Design and optimization of exhaust muffler for L24 diesel engine

To address the challenge of optimizing both acoustic and aerodynamic performances simultaneously in the muffler development and design, the Acoustic Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) method were utilized to design an exhaust muffler using the L24 diesel engine as a prototype in this study. The impacts of different structural parameters on the noise reduction performance and resistance characteristics of the exhaust muffler were investigated. Taking both pressure loss and transmission loss in the frequency band between 20 and 1000Hz as the optimization objectives, the primary structural parameters were optimized using the uniform experimental design method and regression analysis. The results indicate that the original exhaust muffler has poor noise reduction effects in both low-frequency and high-frequency bands, and the ineffective structural layout of its side outlet causes significant pressure losses. The average transmission loss of the initially designed exhaust muffler was 25.1dB higher than that of the original muffler, but its pressure loss was reduced by 1405.331Pa. However, the noise reduction performance in the low-frequency band needed further improvement. When the perforation rate of the interpolated perforated tube, the perforation depth of the perforated plate, and the perforation diameter and depth of the perforated tube were 8%, 1mm, 8mm, and 4mm respectively, the exhaust muffler achieved the best comprehensive performance. As a result, the transmission loss of the optimized exhaust muffler was 5.97dB higher than the initial model, while the pressure loss was reduced by 4.612Pa.