船用柴油机排气冷却消声器流体与消声特性

为了降低船用柴油机排气噪声,并对废气进行冷却以降低红外辐射,实现红外隐身目的,要求在排气系统中安装排气冷却消声器。利用数值算法研究排气冷却消声器的气体流动特性、冷却效果、声学性能。首先利用有限体积法计算并分析了排气冷却消声器在冷却与不冷却时的空气动力性能,得到其阻力损失特性、冷却效果和温度场信息。在流体计算的基础上得到消声器温度场,然后采用声学有限元法计算并分析了排气冷却消声器在室温与高温冷却下的声学特性,将排气冷却消声器的左端共振腔体积减小,改变其共振频率从而改变消声器在低频时的声学性能。

Fluid and Acoustic Attenuation Characteristics of Exhaust Cooling Silencers for Marine Diesel Engine

In order to reduce the exhaust noise of marine diesel engine and to cool the exhaust gas for the sake of reducing the infrared signature,the exhaust cooling silencer is always needed.In this paper,the characteristics of flow and cooling effect of the silencer as well as its transmission loss was analyzed with numerical calculation.The aerodynamic performance of the exhaust cooling silencer was calculated by the Finite Volume Method（FVM） to analyze the internal fluid flow and the temperature field,and then the Finite Element Method（FEM） was used to calculate the acoustic attenuation characteristics.The sound performance in low frequency was optimized as a result of the change of the left resonated chamber.