大型風力發電機扇葉之抖振反應分析

Buffeting Analysis of Large Wind Turbine Blade

劉牧宇(Mu-Yu Liu)

指導教授 ： 林堉溢

淡江大學/工學院/土木工程學系碩士班/碩士(2013年)

https://doi.org/10.6846/TKU.2013.00835

摘要

台灣地理位置四面環海適合發展風力發電，但也是位屬於颱風侵襲地帶，也曾出現風力發電機損壞的報導，儘管國內外的研究者對於扇葉的性質、材料、形狀早已經研究多年。因現階段風力發電扇葉分析比較缺乏動態影響分析和抖振反應的研究，所以本文利用結構風工程的觀點來分析風力發電機扇葉受風力作用下之顫振及抖振反應進行探討。
為了簡化問題，本文假設扇葉為變化寬度水平無扭轉角度方式進行分析，將扇葉視為靜止的懸臂樑進行模擬，模擬分析中的風力係數及顫振導數皆參考於文獻。在顫振臨界風速分析時，採用複數特徵值法疊代計算，而扇葉抖振反應是採用頻譜進行分析。
為了驗證正確性，利用既有機翼來驗證機翼斷面顫振分析，發現與文獻上結果吻合。本文中採用兩種不同的風力發電扇葉之例題模型來進行顫振及抖振分析，例題扇葉於顫振分析中，在風速低於100(m/s)時並沒有顫振現象，是因為扇葉頻率很高的關係；於抖振分析中可以發現垂直向的反應比順風向及扭轉向來的顯著，利用等值勁力風載重的概念，可以求得等值靜力，並且推算出動態載重下扇葉垂直向所受的最大正向應力。

關鍵字

風力發電機扇葉 ； 顫振分析 ； 抖振反應

並列摘要

Since Taiwan is surrounded by sea and is in the typhoon-prone area, it is an appropriate place for developing wind power. However, some damages of wind turbine blades have been reported. Although the aerodynamic behavior of wind turbine blades have been investigated and discussed in many literatures, the buffeting responses of wind turbine blades were seldom studied. The purpose of this thesis is to investigate the flutter wind speeds and the buffeting responses of wind turbine blades by using an analytical approach based on flutter and buffeting theories.
To simplify the analysis, the wind turbine blade was assumed to be horizontal and modeled as a cantilever beam. The static wind force coefficients and the flutter derivatives of airfoils, adopted from literatures, were used in the analysis. The complex eigen-value analysis was used to calculate the flutter wind speed of the wind turbine blade. The buffeting responses of the blade were analyzed based on a spectral analysis.
To examine the validity of this analysis, the flutter wind speed of an airfoil was evaluated first. It can be found that the results agree well with those in the literatures. Two types of wind turbine blades were then studied in this thesis. As the mean wind velocity is less than 100m/s, there is no flutter identified in these blades. This is because the torsional frequencies of these blades are very high. The results also indicated that the buffeting responses in the vertical direction are more significant than those in the drag and torsional directions. Using the vertical displacement, the equivalent static wind loads were then generated and used for the calculations of the maximum stresses in the blades.

並列關鍵字

flutter Analysis ； buffeting Analysis ； Wind Turbine Blade

參考文獻

1. Povl-Otto Nissen, “Wind Power-The Danish Way: From Poul la Cour to Modern Wind Turbines,” (2009).

3. A.K. Kaw,“Mechanics of Composite Materials,” (2006).

5. T. Theodorsen,“General theory of aerodynamic instability and the mechanism of flutter,”NACA Report 496, (1935).

6. H.J. Hassig, “An approximate true damping solution of the flutter equation by determinate iteration,” Journal of Aircraft, PP. 885-889, (1971).

8. D.W. Lobitz,“Aeroelastic Stability Predictions for a Mw-Sized Blade,” Wind Energy Vol. 7, No. 3, PP.211-224, (2004).