小型垂直軸風力機發電功率與環境紊流分析

Abstract

本文主要針對小型垂直軸風力發電機的發電功率與環境條件進行探討，並將研究內容分為兩大項：第一分項為小型垂直軸風力機在高紊流環境下的發電效率分析，第二分項為小型垂直軸風力發電機架設處之環境的模擬計算分析。 都會區地形複雜多變，加上高樓林立，在都會區的風場容易與地形和障礙物的干擾而形成紊流，不利於風力機運轉而致使風力機發電效率不佳。本研究之內容的第一分項的研究內容為：量測此測試環境的自然條件對風力發電機功率的影響，如：風向、水平風速和垂直風速。實驗結果顯示，發現超過90%的發電功率都來自當垂直風速小於或等於水平風速時，而垂直風速在水平風速介於6 m/s到8 m/s之間時有明顯的影響，最多僅剩下沒有垂直風速時的44%，而紊流強度在風速大於8 m/s時會開始收斂，逐漸趨近於約30%。本研究第二部分則是藉由穩態模擬及暫態模擬和長時間蒐集的數據進行比對，了解此測試環境的紊流強度，找出在此環境下風力發電機效率不彰的主因。實驗結果顯示，環境中高聳之建築物為主要障礙，導致風力發電機架設處風速偏低，且紊流強度高，因此理解此測試環境並不適宜於此風力發電機之運作。

The main theme of this thesis is discussing about the relationship between wind turbines’ power output and the environment, and have divided into two parts mainly. The first part is talking about the power efficiency of small vertical wind turbine which operates in high turbulence environment. The second part is the analysis and simulation of the test environment where the small vertical axes wind turbine located. There has complicated topography and lots of buildings in metropolitan areas. The turbulence formed as a result of the interference of the topography and obstacles in urban areas easily. The content of the first part of this thesis: It is going to measure and analyze the test environment which affects the power output of the wind turbine, such as wind direction, horizontal wind speed and vertical wind speed. According to the result of experiment, we found that over than 90% of power output was generated when vertical wind speed is less than or equal to horizontal wind speed. In addition, vertical wind speed has obvious influence when horizontal wind speed is between 6 m/s and 8 m/s, only 44% of the power output without vertical wind speed, and the turbulence intensity will converge about 30 % when the wind speed is larger than 8 m/s. We analyze the turbulence intensity by steady state simulation, transient simulation and compare with the collected data, and find some key points about the worse efficiency of this test environment. According to the result of experiment, we found that the higher building in the environment is the main obstacle, resulting in the low wind speed where the wind turbine located, and the turbulence intensity is high. We get this environment is not suitable for the operation of this test wind turbine.