Optimization of Francis turbine runner and guide vanes for minimizing sediment erosion

PhD Candidate

Ram Lama (ram.lama@student.ku.edu.np)

Supervisors / Advisors

Prof. Hari Prasad Neopane

Dr. Biraj Singh Thapa

Project

EnergizeNepal

Objectives

1. To study and understand the existing design of 92kW Francis turbine at TTL

2. To compare the numerical and experimental results of existing 92kW Francis turbine

3. To propose an optimized design of runner for sediment handling

Summary

Francis turbine are ideal turbines for Himalayan and Andes region where both low and high-altitude mountains are located. Turbines operating in such regions face operational and maintenance problems due to the sediment erosion. In order to reduce the erosion effects on these components the design of components for higher sediment handling is essence. Therefore, this study focuses on proposing an optimized design of Francis runner having higher sediment handling capacity. Besides that validation of CFD is a great challenge for researcher. The validation of CFD results will be done by comparing these results experimental results. The 92kW Francis turbine test rig has been successfully installed at turbine testing Lab for conducting experiments. The experiments on model Francis runner (92kW), a scaled down model of Jhimruk Hydropower Plant of Nepal is on progress. Efficiency measurements at different operating conditions will be noted during experimentation. Numerical hill chart for model turbine has been developed for comparison. In order to propose an optimized design, apart from the conventional efficiency hill chart diagram, this study focuses on the development of a hill diagram of percentile sediment erosion rate density PSERD, such that the prediction of the erosion in turbines can be done similar to the efficiency. Introduction of such PSERD hill diagrams could be a standard mean for the design optimization of turbines in sediment laden water.