[er_ijaz]

Hi all
i tired MATLAB code for finding the power coefficient for NREL Phase VI turbine.But my answer is very below the experimental value.
i took the hub radius as 1.257 m where the actual airfoil starts
I get power coefficent very below the experimental
suddenly I got a doubt whether it is because of the hub diameter
Actually blade cyclindrical section which is attached is 0.508 m and from 0.883 m to 1.257 m it undergoes transition from cylinder to airfoil.

so in BEM I took the hub diameter is 1.257 m where the airfoil starts

[kaya]

Hello er_ijaz,

The root section shouldn't affect that much actually. What are the expected and calculated power coefficients?

[er_ijaz]

Values of Power Coefficient
windspeed in m/s 7 10 13 15 20 25

experimental(NREL) 0.369 0.209 0.094 0.054 0.0218 0.0149
With out correction 0.304 0.096 0.0035 0.009 0.0053 0.00516
Tiploss correction 0.283 0.0939 0.0118 0.016 0.0060 0.00555

[kaya]

First of all, I would include the part from root to the first airfoil section. Than I would compare my Cps with NREL s again.

Still difference? Then I would start having concerns about the tabulated Cl Cd data you use if you got them from another source. (I assume your BEM is correct.. paste your code and I can have a look)

[er_ijaz]

my email id is er_ijaz@yahoo.com.I,m in mobile.I will forward u my code

[kaya]

would be easier to discuss it here if you paste the main solver here. but you can of course mail me also.

[er_ijaz]

Brother can i have ur email id .my id is er_ijaz@yahoo.com

[kaya]

gadruno[ at ] g mail.com

[kaya]

I didn't quite understand the way you get the Cl Cd coefficients. Don't you have a tabulated data for it? Or is this a fitted curve provided from NREL?

[er_ijaz]

Hi
i created an empirical formula based on the experimental results by using genetic programming for cl and cd values.
And sorry for late reply .I will email u the experimental values
other than that did u find any mistakes

[kaya]

don't send me any data. I don't have time to debug your code yet I can direct you to find your own problem.

plot your measured CL vs aoa - CD vs aoa and plot your CL_empiric - aoa and CD_empiric vs aoa up on them. and lets see how correct your empiric curve.

on the other hand, did you check the measured CL and CD whether if its measured at the correct Reynolds? I don't know how big is this turbine but CL and CD datas are very sensitive between RE 100k and 1m.

[er_ijaz]

hi
ya i had plotted n chcked the cl n cd values(empirical) with the experimental.There is no much difference.Anyways thanks for ur help.If u debug pls let me know .anywhere logic is not ok