Sensitivity Analysis of Heated Wall Temperature and Velocity Distribution in CFD Simulations of the Upward Flow of Supercritical Water.

Abstract

The main objective of this work was to investigate sensitivities of the heated wall temperature and radial velocity distribution predictions on selected model parameters, in water flow under supercritical conditions. The study was focused on cases in which deterioration of heat transfer occurs. Numerical simulations of the turbulent, upward flow in a circular tube were performed using the commercial CFD code ANSYS CFX 12.1. Implementation of water properties was according to IAPWS IF97. The model sensitivities were examined on the mesh discretization, boundary conditions and numerical parameters. Results of simulations were compared with the available experimental data.A significant sensitivity was recognized especially for changes of heat flux and mass flux. It was found out that the model is much less sensitive to changes of boundary conditions for high values of mass flux and heat flux than for low mass and heat fluxes.