Wind-Farm Flow Behaviors of S809 Airfoils Using Various Geometric Arrangements

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Project title

Code/計畫編號

MOST103-2221-E019-027

Translated Name/計畫中文名

S809翼型群組風機受不同幾何配置的流場行為

Project Coordinator/計畫主持人

Shun-Chang Yen

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Mechanical and Mechatronic Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=8354767

Year

2014

Start date/計畫起

01-08-2014

Expected Completion/計畫迄

01-07-2015

Bugetid/研究經費

577千元

ResearchField/研究領域

機械工程

"本計畫書擬議一個系統性的實驗方法，以葉片為 S809 翼型在攻角(Angle of attack)、翼根掠角 (Sweep angle)、翼尖上反角(Dihedral angle)與翼展剖面扭角(Twist angle)的條件下，進行對單一風機 (Wind turbine)及群組風機(Wind farm)效能提升之研究。申請人基於前二年進行葉片的縱列(Tandem)、與並行(Side-by-side)排列間隙(Gap ratio)變化的被動式流體調控機制；及先前對於風扇散熱、機翼氣動力特性、鈍體間不同排列等的研究與實務經驗；發現在葉片參數固定下，風機與風機本體之間的幾何配置，對風機效能有很大的影響。因此本計畫將嘗試，如能以「應用」層面的觀點，結合申請人先前研究的結果，以 S809 翼型風機葉片在攻角、翼尖為梢小翼(Winglet)角度、翼根為不同掠角與翼展剖面扭角的變化下，增進風機效能(Wind-turbine efficiency)之提升；最後研究風機塔與風機塔本體間的幾何配置加以探討，有效的將群組風機(Wind farm)效能提升，相信在能源開發上有極高的價值與應用。有鑑於此，在此專題研究計畫中；第一年中，進行以葉片攻角、翼尖梢小翼上反角、翼根掠角及翼展剖面扭角的結果為調控流場條件下；結合設計、開模、製造出實體風機(Wind turbine)，直接進行風力發電之測試。過程中，將風機構置於風洞測試區，進行風機效能發電研究。以風機葉片驅動步進馬達做為發電機使用，類永磁式發電機原理；並以線圈在固定磁場中轉動產生電流脈波，經倍壓器轉為直流電壓輸出；再將電力輸入至充電電路系統中。實驗過程以不同轉速、風速、風向條件下擷取風力發電系統產生的電壓與電流，並計算風能產生的功率。並輔以風機理論分析推算最佳效能之風力發電。研究方式將以煙線流場可視化技術、熱線風速儀偵測風機塔(Wind-turbine tower)本體尾流，流體因不同高度而受柱體、發電機、葉片等不同鈍體影響的複雜流場行為，包含由壓力、及速度梯度所產生的渦街(Vortex street)及剪流層不穩定波(Shear layer instability)之間機制的差異。使用質點影像速度量測儀(PIV)系統以定量的方式，呈現量測時間相關的非穩態流之演化過程及與漩渦尾流之交互作用。並以噪音分貝計(Decibel-meter)偵測風機噪音頻譜與分貝，有效確認葉片通過頻率(Blade passing frequency, bpf)及其倍頻。可以預期的，直接進行風力發電之測試的效果與風機葉片的流場特性結果，將延續給“群組風機最佳相對位置＂的機構，俾利下一年度計畫使用。第二年中，回饋前一年所得到的結果，以實體風機進行風力發電條件下，進行群組風機(Wind farm) 的流場特性及電力性能之研究。過程中，將九組風機以 3 × 3 陣列形式(Wind-turbine array)構置於風洞測試區，進行不同風機塔與風機塔間距、自由流速與紊流大小、及轉速不同所產生交互作用下，所產生的流場特性及電力性能之研究。研究方式將以煙線流場可視化技術、拓樸理論的分析應用，判讀陣列風機間的流場行為是否有相互干涉的影響；及以熱線風速儀偵測陣列風機的流場性質，包含速度的分布、紊流強度與自由流風速、風機轉速與尾流頻率特性間的關係；以噪音分貝計偵測陣列風機所產生的噪音強度，輔以瞭解陣列風機對環境生態之影響。可以預期的，陣列風機的流場特性及電力性能之研究，將可回饋至前一年實體風機的設計。本計畫最終將以探討改善風機葉片幾何裝置與群組風機風力發電的效能相結合。將單一風機的設計方法，與群組風機間在固定面積設限內的間距規範，作有系統相關性的統整與討論。研究結果將在科學理論的呈現及實際應用的層面均有相當大的意義。" "In the current proposal, a S809 blade-airfoil will be utilized to study the efficiency improvement on a single wind turbine and wind farm. The controlling factors include the angle of attack, sweep angle, winglet dihedral angle and wing twist angle. In the last two-year investigations, the applicant has studied the passive flow-modulation mechanism on the tandem-arranged and side-by-side wing blades. Furthermore, the previous results include the fan-cooling efficiency, wing aerodynamic performance of forward/backward swept wings and the wake-flow characteristics around/near the bluff-bodies. The previous experimental results show that the geometrical configuration (tandem or side-by-side) for two specific wing airfoils has a significant effect on the surface-flow and wake-flow patterns. Therefore, the applicant proposes the systematic experiments to study the controlling factors on improving the wind-turbine and wind-farm performance. Basing on the previous studies, the applicant utilizes a S809 blade-airfoil and suggests that the performance of wind turbine can be promoted by (1) joining the winglet at wing tip, (2) changing the dihedral angle of winglet, (3) changing the sweep angle of wing blades and (4) changing the blade twist-angle. These controlling factors of the wing blades and the wind-turbine geometrical configurations will be investigated on the performance improvement of the wind-farm. Specifically, the investigation results will be utilized on the study of energy efficiency. This project includes two-year research programs. In the first-year program, the optimum parameters of winglet dihedral angle, sweep angle, and blade twist-angle will be studied. These factors will be utilized in the designing, molding and manufacturing the wind turbine. Additionally, the power-generator kit will be connected with the wind turbine to test the electric power output. The fabricated wind turbine will be installed in a wind tunnel to control the flow conditions. The permanent-magnet generator will generate the electric power when the motor is driven by the wind turbine. The output voltage and current are recorded to calculate the output power of power generator. In the power analysis, the rotation speeds, upstream velocities and angles of attack of wing blades will be changed. The wind-turbine principle will be utilized to analyze and calculate the optimum wind power. The experimental measure methods include the smoke-wire flow visualization and hot-wire anemometry. For a combination of wind-turbine tower, the airflow moves around tower pillar cylinder, generator hub and wing blade will induce the complicated flow behaviors. These flow behaviors include the pressure and velocity gradients, vortex streets and the shear-layer instability. The particle image velocimetry (PIV) system quantify the time-related vortex-shedding evolution and the wake-flow structures. This project also considers issue of environmental pollution. Therefore, a decibel meter will be utilized to detect the noise spectrum, blade passing frequency (bpf) and multiple-frequency phenomenon when the wind turbine is in operation. The wind-blade flow characteristics and wind-power generation examination will be utilized in the construction conception of wind-farm conducted in the second-year program. In the second year program, the results of previous two-year combining with the real wind-power generator will be examined in the performance of wind farm. During the test of wind-power efficiency, a 3 by 3 wind-turbine array will be setup in the test section of wind tunnel. The flow characteristics and wind-power efficiency will be studied by changing the gap/spacing of wind turbines, the free-stream velocity, and the free-stream turbulence intensity (T.I.). The research approaches includes the smoke-wire visualization and topological analysis to measure/detect the flow interaction between the wind turbines. Furthermore, the hot-wire anemometry detects the relationships of flow characteristics (flow velocity, turbulence intensity, wind-turbine rotation speed) and wake-vortex frequency. Additionally, with considering the effect of wind farm on the ecological resources, a decibel-meter will be utilized to measure the noise level. The investigation of wind farm on flow characteristics and generation efficiency will feedback to the wind-turbine design studied in the first program. Finally, this project will discuss and analyze the geometrical configuration of wind-turbines and wind-farm performance."

Keyword(s)

流動調制
幾何配置
風機效能
群組風機
Wind-turbine efficiency
Flow modulation
Geometrical configuration
Wind farm

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Wind-Farm Flow Behaviors of S809 Airfoils Using Various Geometric Arrangements

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