Search for: nanofluidics
0.008 seconds

    Experimental investigation on laminar forced convective heat transfer of ferrofluid loaded with carbon nanotubes under constant and alternating magnetic fields

    , Article Experimental Thermal and Fluid Science ; Volume 76 , 2016 , Pages 1-11 ; 08941777 (ISSN) Shahsavar, A ; Saghafian, M ; Salimpour, M. R ; Shafii, M. B ; Sharif University of Technology
    Elsevier Inc 
    In this paper, the effects of both constant and alternating magnetic fields on the laminar forced convective heat transfer of a hybrid nanofluid containing tetramethylammonium hydroxide (TMAH) coated Fe3O4 nanoparticles and gum arabic (GA) coated carbon nanotubes (CNTs) flowing through a heated tube were investigated experimentally. The experiments were carried out over wide range of parameters such as Reynolds number (548-2190), volume concentrations of Fe3O4 (0.5-0.9%) and carbon nanotube (0.25-1.35%) nanoparticles, magnetic field strength (300-700 Gauss) and alternating magnetic field frequency (10-50 Hz). In present study, the experimental observations in the case without magnetic field... 

    Potential application of silica nanoparticles for wettability alteration of oil-wet calcite: A mechanistic study

    , Article Energy and Fuels ; Volume 30, Issue 5 , 2016 , Pages 3947-3961 ; 08870624 (ISSN) Dehghan Monfared, A ; Ghazanfari, M. H ; Jamialahmadi, M ; Helalizadeh, A ; Sharif University of Technology
    American Chemical Society  2016
    Oil recovery from carbonate reservoirs can be enhanced by altering the wettability from oil-wet toward water-wet state. Recently, silica nanoparticle (SNP) suspensions are considered as an attractive wettability alteration agent in enhanced oil recovery applications. However, their performance along with the underlying mechanism for wettability alteration in carbonate rocks is not well discussed. In this work, the ability of SNP suspensions, in the presence/absence of salt, to alter the wettability of oil-wet calcite substrates to a water-wet condition was investigated. In the first step, to ensure that the properties of nanofluids have not been changed during the tests, stability analysis... 

    Boiling heat transfer on a high temperature silver sphere in nanofluid

    , Article International Journal of Thermal Sciences ; Volume 48, Issue 12 , 2009 , Pages 2215-2220 ; 12900729 (ISSN) Lotfi, H ; Shafii, M. B ; Sharif University of Technology
    To investigate boiling heat transfer characteristics of nanofluids, transient quenching experiments of a high temperature silver sphere in water-based nanofluids with Ag and TiO2 nanoparticles were performed. A silver sphere with a diameter of 10 mm and an initial temperature of 700 °C was quenched in these nanofluids at a temperature of 90 °C. The results showed a considerable reduction in the quenching ability of nanofluids compared to that of pure water. The presence of nanoparticles in water caused the film boiling mode to vanish at lower temperatures depending on the mixture concentration. Calculated heat transfer rates in nanofluids were lower than those in pure water. In the quenching... 

    Determination of parabolic trough solar collector efficiency using nanofluid:a comprehensive numerical study

    , Article Journal of Solar Energy Engineering, Transactions of the ASME ; Volume 139, Issue 5 , 2017 ; 01996231 (ISSN) Khakrah, H ; Shamloo, A ; Hannani, S. K ; Sharif University of Technology
    Due to significant reduction in fossil fuel sources, several researches have been conducted recently to explore modern sources of renewable energy. One of the major fields in the category of renewable energy harnessing devices is parabolic trough solar collector (PTC). Several parameters have effect on the overall efficiency of the PTCs. As the effect of these parameters is coupled to each other, a comprehensive investigation is necessary. In the present study, a numerical analysis is performed to examine the efficiency of PTCs via variation of several governing parameters (e.g., wind velocity magnitude, nanoparticles volume fraction, inlet temperature, and reflector's orientation). A... 

    Investigation the effect of super hydrophobic titania nanoparticles on the mass transfer performance of single drop liquid-liquid extraction process

    , Article Separation and Purification Technology ; Volume 176 , 2017 , Pages 107-119 ; 13835866 (ISSN) Hatami, A ; Bastani, D ; Najafi, F ; Sharif University of Technology
    Hydrophobic titania nanoparticles were synthesized by a novel in situ sol-gel method and applied in a single drop liquid-liquid extraction column to enhance the overall dispersed-phase mass transfer coefficient (Kod). The chemical system of toluene, acetic acid and water was used, and the direction of solute (acetic acid) mass transfer was from dispersed phase, including: toluene and acetic acid to the continuous phase of water. For such system, much of the mass transfer resistance exists in the dispersed phase, which is nonpolar organic liquid. Hence, modified titania nanoparticles (MTNP's), prepared by sol-gel route, in five different concentrations of 0.001–0.005 wt.% were added in the... 

    Gas absorption enhancement in hollow fiber membrane contactors using nanofluids: Modeling and simulation

    , Article Chemical Engineering and Processing: Process Intensification ; Volume 119 , 2017 , Pages 7-15 ; 02552701 (ISSN) Darabi, M ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
    Elsevier B.V  2017
    In this article, a comprehensive 2D mathematical model has been developed to simulate process intensification of carbon dioxide absorption in the presence of nanoparticles in hollow fiber membrane contactors (HFMCs). The influences of nanoparticle were taken into account considering Brownian motion and Grazing effect as dominant phenomena of mass-transfer enhancement in nanofluids. The obtained simulation results were validated against experimental data reported in the literature and excellent agreement was obtained. It was found that by adding 0.05 wt % silica nanoparticles, the absorption rate could be enhanced by 16%, while the corresponding value is 32% for CNT nanoparticles. High... 

    The role of ion partitioning in electrohydrodynamic characteristics of soft nanofluidics: Inclusion of EDL overlap and steric effects

    , Article Chemical Engineering Science ; Volume 190 , 2018 , Pages 443-458 ; 00092509 (ISSN) Reshadi, M ; Saidi, M. H ; Sharif University of Technology
    Elsevier Ltd  2018
    In this paper, we aim to account for the partitioning of finite sized ions and electric double layer (EDL) overlapping effects on the electrostatics and hydrodynamics of soft nanofluidics by stablishing a modified Poisson-Boltzmann (MPB) equation enjoying mean field approach. The application of the present MPB equation enables us to describe the interaction between the steric effect and electrostatic repulsion of EDL ions due to permittivity difference of polyelectrolyte layer (PEL) and electrolyte solution. Utilizing the Debye-Hückel approximation pertinent to low surface potentials, we analytically derive the solutions of electric potential and velocity profiles of mixed electroosmotic and... 

    How to improve the thermal performance of pulsating heat pipes: A review on working fluid

    , Article Renewable and Sustainable Energy Reviews ; Volume 91 , 2018 , Pages 630-638 ; 13640321 (ISSN) Alhuyi Nazari, M ; Ahmadi, M. H ; Ghasempour, R ; Shafii, M. B ; Sharif University of Technology
    Elsevier Ltd  2018
    Pulsating Heat Pipes (PHPs) are cooling devices that are compact in size and have an ability to transfer heat in low temperature differences. Working fluids strongly affect the thermal performance of PHPs. In this paper, effects of some thermophysical parameters relating to working fluids, such as boiling point, latent heat of vaporization, surface tension, thermal conductivity and dynamic viscosity, are presented based on experimental and numerical studies done in recent years. Addition of nanoparticles to fluids, or making nanofuild, is a new method of improving thermophysical properties of fluids. Recently, many studies are carried out on thermophysical properties of nano-fuild. Results... 

    On the size-dependent behavior of drop contact angle in wettability alteration of reservoir rocks to preferentially gas wetting using nanofluid

    , Article Journal of Petroleum Science and Engineering ; Volume 178 , 2019 , Pages 1143-1154 ; 09204105 (ISSN) Azadi Tabar, M ; Ghazanfari, M. H ; Dehghan Monfared, A ; Sharif University of Technology
    Elsevier B.V  2019
    Wettability alteration of rock surfaces toward gas wetting have been recognized as a practical approach for maximizing the production from the gas condensate reservoirs. Most of the reported work in this area applied the so called sessile drop contact angle measurement technique to examine the change in wetting state of a surface. However, the size-dependent wetting behavior of drop which could affect the exact determination of wettability and wettability changes was not well discussed in the previous studies. Therefore, in this work, the size dependency of contact angle for four different liquid-solid-gas systems; i.e., water-calcite-air, water-treated calcite-air (nanofluid treated... 

    A characteristic-based numerical simulation of water-titanium dioxide nano-fluid in closed domains

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 33, Issue 1 , 2020 , Pages 158-163 Adibi, T ; Razavi, S. E ; Adibi, O ; Sharif University of Technology
    Materials and Energy Research Center  2020
    A new characteristic-based method is developed and used for solving the mixed and forced convection problems. The nano-fluid flow with heat transfer is simulated with a novel characteristic-based scheme in closed domains with different aspect ratios. For this purpose, a FORTRAN code has been written and developed. Water as a pure fluid and water-titanium dioxide as a nano-fluid were considered. The governing equations are solved by the finite volume utilizing a characteristic-based scheme for the convective fluxes. The simulation is done at Grashof numbers from 100 to 104, Reynolds numbers from 100 to 1000, and volume fractions of nano-particles from 0% to 10%. Streamlines, isotherms,... 

    Heat transfer enhancement of a fin-and-tube compact heat exchanger by employing magnetite ferrofluid flow and an external magnetic field

    , Article Applied Thermal Engineering ; Volume 164 , 2020 Bezaatpour, M ; Rostamzadeh, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Compact heat exchangers as modern industrial devices are designed to improve heat recovery and saving energy processes in restricted spaces. In the current study, effect of a uniform external magnetic field with Fe3O4/water nanofluid for heat transfer enhancement of a fin-and-tube compact heat exchanger is numerically investigated. The obtained results are verified by the available experimental data to demonstrate accuracy of the present simulation. The results indicated that the local and average heat transfer coefficients increase around the tubes in the presence of an external magnetic field due to the vortex formation behind the tubes as well as the flow pattern alteration in the heat... 

    A review on the applications of micro-/nano-encapsulated phase change material slurry in heat transfer and thermal storage systems

    , Article Journal of Thermal Analysis and Calorimetry ; 2020 Ghoghaei, M. S ; Mahmoudian, A ; Mohammadi, O ; Shafii, M. B ; Jafari Mosleh, H ; Zandieh, M ; Ahmadi, M. H ; Sharif University of Technology
    Springer Netherlands  2020
    In modern heat transfer systems, thermal storage not only causes the balance between demand and supply, but also improves the heat transfer efficiency in these systems. In the present study, a comprehensive review of the applications of micro- or nano-encapsulated phase change slurries (MPCMs/NPCMs), as well as their effects on thermal storage and heat transfer enhancement, has been conducted. MPCMs/NPCMs have a myriad of applications and various usages such as pipe and channel flows, photovoltaic/thermal, solar heaters, air conditioning systems, storage tanks and heat pipes that have been categorized and studied. It was found that there are many advantageous adding MPCM/NPCM to the base... 

    Investigation on nanofluid flooding effect on enhancement oil recovery process in a random pore distribution incomplete cone

    , Article International Communications in Heat and Mass Transfer ; Volume 117 , October , 2020 Hemmat Esfe, M ; Hosseinizadeh, E ; Mosaferi, M ; Sharif University of Technology
    Elsevier Ltd  2020
    By reducing the exploration of new oil reservoirs, enhanced oil recovery from previous oil reservoirs is a solution to supply energy demand. In order to develop the production, various technologies and methods have been proposed such as steaming, direct heating, flooding by nano-fluid, chemical injection, polymer injection and etc. In the present study, nanofluid flooding has been attempted on a rock reservoir with incomplete cone geometry and its performance has been evaluated on oil recovery. The porous media is considered heterogeneous in simulation in accordance with oil reservoirs. The heterogeneous geometry considered in this study is incomplete cone that is heterogeneous in a random... 

    Heat transfer hybrid nanofluid (1-Butanol/MoS2–Fe3O4) through a wavy porous cavity and its optimization

    , Article International Journal of Numerical Methods for Heat and Fluid Flow ; 2020 Hosseinzadeh, K ; Montazer, E ; Shafii, M. B ; Ganji, D. D ; Sharif University of Technology
    Emerald Group Holdings Ltd  2020
    Purpose: The purpose of this paper is to investigate natural convection in a porous wavy-walled enclosure that is including a cylinder cavity in the middle of it and filled with a hybrid nanofluid contains 1-Butanol as the base fluid and MoS2–Fe3O4 hybrid nanoparticles. Design/methodology/approach: The domain of interest is bounded by constant temperature horizontal corrugated surfaces and isothermal vertical flat surfaces. The numerical outputs are explained in the type of isotherms, streamline and average Nusselt number with variations of the Rayleigh number, Hartmann number, nanoparticle shape factor and porosity of the porous medium. For solving the governing equations, the finite... 

    Application of M5 tree regression, MARS, and artificial neural network methods to predict the Nusselt number and output temperature of CuO based nanofluid flows in a car radiator

    , Article International Communications in Heat and Mass Transfer ; Volume 116 , July , 2020 Kahani, M ; Ghazvini, M ; Mohseni Gharyehsafa, B ; Ahmadi, M. H ; Pourfarhang, A ; Shokrgozar, M ; Zeinali Heris, S ; Sharif University of Technology
    Elsevier Ltd  2020
    In the current study, CuO nanoparticles were dispersed in a mixture of Ethylene Glycol-Water (60/40 wt. %) to prepare stable nanofluid in different concentrations (0.05 − 0.8 vol. %). The samples were used as the coolant fluid in a specific car radiator to evaluate the thermal performance of nanofluid and base fluid in the system. Five different and novel Machine-learning methods were applied over experimental data to predict the Nusselt number and output temperature of the coolant in the system. These methods are M5 tree regression, Linear and Cubic Multi-Variate Adaptive Regression Splines (MARS), Radial Basis Function (RBF), and Artificial Neural Network-Levenberg Marquardt Algorithm... 

    Analysis of microchannel heat sink performance using nanofluids in turbulent and laminar flow regimes and its simulation using artificial neural network

    , Article 10th International Conference on Computer Modelling and Simulation, EUROSIM/UKSim2008, Cambridge, 1 April 2008 through 3 April 2008 ; 2008 , Pages 623-628 ; 0769531148 (ISBN); 9780769531144 (ISBN) Shokouhmand, H ; Ghazvini, M ; Shabanian, J ; Sharif University of Technology
    In this study, silicon microchannel heat sink (MCHS) performance using nanofluids as coolants was analyzed. The nanofluid was a mixture of nanoscale Cu particles and pure water with various volume fractions. Based on theoretical models and experimental correlations, the heat transfer and friction coefficients required in the analysis were used. In the theoretical model, nanofluid was treated as a single-phase fluid. In the experimental correlation, thermal dispersion due to particle random motion was included. The microchannel heat sink performances for a specific geometries with Wch = W fin = 100 μm and Lch =300 μm is examined. In this study, flow in laminar and turbulent regimes using the... 

    The impacts of silica nanoparticles coupled with low-salinity water on wettability and interfacial tension: Experiments on a carbonate core

    , Article Journal of Dispersion Science and Technology ; Volume 41, Issue 8 , 2020 , Pages 1159-1173 Sadatshojaei, E ; Jamialahmadi, M ; Esmaeilzadeh, F ; Wood, D. A ; Ghazanfari, M. H ; Sharif University of Technology
    Taylor and Francis Inc  2020
    Two main reservoir mechanisms that impact oil recovery factors are wettability alteration and interfacial tension (IFT) change. In this study, these two key mechanisms are evaluated experimentally for samples from the Asmari (carbonate) oil reservoir utilizing silica nanoparticles in the presence of low-salinity water. The nanofluid, rock formation and crude oil samples were prepared meticulously to ensure meaningful experimental could be conducted over a range of low-salinity conditions. The results show that across the range of salinities studied, the absolute value of zeta potential of nanofluids decreases with increasing total dissolved solids (TDS) in the water treated with silica... 

    Design and evaluation of flat plate solar collector equipped with nanofluid, rotary tube, and magnetic field inducer in a cold region

    , Article Renewable Energy ; Volume 170 , 2021 , Pages 574-586 ; 09601481 (ISSN) Bezaatpour, M ; Rostamzadeh, H ; Sharif University of Technology
    Elsevier Ltd  2021
    Flat plate solar collectors lose a massive part of heat accumulated near the contact region because of the poor thermal characteristics of the working fluid. A new cost-effective design is numerically studied to cover up such deficiency by equipping the flat plate collector with revolutionary tubes and magnetic field inducer to affect Fe3O4/water working nanofluid in the collector tubes. Results substantiate that each of the applied rotary tubes and magnetic field inducer improves the convection mechanism in the tubes by circulating the flow inside the tubes and saves more of available solar energy. Results reveal that 27.8% and 10.44% of lost energy are restored in the solar collector... 

    Magnetic-induced nanoparticles and rotary tubes for energetic and exergetic performance improvement of compact heat exchangers

    , Article Powder Technology ; Volume 377 , 2021 , Pages 396-414 ; 00325910 (ISSN) Bezaatpour, M ; Rostamzadeh, H ; Bezaatpour, J ; Ebadollahi, M ; Sharif University of Technology
    Elsevier B.V  2021
    In the present study, the effects of rotary tubes and magnetic-induced nanofluid on heat transfer characteristics of a compact heat exchanger are individually investigated. Two-phase Eulerian model is employed to predict the hydrothermal and entropic characteristics of Fe3O4/water ferrofluid in the heat exchanger. Results indicate that utilizing each rotary tubes and magnetic field method can improve the energy and exergy efficiencies of the compact heat exchanger under specific circumstances by forming different types of secondary flow. It is found that employing each method individually can increase the maximum heat transfer rate by more than 60%. In comparison with methods like passive... 

    Theoretical comparative assessment of single- and two-phase models for natural convection heat transfer of Fe3O4/ethylene glycol nanofluid in the presence of electric field

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 146, Issue 2 , 2021 , Pages 981-992 ; 13886150 (ISSN) Etesami, N ; Tavakoli, S ; Pishvaie, M. R ; Sharif University of Technology
    Springer Science and Business Media B.V  2021
    Natural convective heat transfer of Fe3O4/ethylene glycol nanofluids around the platinum wire as a heater in the absence and presence of the high electric field was investigated, numerically. The control volume finite element method was employed for the numerical simulation. Effects of the flow model, the volume fraction of nanoparticles, Rayleigh number, and the electric field intensity on the natural heat transfer coefficient (NHTC) of nanofluid were studied. Simulation results of single-phase and two-phase flow models showed that the two-phase model could better predict experimental data than the single-phase model due to take into account the velocity of each phase in the mixture. The...