Specifcation of Porous Materials for Low-Noise Trailing-Edge Applications
Specifcation of Porous Materials for Low-Noise Trailing-Edge Applications
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DOI：
10.2514/6.2014-3041
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发表时间：
2014-06
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影响因子：
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通讯作者：
M. Herr;Karl-Stéphane Rossignol;J. Delfs;M. Mößner;N. Lippitz
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文献类型：
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作者：
M. Herr;Karl-Stéphane Rossignol;J. Delfs;M. Mößner;N. Lippitz
可用于低噪声后缘(TE)处理的多孔金属的微结构和气动声学性能的系统测试已在合作研究中心SFB 880|未来民用飞机的高升力基础内启动。通用TE噪声实验是在德国航天中心的开式喷气AWB装置中进行的，Re=0.8x10^6到1.2x10^6。TU Braunschweig的封闭试验段MUB风洞中的补充流动测量用于量化诱导的空气动力效应。目前的数据库形成了持续累积努力的一部分，结合了实验和数值方法，以获得对普遍存在的TE降噪机制的更深层次的了解。对于这里测试的多种多孔材料，实现的宽带降噪(最大可达2-6分贝)与流动电阻率有明显的依赖关系。对于低噪声TE应用，推导了材料电阻率和孔洞大小的基本设计建议，后者使高频自噪声贡献最小化。通过多孔区的声学近场压力释放，加上多孔性TE置换的举升性能的不利影响，似乎是主要的降噪要求。
Systematic testing of the microstructural and aeroacoustic properties of porous metals applicable as low-noise trailing-edge (TE) treatments has been initiated within the Col- laborative Research Center SFB 880|Fundamentals of High-Lift for Future Civil Aircraft. Generic TE noise experiments were performed at Re = 0.8x10^6 to 1.2x10^6 in DLR's open-jet AWB facility. Complementary flow measurements in the closed test section MUB wind-tunnel of the TU Braunschweig served to quantify the induced aerodynamic effects. The presented database forms part of an ongoing cumulative effort, combining experimental and numerical methods, to gain a deeper understanding of the prevalent TE noise reduction mechanisms. For the large variety of porous materials tested herein a clear dependence of the achieved broadband noise reduction (reaching 2-6 dB at maximum) on the flow resistivity was identified. Basic design recommendations for material resistivity and pore sizes, the latter to minimize high-frequency self-noise contributions, were deduced for low-noise TE applications. An acoustic nearfield pressure release across the porous region, adversely coupled with a loss in lift performance for porous TE replacements, appears as the major noise-reduction requirement.