Vibrations of water hydraulic systems – an experimental approach

This paper presents an experimental study of the vibrations induced both by cavitating and by non-cavitating flow in a hydraulic installation that comprises the main elements of a water hydraulic system. The cavitation was triggered by progressively closing a butterfly valve. The vibrations were measured on the pump, on the bearings housing, on the pump drive motor, and at nine measurement points located upstream and downstream of the main elements of the installation. The measurements were carried out at different flow rates obtained at different openings of the butterfly valve. The results suggest that the phenomena that take place inside the pump and inside the bearings cause vibrations having frequencies of up to 10 kHz. The results also indicate that the cavitation that occurs at the butterfly valve causes vibrations of high frequency, above 3 kHz, that have a distinct peak at about 18 kHz. These results could be useful in establishing proper maintenance plans for hydraulic installations.