Ribeiro Hélio, Taha-Tijerina Jose Jaime, Gomez Ofelia, Acosta Ever, Pinto Gabriel M, Moraes Lorena R C, Fechine Guilhermino J M, Andrade Ricardo J E, Reinoza Jefferson, Padilla Victoria, Lozano Karen
Department of Informatics and Engineering Systems, University of Texas Rio Grande Valley-UTRGV, Brownsville, TX 78520, USA.
Engineering School, Mackenzie Presbyterian University, Rua da Consolação 896, São Paulo 01302-907, SP, Brazil.
Nanomaterials (Basel). 2023 Oct 10;13(20):2739. doi: 10.3390/nano13202739.
Nanofluids based on vegetal oil with different wt.% of carbon nanotubes (CNT), hexagonal boron nitride (h-BN), and its hybrid (h-BN@CNT) were produced to investigate the effects of these nano-additives on the thermal conductivity and rheological properties of nanofluids. Stable suspensions of these oil/nanostructures were produced without the use of stabilizing agents. The dispersed nanostructures were investigated by SEM, EDS, XRD, and XPS, while the thermal conductivity and rheological characteristics were studied by a transient hot-wire method and steady-state flow tests, respectively. Increases in thermal conductivity of up to 39% were observed for fluids produced with 0.5 wt.% of the hybrid nanomaterials. As for the rheological properties, it was verified that both the base fluid and the h-BN suspensions exhibited Newtonian behavior, while the presence of CNT modified this tendency. This change in behavior is attributed to the hydrophobic character of both CNT and the base oil, while h-BN nanostructures have lip-lip "bonds", giving it a partial ionic character. However, the combination of these nanostructures was fundamental for the synergistic effect on the increase of thermal conductivity with respect to their counterparts.
制备了基于植物油且含有不同重量百分比的碳纳米管（CNT）、六方氮化硼（h-BN）及其混合物（h-BN@CNT）的纳米流体，以研究这些纳米添加剂对纳米流体热导率和流变性能的影响。在不使用稳定剂的情况下制备了这些油/纳米结构的稳定悬浮液。通过扫描电子显微镜（SEM）、能谱仪（EDS）、X射线衍射仪（XRD）和X射线光电子能谱仪（XPS）对分散的纳米结构进行了研究，同时分别通过瞬态热线法和稳态流动试验研究了热导率和流变特性。对于含有0.5重量%混合纳米材料的流体，观察到热导率提高了39%。至于流变性能，已证实基础流体和h-BN悬浮液均表现出牛顿流体行为，而CNT的存在改变了这种趋势。这种行为变化归因于CNT和基础油的疏水性，而h-BN纳米结构具有脂-脂“键”，使其具有部分离子特性。然而，相对于其对应物，这些纳米结构的组合对于提高热导率的协同效应至关重要。
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