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Journal ArticleDOI

Unsteady MHD free convective boundary layer flow of a nanofluid past a moving vertical plate

01 Nov 2017-Vol. 263, Iss: 6, pp 062015
About: The article was published on 2017-11-01 and is currently open access. It has received 4 citations till now. The article focuses on the topics: Convective Boundary Layer & Nanofluid.
Citations
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Journal ArticleDOI
TL;DR: Exact solutions obtained in this paper are interpreted graphically using computational software Mathcad-15 to examine the effects of various pertinent parameters such as Casson fluid parameter, the permeability of porous medium, chemical reaction parameter, heat generation parameter, buoyancy force parameter, magnetic parameter, and radiation parameter.
Abstract: The aim of this article is to study the combined effects of heat generation and chemical reaction on magnetohydrodynamic (MHD) natural convection flow over a moving plate embedded in a porous medium. Natural convection is caused due to buoyancy forced which has been induced because of temperature and concentration gradients. The general condition of velocity has been considered on the plate surface with Newtonian heating and constant wall concentration. The effect of thermal radiation is also considered in the energy equation. The main objective here is to study the relative behavior of the magnetic field. That is the magnetic field shows two types of relative behavior. More exactly, when the magnetic field is fixed relative to the fluid (MFFRF) and the magnetic field is fixed relative to the plate (MFFRP). The general exact solution of the problem is determined by the Laplace transform method. Particular solutions for two special cases namely the plate with variable vibration and the plate with sine and cosine oscillations are also determined. Moreover, the solutions when ζ → ∞ for both cases i.e. MFFRF and MFFRP are also obtained as special cases. The velocity profile is presented in the form of mechanical, thermal and concentration components. Velocity obtained for oscillating plate condition is written in terms of steady-state and transient parts. Exact solutions obtained in this paper are interpreted graphically using computational software Mathcad-15 to examine the effects of various pertinent parameters such as Casson fluid parameter, the permeability of porous medium, chemical reaction parameter, heat generation parameter, buoyancy force parameter, magnetic parameter, and radiation parameter. Results for Sherwood number, skin-friction, and Nusselt number are numerically computed and discussed.

43 citations

Journal ArticleDOI
TL;DR: In this paper, a model of the cooling system in engineering applications is presented, where three different types of water-based nanofluids containing copper Cu, aluminum oxide Al2O3 and titanium dioxide TiO2 are taken into consideration.
Abstract: The natural convection of the nanofluids from a vertical accelerated plate in the presence of the radiation flux and magnetic field is observed in this study. Initially, the plate with a temperature higher than the temperature of nanofluids is at rest and then it accelerates moving upward and then the wall temperature decreases. The governing unsteady equations are solved by the explicit method based on the forward finite difference. Three different types of water-based nanofluids containing copper Cu, aluminum oxide Al2O3 and titanium dioxide TiO2 are taken into consideration. The hydrodynamic and thermal performance of the nanofluids is calculated. The results of the computation show that the velocity profiles are influenced by the type of the nanofluids, Grashof number, radiation parameter, magnetic field and volume fraction of nanoparticles. The shear stress profiles of the nanofluid Cu-water has the lowest values. The temperature distributions are very slightly different for the same volume fraction for all nanofluids. The heat transfer from plate to the nanofluids is influenced by radiation parameter, volume fraction and Prandtl number. This study is a model of the cooling system in engineering applications.

5 citations


Additional excerpts

  • ...Similar work was carried out to investigate the effect of radiation and magnetic field on the nanofluid convection for a vertical accelerated plate (Sravan Kumar and Rushi Kumar, 2017)....

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Journal ArticleDOI
TL;DR: In this article , an analysis has been carried out to study the two-dimensional free convective boundary layer MHD nanofluid flow past an inclined plate with heat generation, chemical reaction and radiation effects.
Abstract: An analysis has been carried out to study the two-dimensional free convective boundary layer MHD nanofluid flow past an inclined plate with heat generation, chemical reaction and radiation effects under convective boundary conditions. The partial differential equations describing the flow are coupled nonlinear. They have been reduced to nonlinear ordinary differential equations by utilizing a similarity transformation, which is then solved numerically with the aid of the Runge-Kutta-based shooting technique. Graphs depict the influence of different controlling factors on the velocity, temperature, and concentration profiles. Numerical findings for skin friction, Nusselt number and Sherwood number are reviewed for distinct physical parameter values. In a limited sense, there is a good correlation between the current study's results and those of the earlier published work.
References
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Journal ArticleDOI
TL;DR: In this paper, it was shown that a "nanofluid" consisting of copper nanometer-sized particles dispersed in ethylene glycol has a much higher effective thermal conductivity than either pure or pure glycol or even polyethylene glycol containing the same volume fraction of dispersed oxide nanoparticles.
Abstract: It is shown that a “nanofluid” consisting of copper nanometer-sized particles dispersed in ethylene glycol has a much higher effective thermal conductivity than either pure ethylene glycol or ethylene glycol containing the same volume fraction of dispersed oxide nanoparticles. The effective thermal conductivity of ethylene glycol is shown to be increased by up to 40% for a nanofluid consisting of ethylene glycol containing approximately 0.3 vol % Cu nanoparticles of mean diameter <10 nm. The results are anomalous based on previous theoretical calculations that had predicted a strong effect of particle shape on effective nanofluid thermal conductivity, but no effect of either particle size or particle thermal conductivity.

3,551 citations

Journal ArticleDOI
TL;DR: In this paper, the authors have produced nanotube-in-oil suspensions and measured their effective thermal conductivity, which is anomalously greater than theoretical predictions and is nonlinear with nanotubes loadings.
Abstract: We have produced nanotube-in-oil suspensions and measured their effective thermal conductivity. The measured thermal conductivity is anomalously greater than theoretical predictions and is nonlinear with nanotube loadings. The anomalous phenomena show the fundamental limits of conventional heat conduction models for solid/liquid suspensions. We have suggested physical concepts for understanding the anomalous thermal behavior of nanotube suspensions. In comparison with other nanostructured materials dispersed in fluids, the nanotubes provide the highest thermal conductivity enhancement, opening the door to a wide range of nanotube applications.

2,546 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the increase of thermal conductivity with temperature for nano fluids with water as base fluid and particles of Al 2 O 3 or CuO as suspension material.
Abstract: Usual heat transfer fluids with suspended ultra fine particles of nanometer size are named as nanofluids, which have opened a new dimension in heat transfer processes. The recent investigations confirm the potential of nanofluids in enhancing heat transfer required for present age technology. The present investigation goes detailed into investigating the increase of thermal conductivity with temperature for nano fluids with water as base fluid and particles of Al 2 O 3 or CuO as suspension material. A temperature oscillation technique is utilized for the measurement of thermal diffusivity and thermal conductivity is calculated from it

2,177 citations

Journal ArticleDOI
TL;DR: In this paper, the authors explore four possible explanations for the anomalous thermal conductivity of nanofluids: Brownian motion of the particles, molecular-level layering of the liquid at the liquid/particle interface, the nature of heat transport in the nanoparticles, and the effects of nanoparticle clustering.

2,008 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used the finite volume technique to solve the governing equations of heat transfer and fluid flow due to buoyancy forces in a partially heated enclosure using nanofluids.

1,783 citations