小型風力發電機葉片之熱影像法檢測與熱學分析

Thermographic inspection and thermal analysis of an experimental wind turbine blade

何厚緯(Hou-Wei He)

指導教授 ： 江支弘

朝陽科技大學/理工學院/營建工程系/碩士(2013年)

摘要

地球環境巨變，極端氣候所產生的災害不斷，使替代能源的選擇更為迫切與需要。風力發電機為替代能源選項之一，目前在風力發電機葉片的檢測與維修仍以目視檢測為主，以遠距離非接觸方式來檢測葉片受損情況的技術仍有待開發。
本研究以紅外線熱影像儀拍攝與紀錄小型葉片溫度分佈情形，實驗分別為室內實驗與戶外實驗兩類，並針對所拍攝的紅外線影像進行不同的影像處理，室內實驗在缺陷內部則為兩種物質，一為空氣，二為水。室內實驗缺陷為空氣的影像經處理後，在背景雜訊的抑制，以整體影像溫度平均值的影像比第一張影像溫度為基準的影像佳；空氣缺陷區域的顯示以第一張影像溫度為基準的影像較整體影像平均溫度值的影像佳；含水缺陷的影像經處理後，以影像中每個畫素的溫度值，均減去以該張影像中的最小溫度值，運算出的影像為佳，空氣缺陷與含水缺陷的顯示自紀錄時間前段到中段皆能清晰看到兩者缺陷，室內實驗不管缺陷為空氣或水，整體影像處理為一階導數影像顯示較合成影像佳。戶外實驗影像處理後，以第一張影像溫度為基準的影像優於整體影像溫度平均值的影像，仍以一階導數影像所獲得的影像好。本研究另以有限元素法模擬受熱與風吹後，比較4種對流類型與9種模型在不同的缺陷寬度、缺陷厚度、缺陷至表面距離與溫差的關係，分析結果以缺陷至表面距離遠近為主要影響溫差的因素；其次為缺陷厚度；而缺陷寬度影響溫差較小。

關鍵字

熱像法 ； 葉片 ； 有限元素

並列摘要

On-site visual inspection of wind turbine blades is time-consuming and labor-intensive. Current study investigates the application of infrared thermography on an experimental scale-down wind turbine blade. The scale-down wind turbine blade has debonded layers in which air or moisture may exist. Thermal images were acquired both indoor and outdoor. Defects contained air layer was found to be cooler while those contained moisture was hotter than the rest of the blade. The images were then analyzed using time-domain polynomial data fitting for synthetic images after temperature difference had been preprocessed using various references. In general the synthetic images of first-order derivative can enhance the defects shortly after the heating in controlled experiments indoor. Two-dimensional finite element models were also applied to the thermal analysis of the blade. The defects were modeled in nine geometrical combinations of three depths, three widths, and three thicknesses. The depth of the defective layer is the most dominate factor in creating the temperature difference on the surface of the blade. The results also confirm that the air layer is in lower temperature and the moisture layer is in higher temperature than the rest of the blade.

並列關鍵字

blade ； final element analysis ； thermal analysis

參考文獻

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