FIDAS: A Three-Fluid Subchannel Code for Dryout Prediction in Rod Bundles

Abstract

A numerical code called FIDAS (film dryout analysis code in subchannels) has been developed with the main objective of simulating dryout and post-dryout heat transfer in rod bundles. This code features three fluid representation of two-phase flow, in which the third fluid is liquid droplets entrained in the vapor phase. Since the code is able to predict the dryout occurrence by the film dryout criterion, no empirical CHF correlation is required. FIDAS gave good predictions of the onset of dryout when compared with experimental results from full-scale dryout tests on a 36-rod bundle. Furthermore, FIDAS gave better accuracy in predicting a wide range of thermalhydraulic conditions when compared with other subchannel codes.