摘要
针对涡扇发动机声衬开展分段式设计,并对声衬对声模态的散射作用进行了分析。应用有限元求解对流亥姆霍兹方程的方法求解了发动机短舱内的声传播,通过与试验以及高精度数值解对比验证了所应用的数值方法及声模态解耦方法;应用梯度搜索法和遗传算法优化设计了4种声衬的声阻抗,结果表明可以通过长度较短的声衬实现多个目标声模态的降噪并达到降噪指标,轴向分段式相比均布式声衬和周向分布式声衬具有更大的降噪量;此外还对分段式声衬的声模态散射现象进行了分析,分析了声衬对声波的模态散射。研究结果表明最优声衬产生的反射声功率要大于通过声衬传递的声功率,周向分段的声衬散射形成了更低阶声模态。建议应用轴向分段式声衬降低风扇前传噪声。
The segmented design of the lining of the turbofan engine was carried out,and the scattering effect of the acoustic lining on the acoustic mode was analyzed. The finite element method for solving the convection Helmholtz equation was used to solve the acoustic propagation in the nacelle of the engine. The numerical method and the acoustic mode decoupling method were verified by comparison with the test and high-precision numerical solution. The gradient search method was applied. The acoustic impedance of four kinds of acoustic linings was optimized by genetic algorithm. The results show that the noise reduction of multiple target acoustic modes can be achieved by the shorter length acoustic lining and the noise reduction index can be achieved. The sound lining and the circumferential distributed sound lining have greater noise reduction. The acoustic mode scattering phenomenon of the segmented sound lining and the modal scattering of the sound lining were also analyzed. The results show that the optimal sound lining produces more reflected sound power than the sound power transmitted through the sound lining,and the circumferential segmented sound lining scattering forms a lower order acoustic mode. It is recommended to use an axial segmented sound lining to reduce fan front noise.
作者
薛东文
燕群
黄文超
XUE Dong-wen;YAN Qun;HUANG Wen-chao(Laboratory of Aeroacoustics and Vibration Aviation Technology,Aircraft Strength Research Institute,Xi'an 710065,China)
出处
《科学技术与工程》
北大核心
2019年第6期270-277,共8页
Science Technology and Engineering
基金
中欧合作项目(688971)资助
关键词
声模态
散射
分段式
声衬
优化
acoustic modes
scattering
segmented
liner
optimized
