金属烧结丝网在内场消声中的应用

利用试验手段研究暂冲式风洞稳定段内安装不同规格烧结金属丝网对风洞上游控制阀后气流噪声和湍流度抑制作用。试验结果表明:多层金属烧结丝网可在全频段内大幅度降低上游气流的噪声,最大可达21 dB;消声量与金属烧结丝网无量纲的压力损失系数成正比,压力降与金属烧结丝网层数呈现出非线性叠加的结果。另外发现烧结金属烧结丝网对气流速度脉动亦具有突出的抑制效果。例如,试验段马赫数Ma=1:5时,120目26层+160目26层组合烧结金属丝网出口气流速压脉动幅值减小为入口来流的18%,湍流度由11.7%降至3%。因此金属烧结丝网适合于暂冲式风洞的内场降噪。

Application of interior noise reduction for metal sintering screen

Metal sintering screens were mounted in settling chamber of the intermittent wind tunnel to reduce noise downstream control valve.An experimental study was conducted to find how this anechoic measure works.The results showed that metal sintering screen could largely attenuate the flow noise in all band,and the flow noise suppression level could reach about 21 dB for some test Mach number.Especially,unlike micropunch plate muffler,there was no amplificatory phenomenon of pressure level in low frequent.And the sound deadening capacity was proportional to the non-dimensional pressure loss coefficient.Moreover,the metal sintering screen could also obviously reduce the fluctuation amplitude and turbulence intensity of air flows through it.Take“26 layers 120 mesh+26 layers 160 mesh”sintering metal screen combinations for example,the flow fluctuation amplitude reduced to 18 percent of inlet and the turbulence intensity changed from 11.7%to 3%when the velocity of coming flow was about 13 m/s.So it could be concluded that metal sintering screen is a very excellent denoising device for the inner field flow of intermittent wind tunnel.