Wind Turbine Design

Discussion in 'Hangar Flying' started by TopherJA, Mar 10, 2012.

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  1. Mar 10, 2012 #1

    TopherJA

    TopherJA

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    Does anyone have experience with QBlade - Wikipedia, the free encyclopedia wind turbine design software or wind turbine design in general? I am designing a blade and learning how different then prop design it is. Any suggestions on using the xfoil file formats?
     
  2. Mar 10, 2012 #2

    Retiree

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    I am glad you brought this topic up. I am working on wind turbine design from the point of view of airfoil design. I had not heard of Qblade.
    I have had some experience with XFoil, but it has been a long time. Maybe if you submit an input file with specific questions I can go back to look at what I did and maybe answer some questions.

    Doug
     
  3. Mar 15, 2012 #3

    jnfrluis

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    A wind turbine is designed to produce a maximum of power at wide spectrum of wind speeds. All wind turbines are designed for a maximum wind speed, called the survival speed, above which they do not survive.
     
  4. Mar 15, 2012 #4

    skeeter_ca

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    I drive out through Palm Springs, Ca pass area every day to work. It always amazed me that the hundreds of windmills would be shut down when the winds are really blowing hard, like 60mph+. I would think you could slow the props by changing the pitch to make sure they don't overspeed, but i'm sure the designers are alot smarter than me.
     
  5. Mar 16, 2012 #5

    skier

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    There are methods of controlling the wind turbines. Most have a rated power output that they try to maintain. At some point the wind gets too strong and the wind turbine needs to be shut down. Below is a typical graph of power output. Not only is the rated output power a function of the wind turbine, but it is also a function of the generator that is being used.

    [​IMG]

    This link describes some of the methods for control of turbine speed: HowStuffWorks "Wind Turbine Output"

    For more information on wind turbines, this is a good introductory book: Amazon.com: Aerodynamics of Wind Turbines (9781844074389): Martin O. L. Hansen: Books
     
  6. Mar 16, 2012 #6

    Retiree

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    One of the reasons the turbines shut down is the turbulent intensity is too large. The blades can't withstand the additional bending moment.
     
  7. Mar 16, 2012 #7

    orion

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    Just FYI - I moved the thread here under Hangar Flying since the subject matter has nothing to do with aircraft. In years past we have deleted discussions of non-related subject matter especially when, like in this case, there are numerous other discussion groups that specialize in this arena.
     
  8. Mar 16, 2012 #8

    bmcj

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    I can see where wind turbines have a bit of relevance to aircraft, at least in terms or R.A.T.'s and wind driven generators, or maybe even a rotor blade in autorotation (i.e. - gyrocopter/autogyro).
     
  9. Mar 17, 2012 #9

    Aircar

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    Actually wind turbines(and power station cooling tower fans) were the first things made in fiberglass by Eugene Hanle who went on to found Glasflugel which built the first commercially available fiberglass sailplane (Libelle)

    Ulrich Hutter designed both the wind turbines and the Libelle and it's predeccesor the H30TS (TS=Turbine sailplane but different meaning to turbine) --the shutting down of wind turbines at the very time when the most energy is available (power proportional to windspeed CUBED) is indeed a perverse thing - one way to avoid it would be to have telescoping blades that 'shrink' in order to limit the loads developed and the stresses .

    Just as an aircraft needs less wing area as speed increases the same thing applies to a wind turbine and in both cases reducing span and area is a load relieving method and makes higher speeds feasible. Variable diameter helicopter and proprotor blades have been tested but not at the scale of the huge wind turbines now in service --but on the other hand the MUCH lower RPM for big wind turbines makes for a massively lower centrifugal force to deal with . Perhaps in future this technology will be developed in wind turbines and then filter down to aviation .

    Of course there is also the autogyro (inspired by watching windmills according to Juan de la Cierva and sometimes referred to as the 'windmill plane' --we have actual flying autogyro type wind power generators now in development (see the Joby thread) and at least one emergency pilot escape systen using an autogyro rotor was prototyped --an alternative to a parachute )

    One other minor note re aviation and wind turbines --I used to do target towing and used a second world war RAF winch to retract the drogue with an external wind turbine (sort of like a ram air turbine but somewhat larger around 4ft 6in diameter) --and finally there is the wind tunnel which uses 'wind making' turbines that helped to develop aerodynamics like nothing else but don't themselves fly.
     
  10. Mar 17, 2012 #10

    stol

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    xxxx
     
    Last edited: May 5, 2012
  11. Mar 18, 2012 #11

    orion

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    Well, yes and no - I spent a couple of years designing wind turbine components (blades, towers, mounting systems, etc.) so I can address some of the structural issues. Wind turbines are simply just huge cyclic fatigue machines (more so than even helicopters) and as such, virtually all limitations that are set forth are structural in nature. You are correct that turbine speed is controlled by blade pitch but despite that, turbines shedding blades is still a fairly common event, especially at the larger wind farms. But it is the structural and dynamic (harmonic) issues that set how fast the blades should turn and as with wings, the pitch is set so the blades deliver the highest efficiency of power (within structural limits) for any given wind speed, but this is not always the fastest rotation possible.

    Current frequency is set by the electrical system, not turbine or generator speed.

    Because of the constant upkeep and maintenance though, the wind farms are not competitive with other forms of energy creation, often needing various forms of subsidies or regulatory support (requirements that the utility companies purchase "green" power) in order for them to be able to sell power to the grid. Current estimates are that the power from wind farms costs as much as 50% more than hydro or even natural gas or coal. I'm not sure about nuclear.

    Another interesting side note - as of about five years ago, it was estimated that the modern turbine would not be able to generate in its life time as much energy as it took to build it. Since components have to be regularly replaced, it is virtually impossible for the turbine to catch up to that energy use curve.
     
  12. Mar 18, 2012 #12

    stol

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    Last edited: May 5, 2012
  13. Mar 19, 2012 #13

    Dana

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    Depressing that it's still the case. In the early 1980's a bunch of guys I worked with were all excited about buying wind generators (this was on the NJ shore where the wind is consistent). "Generate your own power, sell the excess back to the grid, etc., etc." Sounded great until I looked at the numbers... the market cost of the amount of electricity generated over the expected lifetime of the generator was almost exactly the cost of the generator so it was a wash, and thus, IMO, not worth the hassle. And this was with tax credits... if you paid full price for the generator without the tax breaks it would have clearly been a losing proposition.

    Just in the past few days I saw a news article on wind turbine operators in the Pacific Northwest being paid subsidies (i.e. tax dollars) to not generate power... seems production is outstripping demand.

    I can see wind turbines making sense in remote "off grid" areas, or as a backup in certain situations, but for the most part they seem to be a "feel good" green project with no real benefits.

    -Dana

    Thoughts on the bailout: Back in 1990, the Government seized the Mustang Ranch (a legal Nevada brothel) for tax evasion and, as required by law, tried to run it. They failed and it closed. Now, we are trusting the economy of our Country and 850+ Billion Dollars to a pack of nitwits who couldn't make money running a *****house and selling booze.
     

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