Effect of blade aspect ratio on the performance tradeoff between figure of merit and bending-torsion dynamics of wind turbines with synthetic jets
Effect of blade aspect ratio on the performance tradeoff between figure of merit and bending-torsion dynamics of wind turbines with synthetic jets
复制标题
叶片展弦比对合成射流风力涡轮机品质因数和弯扭动力学之间性能权衡的影响
DOI：
10.1016/j.egyr.2023.04.017
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发表时间：
2023
期刊：
影响因子：
5.2
通讯作者：
Dufflis, Guilherme
中科院分区：
文献类型：
--
作者：
Maldonado, Victor;Peralta, Nicolas;Ayele, Wolduamlak;Santos, Dioser;Dufflis, Guilherme
在这项实验研究中，两个三叶片转子叶片展弦比为7.79和9.74，代表了25%的增加进行了测试。每个叶片包含一个S809翼型与零预建扭曲和20个高性能合成射流致动器分布沿着跨度。在四种转子速度（Ω为250、500、750和1，000转/分钟（RPM））和三种总叶片桨距角（θ c为2、5和8度）下对转子进行了测试。使用高容量测压元件测量转子推力，并使用四个机载惯性测量装置在叶片上的四个等距径向位置（r/R= 0.24、0.48、0.72和0.96）测量叶片弯曲和扭转。采用激光多普勒测速技术（LDV）测量了叶片吸力面的展向流动。实验测得的转子转速产生的局部雷诺数范围为8.31× 104 ≤ Re ∞≤ 9.49× 105。结果发现，转子的气动效率量化的品质因数是直接链接到叶片的展弦比和跨叶片的展向流的大小。具有更高叶片展弦比的转子产生更少的总展向流，并且空气动力学效率更高，但是叶片也产生更大的平均和波动弯曲和扭转位移，这对于气动弹性稳定性是不期望的。在叶片上使用合成射流可减轻弯曲和俯仰位移的均方根（高于Ω= 250 RPM和θ c= 2°）。结果发现，在Ω= 1，000 RPM时，叶片结构经历第二模态弯曲响应，表明由于较高的气动载荷而导致的结构不稳定状态。在此转子速度下，与展弦比为9.74的转子基线相比，叶片外侧的气流控制可将非定常弯曲（以r m s量化）降低至最大值36.5%，并将非定常扭转（θ r m s）降低至最大值22.9%。
In this experimental study, two three-bladed rotors with a blade aspect ratio of 7.79 and 9.74 representing a 25% increase were tested. Each blade contains an S809 airfoil with zero pre-built twist and 20 high-performance synthetic jet actuators distributed along the span. The rotor was tested at four rotor speeds, Ω of 250, 500, 750, and 1,000 revolutions per minute (RPM) and three collective blade pitch angles, θ c of 2, 5, and 8 degrees. Rotor thrust was measured using a high-capacity load cell, and blade bending and torsion was measured at four equally spaced radial locations on the blade defined by r/R= 0.24, 0.48, 0.72, and 0.96 using four onboard inertial measurement units. The spanwise flow over the suction surface of the blade was measured using laser Doppler velocimetry (LDV) techniques. The local Reynolds number produced with the test rotor speeds at the measurement locations ranges from 8.31× 1 0 4≤ R e∞≤ 9.49× 1 0 5. It was found that rotor aerodynamic efficiency as quantified by the figure of merit is directly linked to blade aspect ratio and the magnitude of spanwise flow over the blade. The rotor with a higher blade aspect ratio produces less overall spanwise flow and is more aerodynamically efficient, however the blade also generates larger mean and fluctuating bending and torsion displacements, which are undesirable for aeroelastic stability. The use of synthetic jets on the blade mitigates the root mean square of the bending and pitch displacements above Ω= 250 RPM and θ c= 2°. It was found that at Ω= 1,000 RPM, the blade structures undergo a second mode bending response indicating a condition of structural instability due to higher aerodynamic loading. At this rotor speed, flow control on the outboard of the blade reduces unsteady bending as quantified by a r m s up to a maximum of 36.5%, and unsteady torsion, θ r m s up to 22.9% compared to the baseline for the rotor with an aspect ratio of 9.74.