MechE Seminar: Understanding the fatigue-induced damage in hydraulic machines to secure their flexible operation
Event details
| Date | 06.07.2023 |
| Hour | 09:00 › 10:00 |
| Speaker | Dr. Elena Vagnoni, Technology Platform for Hydraulic Machines, EPFL |
| Location | Online |
| Category | Conferences - Seminars |
| Event Language | English |
Abstract: The increasing flexibility needs of modern power systems represent a major concern for the safe operation of hydropower assets. Extended operating ranges and frequent start-ups and stops are direct consequences of enhanced provision of regulating services to the power grid and the main cause of performance degradation, lifetime reduction and failures that common practices cannot predict. To overcome this hurdle, the seminar discusses how to assess the mechanical stresses leading to fatigue in Francis and Pelton runners through experimental investigations employing strain gauges measurements on reduced-scale models. These measurements are leveraged to develop a predictive method of the fatigue-induced damage considering the full operating range of the hydraulic machine, as well as severe transients’ operations such as the start-up sequence. Since the mechanical stresses’ distribution is inherent to the geometrical properties of the hydraulic machine, two different methodologies are developed: a physics-informed neural network for Francis-type runners, and a reduced-order analytical model for Pelton runners. The forecasts of both predictive models show a good agreement with the experimental measurements representing a leap in predictively understanding the mechanical stresses leading to fatigue-induced damage. Furthermore, the seminar shows how to formulate a complex optimization problem to define the optimal start-up trajectory that minimizes the fatigue-induce damage cost, while preserving a fast response-time of the hydraulic machine. The findings show that the start-up-induced fatigue in both hydraulic machines can be significantly reduced. As an example, variable-speed Francis turbines can experience a runner fatigue reduction of almost 90% by defining a start-up trajectory that avoids operating conditions causing higher stresses on the runner blades.
Biography: Dr. Elena Vagnoni is currently the head of the research projects group at EPFL Technology Platform for Hydraulic Machines and lecturer for the EPFL Mechanical Engineering Section. Her research interests focus on the experimental investigation, numerical simulation and predictive modelling of the hydraulic machines behaviour to improve the hydroelectric units’ exploitation in conventional and unconventional hydropower schemes.
She graduated with honours in Mechanical Engineering from the Politecnico of Milan (Italy) in 2013, and she obtained her Ph.D. in Mechanics at EPFL in 2018. Before her current position, she was a research assistant fellow at Johns Hopkins University (US), a postdoctoral researcher at EPFL, and a SNSF-fellow guest scientist at NTNU (Norway). She is the Swiss expert for the Annex IX of the International Energy Agency (IEA) Hydropower Technology Cooperation Programme and Vice-Coordinator of the European Energy Research Association (EERA) joint program Hydropower.
Biography: Dr. Elena Vagnoni is currently the head of the research projects group at EPFL Technology Platform for Hydraulic Machines and lecturer for the EPFL Mechanical Engineering Section. Her research interests focus on the experimental investigation, numerical simulation and predictive modelling of the hydraulic machines behaviour to improve the hydroelectric units’ exploitation in conventional and unconventional hydropower schemes.
She graduated with honours in Mechanical Engineering from the Politecnico of Milan (Italy) in 2013, and she obtained her Ph.D. in Mechanics at EPFL in 2018. Before her current position, she was a research assistant fellow at Johns Hopkins University (US), a postdoctoral researcher at EPFL, and a SNSF-fellow guest scientist at NTNU (Norway). She is the Swiss expert for the Annex IX of the International Energy Agency (IEA) Hydropower Technology Cooperation Programme and Vice-Coordinator of the European Energy Research Association (EERA) joint program Hydropower.
Practical information
- General public
- Free