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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Effect of Oleic Acid Weight Fraction on stability of hBN Based Nanofluids
Submission Author:
Douglas Machado , SC
Co-Authors:
Douglas Machado, Lucas Militão, Jader Riso Barbosa Jr., Carlos Rambo
Presenter: Douglas Machado
doi://10.26678/ABCM.ENCIT2020.CIT20-0049
Abstract
Recently, a great variety of efforts have been made to enhance dielectric fluid properties through the dispersion of nanoparticles. However, the base fluid can only sustain a finite amount of nanoparticles, which is often insufficient to achieve the desired thermal and electrical properties. Therefore, this study intends to evaluate the weight fraction of oleic acid in hexagonal Boron Nitride (hBN) based nano-oil which improves and optimizes the dispersion of the nanoparticles and its stability over time. Samples with weight fractions from 0.1 to 5.0%of hBN were considered for seven different oleic acid fractions: 5.0, 7.5, 10.0, 12.5, 15.0, 17.5 and 20.0%, totaling 42 samples. Homogenization of the suspension was performed using a high intensity ultrasonic processor together with a thermostatic bath for temperature control. In order to evaluate the dispersion, each sample had its absorbance measured by a spectrophotometer, and reported for different time frames: 0, 30 and 60 days after dispersion. Moreover, photographic records were taken in order to qualitatively evaluate the dispersion and stability of each sample. The absorbance results presented an optimal value of dispersant weight fraction for almost all concentrations of hBN; except the lower ones. Besides, an optimal weight fraction of 17.5% of oleic acid was determined for the 1.5 wt% hBN samples, resulting in a sample with a stable and well-dispersed fluid in the qualitative analysis, after a period of 60 days. Consequently, the use of oleic acid as a tool to increase hBN nanoparticle concentration and stability in dielectric oils has shown to be promising.
Keywords
hBN, Dispersant, stability, Dispersion, Oleic Acid
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