Magnetohydrodynamic double-diffusive convection (MHD-DDC) in porous media has substantial significance in broad applications. However, due to the complexity of the DDC problems involving nanofluid, porous media, and external magnetic field at the same time, the MHD-DDC in nanofluid-filled porous media has rarely been studied. Besides, previous research on MHD convection problems usually focuses on magnetic fields or nanofluid effects. Effects of the thermal-to-mass properties, including the buoyancy radio () and Lewis number (), on MHD-DDC problems have rarely been studied, seriously limiting the understanding and regulation of heat and mass transfer. Herein, we numerically study heat and mass transfer in the MHD-DDC within a square cavity containing a nanofluid of FeO–HO and a porous medium using a lattice Boltzmann method. A series of case studies are carried out to investigate the effects of , , and the medium porosity () on the velocity, temperature, and nanoparticle concentration. Results indicate that determines the rotation pattern of the streamline, while and can be utilized to regulate the intensity of heat and mass exchange. The results of this paper present a quantitative insight into regulating heat and mass transfer patterns in MHD-DDC problems.

中文翻译：

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Fe3O4-H2O纳米流体填充多孔介质中磁流体动力学双扩散对流的格子玻尔兹曼研究

多孔介质中的磁流体动力学双扩散对流（MHD-DDC）在广泛的应用中具有重要意义。然而，由于同时涉及纳米流体、多孔介质和外部磁场的DDC问题的复杂性，纳米流体填充多孔介质中的MHD-DDC的研究很少。此外，以往对MHD对流问题的研究通常集中在磁场或纳米流体效应上。热质特性，包括浮力系数 () 和路易斯数 ()，对 MHD-DDC 问题的影响很少被研究，严重限制了对传热传质的理解和调控。在此，我们使用晶格玻尔兹曼方法对包含 FeO-H2O 纳米流体和多孔介质的方形腔内 MHD-DDC 中的传热和传质进行数值研究。通过一系列案例研究来研究 、 和介质孔隙率 () 对速度、温度和纳米粒子浓度的影响。结果表明 决定了流线的旋转模式，同时 和 可用于调节热质交换的强度。本文的结果对 MHD-DDC 问题中的传热传质模式的调节提供了定量见解。