Water erosion resistant surface treatments

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Injecting water to cool the air in the compressor hence increasing the power output of the gas turbines is a common practice. Repeated impacts of water droplets maycause significant erosion along the leading edges of the airfoils resulting not onlyin performance degradation but also in potential for high-cycle fatigue failure of the airfoils due to aerodynamic instability. Consequently, there is a need to develop a more water erosion resistant compressor blades. This project will include the studyof water erosion mechanism of different materials, development of coatings resistant to water erosion, characterization and testing of these coatings. It will also include modeling of the water impingement phenomenon. Different sizes of water droplets provide various kinetic energywhile locally hitting the surface, thus protective coatings should be hard, tough and provide the hydrophobic effect. Various coatings will be studied including hard nanostructure ceramic and hydrophobic coatings. The microstructure, mechanical and functional properties of the developed coatings will be studied. This will include the investigation of the effect of substrate conditions (i.e. microstructure, texture and residual stresses) on the microstructure, properties and erosion resistance of the resulting coating/surface treatment. Testing of erosion resistance will be performed on a special rig designed as per ASTM G73-04 standard (Standard Practice for Liquid Impingement Erosion Testing) and adjusted to simulate the operating conditions inside the compressor. Inthis test rig, it will be possible to determine the resistance to erosion or other damage of the materials and coatings/surface treatments; to investigate the damage mechanisms and how theyare influenced bythe size, velocityand frequencyof water droplets. In this way, we will be able to studya possible interaction between water erosion behaviour and dynamic mechanical properties of the blades materials.