Natural convection of Al2O3–water nanofluid in an inclined enclosure with the effects of slip velocity mechanisms: Brownian motion and thermophoresis phenomenon

Esfandiary, Mohsen; Mehmandoust, Babak; Karimipour, Arash; Pakravan, Hossein Ali

doi:10.1016/j.ijthermalsci.2016.02.006

Cited by 104 publications

(36 citation statements)

References 57 publications

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“…It is found that the results converge to within less than 0.5 % with polynomial order 7, which is used for the simulations reported in this study. Continuous phase modelling is followed in this study and the thermo-physical properties of base fluid and nanoparticles are provided as in [47], and the classic formulae of [48] were used to determine the density and heat capacitance of nanofluids in this study.…”

Section: Fig 1 Geometry Of Rectangular Duct Showing Schercliff Layermentioning

confidence: 99%

Performance Index in MHD Duct Nanofluid Flow Past a Bluff Body at High Re

ARJUN

Kumar

2017

SV-JME

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The quasi-two-dimensional Al 2 O 3 -water nanofluid magneto hydro-dynamics (MHD) flowing over a circular cylinder at higher Reynolds number has been modelled using Ansys FLUENT 15.0 in a rectangular duct to determine the viability of heat transfer enhancement. The effect of the numerical simulations on performance indices were analysed for the range of 1000 ≤ Re ≤ 3000 Reynolds numbers, 10 ≤ Ha ≤ 100 modified Hartmann numbers, 0.5 ≤ φ ≤ 2 nanoparticle volume concentrations, 0.1 ≤ β ≤ 0.4 blockage ratios, 1 ≤ γ ≤ 0.25 position ratios, 0.75 ≤ G/d ≤ 1.5 gap ratios and 0 ≤ d ≤ 10 distance downstream of cylinder along heated duct wall. The results are presented graphically and discussed quantitatively. Grid independence is achieved with the domain having 3 upstream and 20 downstream cylinder diameter distance lengths with element polynomial degree 7 with respect to mean drag coefficient and Strouhal number. Cylinder placement with gaps to the heated wall of diameters between 0.75 and 1.25 and 10 diameters downstream of cylinder performed best, achieving 117 % enhancement of the performance indices at Re = 3000, Ha = 20, φ = 2 %, β = 0.4, γ = 1 and G/d = 1. The performance indices were greater than one for all the cases tested, which indicates that the heat transfer enhancement for this flow is viable. The Nusselt number values of the present study were compared with the analytical and experimental data published earlier and found to be in perfect agreement validating the reliability of the present model. Highlights• A very high performance index enhancement is achieved, incorporating the impacts of Re, Ha and φ in rectangular duct flow. • A circular cylinder is used as bluff body in MHD nanofluid flow at higher Reynold numbers. • Ideal cylinder placement conditions of blockage, position and gap ratios are proposed. • Viable heat transfer enhancements analysed using numerical simulations and the resulting quasi-2D model predictions are validated.

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Section: Fig 1 Geometry Of Rectangular Duct Showing Schercliff Layermentioning

confidence: 99%

Performance Index in MHD Duct Nanofluid Flow Past a Bluff Body at High Re

ARJUN

Kumar

2017

SV-JME

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“…Considering the benefits with the possible use of nanofluids in many industrial systems, natural convection heat transfer studies with nanofluid in the porous cavities are initiated and large numbers of numerical studies were performed [14][15][16][17][18][19][20][21][22][23][24]. Buongiorno [14] summarized the slip mechanisms that act on the nanoparticles whilst moving into the base fluids.…”

Section: Introductionmentioning

confidence: 99%

Natural convection enhancement in a porous cavity with Al2O3-Ethylene glycol/water nanofluids

Solomon

Sharifpur

Ottermann

et al. 2017

International Journal of Heat and Mass Transfer

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The natural convection heat transfer of a differentially heated cavity filled with porous material and saturated with nanofluid is studied. The nanofluid used in the present study contains 60% Ethylene glycol, 40% DIwater and 30 nm size Al2O3 nanoparticles. The volume concentration of nanofluid used is in the range of 0.05% ≤ ≤ 0.4%. The range of Rayleigh number in the present study is 1.2 x 10 8 ≤ Ra ≤ 4 x 10 8 for clear cavity and 3 x 10 3 ≤ Ra ≤ 1.3 x 10 4 for the porous cavity. Viscosity of the nanofluid is also measured at volume concentration of 0.05% and found one available model works for the calculations. In order to explain the heat transfer behaviour of the present system, heat transferred by both clear and porous cavity, heat transfer coefficients of both hot and cold wall, as well as Nusselt number variation with concentrations of nanofluids are presented. It is found that the performance of porous cavity filled with a nanofluid volume concentration of 0.05% is enhanced while the other concentrations of nanofluids deteriorate the performance. At a volume concentration of 0.05%, the heat transfer capability of porous cavity is enhanced to a maximum of 10% compared to the base fluids. 3

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“…Ghasemi & Aminossadati (2009) indicated that the inclination angle has a significant impact on the flow, temperature fields and the heat transfer performance at high Rayleigh numbers on a cavity with nanofluid during natural convection. Esfandiary et al (2016) performed twophase model study on an inclined cavity with Al 2 O 3 -water nanofluid and concluded that the highest Nusselt number is obtained at the inclination of 30°.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional natural convection of CNT-water nanofluid confined in an inclined enclosure with Ahmed body

Al‐Rashed

Kalidasan²,

Kolsi

et al. 2017

JTST

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A finite volume based three dimensional numerical studies on the heat transfer due to natural convection inside the inclined cubical cavity filled with CNT-water nanofluid is solved by vorticity-vector potential formalism. The enclosure contains an Ahmed body at its middle with differentially heated vertical walls. The other walls are adiabatic. The effect due to Rayleigh number (10 3 ≤ Ra ≤ 10 5 ), volumetric fraction (0 ≤ φ ≤ 0.05) of CNT particles, angle of incidence of enclosure (0° ≤ γ ≤ 180°) and thermal conductivity ratio (0.01 ≤ R c ≤ 100) are analyzed. The results of fluid flow with single phase model are elucidated with Particle trajectories, Velocity vectors, Iso-surfaces of temperature and Nusselt number. CNT-particles enhanced the heat transfer in all the considered cases. Maximum average Nusselt number is reported when the angle of inclination is 30° and 150°. The variation in thermal conductivity ratio has a least effect on convection.

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Natural convection of Al2O3–water nanofluid in an inclined enclosure with the effects of slip velocity mechanisms: Brownian motion and thermophoresis phenomenon

Cited by 104 publications

References 57 publications

Performance Index in MHD Duct Nanofluid Flow Past a Bluff Body at High Re

Performance Index in MHD Duct Nanofluid Flow Past a Bluff Body at High Re

Natural convection enhancement in a porous cavity with Al2O3-Ethylene glycol/water nanofluids

Three-dimensional natural convection of CNT-water nanofluid confined in an inclined enclosure with Ahmed body

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