Purpose

This paper aims to present a numerical study that investigates the flow of MgO-Al₂O₃/water hybrid nanofluid inside a porous elliptical-shaped cavity, in which we aim to examine the performance of this thermal system when exposed to a magnetic field via heat transfer features and entropy generation.

Design/methodology/approach

The configuration consists of the hybrid nanofluid out layered by a cold ellipse while it surrounds a non-square heated obstacle; the thermal structure is under the influence of a horizontal magnetic field. This problem is implemented in COMSOL multiphysics, which solves the related equations described by the “Darcy-Forchheimer-Brinkman” model through the finite element method.

Findings

The results illustrated as streamlines, isotherms and average Nusselt number, along with the entropy production, are given as functions of: the volume fraction, and shape factor to assess the behaviour of the properties of the nanoparticles. Darcy number and porosity to designate the impact of the porous features of the enclosure, and finally the strength of the magnetic induction described as Hartmann number. The outcomes show the increased pattern of the thermal and dynamical behaviour of the hybrid nanofluid when augmenting the concentration, shape factor, porosity and Darcy number; however, it also engenders increased formations of irreversibilities in the system that were revealed to enhance with the permeability and the great properties of the nanofluid. Nevertheless, this thermal enhanced pattern is shown to degrade with strong Hartmann values, which also reduced both thermal and viscous entropies. Therefore, it is advised to minimize the magnetic influence to promote better heat exchange.

Originality/value

The investigation of irreversibilities in nanofluids heat transfer is an important topic of research with practical implications for the design and optimization of heat transfer systems. The study’s findings can help improve the performance and efficiency of these systems, as well as contribute to the development of sustainable energy technologies. The study also offers an intriguing approach that evaluates entropy growth in this unusual configuration with several parameters, which has the potential to transform our understanding of complicated fluid dynamics and thermodynamic processes, and at the end obtain the best thermal configuration possible.

中文翻译：

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混合纳米流体磁对流和多孔介质对熵产生的贡献

目的

本文旨在提出一项数值研究，研究多孔椭圆形空腔内MgO-Al ₂ O ₃ /水混合纳米流体的流动，其中我们旨在通过以下方式检查该热系统暴露于磁场时的性能：传热特征和熵产生。

设计/方法论/途径

该结构由冷椭圆分层的混合纳米流体组成，同时围绕非方形加热障碍物；热结构受到水平磁场的影响。该问题在 COMSOL multiphysics 中实现，通过有限元方法求解“Darcy-Forchheimer-Brinkman”模型描述的相关方程。

发现

以流线、等温线和平均努塞尔数以及熵产生表示的结果作为体积分数和形状因子的函数给出，以评估纳米粒子的特性行为。达西数和孔隙率表示外壳多孔特征的影响，最后磁感应强度描述为哈特曼数。结果表明，当增加浓度、形状因子、孔隙率和达西数时，混合纳米流体的热和动力学行为模式有所增加；然而，它也会增加系统中不可逆性的形成，这些不可逆性随着纳米流体的渗透性和优异性能而增强。然而，这种热增强模式被证明会随着强哈特曼值而退化，这也减少了热熵和粘性熵。因此，建议尽量减少磁力影响，以促进更好的热交换。

原创性/价值

纳米流体传热不可逆性的研究是一个重要的研究课题，对传热系统的设计和优化具有实际意义。该研究的结果有助于提高这些系统的性能和效率，并有助于可持续能源技术的发展。这项研究还提供了一种有趣的方法，用几个参数评估这种不寻常配置中的熵增长，这有可能改变我们对复杂流体动力学和热力学过程的理解，并最终获得可能的最佳热配置。