Numerical investigation of effects polydispersed droplets on the erosion rate and condensation loss in the wet steam flow in the turbine blade cascade

The condensation phenomenon in the steam turbines creates a complex spectrum of droplet size. As known, the droplet size distribution can provide important information for steam turbine designers. In simulations, droplets radius are often modeled in the monodispersed model. One size of droplet radius is reported at each location in this model. In the presented study, a new method is presented for grouping droplets into polydispersed model and comparing with monodispersed model. The nucleation zone is geographically divided into 20 parts. The droplets are produced and create a group from the nucleation phenomenon at each part. The results indicate that the droplets that are produced at the beginning of the nucleation zone have the largest size. Also, other droplets that are produced at the end of the nucleation zone have the smallest size. The droplets that are produced at maximum nucleation rate have the greatest effect on erosion rate and condensation loss. The average droplet radius in the polydispersed model is smaller than the monodispersed model. In the proposed method, it is improved 49%.