{"id":2160,"date":"2026-09-10T11:25:10","date_gmt":"2026-09-10T11:25:10","guid":{"rendered":"https:\/\/hydroalpslab.ch\/?post_type=projets&p=2160"},"modified":"2026-09-10T11:28:38","modified_gmt":"2026-09-10T11:28:38","slug":"tips-for-better-predicting-transient-loads-on-hydroelectric-turbines","status":"publish","type":"projets","link":"https:\/\/hydroalpslab.ch\/en\/projets\/tips-mieux-predire-les-sollicitations-transitoires-des-machines-hydroelectriques\/","title":{"rendered":"TIPS \u2013 Better prediction of transient loads on hydroelectric turbines"},"content":{"rendered":"

Research project supported by the Federal Office of Energy<\/strong><\/p>\n\n\n\n

The increasing integration of wind and solar power into the electricity system is heightening the need for flexibility. Thanks to their ability to adjust their output rapidly, hydroelectric power stations play a vital role in balancing the grid.<\/p>\n\n\n\n

However, this increased flexibility entails much more frequent starts, stops and changes in load<\/strong>. These transitional operating modes place significant hydraulic and mechanical stresses on the wheels, shafts, valves and other machine components. The TIPS report therefore points out that the number of start-stop cycles can rise from just a few cycles per year in a conventional operation to several hundred, or even more, in a highly flexible operation.<\/p>\n\n\n\n

Being able to predict these stresses accurately is therefore essential for reconciling flexibility of the electricity system and the service life of hydroelectric power stations<\/strong>.<\/p>\n\n\n\n

Simulate both the machine and the entire hydraulic circuit simultaneously<\/h3>\n\n\n\n

During a transient event, the hydraulic machine cannot be considered in isolation from its environment. Variations in flow rate and pressure generated in the turbine propagate through the pipework, whilst the response of the hydraulic circuit in turn influences the flow within the machine.<\/p>\n\n\n\n

The TIPS project aims to model this interaction by combining two complementary numerical approaches:<\/p>\n\n\n\n

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  • SIMSEN<\/strong>, which enables the pipes, tanks and hydroacoustic phenomena of the entire development to be represented effectively in 1D; ;<\/li>\n\n\n\n
  • ANSYS CFX<\/strong>, used in 3D in areas where a detailed description of the flow is required, particularly inside the turbine.<\/li>\n<\/ul>\n\n\n\n

    The two models exchange their hydraulic conditions during the calculation using a method of 1D\u20133D co-simulation<\/strong>. The aim is to maintain the accuracy of CFD within the machine whilst avoiding the prohibitive cost of a three-dimensional simulation of the entire hydraulic circuit.<\/p>\n\n\n\n

    This project is funding Mathieu Mettille\u2019s PhD thesis.<\/p>\n\n\n\n

    A methodology that has been progressively validated<\/h3>\n\n\n\n

    Development is carried out in stages, progressing from a well-understood academic case study to real-world hydroelectric turbines.<\/p>\n\n\n\n

    The first phase is based on flow around a semi-cylinder placed within a pipe. The periodic detachment of vortices generates fluctuations capable of exciting the natural frequencies of the hydraulic system. This scenario thus allows for a controlled study of the phenomena of hydroacoustic resonance<\/strong>, with or without cavitation.<\/p>\n\n\n\n

    The results show that the co-simulation accurately reproduces the resonance mechanism. In non-cavitation conditions, the configuration combining 1D\u20133D coupling and the SAS-SST turbulence model provides the best agreement with the experimental measurements.<\/p>\n\n\n\n