Cavitation Study in Centrifugal Pumps Through Acoustic Signal Analysis

Abstract

The cavitation phenomenon causes serious problems in centrifugal pumps, such as poor hydraulic performance and damage to the internal structure of the pump produced by material erosion. Additionally, cavitation induces vibrations and noises that do not occur under normal operating conditions. These changes can be used as a guide for the diagnosis of pumps. In this article, different criteria based on the acoustic signals emitted by a centrifugal pump are analyzed to identify its cavitation condition. For this, an experimental assessment, in which the pump operates in four different flow conditions, namely, 20 l/min, 40 l/min, 60 l/min, and 80 l/min, is performed. The detection of acoustic emissions has been carried out through a microphone located at a specific distance from the pump. The results have shown that the use of acoustic parameters such as Loudness, Crest factor, and Zero crossings calculated from the base sound signal, the derivative, and its log dt/dp value, allows the identification of three pump operation zones: one free of cavitation, the onset of cavitation and the fully developed cavitation condition. The study has concluded that acoustic emissions provide sufficient information to diagnose the presence of cavitation. Additionally, the methodology based on this type of signal has the advantage that it does not require high implementation costs, and it can be widely improved depending on the requirements.