2-PHASE RELEASES

Two-phase releases can occur through many different types of breaches, such as wall cracks, orifices, short or long pipes, or piping systems . They include subcooled liquids which flash during their expansion, s aturated vapours or two-component flows. No general correlation or mod el is available to predict choked two-phase flows in such a wide varie ty of situations. On the contrary, many different models or correlatio ns exist, each having been validated on a particular set of data. In a n attempt to help the user find his way through this complex subject, this paper presents the rationale behind the development of models. Se veral particular critical flow models are described, in the developmen t of which the author has been involved during the past 20 years, and the basic assumptions and equations as well as the validation studies are reported.