Sediment erosion in Francis turbines
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Sediment erosion is a major challenge for run-of-river power plants, especially during flood periods. Due to the high content of hard minerals such as quartz and feldspar carried in the river, substantial damage is observed on the turbine components. Material is gradually removed, thus the efficiency of the turbine decreases and the operating time of the turbine reduces. Hydro power plants situated in areas with high sediment concentration suffer under hard conditions, where turbine components could be worn out after only a short period of three months. This short life expectation causes trouble for energy production since the replacement of new turbine parts is a time consuming and costly procedure. It is desirable to design a Francis runner which will withstand sediment erosion better than the traditional designs. The literature states that an expression for erosion is velocity to the power of three. By reducing the relative velocities in the runner by 10%, the erosion will decrease almost 30%. The objective is to improve the design of a Francis turbine which operates in rivers with high sediment concentration, by looking at the design parameters in order to reduce erosion wear. A Francis turbine design tool was developed to accomplish the parameter study. In the search for an optimized Francis runner, several design proposals were compared against a reference design by evaluating the turbine’s performance. The hydraulic flow conditions and the prediction of erosion on the turbine components are simulated by analyzing the models with a Computational Fluid Dynamic (CFD) tool. A Fluid Structure Interaction (FSI) analysis ensures that the structural integrity of the design is within a desired value. Results from this research show that it is feasible to design a runner with an extended lifetime, without affecting the main dimensions and hydraulic efficiency.
Består avEltvik, Mette; Dahlhaug, Ole Gunnar; Neopane, Hari Prasad. Prediction of Sediment Erosion in Francis Turbines. Proceedings of the 4 th International Meeting on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, 2011.
Eltvik, Mette; Dahlhaug, Ole Gunnar; Nielsen, Torbjørn. Numerical analysis of Francis runners exposed to sediment erosion. .
Eltvik, Mette; Nielsen, Torbjørn; Dahlhaug, Ole Gunnar. Hydraulic design of a Francis runner exposed to sediment erosion. .
Neopane, Hari Prasad; Dahlhaug, Ole Gunnar; Eltvik, Mette. NUMERICAL PREDICTION OF PARTICLE SHAPE FACTOR EFFECT ON SEDIMENT EROSION IN FRANCIS TURBINE BLADES. Hydropower’10, 2010.
Thapa, Biraj Singh; Eltvik, Mette; Dahlhaug, Ole Gunnar; Thapa, Bhola; Gjøsæter, Kristine. Effects of turbine design parameters on sediment erosion of Francis runner. Proceedings of the 2nd International Conference on the Developments in Renewable Energy Technology: 1-5, 2012.
Thapa, Biraj Singh; Dahlhaug, Ole Gunnar; Eltvik, Mette; Thapa, Bhola; Gjøsæter, Kristine. Design Optimization of Francis Runners for Sediment Handling. Proceedings of the Fourth International Conference on Water Resources and Renewable Energy Development in Asia, 2012.
Thapa, Biraj Singh; Thapa, Bhola; Eltvik, Mette; Dahlhaug, Ole Gunnar; Gjøsæter, Kristine. Optimizing runner blade profile of Francis turbine to minimize sediment erosion. Proceedings of The 26th IAHR Symposium on Hydraulic Machinery and Systems: Paper Number:-IAHRXXVI-071, 2012.