Question

A rotor reaches maximum cp at a tip speed ratio of 7. Calculate rotor rpm for three different wind turbines (diameters 10,50 and 100 m) at wind speed of 10,20,30 m/s.

Answer 1

Answer:

Explanation:

1-Rotor Diameter

2-Wind Speed

3-Tip Speed Ratio (TSR)

generally, a 20kW wind turbine has a 9-12m Rotor Diameter, TSR=6 and your wind speed is 9m/s,

so i calculated RPM for this  turbine:

9m Rotor : 114.595 RPM

10m Rotor: 103.135 RPM

12m Rotor: 85.946 RPM

you can use this equation:

TSR=(Blade tip speed)/(wind speed mph)= (for 3 blade 5-6) = 6 (assume)

rpm = 60 * V * TSR / ( Pi * D )

V=m/s

TSR~6

D=10m