Abstract In this paper, the analysis of the boiling process is studied in a nucleate regime on a copper surface through using oxide nanoparticles of cobalt (Co3O4) in deionized water at volume fractions of 0.005, 0.01, 0.05, 0.1, and 0.2% by means of a nucleate boiling device. The nanoparticles’ average size is about 45 nm for cobalt oxide. As the nanofluid concentration increases, the deposition and the boiling surface heat resistance increases, the nucleation points and coefficient of the boiling heat transfer decrease due to deposition. Despite the magnetic field positive effect on dilute liquids, sediment has a more negative effect than the magnetic field on concentrated nanofluids. The results reveal the improvement of the heat transfer coefficient of pool boiling under a magnetic field for low volume fractions. Maximum heat transfer of Co3O4/ DI-water is 58% compared to the DI-water observed at the concentration of 0.005%. This nanofluid can be applied to increase the heat transfer rate at low concentrations.

中文翻译：

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磁场对成核状态下由氧化钴和去离子水组成的磁性纳米流体沸腾传热系数的影响：实验研究

摘要 在本文中，通过在去离子水中使用体积分数为 0.005、0.01、0.05、0.1 和 0.2% 的钴 (Co3O4) 氧化物纳米粒子，在铜表面的成核状态下研究了沸腾过程的分析。核沸腾装置。对于氧化钴，纳米颗粒的平均尺寸约为 45 nm。随着纳米流体浓度的增加，沉积物和沸腾表面热阻增加，成核点和沸腾传热系数因沉积而降低。尽管磁场对稀液体有正面影响，但与磁场对浓缩纳米流体的负面影响相比，沉积物的负面影响更大。结果表明，对于低体积分数，在磁场下池沸腾的传热系数有所提高。与在 0.005% 浓度下观察到的去离子水相比，Co3O4/去离子水的最大传热为 58%。这种纳米流体可用于在低浓度下提高传热率。