某轿车排气系统流场测试、仿真及优化

Measurement,Simulation and Optimization of Flow Field for a Vehicle Exhaust System

针对某轿车排气系统背压过高的问题,搭建了排气系统流场和噪声测试平台,通过实验测试了排气系统不同工况下的背压,噪声和温度。建立了该排气系统有限元模型,利用测试的参数设置了边界条件,对排气系统的流场进行了计算分析,得到了排气系统不同工况下压力和流速分布图,并且根据计算的结果对该排气系统结构进行了优化。通过测试发现,优化后的排气系统在最大噪声值仅增加2.4d B(A)的情况下最大背压值减少5.9k Pa,满足了设计要求。

Aiming at the problem that the back pressure of a vehicle exhaust system is too high, a flow field and noise test platform for the exhaust system was built. The back pressure, temperature and noise of the exhaust system under different working conditions were tested through experiments. A finite element model of the exhaust system was established. The boundary conditions were set using the parameters of the test, the flow field of the exhaust system was calculated and analyzed, the weak link of the exhaust system design was found, and then the exhaust system structure was optimized according to the calculated results. Based on the experiment, it was found that the optimized exhaust system increases the maximum noise by 2.4dB （A） , and the maximum backpressure value is reduced by 5.9kPa, which meets the design requirements.