Thermophysical and stability properties of MWCNT-water-ethylene glycol nanofluids: An experimental study.

Nanofluids are playing an important role in industry and multiple solar applications as an excellent heat carrier. In this study, a nanofluid consisting of an additive, multi walls carbon nanotube (MWCNT), is examined to the base fluid consisting of a mixture of water and ethylene glycol (EG) at a ratio of 75% to 25%, respectively. MWCNTs were added in four different volume ratios (0.1, 0.5, 1 and 2%). To obtain a good mixing of the nanoparticles with water/EG, ultrasonic shaking was used. The produced samples were examined and analyzed for their thermophysical properties in addition to their stability. The high thermal conductivity of MWCNT caused a significant increase in the thermal conductivity of the resulted nanofluids, which reached 140% compared to water. The effect of adding MWCNT on the density of the nanofluid was limited and did not exceed 0.075% when adding 2% of it. The viscosity of the nanofluid is affected by the addition of MWCNT, as the suspension viscosity reached 2.8% for adding 2% of the nanoparticles. The stability of the prepared nanofluids was measured using zeta potential. The results of this examination showed that the studied nanofluids have high stability. The nanofluids with 0,1% and 0,5% were the most stable. While the nanofluid with 2% MWCNT was the least stable, yet its stability was high, reaching 48 mV. This stability was confirmed by the camera images. [ABSTRACT FROM AUTHOR]