High Head Francis - HiFrancis
The Norwegian topography has enabled the development of high head power plants, many of which exceed 300-meter head. About 30% of all Francis turbines installed in such plants are located in Norway. Due to its national relevance and competence export potential, it is important for the Norwegian hydropower industry to maintain and develop its competence in this field. HiFrancis was born out of the need for further knowledge regarding a series of Francis turbine failures in the national grid. In the current market, turbines are operating at off-design operational conditions, and the industry is facing problems with both newly installed and old Francis units. The main problem is crack formation in the turbine runner, caused by pressure fluctuations. Computational Fluid-Structure Interaction (FSI) analysis are required to analyze the detrimental effect on the turbines. These are inherently complex and require huge amounts of CPU-time. As a conclusion from previous work, main challenges facing such analysis originates from the natural frequency of the runner and the fluid properties of existing pressure oscillations. Without tools for performing trustworthy FSI analysis, modifying high-pressure plants to for future use becomes risky and challenging. The following knowledge is required to develop tomorrow's high head Francis turbines:
1. Generic parameters needed for a FSI-analysis
2. Understanding fatigue loads during all states of operation.
This will be achieved by 4 work packages where the main challenge in the research process will be to conduct the laboratory tests with sufficient quality for use as verification of numerical tools. These measurements include:
1. Pressure propagation speed and dampening
2. Natural frequencies of a turbine in operation
3. Velocities and pressure oscillations in a model turbine
4. Material stresses inside a runner
Partners from turbine manufacturers, utility companies and consultants will assist the proposed tests and studies.
The primary objective is secure reliable operation and lifetime for high head Francis turbines operating in the future energy market.
1. Determine how water parameters such as vapour and gas content influences the pressure propagation speed and the damping of pressure oscillation in high head Francis turbine components such as a guide vane cascade and in a Francis model turbine.
2. Determine how the water parameters and velocity field impacts the dynamic coupling between fluid and structure for a high head Francis turbine. This includes impact of the water on the natural frequency but may also include new coupled modes as well as change in the modal response.
3. Evaluation of fatigue loads of a high head Francis turbine during steady state and transient operation.
4.Ensure that the project outcome is in line with the industry's best interest and optimize theindustrial value through innovative usage of the project results.
This project is supported by:
In addition to this, the companies below has supported the project with an in-kind contribution:
Kickoff meeting 2.March 2016
The HiFrancis kickoff meeting 2.March 2016 was a success. All partner were present and the project work has started.