Darrieus wind turbine

[Michael]

Hi guys,

Been hard at work again building something new and interesting. We've had a few different versions of this design and are finally up to the stage of testing a working model. It has taken a while to do the dead work of trying different Darrieus designs and have finally got one that actually generated power even if it is a few hundred watts. Sure, there are still a few hiccups. It sure is good to find a new challenge.

Background: We needed to find a location to set up a permanent 2kW turbine for performance monitoring, and we decided to help out our friend Scott. He desperately needed to save money on his electricity bill due to all his wild parties.

Design: An alternate design had to be approached, so we decided to construct a prototype 2kW Vertical Axis Wind Turbine (VAWT) using a straight blade Darrieus design. The Darrieus vertical axis windmill was patented in 1927 by the French Inventor Georges Darrieus and is a lesser known alternative to the typical 3 bladed HAWT

Do you guys have any comments? (apart from 'yeah, your blade fell off')

here's the link with all the pics:

http://warlock.com.au/scottsturbine.htm

Cheers,

Michael

[thefinis]

Well it sounds like it was a fun effort and a little liquid refreshment can help keep the creative juices flowing. Just don't partake to the extent of forgetting to keep your head in the car. Hmmmm how did you come up with 2kw for a rating?

Any way to guy the ends of the blades? It would help keep them from flexing and would add strenth to the junction, the blade and the arm. From the pictures it looks like the blade broke not the junction. Did you have a way to tell how many rpm it was making when it lost the blade?

One big problem with the vawts is the large amount of forces that are exerted on the blades and the fact that they change as you go around the circle.

Good luck and tell Scott that with all the partying it is probably best to keep the hot tub on the ground.

Finis

[wind4Reg]

Hi Michael, cool project, I have a soft spot for the straight bladed Darrieus vertical axis turbines too My H-Rotor. There is a rotor calculator link on that page that does some calculations for H-Rotors if your are interested in plugging in your numbers to see what it estimates.

Did you use a NACA airfoil for this and if so what number? What is the chord length of the blades? What is the height of the blades and what is the diameter of the turbine?

It looks like you attached the blades closer to the trailing edge, am I seeing this right in the picture? Is it attached to some kind of generator/alternator? Did yours self start and if so do you know what speed it started at (km's from the truck speedo I suspect ;-)

I know that is a lot of questions and I will be very interested to see your final windmill after you work the bugs out of your prototype.

wind4Reg

[vawtman]

Seems like you guys are having alot of fun.Thats the way it should be.Have one for me and good luck.

[willib]

Michael i like your pdf about the carbon fiber blades , but i'm gonna use a carbon fiber rod instead of steel and make the sections out of insulation.and coat the works in fiberglass.

http://www.fieldlines.com/story/2006/1/31/20299/2689

[Michael]

hi guys,

The 2kw rating is what we are aiming for, the swept area is 2.2m wide x 0.9m high and we are hoping it will be highly efficient. The two half blades were glued together with fibreglass resin, we got a bit lax after so many blade trials and didn't wrap it in glass cloth or carbon fiber, in retrospect i guess this is not surprising and is an easy problem to fix. We didn't have time to measure the rpm before the blade flew in half, bugger. Will post the next series of tests when we have time to test again.

Cheers,

Mike.

[Michael]

we did use a symmetrical NACA airfoil and were aiming for about 12% thickness.

The chord was about 1/2m. The arm is attached to the center of the blades. it was driving a induction generator and brought up to operating speed by a power drill.

it started turning on its own at 25km/hr+

[jackforeman]

Congratulations, looks like it is a good size project.  How high is it off the ground?  The picture looks like it is close to the ground, but I can't tell for sure.

[vawtman]

Hi Mike,When you say operating speed,How much over rated rpms did you have to go?What hp and what size cap.Could you post a closeup pic of the motor?Thanks.