CHF prediction by a FIDAS code based on the three-fluid, three-field and film dryout model

The Film Dryout Analysis Code in Subchannels, FIDAS, has been developed with a main objective of predicting the dryout and post-dryout heat transfer in a channel and rod bundles. FIDAS code can predict the dryout without any empirical CHF correlations by introducing an annular flow modeling and 'the film dryout criterion' in which dryout is indicated when there is no liquid film on the heated surface. Furthermore, droplet entrainment and deposition models are newly developed to improve the prediction accuracy on dryout founded on entrainment by interfacial shear force balance at the roll wave crest, deposition by turbulent diffusion mechanism in vapor core and deposition suppression phenomenon by vaporization on the heater surface. Dryout experiment for round tubes which were carried out in RISO, AERE and AEEW are analyzed to demonstrate the performance of FIDAS code. Predictions by FIDAS code agree well with the experiments in the critical heat flux