臺灣博碩士論文加值系統

摘要

水平軸風車是目前最重要且最常見的風力發電風車類型，本論文主旨即在試圖應用計算方法預測水平軸風車的性能與流場，論文中應用黏性流RANS程式計算與分析其性能和流場狀況，並同時使用BEM(Blade Element Momentum)理論進行分析，BEM理論並以葉尖端損失修正因子校正其結果。論文中將此兩種數值方法計算所得之結果皆以實驗資料佐證。本論文首先對於風車的基本理論進行介紹，由一維之線動量理論推導到角動量理論，接著介紹葉片元素理論、葉片元素動量理論以及葉尖端損失修正模式。
本論文中之計算例為一NASA曾進行實驗的二葉風車，所應用的翼型是一專為風車設計的S809翼型，我們首先展示此二維翼面的計算結果，其次針對不同的網格作比較，找出適合風車計算的網格結構。對於三維風車進行計算，先應用葉片元素理論求解，再加上葉尖端損失修正模式，得到準確的結果，但此方法卻無法探討流場細節。接下來應用黏性流計算分析葉片的受力與性能，包括扭力、受力狀況、壓力分佈，以及探討三維效應的影響性，結果顯示受力趨勢已掌握，精準度尚可接受，但網格產生與計算時間使其成為較耗成本的計算方法。
關鍵詞：風車葉片、翼面、RANS、葉片元素動量理論

Abstract

The Horizontal Axis Wind Turbine (HAWT) is the most widely used wind power machine, and the objective of this thesis is to compute the flow field around an HAWT. The computational methods used in this thesis are the blade element momentum (BEM) theory and the viscous flow RANS method, and the computational results are validated by experimental data. In this thesis, different computational methods applied to the wind power turbines are first introduced, and the blade element momentum theory with the tip loss corrections and RANS are especially emphasized.
The computational example presented in this thesis is a wind turbine which has been experimented in the NASA Ames Lab., and the foil geometry used by this turbine is a foil especially designed for the wind turbine named S809. The computational results of this two-dimensional foil by RANS are first presented, and the computational results agree well with the experimental data. A multi-layer grid system is found to be the most proper grid arrangement for 3-D wind turbine computations. The computational results of the three-dimensional wind turbine by RANS, including torque, local forces and pressure distributions, are then shown and discussed. The BEM theory with a tip loss correction gives a very good prediction for the torque; however, without the ability to show the detailed forces and flows. The comparisons between the computational results of the RANS method and the experimental data are encouraging. Although the predictions of torques are not as well as the BEM theory, RANS results provide information of the local forces and detailed flows.
Keyword：wind turbine, RANS, blade element momentum theory, airfoil

目 錄

謝誌 I
中文摘要 II
英文摘要 III
目錄 IV
圖目錄 VI
表目錄 XI
第一章 緒論
1-1 前言 1
1-2 文獻回顧 4
1-3 研究方法 8
第二章 風車空氣動力學理論
2-1 一維動量理論與Betz定理 10
2-2 旋轉尾跡流理論 14
2-3 翼面理論 18
2-4 葉片元素動量理論(BEM) 20
第三章 黏性流數值理論
3-1 基本假設 32
3-2 統御方程式 33
3-3 紊流理論 38
3-4 壁函數探討 39
3-5 邊界條件 41
3.5.1 出入口邊界條件 41
3.5.2 固體壁面邊界條件 42
3.5.3 週期性流場邊界條件 43
3-6 收斂條件 43
第四章 數值計算結果與討論
4-1 二維翼型之數值計算與結果 48
4-2 葉片元素動量理論之計算 50
4.2.1 計算方法 50
4.2.2 葉尖損失之修正 52
4.2.3 新葉尖損失修正模式 53
4.2.4 具備葉尖損失修正之計算結果 57
4-3 黏性流之計算 57
4.3.1 網格配置與邊界條件 57
4.3.2 結果與討論 60
4-4 計算結果之檢討 62
第五章 結論與展望 96
參考文獻 98
附錄A 翼面理論 101








圖目錄

圖2-1 風車的驅動盤模式，速度1、2、3、4分別為所在的速度 25
圖2-2 Betz風車的參數關係圖 25
圖2-3 葉片後的尾跡流模式 26
圖2-4 旋轉尾跡流理論之動量圖 26
圖2-5 理想風車的動力係數圖與有尾跡流的風車動力比較圖 27
圖2-6 軸誘導因子與角誘導因子在不同徑下的比較 27
圖2-7 二維翼面所產生的升力與阻力及力矩之示意圖 28
圖2-8 NACA0012不同雷諾數之平板升力係數比較圖 28
圖2-9 NACA0012之不同雷諾數升力係數比較圖 29
圖2-10 DU-93-W-210翼型之升力係數圖 29
圖2-11 DU-93-W-210翼型之阻力與力矩係數圖 30
圖2-12 葉片元素理論示意圖 30
圖2-13 葉片的流場狀況圖 31
圖2-14 風車翼剖面的速力圖 31
圖3-1 (a)無加速作用的座標系統，(b)加速參考座標系統 45
圖3-2 風速7m/s之r/R=0.3之流場圖 46
圖3-3 風速7m/s之r/R=0.95之流場圖 46
圖3-4 風速7m/s之r/R=0.63之流場圖 47
圖3-5 三維風車葉片之網格y+圖 47
圖4-1 二維翼面S809之y plus圖 65
圖4-2 S809於不同攻角下的CL與實驗值之比較 65
圖4-3 S809於不同攻角下的CD與實驗值之比較 66
圖4-4 與 值之經驗曲線圖 66
圖4-5 BEM計算之結果與實驗值扭力比較圖 67
圖4-6 應用修正葉尖端損失法於BEM之結果與實驗值扭力比較圖 67
圖4-7 各式網格之扭力比較圖 68
圖4-8 三維風車葉片之全域網格圖 68
圖4-9 三維風車葉片之區塊網格分配比例圖 69
圖4-10 三維風車葉片之截面網格圖 69
圖4-11 三維風車葉片網格的y plus圖 70
圖4-12 三維風車葉片邊界條件示意圖 70
圖4-13 風車葉片扭力收斂狀況 71
圖4-14 風速7m/s、截面r/R=0.3之黏性流與實驗值壓力分佈比較 71
圖4-15 風速7m/s、截面r/R=0.47之黏性流與實驗值壓力分佈比較 72
圖4-16 風速7m/s、截面r/R=0.63之黏性流與實驗值壓力分佈比較 72
圖4-17 風速7m/s、截面r/R=0.8之黏性流與實驗值壓力分佈比較 73
圖4-18 風速7m/s、截面r/R=0.95之黏性流與實驗值壓力分佈比較 73
圖4-19 風速10m/s、截面r/R=0.3之黏性流與實驗值壓力分佈比較 74
圖4-20 風速10m/s、截面r/R=0.47之黏性流與實驗值壓力分佈比較 74
圖4-21 風速10m/s、截面r/R=0.63之黏性流與實驗值壓力分佈比較 75
圖4-22 風速10m/s、截面r/R=0.8之黏性流與實驗值壓力分佈比較 75
圖4-23 風速10m/s、截面r/R=0.95之黏性流與實驗值壓力分佈比較 76
圖4-24 風速15m/s、截面r/R=0.3之黏性流與實驗值壓力分佈比較 76
圖4-25 風速15m/s、截面r/R=0.47之黏性流與實驗值壓力分佈比較 77
圖4-26 風速15m/s、截面r/R=0.63之黏性流與實驗值壓力分佈比較 77
圖4-27 風速15m/s、截面r/R=0.8之黏性流與實驗值壓力分佈比較 78
圖4-28 風速15m/s、截面r/R=0.95之黏性流與實驗值壓力分佈比較 78
圖4-29 風速20m/s、截面r/R=0.3之黏性流與實驗值壓力分佈比較 79
圖4-30 風速20m/s、截面r/R=0.47之黏性流與實驗值壓力分佈比較 79
圖4-31 風速20m/s、截面r/R=0.63之黏性流與實驗值壓力分佈比較 80
圖4-32 風速20m/s、截面r/R=0.8之黏性流與實驗值壓力分佈比較 80
圖4-33 風速20m/s、截面r/R=0.95之黏性流與實驗值壓力分佈比較 81
圖4-34 風速25m/s、截面r/R=0.3之黏性流與實驗值壓力分佈比較 81
圖4-35 風速25m/s、截面r/R=0.47之黏性流與實驗值壓力分佈比較 82
圖4-36 風速25m/s、截面r/R=0.63之黏性流與實驗值壓力分佈比較 82
圖4-37 風速25m/s、截面r/R=0.8之黏性流與實驗值壓力分佈比較
83
圖4-38 風速25m/s、截面r/R=0.95之黏性流與實驗值壓力分佈比較 83
圖4-39 7m/s風車之正向力與實驗值比較 84
圖4-40 10m/s風車之正向力與實驗值比較 84
圖4-41 13m/s風車之正向力與實驗值比較 85
圖4-42 15m/s風車之正向力與實驗值比較 85
圖4-43 20m/s風車之正向力與實驗值比較 86
圖4-44 25m/s風車之正向力與實驗值比較 86
圖4-45 7m/s風車之切向力與實驗值比較 87
圖4-46 10m/s風車之切向力與實驗值比較 87
圖4-47 13m/s風車之切向力與實驗值比較 88
圖4-48 15m/s風車之切向力與實驗值比較 88
圖4-49 20m/s風車之切向力與實驗值比較 89
圖4-50 25m/s風車之切向力與實驗值比較 89
圖4-51 r/R=0.3風車三維效應之升力係數比較圖 90
圖4-52 r/R=0.3風車三維效應之阻力係數比較圖 90
圖4-53 r/R=0.47風車三維效應之升力係數比較圖 91
圖4-54 r/R=0.47風車三維效應之阻力係數比較圖 91
圖4-55 r/R=0.63風車三維效應之升力係數比較圖 92
圖4-56 r/R=0.63風車三維效應之阻力係數比較圖 92
圖4-57 r/R=0.8風車三維效應之升力係數比較圖 93
圖4-58 r/R=0.8風車三維效應之阻力係數比較圖 93
圖4-59 r/R=0.95風車三維效應之升力係數比較圖 94
圖4-60 r/R=0.95風車三維效應之阻力係數比較圖 94
圖4-61 Fluent扭力計算結果與實驗值比較圖 95















表目錄

表1-1 水平軸特性的不同分析方法 7
表2-1 動力係數 為 的函數 24
表4-1 實驗之風車操作條件 64
表4-2實驗之風車模型尺寸 64

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