Amount of effective sound pressure among pneumatic oscillations in side channel compressors

Machines and plants operating within the vicinity of people need to be subjected to noise investigation and reduction. This includes the fans, pumps and the compressors. It is known that only a small part of the pneumatic oscillations, which result from turbulence, current exchange or by strong expansion currents are emitted as effective sound pressure and released into the environment. Although there are several mathematical models on the origin and propagation of sound, the audible amount of turbulence and/or pressure oscillation has not been known until now. These ratio values can be determined by parallel measurements of the pneumatic oscillation in a machine and of the effective sound pressure on the acoustic sources in relation to the distance to the acoustic source and the operating parameters of the compressor. The following contribution determines these values for a side-channel compressor.