Almost there... again!

Well I had plans drawn up, changed them, drew them up again, and now I am changing them again. The first set of plans involved a two bladed savonius rotor with a twist. Ironically this is not far from my final set of plans. I then removed the twist, added a third blade to balance out the reverberations that would be generated with a two blade rotor, and invented a dynamic superstructure to help direct wind into the turbine. I then (most recently) came across an article discussing how the twist put into a savonius rotor has a direct effect on the efficiency. I'm still puzzling through the article a bit, but it seems that adding the twist back in is the way to go.

The article also uses ABS plastic to create the turbine because of the twist. Creating a twist like that in steel sheet metal might be very difficult, and since Lemelson has the tools to work with ABS plastic I plan to look into that.

Thinking back, it seems I had the right idea in adding a third blade. The result of this is similar to the addition of a twist in that both remove uneven torque on the shaft as the blades turn.

Things to consider: weight of ABS vs. sheet metal, efficiency, ease of implementation of either ABS or sheet metal. In the end I will have to use sheet metal anwyays for the superstructure..!

Another Sketch

Sketched up a slightly different model in Wings which I think is more accurate than the last one. I'm still not too sure about the concept of the blade being smaller at the top... Now that I've modeled it in Wings I'm not too sure where I got that idea...

This one includes a UV Map of one blade, which will greatly help in fabrication...though it might be stretched a bit... I can never tell.

New design

This design accounts for the discharge of the wind currents (they are directed upwards out of the turbine). The two blades could be offset a little bit more to account for the wind switching sides in the middle.

Vertical!

I was ambling through an article on the use of vertical axis wind turbines in new age buildings and came across (amidst a mess of calculations) some different designs for vertical turbines. It seems that some of them use a tunnel effect and some design the blades to shed wind. The tunnel is far better for single direction wind because the returning blades don't have to go against the wind at all. The other style "Savonius" is designed to shed wind which is less efficient but doesn't rely on the direction of wind making it useful for areas that have rapidly changing wind directions. I would think that the wind tunnel version is not worth making because a horizontal axis turbine would be better, although the article discusses the incorporation of these turbines into buildings and a horizontal axis turbine would be difficult to put on a building due to many factors.

Research!

Exactly that.

I've been reading everything seemingly pertinent to the design and construction of wind turbines, both horizontal and vertical. The articles I have found discuss such matters as the optimum angle to have the blades at (assuming they are not twisted) for a horizontal turbine, the plans to generate power from a kite, the practical use of vertical axis turbines, and wind power systems for housing development in the United States! I've also reintroduced myself to this website: http://www.otherpower.com

VAWT Design

This design is for a wind turbine to calculate the most efficient angle at which wind is caught for the blades of a vertical axis turbine. It does this by using an adjustable wind director with the actual turning mechanism being non-adjustable. The wind will travel through the wind director, be directed one way to a set degree, and then it will turn the turbine. The diagram below will hopefully clarify this.

In this diagram, the central shape with the fins sticking out perpendicular to the cylinder in the middle is the part of the turbine that rotates. The angled fins attached to the two rings is stationary where it almost touches the center, but the two rings can rotate causing a change in angle for only the outer fins. This means that as the outer fins are adjusted, the efficiency of the turbine changes. They can be adjusted even while the turbine is in motion making setup and testing much easier.

The middle will be mounted on a pole with ball bearings. This pole will have to be as close to vertical as possible. The center most edges of the outer adjustable ring will be fastened to a bottom plate with some sort of hinge to allow them to rotate. Also, once they are adjusted there will be some sort of mechanism to lock them in place. If they are not locked in place, the wind will probably blow them out of alignment. The alternator will be positioned at the bottom of the turbine on the bottom plate and will be either belt or gear driven.

(Image will be up soon!)

Excerpt

Here is an excerpt sent to my adviser via email early on:

"I've been working on assembling a working structure for
myself (turning my proposal into a schedule) as well as some preliminary
research. The design journal is a great idea and soon I will have one. For
now I've been recording information on the computer.

I've found several primary and secondary articles on subjects such as small wind
turbine blade efficiency and gearbox efficiency and recent technological
discoveries. It appears that there are multiple kinds of wind turbines, namely
vertical axis wind turbines (VAWT) and horizontal axis wind turbines (HAWT).
Each appear to have their own pros and cons depending on the situation, though
for any large scale power source a horizontal axis seems to be the way to go.

My interests in this subject, however, are mainly stemmed from the desire for
sustainable living which may not require a large amount of electrical power in
which case a vertical axis wind turbine may prove to be more suited to the
situation.

Most of the articles on blades are referring to the horizontal axis wind
turbines but further searching may uncover some studies on the blades for
vertical axis turbines. In this case, however, I have procured a sketch for a
vertical axis wind turbine with an easily modified "blade" so as to test the
efficiencies for different blade settings. This could, if built correctly,
turn into an ongoing study paralleling my other research.

Despite the talk about the vertical axis turbine I have not given up on the
horizontal alternative. It is far more efficient, but tends to spin at far
greater velocities as a result. It is also more prone to make unnecessary
noise and to become damaged from poor quality construction. The keywords are
"far more efficient." The reason they are more efficient is because none of
the parts are turning into the wind thus making the rotor able to turn at
speeds greater than the wind speed."