Numerical and experimental research on the grinding temperature of minimum quantity lubrication cooling of different workpiece materials using vegetable oil-based nanofluids

Abstract

This study investigated the grinding temperature of minimum quantity lubricant cooling (MQLC) for heat transfer. Three typical workpiece materials, namely, 45 steel, Ni-based alloy, and nodular cast iron, were surface grinded. These materials are the most frequently used for mechanical processing. Palm oil with good lubrication and heat transfer performance was chosen as the base oil for the nanofluids. Carbon nanotube (CNT) nanofluids with volume fractions of 2 and 2.5%, as well as excellent heat transfer performance, were prepared for the MQLC fluid. Results showed that the 45 steel grinding had the highest temperature (363.9 °C), and the grinding temperature of the 2% nanofluid (363.9 °C) was slightly higher than that of the 2.5% nanofluid (352.9 °C). A numerical simulation heat transfer model conducting the finite difference method was established for the numerical analysis of the MQLC grinding temperature. Results indicated that the model predictions and experimental results are in good agreement, with 4.8% average model error. The heat transfer mechanism of the nanofluids was also analyzed. This study confirmed that nucleate boiling heat transfer was achieved when grinding the Ni-based alloy.