小型水平軸式風力發電機空氣動力特性探討

Studies of aerodynamic characteristics of small horizontal-axis wind turbines

劉立仁(Li-Jen Liu)

指導教授 ： 陳增源

淡江大學/工學院/航空太空工程學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00951

摘要

本研究實驗探討小型風力發電機之空氣動力特性，實驗參數包括風速、葉片外型、葉片數、葉片阻塞比及葉片螺距角等，使用之葉片為NACA2415及NACA4415兩種翼型之無扭角葉片，並連接於一直徑15公分的錐形輪轂。實驗設備包括一全長9米、測試斷面1.3米x1.3米之開放型風洞，皮托管風速量測系統、轉速計、扭力計及模擬負載之電子式煞車系統。本研究之風洞阻塞比(blockage ratio)約為28.3%，因此，先就風洞阻塞效應作探討；結果顯示，風洞阻塞效應與風力發電機功率係數，尤其是葉片螺距角，有很大關聯，且修正有一極限值，最大之功率係數修正約27%，在低尖速比及高葉片螺距角下，則僅需作少許修正。在葉片空氣動力特性方面，較低的螺距角、寬度較窄的翼尖，有較高的葉片效率，但也需較高之啟動風速；而葉片增加雖有助於能量擷取，藉以降低啟動風速與增加低速領域的使用，但卻可能因重量而減低最高葉片轉速。

關鍵字

水平軸式風力發電機；風力發電

並列摘要

This research experimentally investigated the aerodynamic characteristics of small horizontal-axis wind turbines in a 1.3 m x1.3 m wind tunnel. The experimental parameters include blade number, tip chord length, wind speed, solidity ratio, and pitch angle. The turbine blades are no twisted. Two types of airfoil, NACA2415 and NACA4415, are used in this research. Turbine blades were attached to a cone hub with a base diameter of 15 cm, which was connected to a measurement apparatus including torque, rotor rotating speed, axial force sensors, and a brake system. The whole apparatus was placed on a support located in the middle of the tunnel test section. A pitot-static tube measured wind velocities. Effects of tunnel blockage on the turbine power coefficients were first determined by measuring the tunnel velocities with and without rotors using a pitot-static tube under various test conditions. Results show that the rotor blockage factor (BF) depends strongly on the rotor tip speed ratio (TSR), the blade pitch angle (β), and the tunnel blockage ratio (BR). The larger the TSR and BR are, the smaller the BF is. The BF approaches a constant value when the TSR exceeds a certain value. This study also shows that the blockage correction is less than 5% for a BR of 10%. No blockage correction is necessary for small TSR under all of the investigated conditions, and for the investigated blade pitch angle of 25o. In the blade aerodynamic aspect, results show that small blade pitch angle and short tip chord length have higher blade efficiencies, but also have higher starting wind speeds. Larger number of blades may have more energy extract, lower starting wind speed but also have lower RPM because of the weight.

並列關鍵字

wind turbines

參考文獻

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