Modeling the accumulation of erosion damage to materials during the incubation period of droplet impact wear using a Markov chain

The droplet impact effect from the two-phase flows of the working fluid and the erosive wear of the hard surfaces of structural elements caused by it is observed during the operation of various critical equipment — steam and wet-steam turbines, space and aircraft power plants, wet steam pipelines, etc. The kinetics of material loss from the surface of eroding elements is characterized by irregularity and the presence of several distinct wear stages. Of practical interest is predicting the initial stage of erosive wear, the incubation period, during which a cumulative buildup of fatigue damage occurs in the microstructure of the material in the surface layer of structural elements, without visible material removal. The duration of the incubation period largely determines the further kinetics of droplet impact wear, in particular, the intensity of wear during periods of maximum and steady-state material loss. The article presents a technique for modeling the accumulation of erosive damage in the material of the surface layer of structural elements during the incubation period. The method takes into account the probabilistic nature of the phenomenon being studied. To do this, the process of damage accumulation is modeled using the Markov chain. This technique also allows for predicting the duration of the erosion wear incubation period in a probabilistic manner, taking into account the operating mode of the equipment and quantitative parameters of drop impact.