Nanofluids have the solid-fluid interface which affects their thermal properties during heat transfer processes. In this study, nanolayer and thermal interfacial resistance (TIR) at the solid-fluid interface are discussed to determine their role in the enhancement of thermal conductivity of Al2O3-CO2 nanofluid. The current work focuses on molecular dynamics (MD) simulations to study the TIR and nanolayer formed of CO2 molecules around the Al2O3 nanoparticle (np) for supercritical and gaseous phases. The diameter of np (dNP) used in this study is between 2 and 5 nm to determine the diameter effect on thermal conductivity of nanofluid and on TIR. The current research talks about the comparison in both phases. The results show the impact of TIR is more with bigger diameters. Temperature and surface wettability (interaction strength) effect on thermal interfacial resistance shows that TIR decreases with increase in temperature and wettability, but at elevated temperatures, TIR does not depend on temperature. The monolayer and nanolayer are studied using density distribution, and the results show that monolayer is more uniform in case of smaller diameters with low TIR. However, the thermal conductivity is more extensive in case of larger dNP due to thick nanolayer formed around bigger np. Results show that the nanofluid with larger dNP are responsible for enhanced heat transfer due to thickened nanolayer, while TIR influence diminishes.

中文翻译：

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热界面电阻和纳米层对Al2O3-CO2纳米流体导热系数影响的分子动力学方法

纳米流体具有固-液界面，这会影响其在传热过程中的热性能。在这项研究中，讨论了固液界面处的纳米层和热界面电阻（TIR），以确定它们在增强Al2O3-CO2纳米流体的导热性中的作用。当前的工作集中于分子动力学（MD）模拟，以研究TIR和Al2O3纳米颗粒（np）周围由CO2分子形成的纳米层的超临界和气相状态。本研究中使用的np（dNP）的直径在2至5 nm之间，以确定直径对纳米流体的热导率和TIR的影响。当前的研究讨论了两个阶段的比较。结果表明，直径越大，TIR的影响越大。温度和表面润湿性（相互作用强度）对热界面电阻的影响表明，TIR随温度和润湿性的增加而降低，但在高温下，TIR不依赖于温度。使用密度分布研究了单层和纳米层，结果表明，在较小直径的情况下，低TIR，单层更为均匀。然而，由于较大的np周围形成的厚纳米层，在较大的dNP的情况下，热导率更广泛。结果表明，由于纳米层增厚，具有较大dNP的纳米流体可增强传热，而TIR的影响则减小。使用密度分布研究了单层和纳米层，结果表明，在较小直径的情况下，低TIR，单层更为均匀。然而，由于较大的np周围形成的厚纳米层，在较大的dNP的情况下，热导率更广泛。结果表明，由于纳米层增厚，具有较大dNP的纳米流体可增强传热，而TIR的影响则减小。使用密度分布研究了单层和纳米层，结果表明，在较小直径的情况下，低TIR，单层更为均匀。然而，由于较大的np周围形成的厚纳米层，在较大的dNP的情况下，热导率更广泛。结果表明，由于纳米层增厚，具有较大dNP的纳米流体可增强传热，而TIR的影响则减小。