In this contribution, double-diffusive natural and mixed convection of nanofluids in porous cavities are simulated for cases wherein the base fluid is itself a binary mixture (i.e., salty water). To this aim, a new mathematical model based on the Buongiorno's two-phase model is proposed. The current model incorporates thermophysical properties of a solid matrix, nanoparticles, salt, and water in the governing parameters. The resulting equations are solved using the finite volume approach and the outcomes are successfully validated against previous works. Simulation results are presented and discussed for several cases with the solid matrix being aluminum foam or glass balls and the nanoparticles being Ag, Al₂O₃, carbon nanotubes (CNT), Co, Cu, CuO, Fe₃O₄, MgO, TiO₂, or ZnO. Inspection of the results in the natural and mixed convection environments demonstrates that CuO−salty water nanofluid leads to the highest heat and mass transfer rates. Moreover, it is found that with replacement of glass balls with aluminum foam, the flow strength rises but the heat transfer rate deteriorates.

中文翻译：

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多孔腔中二元纳米流体的自然扩散和混合对流

在这种贡献中，对于基础流体本身是二元混合物（即咸水）的情况，模拟了多孔腔中纳米流体的自然扩散和混合对流。为此，提出了一种基于Buongiorno两阶段模型的新数学模型。当前模型在控制参数中结合了固体基质，纳米颗粒，盐和水的热物理性质。使用有限体积方法求解所得方程，并针对先前的工作成功验证了结果。给出并讨论了几种情况的模拟结果，其中固体基质为泡沫铝或玻璃球，纳米颗粒为Ag，Al ₂ O ₃，碳纳米管（CNT），Co，Cu，CuO，Fe ₃ O_{如图4所示}，MgO，TiO ₂或ZnO。在自然和混合对流环境中检查结果表明，CuO-咸水纳米流体导致最高的传热和传质速率。此外，发现用铝泡沫代替玻璃球时，流动强度增加，但传热率降低。