In this study, Green-Kubo formulism was employed to quantitatively assess thermal conductivity of nanofluids with different solid-liquid interaction energy. Anomalous thermal conductivity enhancement was observed in well-dispersed dilute nanofluids with strong solid-liquid interaction energy. The simulation results indicated that solid-liquid interaction is the key factor for the understanding of the heat conduction mechanism in nanofluids. Green-Kubo theory and Brownian motion were studied in detail to derive the physical origin of thermal conductivity enhancement. The results suggested that the phonons across the solid-liquid interface or micro-convection induced by Brownian motion of nanoparticles is responsible for thermal conductivity enhancement. In addition, a wide range of thermal conductivity enhancement and nonlinear increasing with volume fraction was observed, which is consistent with experiment investigations. The effect of solid-liquid interaction energy on the viscosity of nanofluids was also studied and was found to be an insignificant factor. Our results indicated that the nanofluids with strong solid-liquid interaction energy should have more significant application potential.

在这项研究中，Green-Kubo公式被用于定量评估具有不同固液相互作用能的纳米流体的热导率。在良好分散的具有强固液相互作用能的稀纳米流体中观察到反常的热导率增强。仿真结果表明，固液相互作用是理解纳米流体导热机理的关键因素。详细研究了Green-Kubo理论和布朗运动，以得出热导率增强的物理起源。结果表明，由纳米粒子的布朗运动引起的跨固-液界面或微对流的声子负责导热率的提高。此外，观察到大范围的导热系数增强和非线性随着体积分数增加，这与实验研究一致。还研究了固液相互作用能对纳米流体粘度的影响，发现这是一个无关紧要的因素。我们的结果表明，具有强大的固液相互作用能的纳米流体应具有更大的应用潜力。