Rotating Disc Apparatus (RDA) for Estimation of Erosion in Micro Crossflow Hydro Turbines

Abstract

Several research studies have been conducted on the development of erosion-resistant alloys, coatings, and optimized hydraulic design of components to overcome sediment erosion-induced problems in hydro turbines. This research work has attempted to investigate the erosion wear on CFT blades made up of different materials and coatings, using a modified version of Rotating Disc Apparatus (RDA). The main consideration in designing the RDA is to accelerate the rotating speed and the relative velocity to achieve rapid erosion results. The materials of blades used for the experiment were SUS304, SUS440C, SUS630, SCM440, and STD11. These test specimens were exposed to a high sediment concentration of 127000 ppm. From the calculated amount of erosion and erosion rate data that the rate of erosion exhibits a strong relationship to characteristics of the material, such as mechanical and chemical properties. The estimation further suggests that the coated specimens follow a similar trend as of the parent materials’ erosion rate with an increase in the time of exposure to erosion. The numerical study was used to compare hydrodynamic flow visualization in an RDA and CFT turbine. RDA establish a similar velocity pattern and pressure along the surfaces of specimen nonetheless vortex is formed between them.