具翼尖小翼風力發電機葉片噪音評估之研究

Abstract

本文將選取東元風車葉片進行流場分析，進而研究氣流流經三維風車翼面時，因氣流場壓力變動所產生的氣動噪音，並且研究風力發電機葉片增加翼尖小翼後，渦流的變化以及對噪音的影響。憑藉著現代計算機的發達，一開始運用Gambit前處理器進行幾何繪圖及邊界劃分，並且將計算域以非結構網格劃分，再透過Fluent軟體進行建立離散控制方程式，離散後的代數方程式，利用疊代方式求解。其中，控制方程式是用雷諾平均方程式（RANS）進而求解，包括扭力、壓力、速度分佈，再計算出各個風速下之最佳的轉速，最後，比對廠商結果驗證分析的正確性，藉此比對後所可得到流場資訊，以用來計算其風力發電機效率，方便以後風能開發上的比照。接著，以此流場資訊為基礎，來進行氣動噪音分析。 我們由文獻可知，翼尖小翼是可用來減小機翼的誘導阻力和減弱大型飛機的尾流，因此，針對東元風力發電機葉片加裝翼尖小翼，改變其漸縮比及長度，以觀測翼尖渦流變化對聲場的影響，探討所產生之氣動噪音對環境的影響，觀察聲功率是否得到改善。其中，針對聲場模擬所使用的理論，採用了Fluent軟體中的寬頻帶噪音模式（Broadband Noise Source Model, BNS）之Curle 方程式進行模擬分析，可供事前預測。

This study choose TECO wind turbine blade to investigate the noise of three-dimensional air flowing through the windmill wing generated by its pressure variation, and the impact of increasing the wind turbine blades winglet g tip on the change of vortices and the noise. First, this study generate the analysis mesh with a geometrical pre- processor Gambit, then use the Fluent software to construct the discrete control equation which solution solved by iterative methods. Reynolds averaged Navier-Stokes (RANS) equations are used to describe the turbulent flow field. The computational results by RANS, including torque and pressure distributions. Fluent can calculate its optimum factor under each wind speed corresponding to RPM. After comparing and verifying our results with the manufacturer data, we continued calculating the efficiency of wind turbines, We also analysd the noise of turbulent flow, based on our results. Installing the winglet can reduce the drag and the wake of large aircraft. Therefore, investigating the changing of winglet its length and tapered ratio installing on TECO wind turbine blades we can know if the effect of noise on the environment is improved or not. And this study analyzed the sound field with Broadband Noise Source Model (BNS), which based on the Lighthill’s acoustic analogy.