CẤU TRÚC VÀ HIỆU SUẤT ÂM CỦA ỐNG XẢ ĐỘNG CƠ DÙNG CHO MÁY VÀ THIẾT BỊ XÂY DỰNG

Abstract

The main objective of the present work is to characterize numerically the link between the geometrical parameters and the functional noise reduction properties of typical engine exhaust mufflers for construction equipment and machinery. To this regard, the acoustical modeling of these devices is first presented using the finite element approach. Then, we investigate the effects of both the geometrical parameters and the shape configuration of some typical mufflers (e.g., chambered, turbo, reactive, absorptive…) on their sound transmission loss. In terms of acoustics, for a given total length (600 mm), mufflers show a better acoustic performance (up to 50 dB) with a high number of chambers/partitions or using absorbing layers, especially micro-perforated panel with hole size of 24 mm and its fraction 48% can improve the sound transmission loss up to 100 dB at low frequency less than 1 kHz. The obtained results show clearly that the noise reduction target could be successfully achieved over an individual octave band or the whole frequency range by tuning structures of appropriate engine exhaust mufflers.