Investigation on measurement method for hydrodynamic noise in centrifugal pumps using reverberation tanks

Pumps are considered as a primary source of acoustic energy in industrial piping. At present, the measurement of the hydrodynamic noise of the pump is done by installing the sensors in the pipeline attached to the pump. This technique is based on the fact that plane waves are formed inside the pipeline and the pulsating pressure travels in the form of sound waves. However, in actual there are no plane waves in an elastic pipe due to the phenomenon of low frequency cut-off. In fact, this pulsating pressure inside the pipeline will result in further vibration of the pipeline. This paper proposes a method for measuring the hydrodynamic noise of the pump by using the reverberation tank. The vibration of a pipeline attached to a centrifugal pump can be avoided by replacing the elastic pipeline with a flexible hose. The water outlet of the hose is then placed in the reverberation tank fitted with hydrophone arrays. The hydrodynamic noise of the water pump is measured using low frequency expansion technique of the reverberation method. Experiments show that this method can be used effectively to differentiate between the hydrodynamic noise and other associated noises of a pump.