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Scaling the NREL 5MW Turbine Model
Hello,
I am currently creating a scaled-up NREL 5MW turbine model in QBlade for a study comparing the performance of multiple wind turbines with a single large wind turbine.
Currently, I have modified the following parameters.
Blade Definition
- Position
- Hub Radius
- Chord
Structural Definition (.str)
- HAWT TURBINE CONFIGURATION (OVERHANG, TWR2SHFT)
- Hub and Nacelle parameters
- Drivetrain parameters (GENINER, DTTORSPR, DTTORDMP)
- BLADE DATA (MASSD, EIx, EIy, EA, GJ, GA)
I am also working on the TUB Controller parameters. However, before tuning the controller, I would first like to confirm that my structural model has been set up appropriately.
I have two questions.
- When scaling up the NREL 5 MW turbine, are these the appropriate parameters to modify? Are there any additional parameters that should also be changed?
- Currently, I am scaling these parameters using geometric similarity. Is this an appropriate approach for a comparative study, or would you recommend a different modeling or scaling method in QBlade?
Thank you very much for your time and advice.
Hello,
Yes, the parameters you listed cover the main parts that need to be adapted. In addition, make sure that all other dimensional properties are scaled consistently, in particular the tower and blade geometry and structural properties, as well as the relevant hub, nacelle and drivetrain inertias and stiffnesses.
For the aerodynamic model, I would also check the resulting blade Reynolds numbers. Depending on the scaling factor and operating conditions, the relevant Reynolds number range may change significantly, so the blade polars may need to be revised as well.
Using geometric similarity is a reasonable approach for a comparative study, but it does not automatically ensure dynamic similarity. Quantities such as Reynolds number, natural frequencies, rotor speed and controller time scales do not all scale in the same way.
I would therefore first finalize the aerodynamic and structural scaling consistently and then retune the controller for the scaled turbine.
Best regards,
David
