applied sciences Article  
Numerical Investigation on Thermal Performance of Duplex Nanocoolant Jets in Drilling of Ti-6 Al-4V Alloy R. Mohan  
carbide skeleton and cobalt erosion are the criteria that negatively affect the machinability of the workpiece. Furthermore, [PERSON] et al. [12] analyzed the carbide particles in cutting tools material structure that go through various stages during the machining of Ti-6 Al-4V alloy, causing attrition wear, cobalt diffusion, coating delamination, flaking, and cracking. These high-speed machining elements cause an increase in cutting forces and heat energy, shortening the tool life and leading to severe plastic deformation and subsurface defects in the machined parts [13]. [PERSON] et al. [14] and [PERSON] et al. [15] investigated on the machining method, tool geometry and tool material that improves the surface integrity of the work piece surface, tool life and also decrease cutting forces and cutting temperature. Moreover, [PERSON] et al. [16] studied whether maintaining significant parameters such as lubrication and cooling method could lower the power and specific cutting energy. Attention must be given to the role of cutting fluid, as conventional cutting fluids do not satisfy the regulations of green manufacturing in terms of energy saving, cost, health, and environmental effects [17]. The solution is to minimize the use of lubrication in machining operations. Minimizing or eliminating conventional cutting fluids is the key to abating manufacturing costs. Although, estimating heat partition parameters during a drilling operation remains a significant challenge. Because of the complicated drill geometry and geometry along the cutting edge, there is a variation in the cutting velocity of the drill; the generated heat fluctuates, hence, the consequent heat partition parameters. To enhance the cooling and lubrication effects of the mechanical manufacturing processes, metalworking fluids (MWF) have been commonly used. However, excessive usage of MWF has significantly affected environmental burdens and induced health issues for plant workers. Recent studies emphasize limiting the use of MWF throughout the machining operation. Among numerous methods to minimize the total leverage of MWF, hybrid nanofluid with minimum quality lubrication (MQL) is sustainable and ecologically sound. A Nanofluid is a fluid comprising nanoparticles such as Al\({}_{2}\)O\({}_{3}\), TiO\({}_{2}\), Cu, and carbon nanotube (CNT). [PERSON] et al. [18] and [PERSON] et al. [19] found that nanoparticles are superior materials for enhancing the thermal conductivity of the base fluid. In addition, [PERSON] et al. [20] and [PERSON] et al. [21] noted the ball-bearing rolling effect in nanoparticles, which significantly improves material wear and tribological characteristics. Therefore, nanofluids are implemented in numerous applications, including pharmaceutical processes, fuel cells, microelectronics, hybrid-powered engines, and mechanical machining processes. Because of their fruitful results, many scientists and researchers may analyze these cooling methods. Various authors have accentuated the bright potential of hybrid nanofluids in the perspective of excellent thermal properties [22] and thermo-physical properties with an increased potential for heat transfer rather than individual nanoparticle-based nanofluids [23]. [PERSON] et al. [24] conducted an experimental study. They compared two sustainable cooling methodologies of cryogenic cooling and hybrid nanofluid-based MQL environment, observing a very immediate difference in temperature between the two methods. The authors emphasized that Al\({}_{2}\)O\({}_{3}\)-MWCNT-based MQL significantly diminished the main cutting forces and surface roughness compared with cryogenic CO\({}_{2}\)-based cooling. Moreover, tool life was prolonged under a hybrid nanofluid because of the slighter major cutting force and the resultant passive force on the tool edge of the cutting insert. [PERSON] et al.