1.2 m rotor diameter limitation bypass

1 post / 0 new
Adriprevost
1.2 m rotor diameter limitation bypass

Hello OpenAFPM community!

First, I would like to thank all the OpenAFPM team for these amazing tools !!

I am currently simulating a generator for a 0.8m diameter small wind turbine for an educational wind tunnel. The wind turbine has been constructed already.
I would like to simulate the generator to get its theoritical parameters, however, the openafpm tools have a limitation for the rotor diameter (1m20).
At the moment, i bypassed the limitation by giving biased Cp and Lambda to compensate the smaller radius of my wind turbine in terms of power and rotational speed according to the following formulas :

Simulated Turbine Radius : R=0.6m
Real (') Turbine Radius : R'=0.4m

Cp=Cp'/K (to compensate the smaller area of the equivalent rotor radius R'=0.4m )
(K=(R^2)/(R'^2)=2.25)
Omega'=(Lambda'*Vw)/R'
Lambda=(Omega'*R/Vw)

 

Which theoritically gives a 0.8m_equivalent_power 1.2m rotor spinning at the same speed as the 0.8m (so with a higher TSR).
To match the Cp/Lambda curve, I divided the CP values by K.

According to you, are these tricks enough to bypass the limitation or are there other factors playing that makes the corresponding generator senseless?
Would it be possible to move the rotor radius limitation to 0.4m ?

Many thanks for your help and feedback,

Adrien

PS : it would be great to be able to insert LaTex equations via the text editor