尾流激励下的叶片气动力快速分析

Fast analysis of blade aerodynamic force under wake excitation

为快速求解尾流引起的叶片气动力,提出了基于谐波平衡法的尾流激励的叶片气动力降阶模型方法。对该气动力降阶模型方法进一步的研究发现:小扰动情况下,尾流谐波引起的叶片气动力谐波振幅和尾流谐波振幅的比例系数只与尾流频率有关。基于这一发现,进一步提出了尾流激励下的叶片气动力快速分析方法。该方法首先得到若干谐波尾流引起的叶片气动力谐波振幅与谐波尾流振幅的比例系数,并拟合出这些比例系数与尾流谐波频率的关系曲线;对任意尾流通过该曲线插值出该尾流各谐波对应的比例系数,得到叶片气动力谐波振幅,再由气动力降阶模型求得尾流激励的叶片气动力。算例结果表明:提出的气动力快速分析方法可以快速准确的估计任意尾流激励下的叶片气动力,而无需对不同频率尾流反复的进行CFD气动力计算。

To quickly solve blade aerodynamic force under wake excitation,the blade aerodynamic force reduced order model(ROM)method based on the harmonic balance method was proposed here.Through further studying this method,it was found that under small turbulence,proportional coefficients between aerodynamic force’s harmonic amplitudes and wake harmonic amplitudes are only related to wake frequencies.Based on this finding,the fast analysis method of blade aerodynamic force was proposed.Firstly,proportional coefficients between aerodynamic force’s harmonic amplitudes caused by wake harmonics and wake harmonic amplitudes were obtained,and then the relation curves between these proportional coefficients and wake harmonic frequencies were fitted.For any wake,proportional coefficients corresponding to its various harmonics were acquired through these curves interpolation,further blade aerodynamic force harmonic amplitudes were gained.Finally,the blade aerodynamic force ROM was used to solve blade aerodynamic force under wake excitation.The example calculation results showed that the proposed fast analysis method can be used to rapidly and accurately estimate blade aerodynamic force under any wake excitation without needing to do repeatedly CFD aerodynamic force computation for wakes of different frequencies.