TRANSIENT VAPOUR-LIQUID TWO-PHASE FLOWS IN LARGE VOLUMES OF STEAM GENERATORS

Abstract

A numerical method for the simulation and analyses of transient two-phase flows in large volumes on shell sides of steam generators with boiling around tubes in bundles is presented. Modelling of two-phase flow on the secondary side of the steam generator is conducted by porous media approach. Interfacial mass, momentum and energy transfers are modelled by constitutive correlations developed for the two-phase flow around tubes in a bundle. Balance equations are solved by the modified SIMPLE method applicable to the multi-phase flow conditions. The method is applied to the prediction of a tube rupture incident with a heating fluid leakage from pipes to the shell side. Obtained results show the secondary side velocity flow fields for both water and steam phase, the void fraction distribution, as well as the swell level increase. These results are a support to safety analyses.