傳統流道式風機設計原理主要為增加入口截面積以提高氣流量,然而提升風速才是真正提高空氣動能的有效方式。本研究發現,桶形流道利用 Bernoulli 原理造成抽吸效應,可有效地提高流道內的氣流速度,並藉此提升風機效率。本研究更進一步改良固有的Complex演算法,並配合物件導向的最佳化程式介面,以及計算流體力學軟體模擬,對流道幾何外型進行最佳化設計。根據最佳化結果顯示,最適合此桶型流道的內部幾何形狀為一非傳統噴嘴,在最佳情況下可將氣流速度提升60% 以上。 以配備此最佳化噴嘴之桶型流道為基礎,本研究成功設計並製造出一部流道式風力發電機組,並經過CFD模擬及實地測試,證明確實能改善風機的工作流場,並將風機的動能擷取效率提高約80%。
Designs for conventional ducted wind turbines usually include a large inlet for more absorption of the air flow. However, the most efficient solution should be increasing the speed of wind. It has been observed that a bucket-shaped duct produces a sucking effect according to the Bernoulli’s Theorem, and thus significantly increases the wind speed inside the duct, while the efficiency of the wind turbine can be substantially enhanced. Moreover, the geometry of the duct is optimized by the combination of an improved Complex algorithm, an object-oriented optimizing program interface, and the simulations by CFD software. According to our studies, the optimal shape for the interior of the duct appears to be an unconventional nozzle, which extends the range of wind speed by 60%. Based on this bucket duct equipped with the optimal nozzle, a wind power generator has been practically designed and constructed. The results of the field tests show that the proposed ducted turbine does improve the flow around the generator and thus increase its power extraction efficiency by about 80%.