1.前言在迄今可用的计算废气流量和消声器消声作用的方法中,绝大部分是建立在一维声学理论基础上的。其原因主要在于:描述消声器管系中流动的公式属非线性双曲线方程,不能收敛求解。因此人们采用近似法,其中声学滤波器的理论是最流行的。这种方法的基础是假设干扰很小,就是说排气压力波的振幅很小,以致排气压力波对废气状态的影响小得可忽略不 1. Introduction Most of the methods available to date for calculating exhaust gas flow and muffler muffling are based on one-dimensional acoustic theory. The main reason is that: describe the muffler flow in the system is a nonlinear hyperbolic equation, can not converge solution. Therefore, people adopt the approximation method, of which the theory of acoustic filters is the most popular. This method is based on the assumption that the disturbance is small, that is, the amplitude of the exhaust pressure wave is so small that the effect of the exhaust pressure wave on the exhaust gas state is negligible