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Sensitivity analysi...
Sensitivity analysis of a swirling flow to the GEKO model
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- Kranenbarg, Jelle (författare)
- Luleå tekniska universitet,Strömningslära och experimentell mekanik
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- Jonsson, P. P. (författare)
- Vattenfall AB, R&D, Sweden
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- Mulu, B. G. (författare)
- Vattenfall AB, R&D, Sweden
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- Cervantes, Michel J. (författare)
- Luleå tekniska universitet,Strömningslära och experimentell mekanik
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(creator_code:org_t)
- Institute of Physics Publishing (IOPP), 2022
- 2022
- Engelska.
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Ingår i: 31st IAHR Symposium on Hydraulic Machinery and Systems 26/06/2022 - 01/07/2022 Trondheim, Norway. - : Institute of Physics Publishing (IOPP).
- Relaterad länk:
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https://doi.org/10.1...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Accurate numerical models for hydraulic turbine applications are highly coveted. They must be able to correctly capture the swirling flow found at off-design operating conditions in the turbine draft tube. The GEKO model is a relatively fast and flexible eddy viscosity turbulence model with adjustable coefficients to tune the model to different flow scenarios. In this study, the GEKO model is tested on a swirling flow inside a diffusor similar to the flow conditions found at part-load operation of a propeller turbine. The diffusor investigated corresponds to the Porjus U9 draft tube cone section, including the runner cone. Results showed that the near-wall coefficient, with a value of 2, increased the wall shear stress and moved the separation point from the runner cone further downstream. Moreover, with a value of 0.7, the separation coefficient increased the eddy viscosity, which also moved the separation point from the runner cone further downstream. Both coefficients gave velocity profiles closer to experimental values and increased the swirl number at the outlet of the diffusor by up to 36.9 % compared to the GEKO default model. Overall, the near-wall coefficient with a value of 2 gave the best results. The GEKO model provides an opportunity to tweak numerical models to swirling flow.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)
Nyckelord
- Swirling flow
- diffusor
- GEKO model
- flow separation
- hydraulic turbine
- Strömningslära
- Fluid Mechanics
Publikations- och innehållstyp
- ref (ämneskategori)
- kon (ämneskategori)