Date of Award

January 2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

First Advisor

Clement Tang

Abstract

This research seeks to determine for the flow of stable dispersion of 9.58% silicon-oxide (SiO2) nanoparticles by volume in water through three hexagonal tubes of hydraulic diameters 1.67 mm, 2.42 mm and 3.26 mm, the pressure drops across the length of the tubes with and without the application of constant heat flux to the test section. Constant heat flux was applied on the wall of each test section (by electric resistance method). The operating temperature range of 15-63°C was maintained for the experiments. Data were analyzed using conventional hydrodynamic and thermal correlations. The test sections were selected and set up (or instrumented) in a manner enabling the measurements of lengthwise local surface temperatures of test sections and the drop in pressure of fluid flow across the axial length of the test sections. Viscosity and thermal conductivity measurements for the nanofluid of interest were acquired by Sharif (2015), and were used in this study.

The 9.58% volume concentration SiO2-water nanofluid friction coefficients were found to follow the same trend obtained by classical correlations for Newtonian fluids. Results show no significant difference between the friction coefficients of nanofluid and water if the nanofluid is modeled as a power law fluid. The nanofluid, however, sustained laminar flow longer than water over the range of Reynolds number tested when no heat had been applied, the effect is even more pronounced for decreased hydraulic diameter of test section.

For the thermally developing flow, convective heat transfer values for the nanofluid were significantly enhanced compared to water, nearing 20% in the laminar flow regime. The measured local Nusselt numbers for the nanofluid lie within ±30% of the Lienhard and Lienhard (2013) model for laminar thermally developing flow, and about 30% or less of the Gnielinski (1976) correlation for turbulent flow. Pressure drops for the nanofluid flows exceed those of water by over 100%.

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