Hi
I am onto design a wind turbine blade where I selected multiple airfoils of S-series from root to tip.Now how to calculate my rotor radius.Can I assume or is there any mathematical relation between rotor radius and Power and Wind Speed.If so,please explain (or) share any links .Thank You
Karthik,
Wind turbines range in size from tiny micro turbines to large scale power production facilities that have a rotor diameter of nearly 200m.
There is a relationship between rotor radius (r), power (available in the wind stream) and wind speed (v):
P= 0.5*rho*A*V3, where rho is the air density, and A is the swept area of the turbine (A=pi*r2).
This equation is well known and could be derived as the rate of change of energy (P=dE/dt).
However, Albert Betz concluded that no wind turbine can convert more than 16/27 (59.3%) of the kinetic energy of the wind into mechanical energy turning a rotor. This is known as the Betz Limit or Betz' Law. So, the theoretical maximum power efficiency of any design of wind turbine is 0.59 (Cpmax- maximum power coefficient). In addition, wind turbines cannot operate at this maximum limit. The common real values of power coefficient are 0.3-0.4.
Nevertheless, from the above relationship two important conclusions could be made:
1. Power is related to the cube of the wind velocity.
2. Power is related to the square of the rotor radius and that means that even small increases in rotor diameter can make significantly more power available to the turbine (this is the reason why turbines are growing larger and larger in size)
Good luck.
Thank you. need more clarified answer.If my wind speed is 8m/s and im using 3 blades,what will be my rotor dia?Thanks
An extremely important factor in wind turbine design is the tip speed ratio (TSR, lambda), which refers to the ratio between the wind speed and the speed of the tips of the wind turbine blades:
TSR = (Tip Speed of Blade)/( Wind Speed) = D*pi*n/(60*v).
Wind turbines must be designed with optimal tip speed ratios to get the maximum amount of power from the wind.
Don't forget that your deflections are going to get larger for higher diameter rotors. So after doing all these configuration based power estimates and optimizations, you shouldn't ever forget to give your rotor enough structural stiffness. Otherwise the excessive deflections may cause your rotor to perform sub-optimally. (i.e, your rotor should be thick enough)
I suggest to check out the following book:
https://books.google.de/books/about/Wind_Energy_Handbook.html?id=4UYm893y-34C&redir_esc=y
Its a great resource for wind turbine design.
I cant download it.if you have a copy of book,can you share now?
Thanks
Unfortunately I don't have a digital copy. Perhaps you can find it in your local library.
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