Purpose

The purpose of this paper is to evaluate the temperature, the Dirichlet conditions have been considered to the parallel horizontal plates. The model of generalized Brinkman-extended Darcy with the Boussinesq approximation is considered and the governing equations are computed by COMSOL multiphysics.

Design/methodology/approach

In the current study, the thermodynamic irreversible principle is applied to study the unsteady Poiseuille–Rayleigh–Bénard (PRB) mixed convection in a channel (aspect ratio A = 5), with the effect of a uniform transverse magnetic field.

Findings

The effects of various flow parameters on the fluid flow, Hartmann number (Ha), Darcy number (Da), Brinkman number (Br) and porosity (ε), are presented graphically and discussed. Numerical results for temperature and velocity profiles, entropy generation variations and contour maps of streamlines, are presented as functions of the governing parameter mentioned above. Basing on the generalized Brinkman-extended Darcy formulation, which allows the satisfaction of the no-slip boundary condition on a solid wall, it is found that the flow field and then entropy generation is notably influenced by the considering control parameters. The results demonstrate that the flow tends toward the steady-state with four various regimes, which strongly depends on the Hartman and Darcy numbers variations. Local thermodynamic irreversibilities are more confined near the active top and bottom horizontal walls of the channel when increasing the Da and decreasing the Hartmann number. Entropy generation is also found to be considerably affected by Brinkman number variation.

Originality/value

In the present work, we are presenting our investigations on the influence of a transverse applied external magnetohydrodynamic on entropy generation at the unsteady laminar PRB flow of an incompressible, Newtonian, viscous electrically conducting binary gas mixture fluid in porous channel of two horizontal heated plates. The numerical solutions for the liquid velocity, the temperature distribution and the rates of heat transport and entropy generation are obtained and are plotted graphically.

中文翻译：

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磁化多孔通道传热不可逆现象的计算分析

目的

本文的目的是评估温度，Dirichlet 条件已考虑到平行水平板。考虑了具有 Boussinesq 近似的广义 Brinkman-extended Darcy 模型，并通过 COMSOL multiphysics 计算控制方程。

设计/方法/方法

在目前的研究中，热力学不可逆原理被应用于研究通道中不稳定的 Poiseuille-Rayleigh-Bénard (PRB) 混合对流（纵横比 A = 5），具有均匀横向磁场的影响。

发现

各种流动参数对流体流动的影响，哈特曼数（Ha）、达西数（Da）、布林克曼数（Br) 和孔隙率 (ε) 以图形方式呈现和讨论。温度和速度分布、熵产生变化和流线等高线图的数值结果作为上述控制参数的函数呈现。基于广义 Brinkman-extended Darcy 公式，它允许满足固体壁上的无滑移边界条件，发现流场和熵的生成受所考虑的控制参数的影响显着。结果表明，流动趋向于具有四种不同状态的稳态，这在很大程度上取决于哈特曼和达西数的变化。当增加 Da 和减少哈特曼数时，局部热力学不可逆性更受限制在通道的活动顶部和底部水平壁附近。

原创性/价值

在目前的工作中，我们正在研究横向应用的外部磁流体动力学对不可压缩、牛顿、粘性导电二元气体混合物流体在两个水平加热板的多孔通道中的不稳定层流 PRB 流中熵产生的影响。获得了液体速度、温度分布和热传输率和熵产生率的数值解，并以图形方式绘制。