The Numerical Simulation Analysis On Acoustic And Fluid Dynamic Performance Of Exhaust Muffler Based On FLUENT

Noise is not only harmful to human health but also affects their daily life and work.Nowadays, the car is popular all over the world. Traffic noise especially the automotive exhaust noise, has become the most important facts that affects the urban environment and human health. The most effective method to control exhaust noise is to use the exhaust muffler.Although the exhaust muffler can effectively reduce exhaust noise, it’s complexity of structure undoubtedly increases the resistance of the exhaust gas, which results in the waste of engine power and the increase of fuel consumption. So the goal of muffler design and improvement is to reduce the pressure loss as much as possible based on high sound deadening capacity.Traditional methods of muffler design and improvement are to calculate and test the muffler on the basis of the one-dimensional plane-wave theory, the calculation process is complex, test should conduct more times, and the final result of the calculation is not necessarily the optimal results. In contrast, the numerical simulation method is more intuitive and easier to make changes to the relevant parameters, until the optimal solution is found.On the basis of acoustic and hydrodynamic theory related to the muffler, this paper respectively used Virtual Lab and FLUENT to execute the acoustic and hydrodynamic simulation of the muffler, after obtained the relevant information about transmission loss and pressure loss, the performance of the muffler were analysed and evaluated.The orthogonal experiment was designed according to the structure parameters which have important affect on the performance. The transmission loss and pressure loss of muffler were set as the main evaluation indexes. The comprehensive scoring method is used to analyze the results. The impact factors were sorted to find the best combination of different factors. The acoustic and fluid dynamics simulation was conducted with the optimal parameter combination, the result was compared with original muffler to analyse the difference in performance between two mufflers.