Prediction of transfer loss in a straight-through perforated pipe dissipative muffler under tangential flow

Here, the frequency-domain linearized Navier-Stokes equations (LNSEs) considering eddy viscosity coefficient was used to calculate transfer loss of a straight-through perforated pipe dissipative muffler under tangential flow. Calculation steps were as follows: (1) CFD (computational fluid dynamics) method was used to solve time-averaged flow variables in calculation domain, and then theses variables were mapped to acoustic grid; (2) acoustic propagation medium was divided into air and sound-absorbing material, the latter was equivalent to a fluid with complex sound velocity and complex density, the frequency-domain LNSEs was used to calculate sound field, at last the plane wave decomposition method was used to calculate and predict the transfer loss of the muffler. The calculation results agreed well with the experimental measurement results to verify the correctness of the calculation method. Influence laws of tangential flow Mach number on transfer losses of dissipative mufflers with different flow resistance rates and perforated structures were analyzed with numerical calculation. The results showed that with increase in tangential flow Mach number, the transfer loss of the muffler within low frequency-domain decreases, but there is no obvious law for the change of the muffler performance at mid and high frequencies to follow; effects of tangential flow on transfer losses of mufflers with low perforation rate are larger than those with high perforation rate. © 2023 Chinese Vibration Engineering Society. All rights reserved.