Date of Award

2014

Document Type

Open Access Thesis

Department

Mechanical Engineering

First Advisor

Jamil A Khan

Abstract

DISS_abstract> This thesis investigate thermal characteristic of a single-phase nano-fluid in a single heater element loop tester and provides a comparison between heat transfer enhancement results achieved using water as a coolant and using nano-fluids with different volume percentage. The experimental investigation is performed on two simulated nuclear fuel rods with two different types of modified outer surfaces roughness. The fuel rod surfaces modified are termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (Diamond shaped blocks). The nano-fluid used are 0.5% and 2% ZnO-Deionized water based nano-fluid. The maximum heat transfer co-efficient enhancement achieved compared to DI-water was 33% at Re=1.15e5 for fuel rod with three-dimensional surface roughness using 2% (volumetric concentration) ZnO nano-fluid. It was also observed that the increase in Re number results in higher heat transfer co-efficient. It's concluded in this report that the Nano-fluids give a better thermal performance than the deionized (DI) water and diamond shape roughness devotes higher heat transfer coefficient than helically ribbed surface roughness using nano-fluid. A substantial amount of nano-particle deposition was observed on the fuel rod surface when the experiments were performed at higher bulk fluid temperature. The nano-particle deposition layer created hot spots along the rod surface resulting in inconsistent heat transfer in the fuel rod bundle. Therefore experiments were suspended at higher temperatures.

Share

COinS