Rakish Shrestha ^1,2 Kushal Shrestha ^1,2* Sailesh Chitrakar ^1,2 Hari Prasad Neopane ¹ Bhola Thapa ¹ Zhongdong Qian ² Zhiwei Guo ²

• ¹ Kathmandu University, Dhulikhel, Nepal
• ² Wuhan University, Wuhan, Hubei Province, China

Guide Vanes (GVs) are one of the most vulnerable components of the Francis turbine due to sediment erosion. High sediment concentration containing hard minerals including quartz and feldspar cause erosion on different parts of the Guide Vane such as the leading edge, trailing edge, clearance gap and facing plates. This results in damage and disturbances in the functioning of the turbine. CFD methods have been used to predict the erosion in turbines. The three-guide vane cascade rig setup allows for the investigation of fluid flow and pressure distribution with the angle of attack and pressure as control parameters. In this study, a RANS-based SST turbulence model has been used for a three-guide vane cascade rig. A Eulerian-Lagrangian approach has been used to facilitate multiphase flow. The erosion caused by the sediment-laden flow has been quantified and visualized by employing Finnie, Nandakumar, Oka, and Tabakoff and Grant erosion models. This study has been conducted to determine which of the erosion models predict the erosion pattern closer to the real case of eroded Guide Vane of Jhimruk Hydropower plant. Less severe erosion in the leading-edge area and severe erosion in the following edge of the suction side were predicted by Finnie model more precisely than the leading-edge suction side. Finnie erosion model could correctly predict at three different locations which are SS-TE, SS-LE and MS-LE. The severity and area affected due to erosion as predicted by Finnie erosion model was found to most closely match the erosion observed in guide vane clearance gap of real hydropower plant.