目前新能源中的海流發電,對我國而言屬於剛起步的階段,將來必定需加強相關的技術研究,以便能推動綠色能源的發展。現今國際上已開發海流機的國家,在發電技術上幾乎都是以單一一台海流原型機的方式作商業化前的實際測試。然而,為了要獲得更大的額定發電量,未來海流發電勢必會同時集合多組的海流機,以組成陣列的方式,來進行大規模發電,此稱之為「海流場」。因上游的海流機會對下游的海流機形成遮敝作用,而使得到達下游海流機的海流流速變慢,降低發電量,此現象稱之為「尾流效應」。因此,瞭解海流場中多部海流機尾流的相互影響,對於海流場的發展是相當重要的。 本論文研究目的之一,是利用商業化計算流體動力學軟體Fluent,來模擬出水平軸與垂直軸海流機之尾流效應,以瞭解海流機在海流中的流體力學特性。根據海流機在不同的推力係數、不同的亂流強度、不同的海流初始速度及不同的海流機深度下的尾流特性作分析及探討。除此之外,本論文亦利用此模擬的尾流特性配合線性動量守恆理論,推導出一半實驗簡化尾流效應模型,以作為未來大型海流場中海流機最佳擺放位址配置之應用。
At present, the development of new energy such as ocean current power generation is only on the first stage, the enforcement of technical research is necessary in the future, as to promote the development of green energy. Nowadays, the countries with the capability to develop ocean current generators are almost testing their prototype machines using single ocean current generator to be commercialized. However, in order to obtain more generating capacity, multiple ocean current generators must be aggregated in the future. This can form a machine array to generate more power. This kind of array can be called “ocean current farm”. Because the upstream turbine may shelter the downstream turbine, it makes the downstream current velocity slow down and its power generation amount reduced. This phenomenon is called “wake effect”. Therefore, it is important for the development of ocean current farm to understand the wake interaction between multiple ocean current generators. One purpose of this theses utilizes commercial computational fluid dynamics software “Fluent” to simulate the wake effect of the horizontal and vertical axis ocean current turbines as to understand the fluid dynamic characteristics of the turbines in the ocean current. Under different thrust coefficient, turbulence intensity, initial current velocities and turbine located depths, the wake characteristics of ocean current generators is analyzed and discussed. In addition, the wake effect simulated results and linear momentum conservation theory are also utilized to derive a semi-empirical simplified wake effect model in this theses. This model can be used to allocate the optimal positions of ocean current turbines in a large ocean current farm.