Effect of Particle Shape Silica Coating and Laser Irradiation on Thermal Conductivity of Some Metal Oxide Based Nanofluids

Abstract

This thesis represents an effect of particle shape, silica coating and laser irradiation on thermal conductivity of some metal oxide nanoparticles in basefluids. Heat conduction of the metal oxide nanoparticles varied as a function of geometric morphology and surface area of elongated nanoparticles. Dispersion stability of the nanoparticles in basefluids is a major problem in nanofluids; therefore, nanoparticles have been coated with a thin layer of SiO2 for improved dispersion stability and thermal conductivity. Metal oxide (TiO2, CuO and WO3) nanoparticles in basefluids have also been irradiated by UV-Vis light LASER irradiation and investigated their effect on thermal conductivity. The whole work is divided into five chapters which are described below. Chapter 1: Introduction and Literature: The first chapter provides brief introduction about thermal conductivity, nanofluids, metal oxide s size and shape, core/shell structure and importance of silica coating and LASER irradiation. Literature review, research gap, objectives, experimental section and characterization techniques are also incorporated in this chapter. Chapter 2: Section A: Shape dependent thermal conductivity of TiO2-ethylene glycol and de-ionized water based suspension: This section demonstrates the importance of various shapes and crystal phases of TiO2 nanostructures such as TiO2 P-25 (70:30 anatase and rutile), as-prepared nanorods (pure anatase) and sodium titanate nanotubes (orthorhombic Na2Ti2O5.H2O crystal) on the thermal conductivity of ethylene glycol and de-ionized water.