低空急流高度变化对水平轴风力机气动载荷的影响

Influences of the Heights of Low-level Jet on Aerodynamic Loads of Horizontal Axis Wind Turbine

对比分别由Great Plains Low-Level Jet谱模型和基于平面壁面射流原理建立的低空急流工程化模型得到的平均风速廓线,确定低空急流工程化模型中的参数。在此基础上,基于Von Karman谱和低空急流工程化模型建立不同高度的低空急流脉动风场,并将其作为FAST开源代码的输入条件计算和分析水平轴风力机的气动载荷。研究表明:当急流强度一定,急流高度由风轮扫掠面的底部位置增加到顶部位置时,风轮气动载荷发生了明显的变化,与最小值相比,风轮推力、横向力、纵向力、转矩、偏航力矩和倾覆力矩系数均方根的最大值分别增加了12.9%、75.6%、73.4%、27.7%、99.9%和98.5%。在低空急流条件下,风轮转矩和推力功率谱曲线峰值的频率与叶片通过频率的整数倍相关。研究结果可为低空急流条件下水平轴风力机气动载荷的分析提供参考。

Comparing the average wind speed profiles obtained from the Great Plains Low-Level Jet(GP_LLJ) spectral model and the low-level jet(LLJ) engineering model based on the plane wall jet principle, the parameters in the LLJ engineering model were determined. On this basis, the LLJ fluctuating wind fields with different LLJ heights were simulated based on the Von Karman spectra model and LLJ engineering model, and were used as the input condition of FAST open source code to calculate and analyze the aerodynamic loads of the horizontal axis wind turbine. The results show that when the LLJ intensity is constant and the LLJ height increases from the bottom-tip to top-tip of the rotor, the RMS of the rotor aerodynamic load coefficients, including ones of thrust, torque, lateral force, longitudinal force, yaw moment and tilt moment, shows obvious change, and the respective maximum is increased by 12.9%, 75.6%, 73.4%, 27.7%, 99.9% and 98.5%, compared with their minimum. The peak frequencies of the power spectrum of the rotor torque and thrust are related to the integral multiples of the blade passing frequency.