We report, in this work, our study of the thermal conductivity of high-viscosity nanofluids based on glycerol. Three nanofluids have been prepared with different thermal contrasts, by suspending graphene flakes, copper oxides, or silica nanoparticles in pure glycerol. The nanofluids were thermally characterized at room temperature with the 3ω technique, with low amplitudes of the temperature oscillations. A significant enhancement of the thermal conductivity is found in both the glycerol/copper oxide and the glycerol/graphene flake nanofluids. Our results question the role played by the Brownian motion in the microscopic mechanisms of the thermal conductivity of high-viscosity glycerol-based nanofluids. A similar behavior of the thermal conductivity as a function of the nanoparticle volume fraction was found for all three glycerol-based nanofluids presently investigated. These results could be explained on the basis of fractal aggregation in the nanofluids.

中文翻译：

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不同热对比下甘油基纳米流体热导率的实验测量

我们在这项工作中报告了我们对基于甘油的高粘度纳米流体的热导率的研究。通过将石墨烯薄片、氧化铜或二氧化硅纳米粒子悬浮在纯甘油中，制备了三种具有不同热对比度的纳米流体。纳米流体在室温下用 3 ω进行热表征技术，具有低幅度的温度振荡。在甘油/氧化铜和甘油/石墨烯薄片纳米流体中都发现了热导率的显着增强。我们的结果质疑布朗运动在高粘度甘油基纳米流体的导热性微观机制中所起的作用。对于目前研究的所有三种基于甘油的纳米流体，都发现了作为纳米颗粒体积分数函数的类似热导率行为。这些结果可以基于纳米流体中的分形聚集来解释。