Alvaro Olcoz
19th November 2018, 14:09
Dear,
I'm designing a VS-FP (passive stall regulated, 10 kW rated) for my Master Degree Final Project and after designing the blade on my own BEM code (Matlab) I have created the blade and performed the P-v and Cp-v characteristic curves in Q-Blade. The variable speed region is between U=2 m/s and U=6 m/s.
I have done 2 simulations, one setting the Re number equal to 400000 for all the blade stations (green curve on the attached figure) and the other one (blue curve) with a multi Re number within 50000 and 1200000 (the real range that appears spanwise and within Vcutin and Vcutout in each station). When the Re number is constant (green), Cp=Cpmax for the variable velocity gap ( optimum TSR zone).
My doubt is: which of the 2 curves represents better the reality of a Wind Turbine, as in text books I have only seen the green curve as example. Are they taking into account the variability of Cl and Cd with Re number?
As design velocity for my blades, I have used U=4 m/s (wind site Weibull parameters k=1.79 and c=5) and I have designed all the stations for maximum glide ratio (Cl/Cd) taking into account the Re number in each station.
Thank you in advance
Alvaro
I'm designing a VS-FP (passive stall regulated, 10 kW rated) for my Master Degree Final Project and after designing the blade on my own BEM code (Matlab) I have created the blade and performed the P-v and Cp-v characteristic curves in Q-Blade. The variable speed region is between U=2 m/s and U=6 m/s.
I have done 2 simulations, one setting the Re number equal to 400000 for all the blade stations (green curve on the attached figure) and the other one (blue curve) with a multi Re number within 50000 and 1200000 (the real range that appears spanwise and within Vcutin and Vcutout in each station). When the Re number is constant (green), Cp=Cpmax for the variable velocity gap ( optimum TSR zone).
My doubt is: which of the 2 curves represents better the reality of a Wind Turbine, as in text books I have only seen the green curve as example. Are they taking into account the variability of Cl and Cd with Re number?
As design velocity for my blades, I have used U=4 m/s (wind site Weibull parameters k=1.79 and c=5) and I have designed all the stations for maximum glide ratio (Cl/Cd) taking into account the Re number in each station.
Thank you in advance
Alvaro