多腔穿孔型宽频消声器声学特性的理论计算与优化

Theoretical Calculation and Optimization of the Acoustic Characteristics of a Multi-chamber Perforated Broad-band Muffler

多腔穿孔型消声器可衰减涡轮增压发动机进气系统工作时产生的宽频噪声。本文根据将多腔消声器视为若干单腔消声元件串联而成的思路,结合单腔穿孔声阻抗模型,提出多腔消声器的声学计算方法,并以某多腔穿孔消声器为例,预测其传递损失。实验验证表明该计算方法在计算传递损失方面具有较高的精度。然后在此基础上,设定优化目标,选定3种不同优化变量的组合模式,采用非线性最小二乘法进行优化。结果表明,不同优化模式均可满足目标要求,可灵活地确定符合工程实际的最佳方案。所提出的方法可为增压发动机进气系统声学设计提供理论支撑和应用指导。

The multi-chamber perforated muffler can attenuate the broadband noise generated by the air intake system of turbocharged engine. Based on the idea of regarding multi-chamber muffler as the series combination of several single-chamber silencing elements,and combined with the acoustic impedance model for perforated single chamber,an acoustic calculation method for multi-chamber muffler is proposed in this paper. With the method,the transmission loss of a multi-chamber muffler is predicted and verified by tests,demonstrating the high accuracy of the method in calculating transmission loss. Then on these bases,by setting optimization objective and selecting three combination modes of different variables to be optimized,an optimization is conducted with nonlinear least square algorithm. The results indicate that all three combination modes can meet the objective requirements,so the best scheme can be flexibly determined to accord with engineering practice. The method proposed provides a theoretical base and application guidance for the acoustic design of the induction system in a turbocharged engine.