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標題: Wind blade chord and twist angle optimization [打印本頁]

作者: wumingsheng 時間: 2009-3-20 20:05
標題: Wind blade chord and twist angle optimization
This paper shows a method to obtain optimal chord and twist distributions in wind
turbine blades by using genetic algorithms. The distributions are computed to maximize
the mean expected power depending on theWeibull wind distribution at a specific
site because in wind power systems optimization is highly site dependent [1]. This approach
avoids assumptions about optimal attack angle related to the ratio between the
lift to drag coefficients.
Genetic algorithms are global optimizers that have a wide trade-off between exploration
and explotation on the space problem. The geometry definition of a wind
blade is a problem with many degrees of freedom being suitable to fall in local optima,
which can be surpassed using evolutionary methods. Evolutionary Algorithms
are frequently used as powerful optimization methods. They are stochastic methods
inspired in the natural process of evolution[2, 3], and among their advantages are their
global search due to the management of a population of candidate solutions instead
only one, and also the only requirement of the knowledge of the fitness function value
to perform a evolutionary optimization, without any other consideration such as derivability
or continuity of the function. Many different optimum design problems in
multiple fields of sciences and engineering have been solved outperforming any other
previous results with evolutionary algorithms [4].
To optimize chord and twist distributions, an efficient implementation of the Blade-
Element and Momentum(BEM) theory [1, 5, 6] is used. It is basically a simplified
theory that is used routinely by wind power industry because it provides reasonably
accurate prediction of performance. The BEM theory has shown to give good accuracy
with respect to time cost, and at moderate wind speeds, it has sufficed for blade
geometry optimization.
In the implementation of BEM, the sophistication is dismiss to reduce computational
cost. The time required to evaluate the forces in a typical turbine is in the order
of milliseconds, which allows massive evaluation of trial turbines. The implementation
is validated by comparing power prediction with the experimental data of the

Risø test turbine that is one of six experimental turbines widely tested by the IEA. The
data are contained in the Annex XVIII report [7] and in the public database of rotor
performances at the ECN.
High quality in results is obtained until the stall zone, about wind speed of 13m/s
proximately. Predictions are used to compute the mean power that is the fitness function
in the genetic algorithm. The mean power, which is proportional to the annual
generated energy, is obtained by averaging power predictions with the probability obtained
from the Weibull distribution of the specific site. To obtain the optimal blade,
the upper and lower limits of chord and twist are needed as well as an optional upper
limit of the blade area.

作者: samwu001 時間: 2009-5-19 14:45
twist angle 我一直搞不懂

作者: wumingsheng 時間: 2009-5-19 16:23
最直觀的就是回去打開葉片切割打孔的那張圖紙，以根部界面和葉尖為參照，看葉型的偏離中軸線的角度，

然后即可
（不是距離）

作者: wumingsheng 時間: 2009-5-19 16:25
或者是葉型截面圖的那張，里面應該有ｔｗｉｓｔ哪一項的。

作者: chnkn 時間: 2009-6-5 16:22
對于葉片的弦長、扭角和相對厚度分布的優(yōu)化，通常就是葉片的氣動外形優(yōu)化設計，我正好是做這個的。一般與葉片選擇的翼型族、葉片運行最優(yōu)葉尖速比有關。

作者: wumingsheng 時間: 2009-6-5 17:26
陳兄，來說說。你是局內(nèi)人。

啥時候，咱們在搞漢翔這些東西的時候不用去烏克蘭求人家搞飛機翼型呢？

你認為俺們在大飛機上面翼型會是真正的自主研發(fā)還是“借鑒”他人的研究（比如暴力美學締造者--老毛子，據(jù)說波音，空客就經(jīng)常就復雜的空氣動力學問題拋給老毛子，你的觀點呢？）。

作者: chnkn 時間: 2009-6-6 10:29
怎么不能回復帖子了？難道有敏感詞？？

作者: chnkn 時間: 2009-6-6 10:36
吳兄對暴力美學研究比較透徹，呵呵。

作者: chnkn 時間: 2009-6-6 10:38
目前，目前山寨文化深入人心，不過對于大飛機這么敏感的話題，則不敢妄言。實際上，對于空氣動力學方面研究，飛機上應用的翼型研究應該不是什么難點，難點在于整機空氣動力學的研究？我本人一直從事風電機組空氣動力學研究，對于飛機，好像變得一知半解了，不好意思。

作者: chnkn 時間: 2009-6-6 10:39
回到風能領域，有個8 6 3計劃課題，說是要研究我國自主知識產(chǎn)權的風電機組專用翼型族，最后恐怕也是把DU？NREL S或者某個翼型族拿來作作風洞試驗了事？等著瞧吧。

作者: chnkn 時間: 2009-6-6 10:39
這個樣子應該不算暴力美學范疇了吧？

作者: chnkn 時間: 2009-6-6 10:41
幫我分析一下，上面哪個詞敏感？怎么合一起就發(fā)不出來？

作者: wumingsheng 時間: 2009-6-6 11:45

引用第9樓chnkn于2009-06-06 10:39 AM發(fā)表的 :
回到風能領域，有個8 6 3計劃課題，說是要研究我國自主知識產(chǎn)權的風電機組專用翼型族，最后恐怕也是把DU？NREL S或者某個翼型族拿來作作風洞試驗了事？等著瞧吧。

呵呵，開玩笑說說阿。

自主知識產(chǎn)權？

汽車的自動變速箱還是前不久由吉利汽車拿下來的呢。

從老毛子50年代援建的解放汽車開始，50年，發(fā)動機不說了。連個變速箱搞了50多年都沒搞出來。

在8年前，也是所謂地863計劃，賣國債籌資8個多億，搞了400多磚家來搞變速箱，所有的國有精英集合起來，5年后自動放棄，無論怎么拆，怎么模仿，還是搞不清。

然后吉利出來自己搞。搞成了。花點點錢，點點人。

對于國家的研究機構，算了吧。

上上新聞可以，用上場不行。

多少老毛子在中國航空工業(yè)？[s:7]

看看長征火箭的發(fā)動機是誰的？

運輸我們的洲際導彈的車是誰的？

隨便說說阿[s:7] 比較悲觀。

作者: chnkn 時間: 2009-6-6 12:22
吳兄，與您看法一致，比較悲觀！

相反，我比較看好民營企業(yè)。可是目前的環(huán)境，對中小民營企業(yè)生存不易啊 [s:6]

作者: wumingsheng 時間: 2009-6-6 12:25
陳兄，是的，

目前投資經(jīng)商環(huán)境惡化，民營日子不好過。

但是他們是最有活力，最富創(chuàng)造力的一個群體了。

給了合適的陽光，溫度，就能長出奇跡。

當然，如果人有老毛子那么厲害，我們應早就有了我們自己的暴力美學史了。 [s:2]

作者: 大腳丫 時間: 2010-2-26 11:47
看來，這里的都是高人阿！
學習、受教了！呵呵

作者: 大腳丫 時間: 2010-2-26 11:54

引用第9樓chnkn于2009-06-06 10:39 AM發(fā)表的 :
回到風能領域，有個8 6 3計劃課題，說是要研究我國自主知識產(chǎn)權的風電機組專用翼型族，最后恐怕也是把DU？NREL S或者某個翼型族拿來作作風洞試驗了事？等著瞧吧。

請問各位大哥，現(xiàn)在國內(nèi)主流葉片采用的是什么翼型啊？

作者: lewjane84 時間: 2010-2-26 12:12
naca
du
ffa

作者: 大腳丫 時間: 2010-2-26 12:51

引用第17樓lewjane84于2010-02-26 12:12 PM發(fā)表的 :
naca
du
ffa

ffa是不是收費的啊？

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