Analysis and Computational Predictions of CHF Position and Post-CHF Heat Transfer

摘要

The objective of the current study is to investigate the capability of the US NRC TRACE code to predict the Critical Heat Flux (CHF) position and temperature profiles for different axial heat flux distributions in the reflooding of a hot single tube. Measurements of each of Bennett, Keeys and Becker were used for this. Hydrodynamic and post-dryout heat transfer calculations were performed using TRACE Code. CHF and critical quality correlations (based on the look-up tables of Groeneveld, the local conditions hypothesis, and the boiling length/quality relationship) are usually implemented in system codes. Each of these has been used to analyze the experiments. These simulations showed that generally the CHF position was well predicted whereas the estimation of the wall temperature was not correct for particular ranges of mass and heat fluxes. This is investigated and possible causes, associated with local conditions issues, are proposed.