風洞阻塞效應影響小型水平軸風力機性能測試之數值模擬

Numerical Simulation of Wind Tunnel Blockage Effects on the Performance Tests of Small Horizontal-Axis Wind Turbines

林祐新(Yu-Hsin Lin)

指導教授 ： 林鴻佳

國立虎尾科技大學/工程學院/航空與電子科技研究所/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00025

摘要

本研究主要針對一葉片直徑2.4公尺、定尖速比設計的水平軸風力機使用數值模擬計算流體力學FLUENT 12版軟體，來評估風洞實驗時風洞壁對水平軸風力機性能測試之影響。因為風洞壁會產生阻塞效應（Blockage Effects），使流場加速而高估風力機性能，本研究探討不同尺寸風洞對此水平軸風力機性能測試之影響。本研究以滑動網格來模擬葉片的轉動及求解三維非穩態不可壓縮流場，計算在設計尖速比條件下之功率係數與阻塞比(風力機掃掠面積/風洞截面積)之關係。研究結果顯示阻塞比為10 %時，風速為8公尺/秒，功率係數增加達7.8 %，風速為10公尺/秒，功率係數增加達6.8 %，而阻塞比為20 %時，風速為10公尺/秒，功率係數增加達17 %，皆與Pope和Harper對鈍形體建議修正公式之修正值相當接近。

關鍵字

風洞效應 ； 水平軸風力機 ； FLUENT ； 性能測試

並列摘要

This study uses computational fluid dynamics software FLUENT 12 to assess the performance of a 2.4 m-diameter horizontal-axis wind turbine designed for constant tip speed ratio operation in wind tunnel testing. Because the blockage effects of the tunnel wall, the acceleration of air flow may increase the wind turbine’s performance.

This research investigates the blockage effects of the test section on the wind turbine performance by using a moving mesh method to simulate blade rotation and by solving unsteady, three-dimensional incompressible flow with the free stream velocity of 8 and 10 m/s to determine the relationship of power coefficient and blockage ratio under design tip speed ratio operation condition.

The result shows that the blockage ratio is 10%, the power coefficient increases 7.8 % for the free stream velocity is 8 m/s, 6.8 % for the free stream velocity is 10 m/s and the blockage ratio is 20 %, the power coefficient increases 17.0 % for the free stream velocity is 10 m/s, respectively, which is close to the simple formula suggested by Pope and Harper for bluff body correction.

並列關鍵字

Blockage Effects ； HAWT ； Blockage Ratio ； Bluff-Body Correction

參考文獻

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