Heat transfer and rheological properties of transformer oil-oxidized MWCNT nanofluid

• Published in: Journal of thermal analysis and calorimetry 2014-12, Vol.118 (3), p.1451-1460
• Main Authors: Beheshti, Amir, Shanbedi, Mehdi, Heris, Saeed Zeinali
• Format: Article
• Language: English
• Subjects: Analysis; Analytical Chemistry; Chemistry; Chemistry and Materials Science; Dielectrics; Electric potential; Electric power generation; Electric properties; Electric transformers; Electrical conductivity; Heat transfer; Inorganic Chemistry; Measurement Science and Instrumentation; Nanofluids; Nanostructure; Nanotubes; Physical Chemistry; Polymer Sciences; Stress concentration; Thermal conductivity; Thermodynamics; Transformers; Voltage
• ISSN: 1388-6150; 1588-2926; 1572-8943
• DOI: 10.1007/s10973-014-4048-0

Power transformers play a key role in power and electrical industries and thus boosting their efficiency is necessary. In this study, the effect of oxidized multi-walled carbon nanotubes on transformer oil thermophysical properties was experimentally investigated. The maximum amount of carbon nanotubes was chosen up to 0.01 mass% to assure the maximum purity of transformer oil. Heat transfer characteristics of transformer oil and nanofluids in two cases of free and forced convection were studied. Breakdown voltage, flash point, pour point, density, electrical and thermal conductivities, viscosity and shear stress, as eight important quality parameters, were determined. According to the experimental results, the Breakdown voltage decreased through concentration increasing. Electrical conductivity is not changed considerable with increasing concentration and temperature. Thermal conductivity of nanofluids and transformer oil changed with increasing temperature and concentration. Furthermore, at all concentrations and temperatures, the viscosity of the nanofluids was lower than that of transformer oil.