Date of Award


Document Type

Open Access Thesis


Mechanical Engineering


College of Engineering and Computing

First Advisor

Jamil A. Khan


Spacer grids are used in pressurized water reactors (PWRs) fuel assemblies which enhances heat transfer from fuel rods. However, there remain regions of low turbulence in between the spacer grids which contributes to lower heat transfer. To enhance turbulence in these regions surface roughness is applied on the fuel rod walls. Meyer et al [1] used empirical correlations to predict heat transfer and friction factor for artificially roughened fuel rod bundles at high performance light water reactors (LWRs). At present, several types of materials are being used for fuel rod cladding including zircaloy, uranium oxide, etc. But researchers are actively searching for new material that can be a more practical alternative. Silicon carbide (SiC) has been identified as a material of interest for application as fuel rod cladding [2].

The current study deals with the experimental investigation to find out the friction factor increase of a SiC fuel rod with 3D surface roughness. The SiC rod was tested at USC’s Single Heater Element Loop Tester (SHELT) loop. The experiment was conducted in turbulent flowing Deionized (DI) water at steady state conditions. Measurements of flow rate and pressure drop were made. The experimental results were also validated by Computational Fluid Dynamics (CFD) analysis in ANSYS Fluent. To simplify the CFD analysis and to save computational resources the 3D roughness was approximated as a 2D one. The friction factor results of the CFD investigation was found to lie within ±8% of the experimental results. Simulations were also conducted with the energy equation turned on,and a heat generation of 8 kW applied to the rod. A maximum heat transfer enhancement of 18.4% was achieved at the highest flow rate investigated (i.e. Re=109204).