Abstract This paper deals with natural convection around a circular cylinder with constant heat flux in a cavity using computational fluid dynamics. As fluids ethylene glycol and a mixture of ethylene glycol with Al2O3 nanoparticles (mass concentrations of nanoparticles: 0.1% and 1%) are chosen. Rayleigh number ranges from 3 × 104 to 3 × 105. The nanofluids are modeled with single-phase approach. For the investigated range of nanoparticle concentration, the influence of concentration on Nusselt, Rayleigh number and heat transfer coefficient is small. Nevertheless, a slight shift toward lower Nusselt, Rayleigh numbers and an increase in heat transfer coefficient occur. The Nusselt number depends on Rayleigh number and only negligible on Prandtl number, which is in accordance with literature for Prandtl numbers of around 200. The numerically obtained results are compared with own preliminary experimental data, deviations are discussed.

中文翻译：

---

水平圆柱体中乙二醇-Al2O3 纳米流体自然对流的数值模拟

摘要 本文使用计算流体动力学研究了空腔中具有恒定热通量的圆柱体周围的自然对流。选择乙二醇和乙二醇与 Al2O3 纳米颗粒的混合物（纳米颗粒的质量浓度：0.1% 和 1%）作为流体。瑞利数的范围从 3 × 104 到 3 × 105。纳米流体采用单相方法建模。对于所研究的纳米颗粒浓度范围，浓度对努塞尔特、瑞利数和传热系数的影响较小。尽管如此，还是会出现向较低努塞尔特数、瑞利数和传热系数增加的轻微转变。Nusselt 数取决于 Rayleigh 数，仅对 Prandtl 数可忽略不计，这与文献中关于 200 左右的 Prandtl 数一致。