Dolatabadi Nader, Rahmani Ramin, Rahnejat Homer, Garner Colin P
Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University Leicestershire LE11 3TU UK
RSC Adv. 2019 Jan 21;9(5):2516-2524. doi: 10.1039/c8ra08987f. eCollection 2019 Jan 18.
Fluid media such as water and ethylene glycol are usually quite poor conductors of heat. Nanoparticles can improve the thermal properties of fluids in a remarkable manner. Despite a plethora of experimental and theoretical studies, the underlying physics of heat transport in nanofluids is not yet well understood. Furthermore, the link between nanoscale energy transport and bulk properties of nanofluids is not fully established. This paper presents a thermal conductivity model, encapsulating solid-liquid interfacial thermal resistance, particle shape factor and the variation of thermal conductivity across a physisorbed fluidic layer on a nanoparticle surface. The developed model for thermal conductivity integrates the interfacial Kapitza resistance, the characteristics of a nanolayer, convective diffusion and surface energy with capillary condensation. In addition, the thickness of the nanolayer is predicted using the Brunauer-Emmett-Teller (BET) isotherms and micro/nano-menisci generated pressures of condensation. Such a comprehensive model for thermal conductivity of nanoparticles and systematic study has not hitherto been reported in the literature. The thermal conductivity model is evaluated using experimental data available in open literature.
诸如水和乙二醇之类的流体介质通常是相当差的热导体。纳米颗粒能够显著改善流体的热性能。尽管有大量的实验和理论研究，但纳米流体中热传输的基本物理原理尚未得到很好的理解。此外，纳米尺度能量传输与纳米流体宏观性质之间的联系也尚未完全建立。本文提出了一个热导率模型，该模型涵盖了固液界面热阻、颗粒形状因子以及纳米颗粒表面物理吸附流体层内热导率的变化。所开发的热导率模型将界面卡皮查热阻、纳米层的特性、对流扩散以及具有毛细凝聚作用的表面能整合在一起。此外，纳米层的厚度是使用布鲁诺尔 - 埃米特 - 特勒（BET）等温线以及微/纳米弯月面产生的凝聚压力来预测的。迄今为止，文献中尚未报道过如此全面的纳米颗粒热导率模型及系统性研究。该热导率模型利用公开文献中的实验数据进行了评估。
