On the study of wavy leading-edge vanes to achieve low fan interaction noise
On the study of wavy leading-edge vanes to achieve low fan interaction noise
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波浪形前缘叶片实现低风扇交互噪声的研究
DOI：
10.1016/j.jsv.2018.01.017
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发表时间：
2018
影响因子：
4.7
通讯作者：
Wang Xunnian
中科院分区：
文献类型：
--
作者：
Tong Fan;Qiao Weiyang;Xu Kunbo;Wang Liangfeng;Chen Weijie;Wang Xunnian
对波纹前缘叶片在降低单级轴流风机噪声中的应用进行了数值研究。采用非定常雷诺平均Navier-Stokes(URANS)/声学类比方法(Goldstein方程)对风机的气动和声学性能进行了数值研究。首先，发展了URANS/Goldstein混合方法，并与实验结果进行了成功的验证。其次，对波纹前缘叶片的降噪效果进行了数值模拟研究。对具有两种不同波纹前缘外形的叶片风扇的气动和声学性能进行了评估，并与常规的直叶前缘叶片的性能进行了比较。结果表明，前缘叶片为波浪型的风扇在气动性能没有明显损失的情况下，其干扰噪声比基线风扇低。事实上，波浪形前缘叶片具有改善气动和声学性能的潜力。结果表明，这两种不同的前缘波形能成功地将风扇音声功率级分别降低1.2 和4.3 分贝。使用其中一种测试的波浪形前沿轮廓，风扇效率也提高了约1%。对简化的风扇级模型也进行了大涡模拟(LES)，以评估波纹前缘叶片对宽带风扇噪声的影响。结果表明，在前缘波纹较大的情况下，风机的总声功率级可降低约4 分贝。最后，对降噪机理进行了研究和分析。结果表明，波浪型前缘叶型可以在前缘凸起周围诱导出明显的流向涡量，减小压力波动(特别是在波状前缘丘陵处)和静叶上的非定常作用力。通过考察噪声源附近速度和压力波动之间的幅值平方相干性，讨论了降低压力波动的潜在机制。此外，观察到沿叶片前缘的壁面压力波动的相关程度降低，以及沿叶片前缘的破坏性相位干涉。
The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude-squared coherence between the velocity and pressure fluctuations in the vicinity of the noise sources. Moreover, a reduction in the correlation level of the wall pressure fluctuations along the vane leading-edge is observed, as well as destructive phase interference along the vane leading-edge.