流致共振分析方法與風機葉片實例應用

Methodology and Application of Flow-induced Resonance in Wind Turbine Blades

吳柏均(Bo-Jiun Wu)

指導教授 ： 林輝政

共同指導教授 ： 黃心豪(Hsin-Haou Huang)

國立臺灣大學/工學院/工程科學及海洋工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.01590

摘要

本文建立一套完整的動態流致共振分析流程，並選擇大型離岸風力發電機水平軸葉片進行實例應用探討之標的，欲提供產業界及學術界一套流致共振分析方法。
首先針對額定功率3.6MW及5MW大型風機葉片進行三維模型幾何外型之修正與繪製，並透過穩態流場分析進行額定功率計算，驗證模型之正確性。
接下來使用有限元素分析軟體COMSOL進行模態分析，先是透過模擬驗證，與文獻及理論比對，驗證本模態分析之可行性，然後才針對兩支葉片求取在不同轉速狀態下之自然頻率值，並探討其是否與操作頻率共振，且還針對5MW風機塔柱進行模態分析，探討塔柱是否會與葉片耦合。
再來同樣使用有限元素分析軟體COMSOL進行風振分析，先透過模擬驗證，與文獻比對，驗證模擬正確性，然後才針對兩支葉片各選取六個斷面，求取常態風況與極端風況之馮卡門渦列釋放頻率(風振頻率)，觀察各斷面是否有與葉片產生共振之疑慮。
最後進行風振損壞判定及實例應用，參考眾多文獻，分析並觀察葉片各斷面之共振風速範圍，最後挑選兩日之每秒風速實測數據，判斷葉片是否有「風振損壞」之疑慮。

關鍵字

離岸型風機葉片 ； 有限元素分析 ； 模態分析 ； 馮卡門渦列 ； 渦致振動 ； 鎖定

並列摘要

In this thesis, a complete set of process of dynamic flow-induced resonance analysis is established, through application of large-scale offshore wind turbine blades, which provides industry and academia with a set of method of flow-induced resonance analysis.
First, geometric shape of 3.6-MW and 5-MW large-scale wind turbine blades are designed, plotted. After that, steady flow field analysis is performed to calculate rated power to confirm accuracy of the model.
Second, modal analysis is performed by using finite element analysis software “COMSOL Multiphysics”. Through simulation verification, we confirm accuracy of the simulation compared with references and theory. After that, we study the natural frequency of two blades for different rotor speed, and then study if blades are resonant with operating frequency. Moreover, we perform modal analysis for 5-MW wind turbine tower, and then study if tower is coupled with blade.
Third, wind-induced vibration analysis is performed by using finite element analysis software “COMSOL Multiphysics”, too. Through simulation verification, we confirm accuracy of the simulation compared with references. After that, we choose 6 sections of each blade to calculate Von Karman vortex shedding frequency for normal wind conditions and extreme wind conditions, and then study if blades are resonant with vortex shedding frequency.
Finally, determination and application of wind-induced vibration damage is performed. Through a variety of references, we obtain the range of resonance wind speed for 6 sections of each blade. After that, we select experimental data of the wind speed per second for 2 days, determine whether there is wind-induced vibration damage on blades.

並列關鍵字

Offshore wind turbine blades ； Finite element analysis(FEM) ； Modal analysis ； Von Karman vortex street ； Vortex-induced vibration(VIV) ； Lock-in

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