DNB Prediction Using Local Void Distribution in High Quality Flow

Abstract

A coupled code between a sub-channel analysis code and a computational multi-fluid dynamics code was developed for predicting departure from nucleate boiling (DNB). Local void fraction near the wall was used to define the onset of DNB. The local void fraction distribution in a sub-channel was determined by a bubble diffusion equation. To cover the flow regime at the high quality condition, a new source term was introduced. The present method was applied to the analysis of DNB test data including high quality condition. The result showed remarkable improvement of predictability by introducing the new source term.