Delchini, Marc Olivier (2010-05). A Preliminary Study to Assess Model Uncertainties in Fluid Flows. Master's Thesis.
In this study, the impact of various flow models is assessed under free and
forced convection: compressible versus incompressible models for a Pressurized Water
Reactor, and Darcy's law vs full momentum equation for High Temperature Gas
Reactor. Euler equations with friction forces and a momentum and energy source/sink
are used. The geometric model consists of a one-dimensional rectangular loop system.
The fluid is heated up and cooled down along the vertical legs. A pressurizer and a
pump are included along the horizontal legs. The compressible model is assumed to
be the most accurate model in this study.
Simulations show that under forced convection compressible and incompressible
models yield the same transient and steady-state. As free convection is studied,
compressible and incompressible models have different transient but the same final
steady-state. As Darcy's law is used, pressure and velocity steady-state profiles yield
some differences compared to the compressible model both under free and forced
convections. It is also noted some differences in the transient.