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fluids
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Heat transfer intensification of turbulent forced convection by inserting discontinuous twisted tapes in a wavy tube; hydrothermal and thermodynamics analysis
, Article Chemical Engineering and Processing - Process Intensification ; Volume 181 , 2022 ; 02552701 (ISSN) ; Sadrhosseini, H ; Kazemzadeh Hannani, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The current study presents a numerical investigation on turbulent hydrothermal characteristics in a wavy passage equipped with discontinuous twisted tapes. The working fluid is water and passage walls are kept under constant wall temperature. The effect of Reynolds number (Re = 2500, 4500, 6500, 8500 and 10500), twist angle (TA = 90∘ and 180∘) and inclination angle (IA = 15∘ and 30∘) on velocity fields and streamlines, temperature contours, Nusselt number, friction factor, turbulent kinetic energy (TKE), thermal performance factor (TPF), energy efficiency factor (EEF) and entropy generation rate are evaluated. More uniform temperature and velocity fields can be found as both wavy passage and...
New insight into hydrodynamic and cake erosion mechanism during rotating-disk dynamic microfiltration of concentrated bentonite suspensions at different salinity conditions
, Article Separation and Purification Technology ; Volume 300 , 2022 ; 13835866 (ISSN) ; Jamshidi, S ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The present study investigates the dynamic filtration of concentrated slurry fluids containing colloidal clay particles under different salinity, shear flow, and flux rate conditions. The dynamic filtration study was carried out by the filtration cell equipped with a rotating disk to apply shear stress over the membrane surface. A 3D CFD simulation has been implemented to model the hydrodynamic flows inside the filtration cell to obtain the wall shear stress (WSS) on the membrane surface at different disk rotation speeds. The thickness and surface patterns of fouling were captured utilizing a surface profilometer. First, the cake-filtration model was used to predict the flux rate and fouling...
Forced and free vibrational analysis of viscoelastic nanotubes conveying fluid subjected to moving load in hygro-thermo-magnetic environments with surface effects
, Article Archives of Civil and Mechanical Engineering ; Volume 22, Issue 4 , 2022 ; 16449665 (ISSN) ; Alibeigloo, A ; Borjalilou, V ; Koochakianfard, O ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Forced and free vibrational analyses of viscoelastic nanotubes containing fluid under a moving load in complex environments incorporating surface effects are conducted based on the nonlocal strain gradient theory and the Rayleigh beam model. To model the internal nanoflow, the slip boundary condition is employed. Adopting the Galerkin discretization approach, the reduced-order dynamic model of the system is acquired. Analytical and numerical methods are exploited to determine the dynamic response of the system. The impacts of geometry, scale parameter ratio, Knudsen number, fluid velocity, rotary inertia parameter, viscoelastic parameter, surface residual stress, surface elastic modulus, and...
Numerical simulation of vortex-induced vibration of a smooth circular cylinder at the subcritical regime
, Article Proceedings of the Institution of Mechanical Engineers Part M: Journal of Engineering for the Maritime Environment ; Volume 236, Issue 4 , 2022 , Pages 916-937 ; 14750902 (ISSN) ; Nemati Kourabbasloo, N ; Mohtat, P ; Tanha, A ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
The present paper focuses on the simulation of vortex-induced vibration (VIV) of a rigid, smooth circular cylinder with elastic supports subject to a cross-flow at the subcritical regime of Reynolds number, 30,000
The effect of Ag incorporation on the characteristics of the polymer derived bioactive silicate phosphate glass-ceramic scaffolds
, Article Boletin de la Sociedad Espanola de Ceramica y Vidrio ; Volume 61, Issue 6 , 2022 , Pages 653-663 ; 03663175 (ISSN) ; Godary, T ; Khalilifard, R ; Malek Khachatourian, A ; Abdollahi, F ; Abdollahi, S ; Sharif University of Technology
Sociedad Espanola de Ceramica y Vidrio
2022
Abstract
In the bone tissue engineering field (BTE), it is of significant importance to develop bioactive multifunctional scaffolds with enhanced osteoconductivity, osteoinductivity, and antibacterial properties required for lost bone tissue regeneration. In this work, a bioactive glass-ceramic scaffold was manufactured via a novel polymer-derived ceramics (PDC) manufacturing method. To gain antibacterial properties, the silver ions were incorporated in controlled amount along with other precursors in the PDC processing stage. Microstructural and structural properties of the fabricated silicate-phosphate glass-ceramic scaffold were evaluated by scanning electron microscopy (SEM) equipped with energy...
Performance evaluation of the solar-driven multi-ejector refrigeration cycle without an auxiliary heat source
, Article Applied Thermal Engineering ; Volume 217 , 2022 ; 13594311 (ISSN) ; Hakkaki Fard, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Solar-driven ejector refrigeration (SER) systems have been granted special attention as a green and sustainable replacement for conventional vapor compression cooling systems. However, despite their significant advantages, SER systems suffer from a relatively low coefficient of performance and failure at high ambient temperatures and low solar radiations. Therefore, the need for an auxiliary heat source and cooling system has hindered their adoption in practice. In an attempt to eliminate the need for an auxiliary heat source and cooling system, this contribution puts forward a novel Solar-driven Multi-Ejector Refrigeration (SMER) system with an internal heat exchanger, a regenerator, and a...
Continuous submicron particle separation Via Vortex-Enhanced ionic concentration polarization: a numerical investigation
, Article Micromachines ; Volume 13, Issue 12 , 2022 ; 2072666X (ISSN) ; Amiri, H.A ; Collins, D.J ; Miansari, M ; Sharif University of Technology
MDPI
2022
Abstract
Separation and isolation of suspended submicron particles is fundamental to a wide range of applications, including desalination, chemical processing, and medical diagnostics. Ion concentration polarization (ICP), an electrokinetic phenomenon in micro-nano interfaces, has gained attention due to its unique ability to manipulate molecules or particles in suspension and solution. Less well understood, though, is the ability of this phenomenon to generate circulatory fluid flow, and how this enables and enhances continuous particle capture. Here, we perform a comprehensive study of a low-voltage ICP, demonstrating a new electrokinetic method for extracting submicron particles via flow-enhanced...
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) ; 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...
In vitro bioactivity and biocompatibility of magnesium implants coated with poly(methyl methacrylate) - bioactive glass composite
, Article Materials Today Communications ; Volume 33 , 2022 ; 23524928 (ISSN) ; Jafari, H ; Pishbin, F ; Mohandes, F ; Simchi, A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Magnesium (Mg) and its alloys have proved promising as biodegradable candidates for the repair of bone tissue. Despite the encouraging bio-related properties of Mg, its high corrosion rate in contact with body fluids still presents a major challenge. An efficient approach to address this issue is to provide a protective coating on Mg. The present research evaluates, for the first time, in vitro bioactivity and biocompatibility of a novel multifunctional composite coating based on poly(methyl methacrylate) (PMMA) biopolymer and bioactive glass (BG) particles on Mg-based implant. Electrophoretic deposition (EPD) was utilized to obtain this coating from a bi-component suspension. Coatings’...
Unified modeling and experimental realization of electrical and thermal percolation in polymer composites
, Article Applied Physics Reviews ; Volume 9, Issue 4 , 2022 ; 19319401 (ISSN) ; Arabshahi, Z. S ; Saberi, A. A ; Moshfegh, A. Z ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
Correlations between electrical and thermal conduction in polymer composites are blurred due to the complex contribution of charge and heat carriers at the nanoscale junctions of filler particles. Conflicting reports on the lack or existence of thermal percolation in polymer composites have made it the subject of great controversy for decades. Here, we develop a generalized percolation framework that describes both electrical and thermal conductivity within a remarkably wide range of filler-to-matrix conductivity ratios (Y f / Y m), covering 20 orders of magnitude. Our unified theory provides a genuine classification of electrical conductivity with typical Y f / Y m ≥ 10 10 as...
Numerical study of the effect of hemodynamic variables on LDL concentration through the single layer of the Left Anterior Descending coronary artery (LAD) under the heart pulse
, Article Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine ; Volume 236, Issue 7 , 2022 , Pages 994-1008 ; 09544119 (ISSN) ; Seyedhossein, S. S ; Firoozabadi, B ; MomeniLarimi, M ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Heart attack is one of the most common causes of death in the world. Coronary artery disease is the most recognized cause of heart attack whose onset and progression have been attributed to low-density lipoprotein (LDL) passing through the wall of the artery. In this paper, hemodynamic variables as well as the concentration of LDL through the coronary porous artery at the Left Anterior Descending coronary artery (LAD), and its first diagonal branch (D1) under the heart motion investigated using computational simulation. The geometry that has been studied in this paper is the first bifurcation of Left Anterior Descending (LAD) that has been placed on a perimeter of hypothetical sphere...
A new method for calculating laser intensity distribution on workpiece surface in laser-directed energy deposition process by considering powder stream distribution and laser attenuation
, Article International Journal of Advanced Manufacturing Technology ; Volume 121, Issue 1-2 , 2022 , Pages 337-348 ; 02683768 (ISSN) ; Akbari, J ; Moradi, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Laser-directed energy deposition is a fast-growing method for manufacturing complex geometries and materials that are hard to shape with conventional manufacturing methods. However, there are some aspects of this process that need more researches and experiments to be completely understood. Two of these are laser attenuation and laser intensity distribution on the workpiece surface. In this paper, a new method is proposed for calculating laser attenuation without simplification applied in previous works. Despite other studies that consider a predefined powder distribution, the result of a developed 3D CFD model of the powder stream is utilized for defining the position of particles in the...
Alginate-based multifunctional films incorporated with sulfur quantum dots for active packaging applications
, Article Colloids and Surfaces B: Biointerfaces ; Volume 215 , 2022 ; 09277765 (ISSN) ; Priyadarshi, R ; Rhim, J. W ; Lotfali, E ; Bagheri, R ; Pircheraghi, G ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Sulfur quantum dots (SQDs) were fabricated using a facile hydrothermal method and used for the preparation of functional food packaging film and compared the properties with other sulfur-based fillers like elemental sulfur (ES) and sulfur nanoparticles (SNP). The SQDs have an average size of 5.3 nm and were very stable in aqueous suspension. Unlike other sulfur-based fillers, the SQD showed high antioxidant, antibacterial and antifungal activity, but no cytotoxicity was found for L929 mouse fibroblasts even after long-term exposure of 48 h. When sulfur-based fillers were added to the alginate film, SQD was more evenly dispersed in the polymer matrix than SNP and ES. The addition of SQD to...
A comparative study on bifacial photovoltaic/thermal modules with various cooling methods
, Article Energy Conversion and Management ; Volume 263 , 2022 ; 01968904 (ISSN) ; Kazemian, A ; Habibollahzade, A ; Salari, A ; Gu, W ; Peng, J ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The bifacial photovoltaic/thermal module is an emerging concept that can provide electricity and heat simultaneously, taking advantage of both front and rear sides of the panel; therefore, exhibiting a better performance compared to a conventional photovoltaic module or photovoltaic thermal module. In this study, four configurations of the bifacial photovoltaic/thermal module with different cooling methods have been proposed, i.e., cooling performed at either the upper or the lower surface, in parallel (applied to both upper and lower surfaces having similar start/endpoints), and swinging air back and forth (by guiding the air over the upper and lower surfaces, respectively). The...
Promoting the adoption of residential water conservation behaviors as a preventive policy to sustainable urban water management
, Article Journal of Environmental Management ; Volume 313 , 2022 ; 03014797 (ISSN) ; Tabesh, M ; Yazdanpanah, M ; Zobeidi, T ; Raoof, M. A ; Sharif University of Technology
Academic Press
2022
Abstract
As concerning with water insecurity driven by water scarcity threatens the lives and livelihoods of humanity worldwide, urban water demand management is focused on promoting residential water conservation behaviors (WCBs) as a critical policy response to water scarcity. However, urban water conservation initiatives cannot be successful unless households involve in residential WCBs voluntarily by adopting water curtailment and/or water-efficiency actions. Thus, understanding motivations and mechanisms underlying accepting these two types of WCBs and interpreting their distinctions are primary policy considerations to make sustainable water consumption behaviors. Hence, the purpose of this...
On the yield stress of magnetorheological fluids
, Article Chemical Engineering Science ; Volume 256 , 2022 ; 00092509 (ISSN) ; Alaghehband, N ; Bavil, P. K ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Magnetorheological fluids (MRFs) are a category of functional materials that exhibit magneto-mechanical coupling. These materials exhibit a reversible and instantaneous change from a free-flowing Newtonian fluid to a semi-solid state upon application of a magnetic field. In contrast to ordinary fluids, MRFs can tolerate shear stresses up to a yield value in the presence of a magnetic field. The yield stress strongly depends on intensity of the applied magnetic field and volume fraction of magnetic particles. As the yield stress is the most important parameter of an MRF and must be considered in the design of MR devices, in this work, effects of magnetic field and volume fraction of particles...
Investigation on reactive flow through porous media by quadtree Lattice Boltzmann
, Article Journal of Natural Gas Science and Engineering ; Volume 104 , 2022 ; 18755100 (ISSN) ; 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...
Semi-empirical modelling of hydraulic conductivity of clayey soils exposed to deionized and saline environments
, Article Journal of Contaminant Hydrology ; Volume 249 , 2022 ; 01697722 (ISSN) ; Sadeghi, H ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Clay liners are widely used as porous membrane barriers to control solute transport and to prevent the leakage of leachate both in horizontal and vertical flow scenarios, such as the isolated base and ramps of sanitary landfills. Despite the primary importance of saturated hydraulic conductivity in a reliable simulation of fluid flow through clay barriers, there is no model to predict hydraulic conductivity of clayey soils permeated with saline aqueous solutions because most of the current models were developed for pure water. Therefore, the main motivation behind this study is to derive semi-empirical models for simulating the hydraulic conductivity of clayey soils in the presence of...
Melting process of various phase change materials in presence of auxiliary fluid with sinusoidal wall temperature
, Article Journal of Energy Storage ; Volume 52 , 2022 ; 2352152X (ISSN) ; Khademi, A ; Ushak, S ; Alotaibi, S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper presents a numerical simulation approach to investigate the water effect as an auxiliary fluid in direct contact with various phase change materials (PCMs). The technique is defined as a hybrid method due to the using of an external intermediary for melting process improvement. Oleic acid (OA), coconut oil (CO), hexadecane, and heptadecane are selected as PCMs due to immiscibility in water and differences in density, melting point, and enthalpy of fusion. An auxiliary fluid is embedded above PCM in an enclosure subjected to sinusoidal wall temperature for melting rate increase through density differences improving heat transfer rate due to materials displacement during process....
Computational analysis of heat and mass transfer in a micropolar fluid flow through a porous medium between permeable channel walls
, Article International Journal of Nonlinear Sciences and Numerical Simulation ; Volume 23, Issue 5 , 2022 , Pages 761-775 ; 15651339 (ISSN) ; Ashraf, M ; Ali, K ; Nisar, K. S ; Sharif University of Technology
De Gruyter Open Ltd
2022
Abstract
The present work numerically investigates the mass and heat transport flow of micropolar fluid in a channel having permeable walls. The appropriate boundary layer approximations are used to convert the system of flow model equations in ODEs, which are then numerically treated with the quasi-linearization method along with finite difference discretization. This technique creates an efficient way to solve the complex dynamical system of equations. A numerical data comparison is presented which assures the accuracy of our code. The outcomes of various problem parameters are portrayed via the graphs and tables. The concentration and temperature accelerate with the impacts of the Peclet numbers...