臺灣博碩士論文加值系統

本研究為探討兩種不同幾何外型的水平軸風力發電機葉片之空氣動力性能差異，一種是利用葉片元素動量理論所設計之葉片，另一種是平均弦長無扭矩角之葉片（基準葉片）。主要是探討由葉片元素動量理論設計之葉片為什麼相對於基準葉片，有較好的功率係數。
因此將探討空氣動力特性在葉片上對效率之影響。利用風洞實驗量測兩種葉片的功率係數以提供實驗數據給數值模擬驗證其模擬值；在數值模擬方面，首先利用二維模擬找出最適合的y^+值，並應用於三維模擬找出最適合的紊流模型；因此，在數值模擬計算中利用二階上風離散法之Shear-Stress Transport (SST) k-ω紊流模型結合SIMPLE數值方法去求解穩態Reynolds-averaged Navier Stokes方程式以得到葉片的空氣動力性能；利用數值模擬觀察葉片表面之流場現象以解釋其空氣動力性能之差異。
由葉片流場觀察中，可以發現葉片元素動量理論設計之葉片其根部扭矩角會減少分離流的發生，在風速10m/s翼尖速度比5.236時，由於非常接近設計翼尖速度比，因此葉片吸入側的流場幾乎沒有發生分離現象，所以相對基準葉片有較高的功率係數。

The purpose of this study is to investigate the differences of the aerodynamic performance on the horizontal-axis wind turbine blades of two different type of geometry shape. One of the blade is designed by blade element momentum theory (BEMT), and the other blade is a non-twisted with a constant chord length, which is called Baseline blade. In order to investigate on the BEMT designed blade, in which has a great performance of power coefficient than Baseline blade. Therefore, the effect of the aerodynamic performance on the blades would be investigated in this study.
It would use the wind tunnel experiment to measure the power coefficients of these two blades for the numerical simulation to verify the experimental data. In the numerical simulation, the appropriate y^+ value is found by 2D simulation and the value would apply in 3D simulation in order to find the appropriate turbulence model. In addition, the aerodynamic performances of the blades are obtained by using the SST k-ω turbulence models of 2^nd upwind scheme with SIMPLE algorithm method to solve the Reynolds-averaged Navier Stokes (RANS) equations. It would observe the flow fields phenomenon on blade surface for explaining the differences of the aerodynamic performance by using the numerical simulation.
From observing the flow fields on the blades, it can be seen that the BEMT designed blade would reduce the separated flow occurrence at the root due to the twist angle of the blade. At the wind speed of 10 m/s with the tip speed ratio of 5.236 which is very close to the design tip speed ratio of 5, the BEMT designed blade has a greater power coefficient than Baseline blade, because the flow field on the suction side of the blade is not occurred the separation.

ABSTRACT IN CHINESE i
ABSTRACT ii
ACKNOWLEDGEMENT iv
CONTENTS v
LIST OF TABLES vii
LIST OF FIGURES viii
NOMENCLATURE xii
CHAPTER I INTRODUCTION 1
1.1 Background of Modern Wind Turbines 2
1.2 Literature Review 7
1.3 Motivation and Objectives 10
1.4 Contents of Research 11
CHAPTER II BLADE THEORY AND EXPERIMENTAL ARRANGEMENT 12
2.1 Betz Limit Theory 12
2.2 Airfoil Characteristics 16
2.3 Performance Parameters of HAWT 18
2.4 Theory of Wind Turbine Blade 21
2.4.1 Momentum Theory 21
2.4.2 Blade Element Theory 22
2.4.3 Tip Loss Correction 25
2.4.4 Blade Element Momentum Theory 26
2.4.5 Blade Design Procedure 26
2.5 Experimental Arrangement 27
2.5.1 Experimental Test Model 28
2.5.2 Experimental Setup 30
CHAPTER III NUMERICAL SIMULATION 33
3.1 Governing Equations 33
3.2 Turbulence Model 35
3.2.1 Spalart-Allmaras Turbulence Model 35
3.2.2 Shear-Stress Transport (SST) k-ω Turbulence Model 37
3.3 Numerical Method 40
3.3.1 Discrete Method 40
3.3.2 Upwind Differencing 41
3.3.3 SIMPLE Algorithm 42
3.4 Grid Generation and Validation of Simulation 44
3.4.1 2D Simulation 44
3.4.2 3D Simulation 53
CHAPTER IV RESULTS AND DISCUSSION 58
4.1 Wind Tunnel Experimental Results 58
4.2 Numerical Simulation Results 63
4.3 Investigation on the Flow Field of Blades 66
CHAPTER V CONCLUDING REMARK 82
REFERENCES 84

[1] Manwell, J. F., McGowan, J. G., and Rogers, A. L., Wind Energy Explained—Theory, Design and Application, John Wiley ＆ Sons Ltd, United Kingdom W. S., pp.83-138., 2009.
[2] Giguere, P. and Selig, M. S., Design of a Tapered and Twisted Blade for the NREL Combined Experiment Rotor, NREL/SR-500-26173, NREL, Golden, CO, 1999.
[3] Simms, D. A., Hand, M. M., Fingersh, L. J., and Jager, D. W. Unsteady Aerodynamics Experiment Phases II-IV Test Configurations and Available Data Campaigns, NREL/TP-500-25950, NREL, Golden, CO, 1999.
[4] Hansen, A. C. and Butterfied, C. P., Aerodynamics of Horizontal-Axis Wind Turbines. Fluid Mechanics, Vol. 25(1):15-49., 1993.
[5] Mukesh M. Yelmule et al., CFD predictions of NREL Phase VI Rotor Experiments in NASA/AMES Wind tunnel. International Journal of Renewable Energy Research:Vol.3, No.2., 2013.
[6] Tachos, N. S et al., A Computational Aerodynamics Simulation of the NREL Phase II Rotor. The Open Mechanical Engineering Journal 3:9-16., 2009.
[7] Moshfeghi, M et al., Effects of near-wall grid spacing on SST-K-ω model using NREL Phase VI horizontal axis wind turbine. Journal of Wind Engineering and Industrial Aerodynamics 107-108: 94-105., 2012.
[8] Rocha, P. A. C., et al., k–ω SST (shear stress transport) turbulence model calibration: A case study on a small scale horizontal axis wind turbine. Energy 65: 412-418., 2014.
[9] Krogstad, P. -A. and Lund, J. A., An experimental and numerical study of the performance of a model turbine. Wind Energy 15:443-457., 2012.
[10] Hsiao, F. B. and Bai, C. J et al., The Performance Test of Three Different Horizontal Axis Wind Turbine (HAWT) Blade Shapes Using Experimental and Numerical Methods. Energies 6(6): 2784-2803., 2013.
[11] 白啟正, 利用改良型葉片元素動量理論、風洞量測與數值模擬之方法進行水平軸式風力機葉片之設計與性能分析航空太空研究所.Vol.博士論文, 國立成功大學, 2013.
[12] 吳明芳, 四百瓦水平軸式風力發電葉片設計與性能測試, 航空太空研究所.Vol.碩士論文, 國立成功大學, 2009.
[13] Duran, S., Computer-Aided Design of Horizontal-Axis Wind Turbine Blades. Department of Mechanical Engineering, Thesis of Master, Natural and Applied Sciences of Middle East Technical University., 2005.
[14] Ingram, G., Wind Turbine Blade Analysis using the Blade Element Momentum Method. Version 1.1 Durham University., 2011.
[15] Liu, S. and Janajreh, I., Development and application of an improved blade element momentum method model on horizontal axis wind turbines. International Journal of Energy and Environmental Engineering 3:30., 2012.
[16] 李信宏, 內政部建研所風洞實驗室, 內政部建築研究所., 2013.
[17] FLUENT 6.3, User Guide, FLUENT Incorporated, 2006.
[18] ANSYS FLUENT, “ANSYS FLUENT 14.0 Theory Guide,ANSYS Inc, 2011.
[19] Rumsey, C. L. and P. R. Spalart., Turbulence Model Behavior in Low Reynolds Number Regions of Aerodynamic Flowfields. AIAA Journal 47(4): 982-993., 2009.
[20] Wilcox, D. C., Multiscale Model for Turbulent Flows. AIAA Journal 26(11): 1311-1320., 1988.
[21] Menter, F. R., Two-equation Eddy-viscosity Turbulence Models for Engineering Applications. AIAA Journal 32(8): 1598-1605., 1994.
[22] Patankar, S. V. and Spalding, D. B., A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows. International Journal of Heat and Mass Transfer 15(10): 1787-1806., 1972.
[23] Drela, M., XFOIL: An Analysis and Design System for Low Reynolds Number Airfoil, Dept. of Aeronautics and Astronautics. MIT, 1989.
[24] Shepers, J. G., Brand, A. J., Bruining, A., Graham, J. M. R., Hand, M. M., Infield, D. G., Madsen, H. A., Maeda, T., Paynter, J. H., van Rooij, R., Shimizu, Y., Simms, D. A., Final Report of IEA Annex XVIII: Enhanced Field Rotor Aerodynamics Database, ECN-C-02-016, Netherlands Energy Research Foundation., 2002.
[25] Huang, J. C., et al., Parallel Preconditioned WENO Scheme for Three-dimensional Flow Simulation of NREL Phase VI Rotor. Computers ＆ Fluids 45(1): 276-282., 2011.
[26] Lee, S. G., et al., Performance Prediction of NREL (National Renewable Energy Laboratory) Phase VI Blade Adopting Blunt Trailing Edge Airfoil. Energy 47(1): 47-61., 2012.
[27] 王晟桓, 外罩式風力渦輪性能提升之研究. 航空太空研究所.Vol.博士論文, 國立成功大學, 2013.