FIDAS: Detailed subchannel analysis code based on the three-fluid and three-field model

The Film Dryout Analysis Code in Subchannels, FIDAS, has been developed with the main objective of predicting dryout and post-dryout heat transfer in a channel and in rod bundles. In FIDAS, two-phase flow consisting of continuous liquid film, continuous vapor and entrained droplets is modeled by a three-fluid, three-field representation of 12 field equations, i.e. three continuity, three energy and six momentum equations. FIDAS can predict dryout without any empricial CHF correlations by introducing annular flow modeling and the 'film dryout criterion'. Experiments on film flow characteristics, subchannel flow and enthalpy distributions, dryout and post-dryout heat transfer in tubes and rod bundles were analyzed to demonstrate the performance of FIDAS. The predictions of FIDAS are in close agreement with the experiments. (orig.)