Modeling Activities on Cavitating Flows at Centrospazio

The present paper illustrates recent theoretical and numerical activities on cavitating flows carried out at CENTROSPAZIO in the last few years. Specifically, it deals with the development and application of a modified isenthalpic cavitation model that accounts in an approximate but physical way for the occurrence of thermal cavitation effects and the concentration of active cavitation nuclei in the liquid. Expanding on the work of Brennen (1994), the model leads to a quasi-homogeneous barotropic description of cavitating flows, whose sound speed smoothly reduces to that of the liquid in the limit for low void fractions, thus eliminating the inconsistencies of previous formulations. Thermal effects are accounted for by assigning a single parameter expressing the nondimensional thickness of the thermal boundary layer in the liquid surrounding the growing cavities. The value of this parameter is related to the concentration of active cavitation nuclei, whose value can therefore be alternatively used to specify the impact of thermal cavitation effects. Applications to cavitating journal bearings, hydrofoils and helical inducers relevant to space engineering are presented.