Sophisticated models to predict the erosion process in turbine blades exposed to dust laden gas stream quickly become complex and tedious for use for everyday engineering applications. A simpler model for primary erosion can be formulated by assimilating the blade row to a device having a certain size and deflecting the stream through a given angle and at a given rate. The technology which exists for particle impacts physics with bluff bodies can be adapted to cascades. Thus, basically the model is derived from first principles.
This approach is formulated in a quantitative manner in terms of cascade parameters, gas properties, and particulate parameters. The result is a simple equation which is easy to use and the physics of which are logical and intuitively reasonable. Its predictive ability, however, is limited to the frequency of impacts and the strength of the impacts. It does not address the mechanics of the impact process or the properties of the material being impacted. These variables are introduced through an experimental coefficient which, as it turns out, is the only experimental input in the analysis.
The method is tested against quite a few experimental cases with a degree of predictive ability which is acceptable in a simple, first order method. The agreement is thought to be at least as good as the credibility or accuracy of the test data. The method is finally applied to study the effects of various blade cascade parameters on erosion resistance, the results of which are presented in the form of general curves.