摘要
气流再生噪声对消声器性能和声品质影响大,而湍涡耗散是消声器内部流场分布重要体现.利用流场分析及量纲平衡提出了湍涡耗散分布特征系数,建立了关于该系数的穿孔板消声单元气流再生噪声总声功率模型,求解了模型参数,并分析了影响因素.结果表明:随着穿孔板消声单元进口气流速度的增加,气流再生噪声总声功率级快速增大,斜率都超过了1;随着湍涡耗散的增大,气流再生噪声总声功率级减小,尤其当湍涡耗散小于1.0×10~5m~2/s~3,气流再生噪声总声功率级快速下降,当湍涡耗散大于1.0×10~5m~2/s~3时,气流再生噪声总声功率级下降速度趋于平缓,该模型可以定量分析穿孔板消声单元结构参数对气流再生噪声的影响规律,穿孔板消声单元气流再生噪声总声功率级随气流分布速度增大而显著增大.
Flow regenerated noise has huge effects on muffler characteristics and sound quality. The turbulence eddy dissipation is an important expression of the muffler internal flow field. A ratio of turbulence eddy dissipation was proposed by flow field computation and dimensional balance,and a total sound power model on the ratio and the muffler flow regenerated noise was built and model parameters and their effects were analyzed. Results show that the total sound level of the flow regenerated noise quickly increases and its gradient is more than 1 when the flow distribution velocity rises. With the increase of turbulence eddy dissipation the total sound level reduces,especially when the turbulence eddy dissipation is less than 1.0×10~5 m~2/s~3,the total sound level rapidly drops down. Furthermore,the total sound level slowly reduces when the turbulence eddy dissipation is more than 1.0×10~5 m~2/s~3. This indicates that the model can conveniently and quantitatively analyze the influence of structural parameters of perforated plate muffler unit on the flow regeneration noise. Flow regeneration noise power of the perforated plate muffler unit increases heavily with the development of flow distribution velocity.
引文
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