Numerical Method for Wet-Steam Flows with Polydispersed Droplet Spectra

The present work provides a numerical method for the simulation of wet-steam flows with polydispersed spectra. The so-called moment method is used to represent the liquid droplet evolution. This approach is based on a partial modeling of the droplet size dis- tribution, through the resolution of transport equations for the lowest-order moments of the droplet spectrum, which allows evaluating the wetness fraction and the mean radius of the droplets. These transport equations are coupled with the Euler equations that govern the motion of the two-phase mixture. Several equations of state are adopted to model the thermodynamic behavior of the vapor phase. The system of the governing equations is solved through an uncoupled procedure: the main equations for the mixture are solved first, then the main flow properties are frozen and used to solve the additional equations. All of the equations are discretized by means of a third-order accurate centered scheme.