Parametric analysis of a Pulsco vent silencer

In this investigation a parametric study of a Pulsco vent silencer is conducted. The overall objective is to seek the optimum system performance. The vent silencer consists of a perforated diffuser, the silencer body and a tube module, the latter being comprised by a set of perforated tubes surrounded by acoustic packing. The mathematical model for the vent silencer is built upon a modified Helmholtz equation along with the Delany-Bazley model for the tube module, coupled with the linearized-potential and compressible-flow equations for the diffuser and plenum sections. The parameters chosen in the parametric study include: porosity and perforation size of the tubes, type of acoustic packing, bulk density of the packing material, and the flow Mach number. For each set of parameters, the model equations are solved with the finite element method. The numerical results indicate that a perforation size (i.e., tube-hole diameter) of 1/8" with porosity of 0.4, packing density of 48 kg/m3 for TRS-10 and 100 kg/m3 for Advantex packing materials, and low Mach number flows provided the optimum transmission loss. The numerical results are in agreement with the experimental data.