A STUDY OF VISCOELASTIC PROPERTIES AND NON DESTRUCTIVE CHARACTERIZATION OF NANOFLUIDS

Abstract

newlineThis thesis deals with the study of viscoelastic properties and nondestructive characterization of nanofluids. Viscoelastic behaviour of nanofluids was extensively studied along with their physicochemical and tribological characteristics. Cu, MoS2 and Hex BN based nanofluids were synthesized using two step processes in mineral and synthetic oils. Physicochemical analysis and trace metal analysis was done using standard test procedures. newlinePerformance behaviour of the formulated nanofluids was studied on the basis of viscoelastic behaviour, tribological behaviour, contact fatigue behaviour and wettability behaviour. newlinePhysicochemical properties of the nanofluids remain almost the same as the base fluids. Tribological tests performed on base oils and the nanofluids reveal that coefficient of friction decreased in the varying degree in different nanofluids. In most of the lubricants 0.15 wt percent of nanoparticles was reported as the optimum doze. Wear scar diameter for lubricants also showed varying degree of enhancements. RCF tests performed on L4, L5 and their Cu nanofluids and the subsequent Weibull analysis done reveal that L10, L50 and L90 lives of Cu nanofluids enhanced across the board. Viscoelasticity data reveal that viscosity of nanofluids show slight enhancement. Apparent yield stress decreases on increasing the temperature for all nanofluids studied. There is not much alteration in the shear thinning behaviour of the nanofluids, however shear thinning decreases at high temperatures. The given lubricants and their nanofluids exhibit Viscoelasticity in the low shear rate region. Wettability study reveals that contact angle of nanofluids in general increases showing stronger bonding of base fluid molecules and the nanoparticles. newlineThus, the viscoelastic behaviour and nondestructive characterization of nanofluids were investigated for proposing their usage in different industrial and automotive applications. newline newline newline newline newline