A review on influence of nanoparticle parameters on viscosity of nanofluids and machining performance in minimum quantity lubrication

Researchers have been greatly encouraged to utilize nanofluids as an alternative cutting fluid during machining with minimum quantity lubrication conditions in recent decades due to their desirable qualities such as enhanced wetting and spreading ability, acceptable rheological behavior with varying nanoparticle parameters, and dispersion methods. The thermophysical values of nanofluids considerably impact their heat transfer capability. Viscosity is a crucial thermophysical property that is influenced by several factors. The viscosity of the nanofluid increases with increasing particle concentration and reduces with increasing particle size. Surfactants can aid in the reduction of nanofluid viscosity. Furthermore, the effects of particle type, shape, and dispersion in the base fluid on the viscosity of nanofluids deserve further investigation. Due to a lack of information on nanoparticle parameters and their preparation method, the experiments that utilize them often seem untrustworthy, contradictory, not similar, and not reproducible. As a result, defining the minimum amount of information required to characterize the nanofluid fully is critical to assure its composition and property measurements’ reproducibility. This review focuses on how the viscosity of nanofluids is affected by the base fluid, concentration, and nanoparticle parameters such as size, shape, material, and dispersion mechanism. The influence of viscosity on the machining performance in surface roughness as well as tool wear is also studied. In conclusion, some recommendations have been made for the least amount of information that should be provided on a nanofluid to recreate the same nanofluid across all laboratories.