Model Based Assessment of Sediment Effects on Hydropower Turbines

Abstract

This thesis presents the application of four erosion models (Bajracharya, Boes et al., Liu Lu & Zhu, and Padhy & Saini) developed by researchers for estimating the erosion rate of critical turbine components of hydro power plants (HPP). Two case studies were selected for the application of the models: HPP Fieschertal in Switzerland, and HPP Khimti in Nepal. Each of the models were broken down and the methodology and procedure of the studies or experiments that each model based on were thoroughly discussed. The models were then fed with the data of the case studies and the estimated erosion rates were obtained. For Bajracharya’s model, the erosion rate of the average median particle diameter and extreme median particle diameter had to be matched together to come close to the measured erosion rate. Boes’ model made overestimations of the erosion rates of the two projects because its variables and assumptions were specifically developed based on HPP Doferbach. Liu, Lu and Zhu’s model made average erosion rate and extreme erosion rate estimations. The real measured erosion rate was within that range. Finally, Padhy & Saini’s model was the closest to match one the measured values. It’s erosion rate estimation for HPP Khimti comes remarkably close. The models assume fixed, linear conditions and cannot adapt to real-time variations such as floods or glacial events. They also fail to account for downtime and maintenance, limiting their practical application. Future research should focus on standardizing model outputs and developing dynamic erosion models that incorporate both normal operations and extreme sediment events.

Date of Award	2025
Original language	English
Supervisor	Lorenz Neururer (Supervisor)