分流气体对冲消声结构的消声性能与压力损失

Noise Reduction and Pressure Loss of a Split-Stream Rushing Silencing Structure

从排气气流角度出发,利用发动机排气气流自身分流并发生对冲的思路,设计了一种新型消声结构——分流气体对冲消声结构.排气气流分流对冲可有效降低消声器内排气气流速度,减少消声器内湍流噪声的产生,在兼具消声性能的前提下,有效降低了消声器的排气背压,提升了发动机的输出功率.从传统消声结构和分流气体对冲消声结构的数值模拟和试验验证对比结果可见,二者在低频段消声性能相近,但分流气体对冲消声结构在高频段的消声性能优于传统消声结构,且分流气体对冲消声结构在不同入口气流速度下,压力损失比传统消声结构降低均在20%以上.该分流对冲结构还可与传统消声单元耦合,有助于进一步提升消声器的综合性能.

A new structure of muffler,which is called split-stream rushing silencing structure,was designed by using the idea that the exhaust flow of an engine splits and rushes itself.The structure can reduce the exhaust gas velocity and turbulent flow noise in the muffler,leading to effectively reduce the exhaust back pressure and improve the output power of the engine under the premise of noise elimination performance.The results of numerical simulation and experimental verification show that the two structures have similar sound attenuation performance in low frequency band,but the sound attenuation performance of the split-stream rushing silencing structure is better than that of the traditional structure in high frequency band.In addition,the pressure loss of the split-stream rushing silencing structure is reduced by 20%compared with the traditional structure at different inlet gas velocities.The split structure can also be coupled with the traditional muffler unit,which is helpful to further improve the comprehensive performance of the muffler.