Abstract: Through a period operation, due to scaling, corrosion and erosion by solid particles, the surface of flow passage of steam turbine will change from smooth to rough, and the power and the efficiency of various stages of flow passage of steam turbine will be impacted. The factors causing the surface of turbine flow passage to become rough were introduced. The variation process of the surface roughness of the turbine flow passage caused by these factors was expounded, and the mechanism of the performance deterioration of turbine flow passage caused by the rough surface was described. Combining with practical example, the influence of surface roughness on performance of flow passage of the turbine was analyzed.

Key words: flow passage, surface roughness, scaling, corrosion, erosion by solid particles