Experiences on Cavitation Detection Methods

Cavitation is in most cases harmful and undesired phenomenon in fluid power systems. When actions for preventing cavitation are considered, it is essential to recognise the existence of cavitation and location of cavitation inception point. In fluid power components and systems cavitation can occur in various locations where the access for measuring instruments is limited. Therefore, the existence of cavitation is often very difficult to detect. In addition, very high speed of the cavitation phenomenon makes the task difficult. At the Institute of Hydraulics and Automation several cavitation detection methods have been studied. The existence of cavitation can be detected either directly or indirectly. Indirect detection can be done by monitoring steady-state flow properties and with high-speed pressure transducers or accelerometers the cavitation-induced shock waves can be recorded. Measurement of frequency spectrum of acoustic pressure reveals also the presence of cavitation. When flow visualisation is possible to arrange, cavitating flow can be observed directly. In addition, an ultrasonic transmitter-receiver has been tested for direct cavitation detection. The above-mentioned equipment has been used in several cavitation studies at the IHA and promising results have been obtained.