Mass flow determination in flashing openings

The output flow characteristics in most of the industrial accidental releases are related to a two-phase flow and their represent a potential hazard to facilities, personnel, equipments and environment. If these releases involve superheated liquid then a flashing process can take place, where a liquidgas mixture due to the breaking of the metastable state can significantly affect the hazard zone. The calculation of the conditions for the flow after a flashing opening is very relevant in order to understand the mechanisms present after the release opening. Numerical modelling represents an important tool to approach these types of phenomena. However, the accuracy of the obtained results will depend on the realistic values of the flow parameters taken as input information to perform the CFD work. The model proposed here is based on the assumption of the existence of a non reversible work in the system and the use of the thermodynamic jump formulation to model the phase change process in order to predict phase velocity and mass flow. The obtained results have a good agreement with the experimental data available.