The output flow characteristics in most of the industrial accidental releasesare related to a two-phase flow and their represent a potential hazard tofacilities, personnel, equipments and environment. If these releases involvesuperheated liquid then a flashing process can take place, where a liquidgasmixture due to the breaking of the metastable state can significantlyaffect the hazard zone. The calculation of the conditions for the flow after aflashing opening is very relevant in order to understand the mechanismspresent after the release opening. Numerical modelling represents animportant tool to approach these types of phenomena. However,the accuracy of the obtained results will depend on the realistic values ofthe flow parameters taken as input information to perform the CFD work.The model proposed here is based on the assumption of the existence ofa non reversible work in the system and the use of the thermodynamicjump formulation to model the phase change process in order to predictphase velocity and mass flow. The obtained results have a goodagreement with the experimental data available.