Coherent optical fiber interferometric sensor for incipient cavitation index detection

Opticalfiber sensors (OFSs) are nowadays widely adopted in many differentfields and applications. Cavitationin pipeline systems is one of the main concerns of engineers because of its serious consequences for the lifetimeof pipelines and on the performance of hydraulic devices. Among other useful parameters the incipient cavi-tation index is one of the most important because it represents the very beginning of the phenomenon. Thepresent paper discusses the possibility of using opticalfiber technology to detect cavitation in a pipeline. Theexperimental system exploits an interferometricfiber optical sensor based on a coherent demodulation scheme,avoiding the need for working point stabilization systems and coping with the polarization fading. Severaldispositions and geometries for the sensors have been tested to select the most efficient solution. The results arethen compared with cavitation indexes calculated following the standard procedure, using accelerometermeasurements, to prove the opticalfiber sensors’effectiveness