内燃机排气消声器试验系统

Testing System of Exhaust Muffler for Internal Combustion Engines

针对消声器性能测试需在发动机或台架上进行,不方便且成本大的情况,研制一种内燃机排气消声器试验系统。首先阐述该系统的工作原理和系统各组成部分,对试验系统进行声学特性和振动特性分析,然后以分流气体对冲消声单元为对象,采用CFD方法对其计算5种不同入口速度下对应的出口速度,并与用本试验系统实测的数据进行对比验证。结果表明:试验系统的噪声源、气流源均可满足试验需求;试验系统隔声罩隔声效果明显;试验系统音箱隔声罩在噪声和气流同时开启的工况下z轴方向的振动最大,峰值为0.44 g,试验时不会引起试验台共振,也不会对试验设备造成明显的影响。CFD方法计算结果与实测结果基本一致,证明了试验系统设计的正确性,可以满足消声器的测试需求,而且该系统制作成本低、结构简单紧凑。

Muffler performance test usually needs to be conducted on engines or test bench, which is inconvenient andcostly. Therefore, a test system of exhaust muffler for internal combustion engines has been developed. The working principleand components of the system are expounded, and the acoustic characteristics and the vibration characteristics of the system areanalyzed. By taking a muffler unit of out- of- phase stream rushing as the example, the outlet velocities corresponding to fivedifferent inlet velocities are computed by CFD method in Fluent software. The computation results are compared with the testresults. It shows that the noise source and air-flow source of the test system can meet the testing requirements; Sound insulationeffect of the sound insulation cover of the test system is obvious; The z-axis vibration of the sound insulation cover of the soundbox in the test system can reach the maximum when both the airflow source and the noise source are working simultaneouslyand the vibration peak value is 0.44 g, which will not cause the test bench resonance and has no obvious effect on the additiveinstruments. The computation results are in accordance with the measurement results. Therefore, the correctness and feasibilityof the designed test system are proved. In addition, the test system is economic, simple and has a compact structure.