Low-frequency oscillations in hydroturbines caused by cavitation together with the phase transitions effects

Among the unsteady phenomena taking place in hydroturbines one can separate oscillations caused by a cavitation bubble behind the runner. Usually a concept of cavitation compliance is used to model the cavity pulsations (Chen et al.). There was demonstrated the destabilizing effect of the diffuser and swirl. Kuibin et al. had found that the effect of swirl on stability is much smaller than that described by Chen et al. In the present work, the same analysis is repeated, but taking into account influence of the evaporation and condensation on dynamics of the cavity appearing in the draft tube. During analysis a simplified spherical cavity form was considered.