Design Help - NREL S818,S830,S831.

Wind & Water Airfoils
1

Good Day People,

First of all, let me thank Ms. Bonnie.Jonkman for giving me an access to the forum.

Coming straight to the point, I am working on my Master’s Thesis on design of wind turbine blades followed by FSI and optimization. My specifications are:

Power: 1MW
Airfoils: S818 (root)
S830 (Primary)
S831 (tip)
Rotor diameter: 55m
Tip speed velocity: 70.50 m/s
TSR: 8
Design wind speed: - 8.81 m/s
rpm: - 12.5 - 24.5

This data was based on the calculation. Now, I need assistance in:

  1. How do I get/calculate the chord length and twist angle for each section of the blade. (Something like this [url]http://www2.mae.ufl.edu/mdo/papers/5265.pdf[/url] on page 3)
  2. At what sections or length should the airfoils transition take place i.e. from S818 - S830 - S831.
  3. Any other data that I can be provided by NREL which can help me with my design and analysis.

Any other help is greatly appreciated,

Thank you,

Pranav Bhatnagar

2

Dear Pranav,

It sounds like what you want to do is an aerodynamic/performance optimization of a rotor based on a given set of airfoils. The HARP_Opt tool was developed for that purpose: nwtc.nrel.gov/HARP_Opt.

Best regards,

3

Respected Sir,

Thank you very much for your prompt response. I will surely work on it. If there is a doubt I shall revert you back.

Thanking you,

Sincerely,
Pranav Bhatnagar

4

Hello everyone,

I am designing a variable speed variable pitch wind turbine. As posted on the top are the specifications for the turbine. Later, I was advised to use HARP_Opt tool for optimization and calculation of the parameters related to the wind turbine.

I am writing the steps here that I am following, kindly let me know if I am going wrong.

Approach 1:

  1. Use the values from -5 to 20 (from XFoil) and insert in the airfoilprep excel sheet and get data for -180 to +180 degrees.

  2. Use this new data to create a airfoil database in the AeroDyn format. Do this for all 3 airfoils.

  3. Use HARP_Opt and add all 3 files and let it merge together to get all the data.

Approach 2:

  1. User the Airfoilprep excel sheet and blend all 3 airfoils together (1 - 2 - 3) and get the data for Cl and Cd

  2. Use this data to make a new airfoil data in Aerodyn format and upload only 1 airfoil for HARP optimization.

One more question: How do I get the value for Aspect ratio and max CD for extrapolating values from -180 to +180. I did read the forum posts but didn’t get the proper idea of it.

PS: The AirfoilPrep_v2.02.02.xls Excel sheet that is uploaded in the website does not work. I tried to run it by disabling all security but in vain. I suggest you to kindly look into it.

Awaiting for the response.

Thanking you,

Sincerely,
Pranav Bhatnagar