A three–dimensional CFD approach for prediction of noise reduction of mufflers without mean flow
A CFD approach, in which the full equations are solved in the time domain, is proposed to calculate noise reduction of a cleaner and a complex exhaust muffler without mean flow. First, two modelling approaches are used to deal with the outlet boundary and to calculate noise reduction of the cleaner without a filter element. The calculated results agree quite well with measurements. Further, the noise reduction of the cleaner with a filter element and the muffler with E–glass roving in one of its chambers is calculated with the simpler but fairly accurate modelling approach. The calculated results are not as in good accordance with measurements as they are when the porous material is not taken into account, but still are attained with considerable accuracy, especially for the results of the exhaust muffler with approximately homogeneous porous material.
Keywords: 3D CFD, noise reduction, outlet boundary, porous materials, vehicle exhaust, exhaust mufflers, mean flow, modelling, computational fluid dynamics, vehicle noise