Rotor and Nacelle Mass moment of Inertia Tensors

Discuss the theory and modeling of rotor aerodynamics.

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Zahid.Ullah
Posts: 45
Joined: Sun Jul 24, 2016 6:59 pm
Organization: HYU
Location: South Korea

Rotor and Nacelle Mass moment of Inertia Tensors

Postby Zahid.Ullah » Thu Mar 28, 2019 2:20 am

Dear Dr. jason Jonkman

I am trying to determine the inertia tensors of rotor and nacelle separately. I was able to find the combine (RNA) inertia values (Ixx, Iyy, Izz, Ixy, Izx, Iyz) of the 5MW wind turbine on this forum. However, i could not find separately the inertia values of rotor and nacelle. I will highly appreciate if you can guide me on the calculation procedure of these values separately or if you can provide me some values.


Link for combine RNA values: viewtopic.php?f=3&t=645

Best
Zahid

Jason.Jonkman
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Re: Rotor and Nacelle Mass moment of Inertia Tensors

Postby Jason.Jonkman » Thu Mar 28, 2019 8:24 am

Dear Zahid,

The nacelle mass, center of mass, and inertia about the yaw axis are specified in the NREL 5-MW specifications report: http://www.nrel.gov/docs/fy09osti/38060.pdf. The other nacelle inertia terms were neglected. So, the rest of the rotor-nacelle assembly (RNA) inertia comes from the rotor.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Zahid.Ullah
Posts: 45
Joined: Sun Jul 24, 2016 6:59 pm
Organization: HYU
Location: South Korea

Re: Rotor and Nacelle Mass moment of Inertia Tensors

Postby Zahid.Ullah » Fri Mar 29, 2019 7:22 am

Dear Dr. Jason Jonkman

Thank you for your kind response. Following your suggestion i calculated the Rotor inertia about its Center of Mass (Cm) using parallel axis theorem. I have briefly described the procedure of determination in the following steps.

Step 1: Transfer the nacelle inertia from yaw-axis to its Center of mass.
Step 2: Transfer the nacelle inertia from its center of mass to RNA center of mass.
Step 3: Subtract the nacelle inertia form RNA inertia (about RNA center of mass, obtained from another post on this forum) and thus found the Rotor inertia about RNA center of mass.
Step 4: Transfer Rotor inertia from RNA center of mass to Rotor center of mass

I have done this step wise calculation in an excel sheet and attached here. Can you please kindly give a look to the final values of Rotor inertia about Rotor center of mass if they seems correct.
Attachments
5MW_Turbine_Inertia_2019.xlsx
(206.14 KiB) Downloaded 6 times

Jason.Jonkman
Posts: 3999
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
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Re: Rotor and Nacelle Mass moment of Inertia Tensors

Postby Jason.Jonkman » Mon Apr 01, 2019 10:02 am

Dear Zahid,

You're overall approach is correct, but I found several mistakes in your spreadsheet. Please find my commented spreadsheet attached. With my corrections, I calculate the rotor mass and inertia about its CM as follows:
Mass = 110000
Ixx = 4.37E7
Iyy = 1.99E7
Izz = 2.01E7
Ixy = 0
Izx = 8.3E5
Iyz = 0

5MW_Turbine_Inertia_2019_JJ.xlsx
(210.17 KiB) Downloaded 3 times

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Zahid.Ullah
Posts: 45
Joined: Sun Jul 24, 2016 6:59 pm
Organization: HYU
Location: South Korea

Re: Rotor and Nacelle Mass moment of Inertia Tensors

Postby Zahid.Ullah » Mon Apr 01, 2019 8:39 pm

Dear Dr. Jason Jonkman

I followed all the comments and made the corrections and thus obtained the corrected values as you calculated. I am highly grateful for your valuable comments and corrections. Heartfelt thanks.

Zahid Ullah


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