Variable Gravity Effects on Thermal Instability of Nanofluid in Anisotropic Porous Medium

Chand, Ram; Rana, G. C.; Kumar, Sanjeev

doi:10.2478/ijame-2013-0038

Cited by 23 publications

(17 citation statements)

References 18 publications

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“…Following the formalism of Nield and Kuznetsov [11], several studies were undertaken subsequently to investigate various additional effects on the problem by the same authors and others considering the volume fraction of nanoparticles is constant at the boundaries [12][13][14][15][16][17][18]. Recently, Nield and Kuznetsov [19] pointed out that this type of boundary condition on volume fraction of nanoparticles is physically not realistic as it is difficult to control the nanoparticle volume fraction on the boundaries.…”

Section: Introductionmentioning

confidence: 97%

“…Copious literature available on the non-Darcy-Benard convection in isotropic and anisotropic porous media is amply documented in the book by Nield and Bejan [20]. Chand et al [17] studied the effects of variable gravity on thermal instability in a horizontal layer of a nanofluid saturating an anisotropic Darcy porous medium. The intent of the present paper is to study the onset of penetrative convection in a horizontal layer of an anisotropic Brinkman porous medium saturated by a nanofluid via internal heating and heated uniformly from below.…”

Section: Introductionmentioning

confidence: 98%

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Penetrative Brinkman convection in an anisotropic porous layer saturated by a nanofluid

Shivakumara

Dhananjaya

2015

Ain Shams Engineering Journal

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The onset of penetrative Brinkman convection in a nanofluid saturated anisotropic porous layer is investigated via uniform internal heating for rigid-rigid, free-free, and lower-rigid and upper-free boundaries. The flux of volume fraction of nanoparticles is taken to be zero on the isothermal boundaries and the eigenvalue problem is solved using the Galerkin method. The numerical computations carried out indicated the validity of principle of exchange of stability for all types of velocity boundary conditions. The effect of heat source strength, mechanical anisotropy parameter, modified diffusivity ratio, nanoparticle concentration Darcy-Rayleigh number and Lewis number is to hasten, while the Darcy number and thermal anisotropy parameter are to delay the onset of convection. In contrast to the regular fluid saturating a Darcy porous medium, the onset of convection for nanofluids is found to be influenced even when the ratio of mechanical anisotropy parameter to thermal anisotropy parameter is unity. Ó 2014 Faculty of Engineering, Ain Shams University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 98%

Penetrative Brinkman convection in an anisotropic porous layer saturated by a nanofluid

Shivakumara

Dhananjaya

2015

Ain Shams Engineering Journal

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“…They observed that the decreasing gravity parameter postponements the arrival of convective motion. The extension with anisotropic porous medium was also made by Chand et al Very recently, the weight of the variable gravity field on the magnetic nanofluid convection in a porous matrix was observed by Mahajan and Sharma . They proved that gravity coefficient postponements the start of convection.…”

Section: Introductionmentioning

confidence: 77%

Numerical solution of the onset of Buoyancy‐driven nanofluid convective motion in an anisotropic porous medium layer with variable gravity and internal heating

Yadav

2020

Heat Trans

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The onset of buoyancy-driven convective motion in a nanofluid saturated anisotropic porous medium layer is examined numerically in the occurrence of uniform internal heat source under the variable gravity field.Three kinds of gravity force variation functions: (a) G(z) = −z (linear), (b) G(z) = −z 2 (parabolic), and (c) G(z) = −z 3 (cubic) are considered. Wide-range governing parameters impacts are inspected on the beginning of convective motion under the zero nanoparticle flux situation at the boundaries using the higher term Galerkin technique. It is established that the thermal anisotropy parameter η and the gravity variation parameter λ delay the arrival of convective motion, while the mechanical anisotropy parameter ξ, the internal heating parameter Hs, the nanoparticle Rayleigh-Darcy number R np , the modified diffusivity ratio NA nf , and the modified nanofluid Lewis number Le nf rapid the start of convective motion. The size of the convective cells reduces on raising the internal heating parameter Hs, while the gravity variation parameter λ, the mechanical anisotropy parameter ξ, the thermal anisotropy parameter η, the nanoparticle Rayleigh-Darcy number R np , the modified diffusivity ratio NA nf , and the modified nanofluid Lewis number Le nf amplify the dimension of the convective cells. It is also detected that the arrangement is more unstable for case (c), while it is more stable for case (a). K E Y W O R D Sanisotropic porous medium, convective instability, internal heating and variable gravity, nanofluids 1 | INTRODUCTION Anisotropy in porous medium plays in role due to asymmetric arrangement of porous matrix or fibers. Rock, soils, and fibrous insulating materials are good examples of anisotropic porous medium. Thermal convective motion in fluid-flooded anisotropic porous medium with different geometries and different configuration has been a topic of great attention by the scientific community in the earlier few decades due to their widespread uses in nature and engineering such as the pollutant transport in saturated soils, cooling of electronic devices, the underground disposal of nuclear discarded, heat exchangers, fuel drilling, nuclear and packed bed reactors, chemical and food processing, and so forth. 1-12 Different working fluid can be utilized for these systems but utilizing the nanoscale solid particles diffused in working fluids coined by Choi and Eastman, 13 which are called nanofluids, is the useful method to reduce the size and advance the performance of such arrangements by improving their heat transfer characteristics. [14][15][16][17][18] Nguyen et al 19 experimentally examined the heat transport characteristics of Al 2 O 3 -H 2 O nanofluid for relevance in a closed cooling structures such as microprocessors or other heated electronic devices. They observed a 40% enhanced in Nusselt number via Al 2 O 3 nanoparticles at 6.8% concentration when compared with water. Very recently, Yadav 20 studied the convective heat transport of nanofluids in porous enclosures and proved that the he...

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“…Strughan [35] discuss the various type of variable gravity parameter on the stability convection and recently Chand [36][37] studied the variable gravity effects on the thermal instability in fluid layer. Effect of variable gravity in layer of nanofluid in a porous medium is studied by Chand et al [38] and found that gravity parameter play significant role on the stability of fluid.…”

Section: Introductionmentioning

confidence: 99%

Effect of variable gravity on thermal instability of rotating nanofluid in porous medium

Chand¹,

Rana²,

Kango³

2015

FME Transaction

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Variable Gravity Effects on Thermal Instability of Nanofluid in Anisotropic Porous Medium

Cited by 23 publications

References 18 publications

Penetrative Brinkman convection in an anisotropic porous layer saturated by a nanofluid

Penetrative Brinkman convection in an anisotropic porous layer saturated by a nanofluid

Numerical solution of the onset of Buoyancy‐driven nanofluid convective motion in an anisotropic porous medium layer with variable gravity and internal heating

Effect of variable gravity on thermal instability of rotating nanofluid in porous medium

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