The lattice Boltzmann method is utilized to investigate the mixed convection of a CuO/water nanofluid by magnetic field’s effect in a lid-driven U-shaped enclosure filled with a baffle. The bottom wall’s temperature is high. The Koo–Kleinstreuer–Li model, which considering the Brownian motion of nanoparticles, is adopted to obtain the thermophysical properties of the nanofluid. How the Hartmann number (Ha), Richardson number (Ri), Reynolds number (Re), and nanoparticle concentration (ϕ) affect streamlines, isotherms, and average Nusselt number (Nu_ave) is also examined. The results reveal that, at Re = 100 and for a large Ri, the nanofluid strategy degrades the Nu. The favorable effect of increasing the Re on the average Nu and adverse trends of the increment in the Ha on the heat transfer are the main highlights in this study. In addition, the increase in the Re more strongly affects the heat transfer rate at higher Ri.

中文翻译：

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磁场作用下，折流板形U形盖驱动空腔中的混合对流特性

格子Boltzmann方法用于研究在装有挡板的盖子驱动的U形外壳中，磁场作用下CuO /水纳米流体的混合对流。底壁的温度很高。考虑了纳米粒子的布朗运动，采用了Koo-Kleinstreuer-Li模型来获得纳米流体的热物理性质。哈特曼数（Ha），理查森数（Ri），雷诺数（Re）和纳米粒子浓度（ϕ）如何影响流线，等温线和平均努塞尔数（Nu _ave））也进行了检查。结果表明，当Re = 100且Ri较大时，纳米流体策略会降解Nu。增加Re对平均Nu的有利影响以及Ha的增加对热传递的不利趋势是这项研究的主要亮点。另外，Re的增加更强烈地影响在较高的Ri下的传热速率。