两种消除排气系统驻波的解决方案

Two Solutions to Eliminate Standing Waves of Exhaust Systems

研究目的是从理论和模拟计算两方面研究驻波的形成机理和解决措施,其过程是应用GT-power软件建立某项目排气尾管噪声声学模型,分析其排气系统尾管噪音各阶次噪声声学特征,确定某一共同频率的波峰是由长尾管的驻波引起的,提出两种解决方案。方案一是改变排气尾管长度,避开激励频率,弱化驻波波峰的效果,降低波峰处的噪音;方案二是设计针对此共同频率的谐振腔,消除此频率的噪音,从根本上解决驻波产生的噪音;最后通过模型再次模拟分析验证,结果表明两种方案都有明显的效果,达到预期目的。

The mechanism and elimination methodology of standing waves of exhaust systems were studied. The acoustic model for analyzing the noise of exhaust tailpipe was established with GT-power software. The acoustic characteristics of the exhaust tailpipe noise of different orders were obtained. It was found that the wave peak of a common frequency was caused by the standing wave of the long tailpipe of the system. Therefore, two schemes were proposed for solving the problem. One was to change the tailpipe length so that the natural frequencies of the tailpipe can avoid from the common frequency of the excitation source, the effect of the peak of the standing wave can be weakened, and the noise at the wave peak can be reduced. The other is to design a resonator to suppress this common frequency so that the noise of this frequency can be eliminated. Results of simulation show that both schemes have obvious effects for improvement of the acoustic performance of the exhaust system.