Experimental study on glycerol/aldehyde or ketone binary nanofluids for thermal management

Abstract

Glycerol is a bio-based low-cost chemical, which has been widely studied in the field of heat conduction because of its wide working temperature range and superior thermopysical. However, high viscosity of glycerol is a prominent problem that limit the application of glycerol. In this work, low viscosity and high thermal conductivity of glycerol nanofluids are prepared under the dual role of nanoparticles, in which nanoparticles work as the nanoadditives enable an enhancement of thermal conductivity and specific heat capacity of nanofluids and the catalyst make a decline of viscosity of nanofluids. The thermal and viscosity properties of the nanofluid were investigated, and the addition of 15% acetylacetone and 2% TiO2 increased the thermal conductivity of the nanofluid to 0.3194 W/m·K, which was 8.12% higher than that of the glycerol. Meanwhile, the viscosity was reduced to 357.4 mPa (30 °C) with 15% acetylacetone and 0.5% TiO2 nanoparticles, which was 47% lower than that of glycerol at the same temperature. Additionally, results of fourier transform infrared spectrometer and proton nuclear magnetic resonance demonstrate that acetal reaction plays an important role in reducing the viscosity of nanofluids, meanwhile, the tests of X-ray diffraction show that nanoparticles can be utilized circularly.