Simulation Research On Performance Of Exhaust Muflfer Of Automotive Based On Virtual.Lab

The vehicle noise, to some extent, is a larger proportion of automobile exhaust noise.The automobile noise is harmful in various perspectives, such as people’s physical andmental health, social economy, environment, building and so on. It is a universallyacknowledged method to install muffler in noise control engineering. Therefore, theresearch on design and application of the exhaust muffler is greatly significant andsocially valuable.With the help of software Virtual Lab, the thesis focuses on the basic anechoic unit ofthe resistance muffler and structure parameters, simply presenting a brief analysis of theexpansion, offset, inserted into the pipe, and perforated tube muffler performance.Assisted by the simulation method, we can acquire the sound pressure distribution, thesound pressure frequency response function curve, the transmission loss curve, andcome to a simple conclusion. Laying emphasis on the penetrating analysis of variousstructural parameters of the muffler (expansion ratio, expansion room number andlength, inserted into the pipe length, ratio of perforation aperture, silencing length, etc.),we can get the transmission loss curve, together with the corresponding mufflerperformance. Furthermore, the temperature and the flow velocity are also theinfluencing factors to the complicated and complex muffler.With regard to expansion muffler, sound deadening capacity is closely related toexpansion ratio; the length of the expanding cavity has an effect on frequency change.The amount of noise elimination can be increased with the number of expansionchamber. By modifying the length of the insert tube, the passing frequency is eliminated.By adjusting the structure parameters of the muffler, such as perforation rate, porediameter and the effective absorption length, the performance of muffler is optimized.By the numerical simulation analysis of the complex muffler, we obtain that externalfactors (such as temperature, velocity) how influence on the performance ofmuffler.Through the performance simulation of complex muffler are external factorssuch as temperature, velocity, etc. When temperature is high, the noise eliminationperformance in low frequency is not good, the noise elimination performance in highfrequency is good. Considering the velocity, the change of the transmission loss issmall.By the numerical simulation analysis of a certain automobile silencer muffler performance with the Virtual.Lab Acoustic，the noise cancellation effect of this muffleris not ideal and has passing frequency，so it is necessary to optimize this muffler.According to the obtained law and optimization design theory, an improvement schemeneeds to be put forward so as to enhance the previous products. Accurate calculationand preliminary scheme are indispensible and important before the transmission losscurve and acoustic pressure contours, sound pressure frequency response curve areapproached. Taking the compared factors into consideration, the optimal case iseventually determined.