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对梯形封闭腔内Al2O3-EG纳米流体自然对流传热进行了数值模拟,讨论了封闭腔尺寸比、瑞利数、纳米颗粒体积分数以及布朗运动对自然对流流动与传热特性的影响。数值模拟结果表明在考虑布朗运动时,腔体尺寸比与瑞利数对流动传热均有很大影响,且尺寸比为0.5时,对流换热平均Nusselt数达到最大值。随着纳米颗粒体积分数的增加,纳米流体换热效果逐渐增强;但当忽略布朗运动时,添加纳米颗粒削弱了换热效果。
The natural convection heat transfer of Al2O3-EG nanofluids in trapezoidal closed cavity was numerically simulated. The influence of closed cavity size ratio, Rayleigh number, nanoparticle volume fraction and Brownian motion on natural convection and heat transfer characteristics was discussed. Numerical simulation results show that when considering the Brownian motion, the cavity size ratio and the Rayleigh number have a great influence on the flow and heat transfer. When the size ratio is 0.5, the average Nusselt number reaches the maximum. As the volume fraction of nanoparticles increases, the heat transfer effect of the nanofluid gradually increases; however, when the Brownian motion is neglected, the addition of nanoparticles impairs the heat transfer effect.