Dispersion stability and thermophysical properties of environmentally friendly graphite oil–based nanofluids used in machining

Abstract

As environmentally friendly cutting fluids, vegetable-based oil and ester oil are being more and more widely used in metal cutting industry. However, their cooling and lubricating properties are required to be further improved in order to meet more cooling and lubricating challenges in high-efficiency machining. Nanofluids with enhanced heat carrying and lubricating capabilities seem to give a promising solution. In this article, graphite oil-based nanofluids with LB2000 vegetablebased oil and PriEco6000 unsaturated polyol ester as base fluids were prepared by ultrasonically assisted two-step method, and their dispersion stability and thermophysical properties such as viscosity and thermal conductivity were experimentally and theoretically investigated at different ultrasonication times. The results indicate that graphitePriEco6000 nanofluid showed better dispersion stability, higher viscosity, and thermal conductivity than graphite-LB2000 nanofluid, which made it more suitable for application in high-efficiency machining as coolant and lubricant. The theoretical classical models showed good agreement with the thermal conductivity values of graphite oil-based nanofluids measured experimentally. However, the deviation between the experimental values of viscosity and the theoretical models was relatively big. New empirical correlations were proposed for predicting the viscosity of graphite oil-based nanofluids at various ultrasonication times.

Thermophysical Properties and Heat Transfer Performance of Novel Dry-Ice-Based Sustainable Hybrid Lubri-Coolant

“…The thermal conductivity of ethanol (0.171 W/mK) was found to be the highest among all the fluids at 10 • C [23], while ester oil had the lowest thermal conductivity of 0.161 W/mK at 30 • C. Although an increase in temperature decreased the thermal conductivity, temperature change has the least significant effect on the thermal conductivity of the hybrid lubri-coolants. At 30 • C, the thermal conductivity of ethanol was 0.168 W/mK, that of ethanol-ester oil (1:0.25) was 0.167 W/mK, that of ethanol-ester oil (1:0.5) was 0.165 W/mK, that of ethanol-ester oil (1:1) was 0.162 W/mK, and that of ester oil was 0.158 W/mK [24]. A small reduction in thermal conductivity was observed in this range of temperatures.…”

A Review on the Use of Water, Vegetable Oil and Other Liquids as Base-Fluids for Nanocoolants in Machining

“…The study recommended the use of mineral oil as cutting fluids for machines as this could reduce the amount of waste oil from the manufacturing processes. Su et al [10] studied experimentally and theoretically the effect of different ultrasonication times on the dispersion stability, viscosity and thermal conductivity of LB2000 vegetable-based oil and PriEco6000 unsaturated polyol ester dispersed with graphite particles of 35 nm at different concentrations (0.05, 0.25 and 0.5 vol%). The graphite oil-based nanofluids were prepared using the two-step method.…”

Influence of different surfactants on the stability and varying concentrations of TiO2 nanoparticles on the rheological properties of canola oil-based nanolubricants

“…Nevertheless, the rheology of different vegetable oils-based nanolubricant needs to be explored more. The comparative viscosity analysis of LB2000 vegetable oil-based lubricant and PriEco6000 unsaturated polyol ester by adding varying concentrations of graphite nanoparticles was conducted by Su et al (2016). The outcomes showed that the viscosity enhances with the rise of nanoparticle concentration for both oils.…”