Numerical Investigation on Thermal Performance of Duplex Nanocoolant Jets in Drilling of Ti-6Al-4V Alloy

Abstract

In the current industry, coolants are widely used in numerous operations for the purpose of cooling and heat transfer. These operations include all kinds of heat sinks for electronic devices and manufacturing processes such as milling, drilling, turning, and CNC machining. The thermophysical properties of coolants play a vital role in determining the effectiveness of heat transfer and help prevent the components from wear and tear caused by extremely high temperatures. The computational domain consists of a drill bit and rectangular workpiece, and hybrid nanocoolants are sprayed from duplex nozzles. The nanocoolant heat transfer and flow characteristics of the drill bit–workpiece interface were analysed using the large eddy simulation (LES) turbulence model. The workpiece is made of Ti-6Al-4V alloy maintained at a temperature of 1073.15 K. The coolant used is a mineral oil into which different nanoparticles of Al2O3, TiO2, Cu, MWCNT, and SWCNT are dispersed by varying the volume concentration. The variations in temperature, Nusselt number, and wall heat transfer coefficient, with respect to the volume fraction of nanoparticles and the Reynolds number, were investigated. It was concluded that Cu–Al2O3 nanoparticles dispersed in mineral oil depicted the most favourable heat transfer.