Acoustic performance of a water muffler

A water muffler based on Kevlar-reinforced rubber tube and an inner-noise reduction structure is proposed in this study. This muffler aims to achieve optimum vibration damping and hydrodynamic noise reduction. An experimental system is established to investigate the acoustic performance of the proposed water muffler. The function of the system is confirmed by testing the reference tube. Tests on the reference tube at different velocities indicate that the effect of the flow mainly concentrates at the frequency band lower than 400 Hz. The comparison of results of the tests on the reference tube, rubber tube, and water muffler show that the rubber tube can reduce noise at some frequency bands. The insertion of the inner structure reduces noise at a frequency band of 630 to 3150 Hz. Numerical simulations of the acoustic performance of the rubber tube and the water muffler are conducted in commercial software. The simulated results show a good accordance of general tendency with the experimental results which confirms the noise reduction effect of the proposed water muffler.