PREDICTION OF THE ACOUSTIC PERFORMANCE OF SMALL POROELASTIC FOAM FILLED MUFFLERS: A CASE STUDY

The acoustic performance of small, irregularly shaped mufflers in continuous positive airway pressure (CPAP) devices is often enhanced by the inclusion of dissipative materials. In this study, the acoustic properties of two polyurethane foams were determined using a two-cavity method. Acoustic models of two CPAP device muffler designs incorporating a foam insert have been developed using a commercial finite element analysis software package. Experimental results for the mufflers have been obtained using the two-microphone acoustic pulse method. Results of the transmission loss of the muffler designs obtained from the finite element models are presented and validation of the computational results is discussed.