Background

Accurate numerical simulations of hydraulic turbines are challenging, time consuming and demand large computational resources. There is a need for optimizing the numerical techniques/procedures. The Francis-99 workshop series provides an open platform to industrial and academic researchers to enhance their capability in computational fluid dynamic techniques applied to simulate the hydraulic turbines.
The second workshop of Francis-99 will continue with the same spirit as the first workshop. Detailed experimental studies have been conducted at different operating conditions. In addition, some experiments based on input received from the participant of the first workshop have been conducted. Both, steady state and transient, measurements are performed. Three steady state operating points are investigated: part load, best efficiency point, and high load. For the transient conditions, load variation and start-stop are investigated. Both pressure and velocity measurements are available for the detailed validation and investigation of the numerical model.

Scope of the workshop

The second Francis-99 workshop is a continuation of the first workshop with additional challenges. It aims to further determine the state of the art in simulation of the Tokke model under steady state and transient operating conditions. Transient operation of the hydraulic turbines is increasing with the apparition of renewable energies, affecting significantly their life¹. The motivations are multiple and reside in the availability of more powerful computers allowing the use of more advance turbulence models and accurate numerical schemes. Methods allowing uncertainty quantification of the simulations as well as faster result such as non-linear harmonic decomposition are appearing and need to be assessed.
The numerical results will be compared to time dependent experimental pressure and velocity measurements. Experimental data of pressure and velocity measurements are available on the website. Comparison of the experimental and numerical results will be performed by the participants themselves.

The organisers expect from the participants to investigate one or several of the following topics with the provided numerical model (Tokke geometry):

1. Steady state operation simulation (numerical and modelling influence).
2. Transient operation simulation (numerical and modelling influence).
3. Rotor-stator interaction, influence of the operating conditions.
4. Rotating vortex rope simulation.
5. Uncertainty quantification in numerical simulation.

Other topics of interest involving simulation of the Tokke model may be suggested. An abstract should be submitted, see “Important dates”. There will be a peer review process of the papers submitted to the workshop allowing publication in Energia Procedia.

Acknowledgement

The workshop organizers would like to acknowledge the contribution made by Rémi Lestriez (NUMIBERICA) for providing the mesh; Jean-David Buron (Laval University, Canada) and Einar Agnalt (NTNU) for creating geometry of the Francis turbine and providing in different format; Jonathan Nicolle (Hydro-Québec, Canada) and Sebastien Houde (Laval University, Canada) for necessary valuable input during the geometry and mesh creation; Professor Håkan Nilsson (Chalmers University of Technology, Sweden) for his valuable inputs during OpenFOAM compatible mesh creation.

¹Trivedi, C., Gandhi, B., and Cervantes, M., 2013, "Effect of transients on Francis turbine runner life: A review," J Hydraul Res, 51(2), pp. 121-132. doi: 10.1080/00221686.2012.732971.

Disclaimer: The provided data, geometry and mesh under Francis-99 workshop series are free for research and education. Upon the usage of the data and the geometry, acknowledgement must be given. “We/I used the test-case provided by NTNU – Norwegian University of Science and Technology under the Francis-99 workshop series.”

Coordinating committee

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