Giwa Solomon O, Sharifpur Mohsen, Ahmadi Mohammad H, Sohel Murshed S M, Meyer Josua P
Department of Mechanical Engineering, Olabisi Onabanjo University, Ibogun 112104, Nigeria.
Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria 0002, South Africa.
Nanomaterials (Basel). 2021 Jan 8;11(1):136. doi: 10.3390/nano11010136.
The superiority of nanofluid over conventional working fluid has been well researched and proven. Newest on the horizon is the hybrid nanofluid currently being examined due to its improved thermal properties. This paper examined the viscosity and electrical conductivity of deionized water (DIW)-based multiwalled carbon nanotube (MWCNT)-FeO (20:80) nanofluids at temperatures and volume concentrations ranging from 15 °C to 55 °C and 0.1-1.5%, respectively. The morphology of the suspended hybrid nanofluids was characterized using a transmission electron microscope, and the stability was monitored using visual inspection, UV-visible, and viscosity-checking techniques. With the aid of a viscometer and electrical conductivity meter, the viscosity and electrical conductivity of the hybrid nanofluids were determined, respectively. The MWCNT-FeO/DIW nanofluids were found to be stable and well suspended. Both the electrical conductivity and viscosity of the hybrid nanofluids were augmented with respect to increasing volume concentration. In contrast, the temperature rise was noticed to diminish the viscosity of the nanofluids, but it enhanced electrical conductivity. Maximum increments of 35.7% and 1676.4% were obtained for the viscosity and electrical conductivity of the hybrid nanofluids, respectively, when compared with the base fluid. The obtained results were observed to agree with previous studies in the literature. After fitting the obtained experimental data, high accuracy was achieved with the formulated correlations for estimating the electrical conductivity and viscosity. The examined hybrid nanofluid was noticed to possess a lesser viscosity in comparison with the mono-particle nanofluid of FeO/water, which was good for engineering applications as the pumping power would be reduced.
纳米流体相对于传统工作流体的优越性已得到充分研究和证实。最新出现的是目前正在研究的混合纳米流体，因其热性能得到改善。本文研究了基于去离子水（DIW）的多壁碳纳米管（MWCNT）-FeO（20:80）纳米流体在温度范围为15℃至55℃、体积浓度范围为0.1%-1.5%时的粘度和电导率。使用透射电子显微镜对悬浮的混合纳米流体的形态进行了表征，并使用目视检查、紫外可见和粘度检查技术监测了其稳定性。借助粘度计和电导率仪，分别测定了混合纳米流体的粘度和电导率。发现MWCNT-FeO/DIW纳米流体稳定且悬浮良好。混合纳米流体的电导率和粘度均随体积浓度的增加而增大。相比之下，温度升高会降低纳米流体的粘度，但会提高电导率。与基础流体相比，混合纳米流体的粘度和电导率分别最大增加了35.7%和1676.4%。观察到所得结果与文献中的先前研究一致。对获得的实验数据进行拟合后，用于估计电导率和粘度的公式化关联式具有很高的准确性。与FeO/水的单颗粒纳米流体相比，所研究的混合纳米流体的粘度较小，这有利于工程应用，因为可以降低泵送功率。
