垂直軸式水力渦輪機動力行為研究

Abstract

本研究對於水中垂直軸式渦輪機做前置動態分析，包括渦輪機特性以及渦輪機運作性能，做一系列的討論。並將垂直軸式渦輪機做串列組合，應用在台灣馬祖地區海灣之潮汐發電。 首先，對於水中垂直軸式渦輪機做運作原理的探究，並針對兩款具代表性的垂直軸式渦輪機－可變葉片俯仰角式渦輪機與螺旋葉片式渦輪機，作第一步的空氣動力學討論。接著，在渦輪機工作特性分析中，對於兩渦輪機分別進行二維及三維的計算流體力學模擬計算，證明可變葉片俯仰角式渦輪機與螺旋葉片式渦輪機的設計可大幅降低水流對於垂直軸式渦輪機造成的週期性震動並產生較為穩定的輸出力矩(功率)。 完成渦輪機單元運轉性能分析後，我們以螺旋葉片式渦輪機為例，藉由單渦輪機在每一個週期下產生的受力及受力矩變化做串列的組合討論。發現雙渦輪機組合在兩同方向、相差60。葉片相位角的螺旋葉片式渦輪機可以得到最小的受力震盪及受力矩震盪值；再以此同方向相差60。葉片相位角的雙渦輪機組為基礎，渦輪機串列(四渦輪機組合)則是以對稱組合為佳。 最後我們以馬祖地區潮汐為例，計算馬祖南竿與北竿海灣的潮汐能蘊藏量，並使用螺旋葉片式渦輪機串列做發電量的計算，假設開發馬祖潮汐發電能源，每年約可供電28.7GWh，相當於馬祖地區整年所需電力之42.6%。 未來希望能藉此概念，作為設計水力發電廠的基礎。

This research presents dynamic analyses of vertical-axis water turbines, which include the characteristics and the performance of turbines. Combined 4 helical turbines as one turbine set, the turbines are designed as a power plant to capture the tidal energy in Matsu, Taiwan. In this research, two typical kinds of vertical-axis water turbines are discussed: one is variable pitch water turbine, and another is helical water turbine. By aerodynamic theory, the basic characteristics of the vertical turbines are shown in this work; then the Computational Fluid Dynamic (CFD) techniques were used to simulate the variable pitch water turbine and the helical water turbine in 2D and 3D flow field domain respectively. The result shows that both two turbines could diminish the mechanical vibration affected from water flow in contrast with traditional fixed and straight blade vertical-axis water turbines From the CFD result, the turbines combination was descripted. Two turbines with the same direction of 60 degree phase difference are calculated to have the smallest force and moment vibration; in addition, four turbines with the symmetrical direction of zero phase difference, which based on the two turbine set descripted above, are calculated to have the best performance. Take Matsu Islands for instance, the tidal energy potential on the bay region in Beigan and Nangan were calculated. While developed, the tidal energy in Matsu could generate 28.7GWh per year, which is 42.6%requirement of Matsu region in 2011.