Title of Dissertation: ENHANCEMENT OF SPRAY COOLING HEAT TRANSFER USING EXTENDED SURFACES AND NANOFLUIDS Johnathan Stuart Coursey, Ph.D., 2007 Directed By: Associate Professor, Jungho Kim, Department of Mechanical Engineering Spray cooling is a powerful heat transfer technique in which an atomizing nozzle provides a flow of liquid droplets directed towards a hot surface. This dissertation explo...

This study numerically investigates heat transfer augmentation using water-based Al₂O₃ and CuO nanofluids flowing in a triangular cross-sectional duct under constant heat flux in laminar flow conditions. The Al₂O₃/water nanofluids with different volume fractions (0.1%, 0.5%, 1%, 1.5%, and 2%) and CuO/water nanofluids with various volume fractions (0.05%, 0.16%, 0.36%, 0.5%, and 0.8%) are employ...

The objective of this study is to numerically investigate the convective heat transfer of water-based Al2O3 nanofluids flowing through a square cross-section duct with a constant heat flux under laminar flow conditions. The effects of nanoparticle concentration and Peclet number on the heat transfer characteristics of Al2O3-water nanofluids are investigated. The nanoparticle diameter is 25 nm a...

The main reason for using alternative fuels in compression ignition engine is that the consumption and demand of petroleum products are increasing every year due to urbanization, increase in vehicular density and power requirement is going up and to reduce emission produced by today’s diesel engine, which in turns require a clean burning fuel that perform well under the variety of operating con...

Graphene oxide was prepared using modified Hummers method. Stable ethylene-glycol nanofluids containing graphene oxide nanosheets were provided. Nd: YAG pulsed laser was applied to prepare reduced nanofluids. Experimental results revealed that thermal conductivity of the nanofluids is increased with increasing the concentration of graphene oxide (GO) in ethylene glycol. The enhancement ratio of...

Nanofluids are suspension of nanoparticles (less than 100 nm) in the conventional base fluids. The dispersed solid metallic or non-metallic nanoparticles change the thermal properties like thermal conductivity, viscosity, specific heat, and density of the base fluid. Past studies focused on measuring the thermal properties of nanofluids. These suspended nanoparticles effectively improve the tra...

the main purpose of this study is to perform numerical simulation of nanofluids as the coolant in vver-440 fuel rod bundle. the fuel rod bundle contains 60 fuel rods with length of 960 mm and 4 spacer grids. in vver-440 fuel rod bundle the coolant fluid (water) is in high pressure and temperature condition. in the present thermo-hydraulic simulation, water-al2o3 nanofluids containing various vo...

In this study, the nanofluids are produced by dispersing Al2O3 nanoparticles in the H2O/CH3OH binary mixtures using an ultrasonic equipment. Solid Sodium Chlorides (NaCl) with a fixed mass fraction are dissolved in the binary mixture for CO2 absorption. The main objective of this paper is to measure the thermal conductivity of the Al2O3 nanofluids using the transient hot-wire method. The experi...

Nanofluid connotes a colloidal suspension with dispersed nano-sized particles. Experiments in the past decade reveal that nanofluids have a significantly higher thermal conductivity in comparison to that of the base fluid. Recently, a number of phenomenological models have been proposed to explain the anomalous heat transfer enhancement seen in nanofluids. In this paper, we make a systematic su...

nanofluids are kinds of fluids engineered by dispersing nanoparticles in base fluids, a new challenge for thermal sciences provided by nanotechnology. due to their excellent characteristics, nanofluids find wide applications in enhancing heat transfer. this paper presents synthesis and characterization of tio2-cnts nanocomposites by sonochemical method and investigation of some properties of ti...