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Hartmann number
About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.
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TL;DR: In this article, the authors examined numerically the laminar steady magneto-hydrodynamic natural convection in an inclined T-shaped enclosure filled with different types of nanofluids.
Abstract: This paper examines numerically by using the finite difference method the laminar steady magneto-hydrodynamic natural convection in an inclined T-shaped enclosure filled with different types of nanofluids. A uniform heat source is embedded on a part of the upper wall of the enclosure. Both left and right sidewalls of the enclosure leg are maintained at a constant cold temperature, while the other portions of the enclosure walls are considered adiabatic. A magnetic field is applied vertically downward on the bottom wall of the enclosure. Based on the numerical results, the effects of the dominant parameters such as Rayleigh number, Hartmann number, inclination angle, solid volume fraction, location and length of the heat source and enclosure aspect ratio are examined. The numerical results are obtained for Hartmann number varying as 0 ⩽ Ha ⩽ 100, inclination angle varying as 0 ⩽ Φ ⩽ 90°, Rayleigh numbers varying as 103 ⩽ Ra ⩽ 106, aspect ratio 0.3 ⩽ AR ⩽ 0.9, heat source length 0.2 ⩽ B ⩽ 0.8, heat source location 0.2 ⩽ D ⩽ 0.5 and the solid volume fractions varying as 0 ⩽ ϕ ⩽ 0.2. Comparison with previously published numerical work is performed and a good agreement between the results is observed. It is found that the mean Nusselt number increases with the increase of Rayleigh number, inclination angle, aspect ratio, heat source location and volume fraction of nanoparticles, while, it decreases when the Hartmann number and heat source length increase.
72 citations
TL;DR: In this paper, the second law of thermodynamics analysis in a three-dimensional microchannel filled with a nanofluid under a magnetic field is numerically studied and the temperature fields, variation of horizontal velocity, thermal resistance, pressure drop, Hartmann and Reynolds numbers are investigated.
Abstract: In this paper, mixed convection as well as second law of thermodynamics analysis in a three-dimensional microchannel filled with a nanofluid under a magnetic field are numerically studied. The temperature fields, variation of horizontal velocity, thermal resistance, pressure drop, Hartmann and Reynolds numbers are investigated. Moreover, heat, frictional and magnetic entropy generation are surveyed in different volume fractions. Analyzing the results of numerical simulations indicates that with increasing Hartmann number, maximum horizontal velocity along the centre line and the inlet and outlet thermal resistance decrease in the microchannel. On the other hand, by enhancing the strength of the imposing magnetic field, heat entropy generation mitigates, while frictional and magnetic ones increase. However, the increasing of two last is very small compared to heat entropy generation. The ratio of Nuavg/(pressure drop) is greater than 10. Therefore, the thermal gain of this microchannel fairly dominates the loss of pressure reduction.
72 citations
TL;DR: In this article, the authors describe the laminar flow of a nanoliquid in a trapezoidal cavity, in addition to measuring convective exchanges that take place there, showing that the flow of the nanofluid is strongly influenced through the application of a magnetic field, and the thermal performance of the cavity is improved with the augmentation of the Ra and Hartmann numbers.
71 citations
TL;DR: In this paper, the authors investigated the effect of various pertinent parameters such as Rayleigh number, Hartmann number, volume fraction of nanofluid and shape factor of nanoparticle on the convective heat transfer characteristics.
Abstract: The purpose of this study is to peruse natural convection in a CuO-water nanofluid-filled complex-shaped enclosure under the influence of a uniform magnetic field by using control volume finite element method.,Governing equations formulated in dimensionless stream function, vorticity and temperature variables using the single-phase nanofluid model with the Koo–Kleinstreuer–Li correlation for the effective dynamic viscosity and the effective thermal conductivity have been solved numerically by control volume finite element method.,Effects of various pertinent parameters such as Rayleigh number, Hartmann number, volume fraction of nanofluid and shape factor of nanoparticle on the convective heat transfer characteristics are analysed. It was observed that local and average heat transfer rates increase for higher value of Rayleigh number and lower value of Hartmann number. Among various nanoparticle shapes, platelets were found to be best in terms of heat transfer performance. The amount of average Nusselt number reductions was found to be different when nanofluids with different solid particle volume fractions were considered due to thermal and electrical conductivity enhancement of fluid with nanoparticle addition.,A comprehensive study of the natural convection in a CuO-water nanofluid-filled complex-shaped enclosure under the influence of a uniform magnetic field by using control volume finite element method is addressed.
71 citations
TL;DR: In this article, the authors investigated the magnetoconvection of an electrically conducting fluid in a square cavity with partially thermally active vertical walls, and the results were obtained for Grashof numbers between 104 and 106, Hartmann numbers between 0 and 100 and Prandtl numbers 0.054-2.05.
71 citations