Abstract

We report in this study the experimental investigation of the dynamic viscosity of purified multi-walled carbon nanotubes (MWCNT) water and water-propylene glycol-based nanofluids in the temperature range 10–80 °C. Four weight concentrations of MWCNTs are considered, between 0.005 and 0.1 wt.%. Triton X-100, a common nonionic surfactant, is used to disperse the nanotubes and stabilize the nanofluids as evidenced by optical characterization. Purified and non-damaged MWCNTs are used for nanofluid preparation by the two-step method. MWCNT characterization is deeply investigated from a set of complementary techniques such as thermogravimetric analysis, transmission electron microscopy, and Raman spectroscopy. The studied nanofluids behave as Newtonian fluids for low nanotube content while a shear-thinning behavior is noticed for higher concentration. Finally, the viscosity enhancement of nanofluids with MWCNT loading is compared to the modified Maron–Pierce model considering the presence of aggregates and their size obtained from optical observations.

摘要

我们在这项研究中报告了纯化多壁碳纳米管 (MWCNT) 水和水-丙二醇基纳米流体在 10-80°C 温度范围内的动态粘度的实验研究。考虑了四种重量浓度的 MWCNT，介于 0.005 和 0.1 重量％之间。Triton X-100 是一种常见的非离子表面活性剂，用于分散纳米管并稳定纳米流体，如光学表征所证明的那样。纯化的和未损坏的 MWCNT 用于通过两步法制备纳米流体。从热重分析、透射电子显微镜和拉曼光谱等一系列互补技术对 MWCNT 表征进行了深入研究。所研究的纳米流体在纳米管含量低时表现为牛顿流体，而在较高浓度时观察到剪切稀化行为。