From the 21st until the 25th of November of 2022, the UPC team formed by Rafel Roig, Xavier Sánchez and Xavier Escaler visited the Porjus U9 prototype in Sweden. Together with the supervision of Pontus Jonsson, they took advantage of the turbine being empty of water to perform an experimental modal analysis to determine the modes of vibration of the shaft and the runner blades when the structure is non-rotating in air. For that, several impacts were performed radially, tangentially and axially on the hub, the shaft and the blades. The structural response was monitored using some accelerometers placed on the blades and along the shaft.The collected data will be used to validate the numerical models developed in the WP3 of the AFC4Hydro project, which will allow us to determine the turbine modal response as well as its dynamic behaviour induced by the pulsating loads exerted by the draft tube flow. These results will be analysed and presented in the report of the dynamic responses of the model and prototype turbines, which is related to Task 3.2.
