Numerical study of flow phenomena and erosion in three guide vane cascade rig

Abstract

The rivers in certain geological regions like South Asia have sediment particles in them. These particles cause erosion in turbine components which is a major cause of deterioration of turbine and hampers efficient energy production. Out of different modes of erosion in Francis turbines, past studies have shown that erosion is prominent in its guide vanes. Its criticality stems from the ability of eroded guide vane can disturb the flow that reaches the runner and cause erosion in the runner inlet. Numerical study is widely used to study erosion. However, their inability to evolve the geometry with the advent of erosion limits their use. The study uses a three-guide vane cascade geometry, modeled after Jhimruk HPP, to conduct the flow analysis and erosion study. In this study, a RANS-based SST turbulence model has been applied for the flow along with sediments modelled as particles carried by the fluid. The erosion study used the Finnie erosion model to visualize how the erosion occurs in the guide vane. A new framework has been developed that interprets the mathematical values of erosion into the corresponding geometrical changes. Additionally, the study has observed the flow-patterns disruption due to the erosion of the guide vane. This offers a comprehensive overview of the flow in guide vanes cascade and erosion in the guide vanes.