- #1

- 23

- 0

Power 1.65 MW

Rotor radius (blade length) = 37m

calculated swept area = 4,301 m^2

wind speed 12m/s

the rotor speed range is upto 20rpm

i want to calculate the torque but not quite sure how to go about it

Thanks for any help!

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- Thread starter Ziv7
- Start date

- #1

- 23

- 0

Power 1.65 MW

Rotor radius (blade length) = 37m

calculated swept area = 4,301 m^2

wind speed 12m/s

the rotor speed range is upto 20rpm

i want to calculate the torque but not quite sure how to go about it

Thanks for any help!

- #2

rock.freak667

Homework Helper

- 6,223

- 31

You can always use Power = Torque*angular velocity.

- #3

- 374

- 1

You know the radius of the blade so you know the angular velocity, ω=V/r. Make sure ω

is less than 20 rpm.

As noted above power in the wind=τ*ω, the power in the wind is not 1.65 MW that is the rotor power you need to find the Power in the wind=rotor power/efficiency of turbine

You can find the efficiency of turbine(η) because rotor power=η*(.5*A*ρ*v^3)

η=rotor power/power in wind. η accounts for all the losses in generator, transmission etc.

Now you know power in the wind and ω so you can find Torque (τ)

- #4

- 23

- 0

I've done it this way:

We know the rotor is rated up to 20RPM hence so to change it to angular velocity we;

(20*2π)/60=2π/3

We also know P=τω 1.65MW= τ * 2π/3 τ=7.878×〖10〗^5

I've already done this before: (P=1.65mw)

Cp(η) = Rated power/Power = P/(½ρAv3) = 0.369 = 37%

(Power = ½ρAv3 = 4.47MW)

Again thanks a lot for the help :)

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