Modeling of water droplets erosion on a subsonic compressor cascade

In this paper an analysis of the erosion mechanism of water droplets impacting a compressor blade is performed. Three different models are compared: the Springer et al. model, developed in 1974 for predicting rain erosion on wind turbine blades; a new model developed by the authors to predict water droplet erosion on stainless steel surfaces and Tabakoff et al. (1979) model for solid particle erosion. This last model was included in the comparison because in commercial CFD codes a specific model for water erosion is commonly not implemented, and one may be tempted to consider this phenomenon similar to that of solid particle erosion. 50 μm droplets/particles are injected at the inlet of a compressor blade, and erosion predictions are then compared. The results show that while all the tested models provide correct information about the impact sites and accumulated energy, they differ greatly when talking about eroded material and only the new model here proposed returns result in agreement with the industrial evidences. In such kind of application, Springer et al. and Tabakoff et al. models can be only used for qualitative considerations, but their quantitative predictions are quite unrealistic, greatly overpredicting the eroded thickness.