Section: New Results

Two-phase flow numerical simulation with real-gas effects and occurrence of rarefaction shock waves

Participants : Maria Giovanna Rodio, Pietro Marco Congedo [Corresponding member] .

A discrete equation method (DEM) for the simulation of compressible multiphase flows including real-gas effects has been developed. A reduced five equation model is obtained starting from the semi-discrete numerical approximation of the two-phase model. A simple procedure is then proposed for using a more complex equation of state, thus improving the quality of the numerical prediction. Classical test-cases well-known in literature are performed featuring a strong importance of thermodynamic complexity for a good prediction of temperature evolution. Finally, a computational study on the occurrence of rarefaction shock waves (RSW) in a two-phase shock tube is presented, with dense vapors of complex organic fluids. Since previous studies have shown that a RSW is relatively weak in a single-phase (vapor) configuration, its occurrence and intensity are investigated considering the influence of the initial volume fraction, initial conditions and the thermodynamic model [11] . A transition modelling has been also introduced for considering heat and mass transfer terms. In this way, metastable states have been simulated in cavitating flows Finally, a semi-intrusive stochastic technique has been formulated for taking into account uncertainties in the simulation of metastable states.

External contributors. This work has benefitted from the collaboration with the University of Zurich, and in particular with R. Abgrall.