Development of Intelligent Wind Turbine Generator with Tandem Rotors: Optimization of Wind Rotor Profiles

这款智能风力发电机具有以下特点。(1)两个风轮都在低风速下开始旋转，但后风轮与前风轮相反旋转。(2)随着风速的增大，两个风轮的转速都增大，在额定风速下，尾部风轮达到最大转速。(3)随着风速的增大，后风轮逐渐减速，开始与前风轮同向旋转，输出功率保持不变。(4)即使在恶劣的风向条件下，反转也能使产量提高。为了得到该机组的最佳叶型，在台架试验中考察了双旋转电枢式双馈感应发电机的特性，并在风洞和CFD.1中对两个风轮的叶片型线进行了优化。发电机经证实，该发电机与串联风r…配合工作良好更多的电机和二次输出可以从输入电路，也就是内电枢处获得。最佳风轮直径比在D=(后风轮直径)/(前风轮直径)=1的情况下，输出功率随后风轮直径的增大而增加。在较高风速下，D=0.84的后风轮可以与前风轮同向旋转，而D=0.84以上的风轮不能随风速改变旋转方向。也就是说，最佳配比为D=0.84.3。两个风轮之间的最佳间距使后风轮尽可能靠近前风轮，以获得丰硕的输出。风轮周围的流动状况流经风轮的子午线流速每降低一次。在较高风速下，后风轮与前风轮同向旋转，使气流沿轮毂壁面逆流而上。然后，后风轮代替刹车和/或变桨控制，以抑制过度旋转。为给后风轮提供足够的风能，前风轮的叶片型线在轮毂侧不应有外倾。噪声串列风轮的噪声水平大于单风轮的噪声水平，对向旋转时的噪声水平大于同方向旋转时的噪声水平。尾部风轮直径越小，噪声越低。较少

This intelligent wind turbine generator has the following peculiarities. (1) Both wind rotors start rotating at the low wind speed, but the rear wind rotor counter-rotates against the front wind rotor. (2) The increase of the wind speed makes both rotational speeds increase, and the rear wind rotor reaches the maximum rotational speed at the rated wind speed. (3) With more increment of the wind speed, the rear wind rotor decelerates gradually and begins to rotate in the same direction as the front wind rotor, and the output can be kept constant. (4) Moreover, the counter-rotation makes the output higher even if in the poor wind circumstance. To get the optimum profiles of this unit, the characteristics of the double rotational armature type doubly fed induction generator were examined in the bench tests, and the blade profiles of both wind rotors were optimized in the wind tunnel and by CFD.1. GeneratorIt was confirmed that the generator works well in cooperation with the tandem wind r … More otors and the secondary output can be got from the input circuit, namely the inner armature.2. Optimum diameter ratio between both wind rotorsThe output increases with the increase of the rear wind rotor diameter, under the ratio D=(rear wind rotor diameter)/(front wind rotor diameter)=1. The rear wind rotor under D=0.84 can rotate in the same direction as the front wind rotor at the higher wind speed, but the rotor over D=0.84 can not change the rotational direction in response to the wind speed. That is, the optimum ratio is about D=0.84.3. Optimum span between both wind rotorsIt is desirable to make the rear wind rotor close to the front wind rotor as possible, to get the fruitful output.4. Flow condition around wind rotorsThe meridian flow velocity decreases every through the wind rotor. At the higher wind speed, the rear wind rotor comes to rotate in the same direction as the front wind rotor, and makes the flow runs upstream along the hub wall. Then, the rear wind rotor plays in place of the brake and/or pitch control which suppresses the over rotation.5. Proposal of the optimum blade profileIt is desirable that the blade profile of the front wind rotor has not the camber at the hub side for giving the sufficient wind energy to the rear wind rotor.6. Acoustic noiseThe noise level of the tandem wind rotors is larger than that of the single wind rotor, and the level at the counter-rotating operation is larger than that at the rotating operation in the same direction. The noise becomes lower with the decrease of the diameter of the rear wind rotor. Less