Author(s): J. Schmid; C. Bussard; C. Nicolet; S. Forest; S. Stojanovic-Roth; J.N. Saugy

Linked Author(s): Christophe Nicolet

Keywords: No Keywords

Abstract: The Swiss hydroelectricity sector faces challenges under Energy Strategy 2050. The HydroLEAP project aim to address these challenges by improving technology and optimizing performance. This paper focuses on the Ernen run-of-river power plant, a demonstrator of the HydroLEAP project. This power plant includes two double-flow horizontal axis Francis turbines of 16 MW operated under a gross head of 270 mWC which are equipped with Pressure-Relief-Valves, PRV. Since this power plant is subject to a future integration of a new Pelton turbine, detailed hydraulic transient calculation is necessary to validate that the capacity increase is compatible with the integrity of the existing penstock. The first step requires validation and calibration of the 1D SIMSEN model of the existing power plant, with particular attention dedicated to the PRV parameters to replicate transient tests measurements performed at site. During the calibration, discrepancies in the PRV discharge characteristic indicated potential functional irregularities, possibly due to cavitation or restricted flow. To validate these hypotheses, 3D CFD simulation was conducted, providing an analysis of the PRV's 3D steady state flow under specific operational conditions. The 3D CFD analysis results closely correlated with the findings from the 1D optimization, revealing critical insights into the physical phenomena affecting PRV performance. The CFD study enabled to identify cavitation zones and flow restrictions as factors contributing to the irregular discharge characteristics, confirming the hypotheses generated during the 1D modeling phase. The findings underscore the importance of integrating multi-dimensional modeling approaches to address challenges in modern hydropower systems.

DOI: https://doi.org/10.1088/1755-1315/1561/1/012033

Year: 2025