Numerical simulation Kaplan turbine Speed-No-Load
Title: Numerical simulation Kaplan turbine Speed-No-Load
DNr: NAISS 2023/22-1066
Project Type: NAISS Small Compute
Principal Investigator: Jelle Kranenbarg <>
Affiliation: Luleå tekniska universitet
Duration: 2023-10-12 – 2024-05-01
Classification: 20306


Hydraulic turbines are operated away from their design point more frequently as intermittent energy resources gain popularity. Some turbines are required to maintain a spinning reserve, also known as the speed-no-load operating condition, to rapidly respond to power shortages on the electrical grid. The flow inside the turbine is highly turbulent and chaotic and often associated with large pumping regions and vortices extending from the draft tube, past the runner, to the vaneless space. These vortices introduce detrimental pressure pulsations, which are harmful to the turbine. The current project aims to numerically investigate the formation and impact of the vortices during the speed-no-load operating condition of an axial turbine (the U9 model in Älvkarleby at Vattenfall R&D). Until now, the simulations have been run on a desktop with 36 cores and a part of a small cluster at LTU (with a similar number of cores). Utilizing the HPC will allow us to increase the total simulation time significantly, use a smaller timestep, and run more advanced turbulence models. All will help to better understand the development of the vortices and their impact on the runner over time. The learnings will be used to further design and improve a mitigation technique using individual control of the guide vanes.