Loading...
Search for: nanofluidics
0.005 seconds
Total 261 records

    Energy saving in HVAC systems using nanofluid

    , Article Applied Thermal Engineering ; Volume 31, Issue 8-9 , 2011 , Pages 1543-1545 ; 13594311 (ISSN) Firouzfar, E ; Soltanieh, M ; Noie, S. H ; Saidi, S. H ; Sharif University of Technology
    Abstract
    The present study tries to use the methanol-silver nanofluid filled thermosyphon heat exchanger and compares the effectiveness as well as energy saving with pure methanol. Experimental results show that using methanol-silver nanofluid, leads to energy saving around 8.8-31.5% for cooling and 18-100% for reheating the supply air stream in an air conditioning system  

    An experimental study on the effect of ultrasonication on thermal conductivity of ferrofluid loaded with carbon nanotubes

    , Article Thermochimica Acta ; Volume 617 , October , 2015 , Pages 102-110 ; 00406031 (ISSN) Shahsavar, A ; Salimpour, M. R ; Saghafian, M ; Shafii, M. B ; Sharif University of Technology
    Elsevier  2015
    Abstract
    Nanofluids containing Fe3O4 and carbon nanotubes nanoparticles emulsified and dispersed using gum arabic (GA) and tetramethylammonium hydroxide (TMAH) were made and characterized for potential use as heat transfer fluids. Due to the interaction between the TMAH and GA molecules, the magnetic nanoparticles and CNTs were physically adsorbed. This paper reports an experimental work on the effect of ultrasonication on thermal conductivity of this aqueous suspension. The characterization and surface morphology of the dried samples were studied by using XRD and TEM measurements. Experiments were conducted in the magnetic nanoparticles mass concentration range 0.494-2.428%,... 

    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
    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... 

    Application of electrostatically actuated carbon nanotubes in nanofluidic and bio-nanofluidic sensors and actuators

    , Article Measurement: Journal of the International Measurement Confederation ; Volume 73 , September , 2015 , Pages 127-136 ; 02632241 (ISSN) Seyyed Fakhrabadi, M. M ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
    Elsevier  2015
    Abstract
    The paper investigates the effects of fluid flow on the static and dynamic behaviors of electrostatically actuated carbon nanotubes using nonlocal elasticity theory. The influences of various parameters of fluid flow including fluid viscosity, velocity, mass and temperature on the mechanical behaviors of the carbon nanotubes under static and step DC voltages are studied using this theory. The results computed from the nonlocal elasticity theory are compared with those estimated using the classical elasticity theorem and the outcomes demonstrate the applicability of the electrostatically actuated carbon nanotubes as nano sensors and nano actuators in nanofluidic systems. The nanosystem can be... 

    Numerical investigation of thermal performance augmentation of nanofluid flow in microchannel heat sinks by using of novel nozzle structure: sinusoidal cavities and rectangular ribs

    , Article Journal of the Brazilian Society of Mechanical Sciences and Engineering ; Volume 41, Issue 10 , 2019 ; 16785878 (ISSN) Khodabandeh, E ; Akbari, O. A ; Toghraie, D ; Pour, M. S ; Jönsson, P. G ; Ersson, M ; Sharif University of Technology
    Springer Verlag  2019
    Abstract
    In this paper, we present a numerical simulation of a laminar, steady and Newtonian flow of f-graphene nanoplatelet/water nanofluid in a new microchannel design with factors for increasing heat transfer such as presence of ribs, curves to enable satisfactory fluid mixing and changing fluid course at the inlet and exit sections. The results of this study show that Nusselt number is dependent on nanoparticles concentration, inlet geometry and Reynolds number. As the nanofluid concentration increases from 0 to 0.1% and Reynolds number from 50 to 1000, the Nusselt number enhances nearly up to 3% for increase in fluid concentration and averagely from 15.45 to 54.1 and from 14.5 to 55.9 for... 

    A numerical investigation on natural convection heat transfer in annular-finned concentric horizontal annulus using nanofluids: a parametric study

    , Article Heat Transfer Engineering ; 2020 Ashouri, M ; Zarei, M. M ; Hakkaki Fard, A ; Sharif University of Technology
    Taylor and Francis Ltd  2020
    Abstract
    Natural convection heat transfer in a concentric horizontal annulus with annular fins is numerically studied. Due to the low thermal conductivity of water, CuO-water and Al2O3-water nanofluids were used as heat transfer fluids. The effect of three different parameters, including fin spacing, fin eccentricity, and fin thickness at different fin diameters and Rayleigh number range of 104 to 9 (Formula presented.) 105, were studied. The obtained results revealed that Al2O3-water nanofluid has the highest heat transfer rate. The calculated heat transfer rates for Al2O3-water nanofluid for Rayleigh numbers of 9 (Formula presented.) 105, 105, and 104 were respectively up to 12.1%, 26.2%, and 31.6%... 

    Entropy analysis and thermal optimization of nanofluid impinging jet using artificial neural network and genetic algorithm

    , Article International Communications in Heat and Mass Transfer ; Volume 119 , December , 2020 Mahmoudabad Bozchelou, M ; Eghtesad, A ; Jamali, S ; Afshin, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Optimized and informed design of impinging jets can effectively enhance their rate of heat transfer. One practical pathway for such designing is to add nanoparticles to a background fluid. Here, we determine the effects of nanoparticle chemistry, their size, and their total volume fraction in water on the rate of heat transfer. We perform a comprehensive optimization using artificial neural network (ANN) and genetic algorithm (GA) to systematically study the enhanced heat transfer in nanofluids compared to pure water in obtaining a uniform cooling on a constantly heated surface in a turbulent flow. Our results indicate that increasing the size and concentration of nanoparticles enhances the... 

    Enhanced local viscosity around colloidal nanoparticles probed by equilibrium molecular dynamics simulations

    , Article Journal of Chemical Physics ; Volume 155, Issue 17 , 2021 ; 00219606 (ISSN) Rabani, R ; Saidi, M. H ; Joly, L ; Merabia, S ; Rajabpour, A ; Sharif University of Technology
    American Institute of Physics Inc  2021
    Abstract
    Nanofluids - dispersions of nanometer-sized particles in a liquid medium - have been proposed for a wide variety of thermal management applications. It is known that a solid-like nanolayer of liquid of typical thicknesses of 0.5-1 nm surrounding the colloidal nanoparticles can act as a thermal bridge between the nanoparticle and the bulk liquid. Yet, its effect on the nanofluid viscosity has not been elucidated so far. In this article, we compute the local viscosity of the nanolayer using equilibrium molecular dynamics based on the Green-Kubo formula. We first assess the validity of the method to predict the viscosity locally. We apply this methodology to the calculation of the local... 

    A new wind turbine driven trigeneration system applicable for humid and windy areas, working with various nanofluids

    , Article Journal of Cleaner Production ; Volume 296 , 2021 ; 09596526 (ISSN) Rostami, S ; Rostamzadeh, H ; Fatehi, R ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Various methods are devised to capture renewable energy or waste heat from different sectors, where among all, waste heat capturing from the generator of a wind turbine through the cooling process for freshwater and cooling production is paid less attention in Iran, in spite of the fact that many wind farms in Iran are in hot and humid regions and the residents nearby the farms desperately need freshwater and cooling load. To surmount this problem, waste heat extraction from a wind turbine (Enercon 70 Model) for freshwater and cooling production is proposed in this study. Instead of dissipating this thermal energy of the wind turbine into the environment, it can be used for freshwater and... 

    The numerical investigation of the heat transport in the nanofluids under the impacts of magnetic field: applications in industrial zone

    , Article Mathematical Problems in Engineering ; Volume 2021 , 2021 ; 1024123X (ISSN) Adnan ; Khan, U ; Ahmed, N ; Mohyud-Din, S. T ; Khan, I ; Fayz-Al-Asad, M ; Sharif University of Technology
    Hindawi Limited  2021
    Abstract
    The dynamics of the nanofluid flow between two plates that are placed parallel to each other is of huge interest due to its numerous applications in different industries. Keeping in view the significance of such flow, investigation of the heat transfer in the Cu-H2O nanofluid is conducted between parallel rotating plates. For more significant results of the study, the squeezing effects are incorporated over the plates that are electrically conducting. The nondimensional flow model is then treated analytically (VPM), and the results are sketched against the preeminent flow parameters. The remarkable heat transfer in the nanofluid is noticed against the Eckert and Prandtl numbers, whereas the... 

    The numerical investigation of the heat transport in the nanofluids under the impacts of magnetic field: applications in industrial zone

    , Article Mathematical Problems in Engineering ; Volume 2021 , 2021 ; 1024123X (ISSN) Adnan ; Khan, U ; Ahmed, N ; Mohyud Din, S. T ; Khan, I ; Fayz Al Asad, M ; Sharif University of Technology
    Hindawi Limited  2021
    Abstract
    The dynamics of the nanofluid flow between two plates that are placed parallel to each other is of huge interest due to its numerous applications in different industries. Keeping in view the significance of such flow, investigation of the heat transfer in the Cu-H2O nanofluid is conducted between parallel rotating plates. For more significant results of the study, the squeezing effects are incorporated over the plates that are electrically conducting. The nondimensional flow model is then treated analytically (VPM), and the results are sketched against the preeminent flow parameters. The remarkable heat transfer in the nanofluid is noticed against the Eckert and Prandtl numbers, whereas the... 

    A numerical investigation on natural convection heat transfer in annular-finned concentric horizontal annulus using nanofluids: a parametric study

    , Article Heat Transfer Engineering ; Volume 42, Issue 22 , 2021 , Pages 1926-1948 ; 01457632 (ISSN) Ashouri, M ; Zarei, M. M ; Hakkaki Fard, A ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    Abstract
    Natural convection heat transfer in a concentric horizontal annulus with annular fins is numerically studied. Due to the low thermal conductivity of water, CuO-water and Al2O3-water nanofluids were used as heat transfer fluids. The effect of three different parameters, including fin spacing, fin eccentricity, and fin thickness at different fin diameters and Rayleigh number range of 104 to 9 (Formula presented.) 105, were studied. The obtained results revealed that Al2O3-water nanofluid has the highest heat transfer rate. The calculated heat transfer rates for Al2O3-water nanofluid for Rayleigh numbers of 9 (Formula presented.) 105, 105, and 104 were respectively up to 12.1%, 26.2%, and 31.6%... 

    Retraction notice to “Numerical study on free convection in a U-shaped CuO/water nanofluid-filled cavity with different aspect ratios using double-MRT lattice Boltzmann” [Therm. Sci. Eng. Progr. 14(2019), 100373]

    , Article Thermal Science and Engineering Progress ; Volume 21 , 2021 ; 24519049 (ISSN) Hasanzadeh Fard, A ; Hooshmand, P ; Mohammaei, M ; Ross, D ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Concern has been raised about the identity of the author “David Ross” as the listed institution has denied the affiliation of a person with this name. Further inquiry revealed that the names of the co-authors were added to the revised version of the article without notifying the handling Editor, which is contrary to the journal policy on changes to authorship. Also, the co-authors were not able to provide a reasonable description of their contribution to the article.... 

    Nano-Fluid Natural Convection on a Constant Temperature Vertical Plate

    , M.Sc. Thesis Sharif University of Technology Iranmehr, Arash (Author) ; Nouri Boroujerdi, Ali (Supervisor)
    Abstract
    In the present study, Nano-fluid natural convection on a constant temperature vertical plate is numerically investigated, following the similarity analysis of transport equations. After changing the governing differential equations to the ordinary differential equations, they were numerically solved by the fourth order Runge-Kutta method.. The analysis shows that all three main profiles, velocity, temperature and concentration in their specific boundary layers, and the Prandtle number, depend on three important additional dimensionless parameters, namely a Brownian motion parameter, a thermophoresis parameter, and a buoyancy ratio parameter. Finally, it was found that the Nusselt number in... 

    Study on The Influence of Nanoparticles and Magnetic Field on The Liquid-Liquid Mass Transfer Coefficients

    , M.Sc. Thesis Sharif University of Technology Vahedi, Amid (Author) ; Molaei Dehkordi, Asghar (Supervisor)
    Abstract
    Magnetite (Fe3O4) nanoparticles were synthesized and coated with Oleic Acid using the co-precipitation method. The particles were characterized using DLS, FT-IR, SEM, XRD, VSM and UV-Vis spectrophotometry analysis. The mean size of particles was 28.8 nm and the FT-IR analysis indicated that Oleic Acid was coated suitably on the nanoparticles. The vsm test indicated no hysteresis loop for the particles, defining the superparamagnetism of them. A nanofluid containing nanoparticles in 5wt% Acetic Acid in Toluene as the base fliud was prepared. The stability of this nanofluid was determined using UV-Vis spectrophotometry to be less more then 95% in the first two hours. This nanofluid is used as... 

    Simulation of the Effects of Nanofluids on the Thermal Performance of a Heat Pipe

    , M.Sc. Thesis Sharif University of Technology Mirahmadi, Hamid Reza (Author) ; Moosavi, Ali (Supervisor) ; Kazemzadeh Hannani, Siamak (Co-Advisor)
    Abstract
    In terms of thermodynamics and heat transfer, heat pipes such as closed two-phase thermosyphon are of great importance in saving energy. In this study, a computational fluid dynamics model for simulation of a thermosyphon heat pipe with two-phase flow including phase change heat transfer was developed. The study has mainly focused on the effects of volume concentrations of Nanoparticles and the operating temperature on the heat transfer performance of the thermosyphon. The analysis was performed to compare heat transfer performance between a solid copper tube and a thermosyphon heat pipe which contained deionized water and graphene oxide(GO)/water Nanofluid as its working fluids. Based on a... 

    Ion Transport Through Graphene Fibers

    , M.Sc. Thesis Sharif University of Technology Ghanbari, Hamid Reza (Author) ; Esfandiar, Ali (Supervisor)
    Abstract
    Nanostructured graphene based membranes demonstrated excellent capabilities in various applications in nanofiltration and energy conversion due to unique atomically smooth surfaces and adjustable pore size or interlayers spacing at Angstrom scales.In addition to graphitic surface and physical confinement on ions in Graphene-oxide (GO) laminates, surface charges on such 2D-slits provide an attractive aspects to have more channels walls interactions with ions. There are some reports on the osmotic power generation using physical confinements and electrostatic interactions between ions and GO membranes. However, the results indicated insufficient power densities (1 W=m2 ) can be achieved... 

    Experimental Investigation of Pulsating Heat Pipe

    , M.Sc. Thesis Sharif University of Technology Jamshidi, Hamed (Author) ; Shafiee, Mohammad Behshad (Supervisor)
    Abstract
    Pulsating heat pipes (PHP) are complex heat transfer devices which unlike conventional heat pipes do not contain any wick in their structure. The effective parameters consist of; working fluid, volumetric filling ratio, operational orientation and input heat power have been investigated here. The experimental set-up we have contemplated, fabricated and tested included five turns, made of copper tube coupled with two glass tube of internal diameter 1.8 mm. The height of evaporator, condenser and adiabatic section was 60, 60 and 150 mm, respectively. The evaporator was heated with electrical element connected to an AC variant power supply and the condenser was connected to a constant... 

    Determine the Thickness of Boundary Layer in Free Convection on the Vertical Plate With Uniform Heat Flux

    , M.Sc. Thesis Sharif University of Technology ainali, Omid (Author) ; Shafie, Behshad (Supervisor)
    Abstract
    Experiments were performed to explore the free convective hat transfer characteristics of water based nanofluids. Experiments of natural convection over a vertical flat plate with constant heat flux in water-based nanofluids with Ag and TiO2 nanoparticles were performed. Velocity boundary layer measured using PIV method. Also convective heat transfer coefficient obtained using three thermometers behind the wall. Various test cases with different heat fluxes on the wall are considered. Two volumetric concentrations of Ag nanofluid, 1% and 2%, and TiO2 nanofluid, 1% and 2%, were tested in the present study. It was shown that, with increasing nanofluid concentration, velocity boundary layer... 

    Study of the Effect of Presence of Nano- Particles on the Mass Transfer and Hydrodynamics of Drops

    , M.Sc. Thesis Sharif University of Technology Nozari, Ali (Author) ; Bastani, Daruoosh (Supervisor) ; Goodarznia, Iraj (Supervisor)
    Abstract
    Regarding to the effect of nanoparticles on mass transfer and hydrodynamics characteristics, limited number of studiesavailableinthe literature.In this work, mass transfer performanceand hydrodynamic characteristics nanofluidshavebeeninvestigated in the liquid−liquid extraction process. The chemical system of toluene-acetic acid-water was used, and two Extraction columnswith diameter of 10cm and height of 55cm and 6 cm were designed. The drops were organic nanofluids containing silica nano-particles and carbon nano-tubes.Synthesized silica nanoparticles by sol-gel methods, were modified with Triethoxyoctylsilane and Polydimethylsiloxane as well as Carbon nano-tubes were modified with dodecyl...