طراحی و شبیه سازی مافلر برای موتور چهار سیلندر دوزمانه

This study aims at the design, three-dimensional (3D) modeling, and numerical analysis of an efficient muffler (silencer) for the significant reduction of exhaust noise from a four-cylinder, two-stroke engine. The design approach is predicated on advanced principles of engineering acoustics, encompassing the rigorous analysis of sound wave behavior and the meticulous optimization of the muffler's geometrical parameters to achieve maximum sound absorption and damping. High-fidelity geometrical models were created in SolidWorks software and subsequently transferred to the robust COMSOL Multiphysics environment to undergo advanced numerical analyses within the Acoustics Module, utilizing the Finite Element Method (FEM). This precise simulation process enabled the prediction of the muffler's acoustic performance prior to physical fabrication.
In this research, the acoustic performance of two distinct muffler designs was independently investigated and compared, with particular emphasis on evaluating the critical impact of sound-absorbing materials on noise damping efficacy across various frequency ranges. The first muffler, analyzed over the broader frequency range of 0 to 1000 Hz, demonstrated in its optimized state (with absorbent material) that the noise reduction continuously exceeded 30 decibels (dB) from 400 Hz upwards. At the key frequency of 800 Hz, the reduction level reached a remarkable 40 dB, indicating a 10 dB performance improvement compared to the non-absorbent configuration. This highlights the design's efficacy at higher frequencies, which often constitute the dominant engine noise.
The second muffler, designed to target lower frequencies within the 0 to 200 Hz range, exhibited its specialized performance. In this design as well, the addition of sound-absorbing material significantly enhanced the noise reduction, such that from 100 Hz, the noise reduction surpassed 10 dB, and at 200 Hz, a maximum reduction of 28 dB was achieved. This contrasts with the non-absorbent case, where the maximum reduction was merely 20 dB. Overall, the simulation results clearly underscore the superiority of the optimized designs and the high impact of absorbent materials in achieving acceptable and effective noise level reduction at target frequencies, rendering this muffler a more efficient alternative to traditional designs.