Flow Properties of Side-By-Side Blade-Wings and Its Applications on the Performance Improvement of Wind Farm

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Project title

Code/計畫編號

NSC102-2221-E019-018

Translated Name/計畫中文名

並行翼葉片流場特性應用於群組風機之效能提升

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=3095359

Year

2013

Start date/計畫起

01-08-2013

Expected Completion/計畫迄

01-07-2014

Bugetid/研究經費

711千元

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，利用並行葉片與葉片(Side-by-side blade)間隙(Gap ratio)變化的被動式流體調控機制，進行對單一風機及群組風機(Wind farm)效能提升之研究。申請人基於目前進行多級數轉子(Multi-stage rotary rotors)縱列排列(Tandem)方式的調控研究，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；發現葉片與葉片之間的幾何配置，決定了風機效能。因此可藉由葉片與葉片的配置，及葉片攻角、翼根掠角(Sweep angle)、翼尖上反角(Dihedral angle) 與雷諾數條件下，提升風機效能。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，在葉片翼尖為梢小翼(Winglet)角度及翼根為不同掠角的變化下，發展調控葉片間不同幾何配置的設計，進而增進風機效能(Wind-turbine efficiency)之提升；最後研究群組風機效能之提升，將風機與風機本體間的距離因素加以探討，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，進行變化並行葉片與葉片(Side-by-side blade)間隙之流動控制方式，以葉片左、右不同構置於風洞測試區，進行並行葉片間隙及葉片攻角、雷諾數研究。藉由調制葉片間隙進而改變表面流場與提高氣動力性能，並同時回饋將翼尖梢小翼上反角及翼根為不同掠角的影響一併加入探討。研究方式將以煙線流場可視化技術、油膜觀察葉片與葉片間表面流場的特徵模態、拓樸理論的分析應用；及以熱線風速儀偵測葉片與葉片間的流場行為，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。PIV系統以量化的量測時間相關的非穩態流之演化過程以及與漩渦尾流之交互作用；利用六力平衡儀量測氣動力性能。將流體穿過並行葉片不同間隙比時，葉片的表面流場、尾流行為、與氣動力特性的關聯性做討論。找出並行葉片間隙比的最佳值，將結果延續給下一年度計畫，進行風力發電時之測試。第二年中，回饋與彙整前一年所得到的結果，在葉片與葉片間隙比、翼尖梢小翼上反角及翼根掠角的結果調控流場條件下；結合設計、開模、製造出實體風機，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(Wind-turbine efficiency)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。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，將可回饋至前一年風機葉片幾何配置的控制機構。第三年中，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，進行不同風機與風機間距、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(Decibel-meter) 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，將可回饋至前二年風機葉片幾何配置的控制機構。本計畫最終將以探討改善風機葉片幾何配置機構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。研究結果將在科學意義的呈現及實際應用的層面有相當的意義。" "This project proposes a systematic empirical approach to investigate the flow behaviors between/around the side-by-side blade-wings. The side-by-side blade-wings passively modulate the flow field and then improve the performance of wind-turbine. The applicant recently studied the flow-modulation mechanism of tandem multi-stage rotary rotors. Furthermore, based on the previous researches on the cooling efficiency of fans, aerodynamic performance of forward/backward swept wings and the wake-flow characteristics around the bluff-bodies, the applicant found that the geometrical arrangement (tandem or side-by-side) and the configuration (spacing ratio, gap ratio, angle of attack, rotation angle and Reynolds number) of the specific wing airfoils changed the surface-flow and wake-flow patterns. Therefore, the applicant proposes that the control factors can improve the blade-wing performance. Additionally, the applicant proposes that the performance of wind turbine can be improved by (1) joining the winglet at wing tip, (2) changing the dihedral angle of winglet, (3) changing the sweep angle of blade-wings and (4) changing the geometrical configuration of blade-wings. The control factors of the blade-wings combining the effect of gap/spacing of blade-wings will be proposed to investigate the performance improvement of wind farm. The finding of this project will be utilized on energy efficiency. This project includes three-stage experiments and will be performed in three years. In the first year program, the flow-modulation mechanism of side-by-side blade wings will be performed in an open wind-tunnel. The surface-flow patterns and aerodynamic performance will be investigated by changing the gap ratio, angle of attack and Reynolds number. Additionally, the dihedral angle of winglet and the roughness near wing-junction will be considered. The measurement approaches include the smoke-wire flow visualization, oil flow visualization and topological analysis to reveal the characteristic flow patterns on the blade wings. The hot-wire anemometry detects the pressure and velocity gradients, vortex-street behaviors and the shear-layer instability between/behind these blade wings. The particle image velocimetry (PIV) system quantify the time-related vortex-shedding evolution and the wake-flow structures. Furthermore, a six-force balancer will measure the lift, drag and pitching moment. Moreover, the effect of turbulence intensity (T.I.) on the surface-flow structures, wake-flow patterns and aerodynamic performance will be analyzed and discussed. Finally, the dominant factors on aerodynamic loadings will be determined and the optimal control factors will be utilized in the next-year program. In the second year program, the findings of the first-year investigation will be utilized. The optimum parameters of gap ratio, winglet dihedral angle and sweep angle of blade-wings will be applied in the real turbine machine. Moreover, the generator kit will connect to the wind-turbine model to generate the electric power. 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. Expectably, the generated power of wind turbine relates with flow characteristics obtained in the first-year results. Namely, the geometrical arrangement of blade-wings will influence the output efficiency of wind turbine. In the third 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 studies of wind-power efficiency will feedback the flow characteristics to the investigation of first two-year programs. Finally, the geometrical configuration of wind-turbines and wind-farm performance will be discussed and analyzed systematically."

Keyword(s)

流動調制
並行葉片
間隙
風機效能
群組風機
Flow modulation
Side-by-side blade
Gap ration
Wind-turbine efficiency
Wind farm

DSpace CRIS

Flow Properties of Side-By-Side Blade-Wings and Its Applications on the Performance Improvement of Wind Farm

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