阵风入流下翼型凹变对风力机气动噪声影响研究

EFFECT OF AIRFOIL CONCAVITY ON AERODYNAMIC NOISE OF WIND TURBINES UNDER GUST INFLOW

基于自然风非稳定性的特点,依据风力机各项参数拟合出阵风函数,对某S翼型水平轴风力机进行三维非稳态数值计算和试验,研究阵风入流和稳定入流下翼型凹变对尾迹辐射声频谱、声辐射传播和尾迹涡量耗散的影响。结果表明:翼型凹变可有效降低尾迹气动噪声,其基频及倍频声压级明显低于原始叶片;随着轴向距离增加,翼型凹变叶片降噪效果逐渐增大,在轴向500 mm处声压级最大降低3.6 dB,且阵风入流下翼型凹变降噪效果大于稳定入流。同时,翼型凹变叶片尾迹涡量明显降低,验证了翼型凹变降噪的有效性。

Based on the instability of natural wind,a gust function was fitted according to the parameters of the wind turbines.Applying a combination of three-dimensional unsteady simulation and experimental verification on a horizontal axis wind turbines with S-shaped airfoil,the influence of airfoil concavity on the wake radiation acoustic spectrum,acoustic radiation propagation,and wake vorticity dissipation under both gust inflow and stable inflow were studied.The results show that the airfoil concavity can effectively reduce the aerodynamic noise of wake,and its fundamental frequency and high harmonic sound pressure level are significantly lower than those of the original blade.With the increase of axial distance,the noise reduction effect of airfoil concavity blade increases gradually,and the maximum sound pressure level is decreased by 3.6 dB at the axial direction of 500 mm.The noise reduction effect of airfoil concavity blade under the gust inflow is greater than that of the stable inflow.The wake vortex of airfoil concavity blade also has a significant decrease,which verifies the effectiveness of airfoil concavity on the aerodynamic noise reduction.