We are developing a 20MW wind turbine in Korea. We want to reduce the impact of heavy blades and rotors on the generator efficiency. Therefore, we want to evaluate the effect of removing the non-torque loads that are fed into the generator. In addition, we want to identify the input variables of the upper and lower springs and dampers of the elastic element 1, 2 of the attached 5MW baseline model for a specific effect evaluation, and examine whether it is a “good” way to evaluate this effect together with the input variables of the torsion spring and torsion damper (DTTorSpr, DTTorDmp). If there are any input variables or scenarios that are not implemented in FAST, please provide guidance on how to access them. The software that we can use are Matlab, Simulink, Abaqus, Hyperworks, and Python.
Dear @Sunghoon.Park,
As you are likely aware, ElastoDyn is limited in the degrees of freedom (DOFs) it supports for the drivetrain, only consider the generator rotation and shaft torsion DOFs and not considering elastic couplings of the bearings. We have recently worked with a Ph.D. student at NTNU (Veronica Liverud Krathe) who adopted the SubDyn module of OpenFAST to model additional compliance of drivetrains: Main bearing response in a waked 15-MW floating wind turbine in below-rated conditions | Forschung im Ingenieurwesen. I haven’t tried to think how this approach could apply to the Alstom Pure Torque design, perhaps it will give you ideas.
FYI: We have outlined plans to add additional DOFs in ElastoDyn to model compliance of the bearings, but are still awaiting funding to move this work forward.
Best regards,
Dear Dr. @Jason.Jonkman
First of all, thank you very much for your detailed and kind answer.
I have referred to the paper you provided, and although there are some similar parts, it is a little different from what our team is interested in. We are studying a component that structurally separates the non-torque load by applying elastic bearings (elastic couplings) to the blade hub and rotor hub, which are the starting points of the drivetrain. To implement this component, we plan to implement a simple circular cross-section shaft passing through the 4th virtual blade using BeamDyn, and to implement a simple elastic bearing simulation model by applying spring and damper elements to the root node using SubDyn, and linking the root node and end node to the blade and rotor hub and the input of the generator, respectively, with 6DOF. Are there any technical issues or parts that have not been implemented yet to implement this simulation model?
Also, I wonder if the coordinates of the root node of BeamDyn can be freely selected by the engineer, i.e., can it be applied to a completely independent location (between the high-speed shaft and the input of the generator) rather than the blade?
Thank you.
Dear @Sunghoon.Park,
Unfortunately, it is difficult for me to understand what you are describing; perhaps a picture would help.
For the way in which BeamDyn is coupled to ElastoDyn within OpenFAST, the pitch bearing at the root of each blade is located by the geometry specified in ElastoDyn, and this point is used as the root node location of a given BeamDyn instance.
Best regards,
Dear Dr. @Jason.Jonkman
I think the previous question was a misleading question.
To be specific,
First, I want to simulate a shaft using BeamDyn in OpenFAST. What I need in this step is how to implement a shaft using BeamDyn, how to set the coordinates of its root node and tip node, and how to connect the DOF of the root node and tip node to the rotor hub and generator, respectively.
Second, I want to simulate the shaft created with BeamDyn by adding elastic elements and damping elements. How can I reflect the elastic elements and damping elements to the shaft created in the first step using SubDyn?
According to the BeamDyn document “4.6.6 Future Work” on the official website, it is expressed as “Extending applications in FAST to other slender structures in the wind turbine system, for example, towers, mooring lines, and shafts.” Is there currently no way to implement this in OpenFAST? If not, please let me know in which version and when it will be available.
Thank you.
Dear @Sunghoon.Park,
The future work mentioned in the BeamDyn documentation regarding applying BeamDyn to “other slender structures in the wind turbine system” has not yet been implemented. As it is now, there is no way within OpenFAST to model a shaft in BeamDyn. This would require a source code change, but is not work that NREL has pursued yet.
Best regards,
Dear Dr. @Jason.Jonkman
This is a clear answer. Thank you for your help with my research.
I will reply to this answer if I have any additional questions regarding this topic.
Thank you, Have a nice day