在单个叶片旋转一周内存在两个方位角(0°~180°),其当地攻角为零,当地力矩为负值,当地功率输出为负值,降低了风轮整体性能。提出采用扰流来改善两个方位角叶片周围流场,进而提高风轮整体气动性能的新方法。以美国Sandia国家实验室旋转直径2m的中型风轮为研究对象,基于双盘面多流管模型,分析扰流对风轮上盘面和下盘面的气动攻角和力矩以及整体气动性能的影响规律。计算结果证明:在扰流的影响下,0°方位角的气动攻角从0°提高到5°,叶素力矩从0.2Nm提高到1.1Nm,风轮的风能利用系数提高8%;在180°方位角增设扰流后,其气动特性提高幅度较0°方位角低,叶素力矩最大增幅为0.4Nm,风轮的风能利用系数提高3%。经验证双盘面多流管模型计算结果与Sandia试验结果吻合良好,证明计算结果具有可参考性。
Within one cycle of the single blade, two azimuth angles, 0° and 180°, where the local angle of attack is zero, the local torque is negative and the local power output are negative, greatly lower the overall performance of wind turbine. A new technology that an interference air is used to rebuilding the flow field of blade working in the two azimuth angles, is put forward to promote power output of the turbine. USA Sandia experimental Ф- type VAWT with 2 m diameter and 2 m height is of research object. The effects of interference air on angle of attack, torque of blade element in upstream half-cycle and downstream half-cycle, are investigated by double disk multiple stream tube model. The calculation results show that, at 0° azimuth angle, interference air greatly increases the angle of attack from 0° to 5°, the torque of blade element grows from 0.2 Nm to 1.1 Nm, and the growth of power coefficient of the turbine is 8%; At 180° azimuth angle affected by the interference air, the extent of promotion is lower than that of 0° azimuth angle, the max torque growth of blade element is 0.4 Nm, the power coefficient is increase by 3%. The results of double disk multiple stream tube model are consistent with experiment data from Sandia laboratory, which prove the all calculation results are highly credible.