臺灣博碩士論文加值系統

本文主要利用Lighthill聲學類比理論為基礎的寬頻帶噪音源模式(Broadband Noise Source Model, BNS)與FW-H(Ffowcs Williams and Hawkings)方程式，模擬氣流流經風車葉片時所產生的噪音，針對氣動力噪音部分進行研究，探討不同的入流速度、入流攻角及紊流強度對氣動噪音產生的影響。首先對於NACA64(3)-618、S809、S822三種翼剖面進行流場的驗證與比對，在得到正確的紊流場資訊後，方可進行聲場之分析。文中採用不同的氣動噪音預測方法，探討噪音產生之相關機制及影響因素，首先，使用雷諾平均法(Reynolds-averaged Navier-Stokes Equation)求解穩態流場分佈，而紊流之模擬則採用 模式，在數值分析中，將入流紊流強度分別增加至5%與10%，從結果中得知入流紊流強度的增加，會使得流場產生劇烈的變化，對於噪音更是重要的影響因素之ㄧ。在聲場分析中，採用寬頻帶噪音源模式，運用Proudman方程式可得到聲音能量密度在整個計算區域中所分佈的情形，以及使用Curle方程式可進行表面聲功率的預測。另外，本文利用大尺度渦漩模擬方法(Large Eddy Simulation)求解暫態流場，在聲場中以FW-H方程式來分析計算噪音的暫態響應，藉此預測其聲壓訊號，經由快速傅立葉轉換得到聲音壓力位準頻譜，並進而求得其聲功率。而此一方程必須以流場的紊流資訊作為音源項，為獲得正確的紊流場資訊，網格的分割需相當的細膩，因此計算量較為龐大。為簡化分析，在本文僅以小型風車葉片作為分析對象，累積相關分析經驗，以作為將來大型風車葉片噪音預測的參考。

The purpose of the research is to investigate the noises induced by flow over the wind blades. The noise analysis is conducted by the Broadband Noise Source Model and FW-H (Ffowcs Williams and Hawkings) Formula which are based on theory of Lighthill’s acoustic analogy. How the wind velocity, angle of attack as well as the inflow turbulent intensity influence the induced aerodynamic noise is discussed. First of all, the dynamic coefficients and flow field of three airfoils NACA64(3)-618、S809 and S822 were verified, and then the accurate information of turbulence was provided as the source to evaluate the sound energy distribution. Three types of noise models that provided different characteristics of the noise distribution were adopted in this wrok. Firstly Reynolds-averaged Navier-Stokes Equation with the k-e turbulent model was used to predict the turbulent flow field. When the inflow turbulent intensity was increased to 5% and 10%, it causes great changes to the flow field and obviously it is also one of the major facts to the flow induced noise. For aerodynamic noise analysis, Proundman’s BNS model was performed to get the acoustic energy density distribution over the entire calculating domain. Further, Curle’s Formula was adopted to predict the surface acoustic power along the solid boundary. In order to understand the details of flow induced noise one step further, the Large Eddy Simulation approach for the unsteady flow combined with the FW-H equation was used to predict the unsteady sound pressure signal. Then by Fourier Transformation the spectrum of the noise can be calculated and consequently the frequency distribution and the power output are achieved. It might be useful in reducing the flow induced aerodynamic noise. However, LES requires a very fine grid resolution to capture the large scale eddy. At this stage, our current computer resources are extremely difficult to satisfy the computational efforts. Therefore, only the small wind blades were taken as the analysis object in this study. This experience may be useful in large wind blade analysis in the near future.

誌謝 I
中文摘要 II
英文摘要 III
簡稱術語對照表 IV
目錄 V
圖目錄 VIII
表目錄 XII
符號說明 XIII


第一章 緒論
1.1 前言…………………………………………………1
1.2 文獻回顧……………………………………………2
1.3 研究目的與方法……………………………………3
1.4 論文架構……………………………………………4

第二章 基本理論
2.1 統御方程式…………………………………………7
2.1.1 連續方程式……………………………………7
2.1.2 動量方程式……………………………………7
2.2 雷諾方程式…………………………………………8
2.2.1紊流模式……………………………………… 9
2.3 大尺度渦漩模擬方法………………………………11
2.3.1次格點尺度模型……………………………… 12
2.4氣動聲學…………………………………………… 13
2.4.1 Lighthill聲學類比理論…………………… 14
2.4.2寬頻帶連續譜噪音模式……………………… 15
2.4.3 Ffowcs-Williams and Hawkings方程式……17
2.4.4聲音大小之表示……………………………… 19

第三章 數值模擬方法
3.1 計算流程說明………………………………………21
3.2 邊界條件……………………………………………21
3.2.1出入口邊界條件……………………………… 21
3.2.2 固體壁面邊界條件……………………………22
3.2.3 壁面函數法……………………………………22
3.3 有限體積法…………………………………………23
3.3.1求解流程……………………………………… 26
3.3.2 壓力修正方程…………………………………27

第四章 穩態氣動噪音結果與分析
4.1 計算方法……………………………………………31
4.2 計算模型……………………………………………31
4.3 流場驗證結果與討論………………………………32
4.3.1 NACA64(3)-618翼剖面氣動力驗證與分析… 32
4.3.2 S809翼剖面氣動力驗證與分析………………33
4.3.3 S822翼剖面氣動力驗證與分析………………33
4.3.4 分析與討論……………………………………34
4.4 氣動噪音模擬結果與討論…………………………34
4.4.1 NACA64(3)-618氣動噪音分析……………… 35
4.4.2 S809氣動噪音分析……………………………35
4.4.3 S822氣動噪音分析……………………………36
4.4.4 分析與討論……………………………………37

第五章 暫態氣動噪音結果與分析
5.1 計算方法……………………………………………65
5.2 計算模型與網格測試………………………………65
5.3 流場驗證結果與討論………………………………66
5.3.1 NACA64(3)-618翼剖面氣動力驗證與分析… 66
5.3.2 S809翼剖面氣動力驗證與分析………………66
5.3.3 S822翼剖面氣動力驗證與分析………………67
5.3.4 分析與討論……………………………………67
5.4 氣動噪音模擬結果與討論…………………………67
5.4.1 NACA64(3)-618氣動噪音分析……………… 67
5.4.2 S809氣動噪音分析……………………………68
5.4.3 S822氣動噪音分析……………………………69
5.4.4 分析與討論……………………………………70

第六章 結論
6.1 結論…………………………………………………96
6.2 未來展望……………………………………………97

參考文獻 98

[1]江懷德、陳美蘭, "達成我國2010年風力發電目標之推動方案",2004風能應用研討會論文集,2004年.

[2]M. J. Lighthill, "On Sound Generated Aerodynamically. I. General Theory", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 211, NO.1107, pp. 564-587, 1952.

[3]I. Proudman, "The generation of noise by isotropic turbulence", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 214, pp. 119-132, 1952.

[4]N. Curle, "The Influence of Solid Boundaries upon Aerodynamic Sound", Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences Vol. 231, No. 1187, pp. 505-514, 1955.

[5]J.E. Ffowcs Williams and D.L. Hawkings,"Sound Generation by Turbulence and Surfaces in Arbitrary Motion", Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, Vol. 264, No.1151, pp. 321-342, 1969.

[6]M. Boltezar, M. Mesaric and A. Kuhelj,"The influence of uneven blade spacing on the SPL and noise spectra radiated from radial fans" Journal of Sound and Vibration Vol. 216, No. 4, pp. 697-711, 1998.

[7]C. Montavon, I. Jones, P., Szepessy, S., Henriksson, R., el-Hachemi, Z., Dequand, S., Piccirillo, M., Tournour, and F., Tremblay "Noise propagation.from a cylinder in a cross flow: comparison of SPL from measurements and from a CAA method based on a generalized acoustic analogy" IMA Conference on Computational Aeroacoustic, pp. 1-14.2002

[8]O. Fleig, M. lida, Chuichi Arakawa,"Wind turbine blade tip flow and noise prediction by large-eddy simulation" Journal of Solar Energy Engineering Vol. 126, pp. 1017-1024.2004.

[9]S. Khelladi, S. K., F. Bakir, R. Rey."Predicting tonal noise from a high rotational speed centrifugal fan." Journal of Sound and Vibration Vol. 313, pp. 113-133.2008.

[10]袁淑嫈, "二維風車葉片之氣動力噪音分析",國立台灣大學工程科學及海洋工程學系碩士論文, 2008 6月.

[11]N. Sarigul-Klijn and D. Karnopp, "A Computational Aeroacoustic method for Near and Far Field Vehicle noise Prediction", AIAA Journal, 2001.

[12]Y. Addad, D. Laurence, C. Talotte, and M.C. Jacob "Large Eddy Simulation of a Forward-Backward Facing Step for Acoustic Source Identification", Int. Journal of Heat and Fluid Flow, Vol.24, pp. 562-571, 2003.

[13]Fluent Inc. "Modeling Turbulence ", September 29, 2006.

[14]B.E. Launder, D.B. Spalding, "Lecture in Mathematical Models of Turbulence" Academic Press, London, 1972.

[15]N. G. Shan, "A New Method of Computation of Radiant Heat Transfer in Combustion Chambers" PhD thesis, Imperial College of Science and Technology, London,England,1979.

[16]J.Smagorinsky, "General Circulation Experiments with Primitive Equations." , Monthly Weather Rev. Vol. 91, No. 3, pp 99-164,1963.

[17]S. Sarkar, M.Y. Hussaini, "Computation of the Sound Generated by Isotropic Turbulence", NASA Contract Report No. 93-74, NASA Langley Research Center, Hampton VA 24681, 1993.

[18]GAMBIT Version 2.3.16 User’s Guide.

[19]FLUENT Version 6.3 User’s Guide.

[20]S.V. Patankor, D.B. Spalding, "A Calculation Processure for Heat, Mass and Momentum Transfer in Three-Dimensional Parabolic Flow", Int J Heat Mass Transfer, Vol.15, pp.1787-1806, 1972.

[21]R.I. Issa, "Solution of the Implicitly Discretised Fluid Flow Equations by Operator-Splitting", J. comput. Phys., Vol.62, pp.40-65, 1986.

[22]Ira H. Abbott, A, E. Von Doenhoff, "Theory of Wing Sections: Including a Summary of Airfoil Data", McGraw-Hill, New York, 1959.

[23]M.S. Selig and B.D. McGranahan, "Wind Tunnel Aerodynamic Tests of Six Airfoils for Use on Small Wind Turbines", NREL/SR-500-34515, October 2004.

[24]J.L. Tangler, "The Nebulous Art of Using Wind-Tunnel Airfoil Data for Predicting Rotor Performance", NREL/CP-500-31243, January, 2002.

[25]S. Oerlemans, "Wind Tunnel Aeroacoustic Tests of Six Airfoils for Use on Small Wind Turbines", NREL/SR-500-35339, August 2004.

[26]Dan M. Somers, "Design and Experimental Results for the S809 Airfoil", NREL/SR-440-6918, January 1997.

[27]D.M.Somers,"The S822 and S823 Airfoils", NREL/SR-500-36342, January 2005.

[28]S.Sovani,"Acoustics Modeling with FLUENT",Technical Support Engineer, Automotive Team, June 5th,2003.