wind turbines

[kf]

any reason why it would not be possible to have two sets of blades on a turbine.

one would be in front and would turn the first rotor clockwise and another would be behind and turn a second rotor counterclockwise.(no stator)so the relative movement between the two rotors is much greater than the movement for one rotor and stator in for the same wind blowing at it. the first rotor could have 3 blades like a standard wind turbine. the second rotor obviously is blocked whenever it is directly behind the first so it would have maybe six? (or more) so that some blades are always exposed.

 

so the rpm of the standard turbine would be x rpm relative the rest of the turbine. this design would have x rpm for the first and y rpm for the second.combining both would give a greater rpm for the same wind.

 

is this idea just utter bananas? is the force of the wind behind a turbine very little compared to the front force in front due to turbulence being affected by the turbine to not make it feasible?

[J.C.MacSwell]

any reason why it would not be possible to have two sets of blades on a turbine.

one would be in front and would turn the first rotor clockwise and another would be behind and turn a second rotor counterclockwise.(no stator)so the relative movement between the two rotors is much greater than the movement for one rotor and stator in for the same wind blowing at it. the first rotor could have 3 blades like a standard wind turbine. the second rotor obviously is blocked whenever it is directly behind the first so it would have maybe six? (or more) so that some blades are always exposed.

 

so the rpm of the standard turbine would be x rpm relative the rest of the turbine. this design would have x rpm for the first and y rpm for the second.combining both would give a greater rpm for the same wind.

 

is this idea just utter bananas? is the force of the wind behind a turbine very little compared to the front force in front due to turbulence being affected by the turbine to not make it feasible?

 

You have a reduction in kinetic energy available as well, for the second set and for the first set of blades as well.

 

The first set is in reduced flow due to the second set.

 

The second set is in reduced flow and turbulence due to the first set.

 

So you probably have greater inefficiencies than one set of blades alone.(less available power)

[Gasparri]

You have a reduction in kinetic energy available as well, for the second set and

So you probably have greater inefficiencies than one set of blades alone.(less available power)

 

Hello, I know very little about windmills but I had this idea of

making some blades based on something else and although

quite unconventional they worked pretty good. I made pictures

of them and put them here:

 

Them I imagined up this monster:

 

Then it dawned on me to make an oscillating single sail windmill. It works

but needs two opposing ones to power a boat or something.

[CaptainPanic]

There are a number of reasons why one would not put a second rotor (a set of blades) on a turbine:

 

1. The blades will influence each other through turbulence. As was mentioned before, the second blades are always behind the 1st one (regardless of the wind direction), which will reduce the efficiency of the second blades.

 

2. While you save a lot if you put 2 rotors on one mast (seems like you save a lot of money there!), the increased turbulence will cause more vibrations and you need to improve the strength of many components - especially the blades themselves.

 

3. The gearbox will be much more complicated with two rotors. (Obviously, the rotors will turn at a different speed - if they have the same speed, then that is in fact a single larger rotor with more blades).

 

I'm sure that there are more reasons... there is a lot of research being done in the field of wind turbine design... the idea of more than one rotor on one mast has surely been investigated.

[kf]

ok. thanks for the replies.

 

for the gears problem:each set of blades has its own gearbox and rotor. surely the different speeds would not be a problem.with a rotor and stator theres no problem with different speeds so i was thinking here would it not be the same. basically the stator is moving counter to the rotor(but since its moving its name is changed from stator to rotor)

 

and yeah i see the other problems too and accept them.

 

 

has it also been investigated and does anyone know where if this design is feasible.

again the stator is moved so its two rotors. lets say one was inside the other.one millwheel was much bigger than the other and was hollowed out and the smaller was inside. they're both in line with each other and get hit with the wind at the same time. one moves clockwise and the other counter. the inside one does what turbines do anyway. the outside one moves what would be the stator(so again its a second rotor). relative rpm between the two increases for the same wind.

 

aside from needing a stronger material, would it harness more power?

[CaptainPanic]

The question you have to ask yourself is:

 

If I build two sets of blades on top of the turbine, which other components do I have to build twice? Where do I save (materials / money)? Your double-rotor turbine is competing against two separate turbines.

If you have to build also two gearboxes, and a stronger mast, then I don't see how that design is better than just building two turbines next to each other.

 

(If your argument against two separate turbines is space: the turbine with two sets of blades will be less suitable for urban areas because it will be more noisy (due to the increased turbulence)).

[Sisyphus]

If you have to build also two gearboxes, and a stronger mast, then I don't see how that design is better than just building two turbines next to each other.

 

Or for that matter, just a bigger single one.

[CaptainPanic]

Or for that matter, just a bigger single one.

 

You're right.

 

We're talking about development of a new type of turbine... so we shouldn't compare this with two small ones, but with one bigger one (twice the power output). With wind turbines, it seems that bigger is always better

[iNow]

Just to be a bit pedantic, the comments made above by you guys are only accurate if you're referring to a standard horizontal-axis turbine.

 

http://en.wikipedia.org/wiki/Wind_turbine#Horizontal_axis

 

 

However, once users begin referring to vertical-axis turbines, multiple blades (and sets of blades) not only helps performance, but is pretty much required to achieve any output.

 

http://en.wikipedia.org/wiki/Wind_turbine#Vertical_axis

 

 

 

Regardless, you're quite correct about the horizontal-axis turbines, and your explanations are clear and simple, so thanks for that.