Homebrewed Electricity > Wind
Tip speed ratio of GOE 222 blades
ChrisOlson:
I ran GOE222's for several years from Dave at Royal Wind & Solar. Those were cut at 10 deg pitch and ran at ideal TSR of 5.7. They run quite happily anywhere from 4.5 to 6.5, however.
Adriaan Kragten:
My report KD 35 gives the design procedure for the blades of horizontal axis wind turbines (see www.kdwindturbines.nl at the menu KD-reports). The theory in this report gives the variation of the chord and the blade angle as function of the local radius if the rotor diameter, the design tip speed ratio, the number of blades and the airfoil are chosen. This theory can also be used to find the optimum tip speed ratio of existing blades. A problem might be that an existing blade has a certain variation of the chord and the blade twist and the only thing you can vary is the blade angle at the blade root.
You have to measure the chords for about six stations and you also have to measure the difference in blade angle in between the blade tip and the other stations, so this gives you the blade twist. You also have to measure the airfoil itself and find out which airfoil is used. Next you make a certain choice for the number of blades and the design tip speed ratio and make the design calculations for that choice. You compare the results of the calculations with your blades. If your calculated blades have larger chords than what you have found for your existing blades you reduce the design tip speed ratio and do the design calculations again. Probably after two or three steps you will find a design tip speed ratio for which the variation of the chords are about the same as for your existing blades. Next you check if the calculated blade twist is about the same as for your blades. The blade twist might differ but finally for your existing blades, you chose a blade angle close to the tip which is the same as what you found for the calculated rotor.
If your existing blades have an increasing chord at decreasing radius, you have to use the method as given in chapter 5.4.1 of KD 35. If your existing blades have a constant chord, you have to use the method as given in chapter 5.4.2 of KD 35.
Royalwdg:
Thanks for the mention, Chris. The 222s are seriously high torque, high amperage blades. my blades are 18' diameter putting out about 9000 watts at a 20 mph wind. My dump load is 6 1500 watt resistive load heaters where I can check the out put. TSR is 7.5 while charging batteries because it's easier work. TSR is 6.5 while running heaters. You really need to give these blades a lot to do. Wind your stators accordingly. Dave Moller Royal wind & solar
DaveP68:
Thanks for aditional info over the last month. Very useful for when I get around to building my first wind turbine some day soon with those GOE 222 blades.
ontfarmer:
What RPM is the turbine running at for 9000 watts? That is a lot of power!
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version