Identification of Silt Erosion Areas on Francis Turbine Guide Vanes Through Numerical Simulation

Abstract

Hydro power plants in Himalayan region are severely affected by silt erosion and cavitation, and their combined effect, as both of these factors complement each other. The problem of silt erosion is acutely felt during monsoon season of the year, as silt laden water with high silt concentration, enters the turbine. Many researchers have reported the reduction in turbine hydraulic efficiency due to silt erosion in guides and runner vanes. In addition, the erosion in the blades also increases the maintenance cost and downtime period. The present work includes a numerical simulation to investigate the sediment erosion on guide vane. The numerical simulation has been carried out on Fluent software. The k-ω turbulent model has been applied to a 3-D model of NACA4412 blade profile. The simulations have been performed at an angle of attack equal to 20o for the range of water velocity 5–20 m/s and for silt concentration varying from 1000 to 4000 ppm. In all the cases considered in this study, the results shows a significant erosion at the leading edge followed by sparse erosion on the bottom side of the guide vane. The study will act as a precursor for experimental studies in the future. Accurate identification of erosion regions in turbines will help mitigate the problem easily.