Experimental thermal conductivity of alumina nanoparticles in water is measured with the transient thermal probe, in the presence of sonication (i.e., with ultrasounds), or not. We investigate two types of alumina particles, with the diameter equal to 7 nm and 50 nm. The experimental results, with and without sonication, show that the effective thermal conductivity is greater for the alumina nanoparticle with the smaller diameter. The effective thermal conductivity is greater in the presence of sonication, with a larger relative increase for the smaller diameter nanofluid. We compare the present experimental thermal conductivity with the empirical/theoretical prediction models of the literature with a reasonable good agreement.

中文翻译：

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有和没有超声处理的氧化铝纳米颗粒在水中的实验热导率

氧化铝纳米颗粒在水中的实验热导率是用瞬态热探头测量的，无论是否存在超声处理（即，使用超声波）。我们研究了两种直径分别为 7 nm 和 50 nm 的氧化铝颗粒。有和没有超声处理的实验结果表明，具有较小直径的氧化铝纳米颗粒的有效热导率更大。在超声处理的情况下，有效热导率更大，对于较小直径的纳米流体，相对增加更大。我们将目前的实验热导率与文献的经验/理论预测模型进行了比较，并具有合理的良好一致性。