Optimization of Acoustic and Flow Performance in a Perforated Muffler

Muffler is used to minimize the transmitted sound power caused by car exhausted system. Transmission loss (TL) is commonly used to evaluate sound power exiting the muffler and denoted by a signal to noise (S/N) ratio. Firstly, the Taguchi method is twice used to find the optimal acoustic configuration successfully, involved perforation and an additional tube. Then CFD (computational fluid dynamics) analysis is to find the pressure drop (PD) variation under 10 to 50 m/s inflow velocities. When the inflow velocity is 10 m/s and the diameter of additional tube is varied, both performances are evaluated particularly by the weighted analysis, the coefficients are found as 0.8 on TL (S/N 25.177) and 0.2 on PD (341.348 Pa), and additional tube diameter is 0.06 m.