of gas/oil reservoirs. A numerical simulation of proppants transport at both hydraulic fracture (HF) and natural fracture (NF) intersection is performed to provide a better understanding of key factors which cause, or contribute to proppants transport in HF–NF intersection. Computational fluid dynamics (CFD) in association with discrete element method (DEM) is used to model the complex interactions between proppant particles, host fluid medium and fractured walls. The effect of non-spherical geometry of particles is considered in this model, using the multi-sphere... 

    Design of two Inertial-based microfluidic devices for cancer cell separation from Blood: A serpentine inertial device and an integrated inertial and magnetophoretic device

    , Article Chemical Engineering Science ; Volume 252 , 2022 ; 00092509 (ISSN) Nasiri, R ; Shamloo, A ; Akbari, J ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    The separation of cancer cells from a heterogeneous biological sample such as blood plays a vital role in cancer study and future treatments. In this paper, we designed and investigated two microfluidic devices for cancer cell separation, including a serpentine inertial device and an integrated inertial-magnetophoretic device. Firstly, numerical modeling was carried out to study the fluid flow, particles’ trajectories in the inertial device. Then the device was fabricated using soft photolithography and suspension of two types of microparticles with the size of 10 and 15 µm were injected into the microchannel separately to investigate the particles’ trajectories and focusing behavior at... 

    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
    Abstract
    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,... 

    Quantifying lake–aquifer water exchange: the case of Lake Urmia, Iran

    , Article Hydrological Sciences Journal ; Volume 67, Issue 5 , 2022 , Pages 725-740 ; 02626667 (ISSN) Parizi, E ; Hosseini, S. M ; Ataie Ashtiani, B ; Nikraftar, Z ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    This study investigated the lake–aquifer hydraulic interactions in Lake Urmia (LU) as the second largest hypersaline lake in the world. Due to the scarcity of hydrogeological data required for modelling, a method based on Darcy’s Law and lake water budget was used to quantify the lake–aquifer interaction. Long-term ground- and satellite-based hydrological datasets over the time frame 2001–2019 were used. Results indicate that the groundwater flux between LU and the aquifers controls 18.74 ± 1.67% of the lake’s water storage. While 10 out of 14 adjacent aquifers recharge LU at a rate of less than 180 m3/m.month, one phreatic aquifer recharges the LU up to 1400 m3/m.month. Two aquifers are... 

    Internal cooling sensitivity analysis to improve the thermal performance of gas turbine blade using a developed robust conjugate heat transfer method

    , Article International Journal of Engine Research ; 2022 ; 14680874 (ISSN) Darbandi, M ; Jalali, R ; Sharif University of Technology
    SAGE Publications Ltd  2022
    Abstract
    The heat transfer simulations of turbine blades with internal cooling are faced with so many uncertainties, of which some originate from the secondary air system, including the inlet hot gas temperature and pressure and the cooling side boundary conditions, and the blade material. The main objective of this work is to carry out a suitable sensitivity analysis on a specific novel turbine vane to improve the thermal performance of its internal cooling system and to quantify how the uncertainties on the designed/calculated values can desirably/undesirably affect the maximum blade surface temperature, which can consequently affect the gas turbine engine efficiency. Furthermore, the sensitivity... 

    Magnetic field-induced control of a compound ferrofluid droplet deformation and breakup in shear flow using a hybrid lattice Boltzmann-finite difference method

    , Article International Journal of Multiphase Flow ; Volume 146 , 2022 ; 03019322 (ISSN) Majidi, M ; Bijarchi, M. A ; Ghorbanpour Arani, A ; Rahimian, M. H ; Shafii, M. B ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    The deformation and breakup dynamics of a compound ferrofluid droplet under shear flow and uniform magnetic field are numerically studied in this paper. Utilizing magnetic field provides the possibility to obtain better control over the compound droplet morphology and breakup in a simple shear flow. To solve the governing equations for interfaces motion and hydrodynamics, the conservative phase field lattice Boltzmann model is employed, and a finite difference approach is applied for calculating the magnetic field. To verify the accuracy of present simulations, the results are validated with those of four relevant benchmarks including liquid lens between two stratified fluids, three-phase... 

    Computer simulation of the effect of particle stiffness coefficient on the particle-fluid flows

    , Article Particulate Science and Technology ; Volume 40, Issue 2 , 2022 , Pages 233-242 ; 02726351 (ISSN) Akhshik, S ; Rajabi, M ; Sharif University of Technology
    Taylor and Francis Ltd  2022
    Abstract
    The Computational fluid dynamics (CFD)–discrete element method (DEM) numerical simulation may be applied to predict the hydrodynamic behavior of dense particle–fluid flows. The main drawback of this simulation is the long computational time required owing to the large number of particles and the minute time-step required to maintain a stable solution. In this work, a new method to improve the efficiency and accuracy of CFD–DEM simulations is presented. The particle stiffness coefficient is used as a flexible parameter to improve the accuracy and efficiency of the model. The particle concentration distribution results are compared with experimental one’s to derive the optimum effective... 

    Investigation of the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three dimensional lattice Boltzmann flux solver

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; Volume 32, Issue 1 , 2022 , Pages 283-312 ; 09615539 (ISSN) Ashouri, M ; Zarei, M. M ; Moosavi, A ; Sharif University of Technology
    Emerald Publishing  2022
    Abstract
    Purpose: The purpose of this paper is to investigate the effects of geometrical parameters, eccentricity and perforated fins on natural convection heat transfer in a finned horizontal annulus using three-dimensional lattice Boltzmann flux solver. Design/methodology/approach: Three-dimensional lattice Boltzmann flux solver is used in the present study for simulating conjugate heat transfer within an annulus. D3Q15 and D3Q7 models are used to solve the fluid flow and temperature field, respectively. The finite volume method is used to discretize mass, momentum and energy equations. The Chapman–Enskog expansion analysis is used to establish the connection between the lattice Boltzmann equation... 

    Coupled hydro-mechanical analysis of underground gas storage at Sarajeh field, Qom formation, Iran

    , Article Journal of Natural Gas Science and Engineering ; Volume 92 , 2021 ; 18755100 (ISSN) Bakhtiari, M ; Shad, S ; Zivar, D ; Razaghi, N ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Production or injection of fluids from/in an underground storage site causes variations of pore pressure and stress states. These fluctuations significantly affect implications for hydraulic fracturing, wellbore integrity, top surface subsidence and heave, fault-reactivation, and stability of reservoir and caprock. Therefore, in order to keep optimal conditions during the process of gas injection and production, it is of paramount importance to have accurate estimates of the pore pressure. In this investigation, coupled fluid flow and geomechanical simulations, as well as rock mechanical tests, are performed on the Sarajeh field, Iran to investigate the geomechanical behavior of the Sarajeh... 

    Modeling fluid flow in fractured porous media with the interfacial conditions between porous medium and fracture

    , Article Transport in Porous Media ; Volume 139, Issue 1 , 2021 , Pages 109-129 ; 01693913 (ISSN) Hosseini, N ; Khoei, A. R ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Abstract
    One of the most popular models that has been applied to predict the fluid velocity inside the fracture with impermeable walls is the cubic law. It highlights that the mean flux along the fracture is proportional to the cubic of fracture aperture. However, for a fractured porous medium, the normal and tangential interface conditions between the fracture and porous matrix can change the velocity profile inside the fracture. In this paper, a correction factor is introduced for flow equation along the fracture by imposing the continuity of normal and tangential components of velocity at the interface between the fracture and porous matrix. As a result, the mean velocity inside the fracture... 

    Modeling non-isothermal two-phase fluid flow with phase change in deformable fractured porous media using extended finite element method

    , Article International Journal for Numerical Methods in Engineering ; Volume 122, Issue 16 , April , 2021 , Pages 4378-4426 ; 00295981 (ISSN) Khoei, A. R ; Amini, D ; Mortazavi, M. S ; Sharif University of Technology
    John Wiley and Sons Ltd  2021
    Abstract
    In this article, a computational model is presented for the analysis of coupled thermo-hydro-mechanical process with phase change (evaporation/condensation) in fractured porous media in order to model multiphase fluid flows, heat transfer, and discontinuous deformation by employing the extended finite element method. The ideal gas law and Dalton's law are employed to consider vapor and dry air as miscible gases. To take into account the phase change, latent heat and specific vapor enthalpy are incorporated into the physical model. The set of governing equations consists of linear momentum for the solid-phase, energy balance equation and mass conservation equations of water species (liquid... 

    Prediction of waterflood performance using a modified capacitance-resistance model: A proxy with a time-correlated model error

    , Article Journal of Petroleum Science and Engineering ; Volume 198 , 2021 ; 09204105 (ISSN) Mamghaderi, A ; Aminshahidy, B ; Bazargan, H ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Capacitance-Resistive Model (CRM), as a fast yet efficient proxy model, suffers from some limitations in modeling relatively complex reservoirs. Some current improvements on this proxy made it a more powerful simulator with updating parameters over time. However, the model's intrinsic uncertainty arisen from simplifying fluid-flow modeling by some limited number of constant parameters is not addressed yet. In this study, this structural limitation of CRM has been addressed by introducing a time-correlated model error, including stochastic and non-stochastic parameters, embedded into this proxy's formulation. The error term's non-stochastic parameters have been tuned to be used in forecasting...