Boundary and internal heat source effects on the onset of Darcy–Brinkman convection in a porous layer saturated by nanofluid

IF 5 2区工程技术 Q1 ENGINEERING, MECHANICAL International Journal of Thermal Sciences Pub Date : 2012-10-01 DOI:10.1016/j.ijthermalsci.2012.05.011

Dhananjay Yadav , R. Bhargava , G.S. Agrawal

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引用次数: 116

Abstract

The effect of internal heat source on the onset of Darcy–Brinkman convection in a porous layer saturated by nanofluid is studied. The boundaries are considered to be free–free, rigid–rigid and lower-rigid and upper-free boundaries. The Brinkman–Darcy equation with fluid viscosity different from effective viscosity is used to characteristic the nanofluid motion. The model used for nanofluid includes the effects of Brownian motion and thermophoresis. The linear stability theory is employed and the resulting eigenvalue problem is solved numerically using the Galerkin technique with the Rayleigh number as the eigenvalue. The influence of internal heat source strength, nanoparticle Rayleigh number, modified particle-density increment, modified diffusivity ratio, Lewis number, Darcy number and the porosity on the stability of the system is investigated graphically. It is found that the internal heat source, nanoparticle Rayleigh number, modified diffusivity ratio and Lewis number have a destabilizing effect while Darcy number and the porosity show stabilizing effects on the system.

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边界和内部热源对纳米流体饱和多孔层中达西-布林克曼对流发生的影响

研究了内热源对纳米流体饱和多孔层中达西-布林克曼对流发生的影响。边界被认为是自由-自由、刚刚性和低刚性和上自由边界。采用流体粘度与有效粘度不同的Brinkman-Darcy方程来表征纳米流体的运动。用于纳米流体的模型包括布朗运动和热泳的影响。采用线性稳定性理论，以瑞利数为特征值，利用伽辽金技术对得到的特征值问题进行数值求解。研究了内热源强度、纳米颗粒瑞利数、改性颗粒密度增量、改性扩散比、路易斯数、达西数和孔隙率对体系稳定性的影响。研究发现，内部热源、纳米颗粒瑞利数、修正扩散比和路易斯数对体系具有不稳定作用，而达西数和孔隙率对体系具有稳定作用。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.