Study On Design Method Of Wideband Large Noise Elimination Quantity Exhaust Muffler

Some large internal-combustion engines produce large exhaust noises when they are running, working in such environment will do harm to human health. To control these kinds of noises, wideband large noise elimination quantity exhaust muffler is needed. Since there is no matured theory on designing such kind of mufflers, to design a muffler of ultimate performance requires repeated calculations and experiments. And the whole process is very complicated. In this paper, a design method of wideband large noise elimination quantity exhaust muffler is offered, which is aimed at shortening the product design period while acoustic attenuation performance of the muffler is guaranteed.Study in this paper was going on with a muffler design subject of one muffler manufacturer. At first, according to the exhaust data offered by the manufacturer, we designed a wideband large noise elimination quantity exhaust muffler with experience formula method, which successfully kept the exhaust noise in the limits of related standard, and solved the acoustic attenuation problem of low radical frequency, multi-orders, large amplitude low frequency noise within the exhaust noise.Next, we carried out numerical simulations with the acoustic software SYSNOISE as a platform. By imposing impedance transfer matrix to simulate the perforated tube muffler's acoustic performance, the numerical model of the muffler was much simplified. Also we studied the effect of porosity, structure parameters and temperature on perforated tube muffler's acoustic performance, and the effect of mutual influences between two chambers when two resonant perforated tube mufflers were in series on the mufflers'acoustic performance, which had a certain directive significance for perforated tube muffler design.Given the lack of low frequency acoustic attenuation performance of the new muffler, we optimized parameters of the new muffler with method of transfer matrix, and verified by finite element simulation. It shows that the low frequency acoustic attenuation performance of the muffler had improved after optimization. So the transfer matrix method can be used in parameter optimization of low frequency acoustic attenuation performance of wideband large noise elimination quantity exhaust muffler.Finally, by summarizing the processes of design and optimize the muffler, we offered a design method of wideband large noise elimination quantity muffler, namely, calculating the muffler's parameters with traditional experience formula, then predicting and optimizing with transfer matrix method, and finally verifying by finite element simulation, which has a certain engineering value.