Acoustics Performance Of Vehicle Muffler By Finite Element Method And Experiment

Vehicle as a product of industrial civilization today,has been the mainstay of families'travel tools.Car's noise give drivers and passengers a very intuitive feeling,their origins are:wind noise,tire noise and engine noise.Wind noise and tire noise are with bodywork and tire quality,which have a very important relationship,there is a direct link between the engine noise and the various factors,such as the front of the sound insulation performance,exhaust noise control and so on.Exhaust noise is one of the main noise sources for vehicles,so design a high noise elimination performance,low pressure loss of exhaust muffler has become an important subject nowadays in automobile exhaust noise control.In this thesis,through experiment and theoretical method to analysis the fluent and acoustics of the exhaust muffler.First of all,based on the real vehicle exhaust pipe build a PROE modeling,test natural frequencies by ANSYS simulation software for the simulation research,concluded that the exhaust pipe of the low order natural frequencies avoid engine running frequency;Second,using FLUNT fluid analysis software on the aerodynamic performance of the exhaust pipe,it is concluded that the speed of the interior fluid field,temperature and pressure loss,the pressure loss is an important index measured exhaust aerodynamic,through which can evaluate its performance in fluid dynamics;Acoustic software.Again,use Virtual lab Acoustics to test muffler performance,it is concluded that the transmission loss,and transmission loss as the main measure of muffler performance evaluation indexes,to measure vehicle noise reduction ability,but also on the study of the muffler performance fully take into account the influence of temperature and velocity on the noise reduction ability.The experiment part,the learning lab equipment operation and the results of the experiment process;First before the theory of modal analysis using the BK system on the real natural frequency test experiment was carried out,through the experiments it is concluded that the low order natural frequency,which compared with the finite element simulation,the effectiveness of the experimental results are obtained.Next is on a certain car exhaust pipe to improve the performance of the tests,through the experiment of special equipment and the exhaust pipe model experimental data,and in accordance with the above theoretical analysis by use of the exhaust pipe do contrast analysis,it is concluded that the improved exhaust pipe excellent aerodynamic performance and noise reduction performance.