Monitoring Cavitation Regime From Pressure and Optical Sensors: Comparing Methods Using Wavelet Decomposition for Signal Processing

Abstract

A cavitating two-phase flow of water in a pipe with area shrinkage was experimentally investigated, acquiring at high sampling rate pressure signals and images of the cavitating flow-field. The fluctuations of the pressure measurements in the internal orifice and of the intensity level of the images' pixels were decomposed using the wavelet transform to analyze the frequency distribution of the signals energy with respect to the flow behavior and to highlight the influence of temperature on the phenomena under investigation. It was shown that the energy content at each frequency band of the acquired signals is well related to cavitation flow-field behavior.

Cavitation Regime Detection by LS-SVM and ANN With Wavelet Decomposition Based on Pressure Sensor Signals

“…As found by the authors in [9] in absence of cavitation the pressure fluctuations are small, while oscillations dominate the pressure fluctuations in the different two phase flow patterns. Hence cavitation regime recognition could be performed by the power spectral density (PSD) of the measured pressure fluctuations, recorded up-and downstream the orifice, were analyzed.…”

“…The experimental setup is described in details in [5], [9], [32], and [33]. A centrifugal pump was used to generate the fluid flow.…”

“…The power spectral density (PSD) of the measured pressure fluctuations, recorded up-and downstream the orifice, can be used to analyze the cavitation behavior, as reported in [9] and [22].…”

“…The various cavitating flow regimes could be identified by means of methods based, for example, on statistical analysis of pressure signals that reflect the unsteady characteristics of the cavitating flow [5], [9].…”

Modeling and Designing a Full Beamformer for Acoustic Sensing and Measurement

“…Beamforming allows impressive and unexpected use of array of sensors in many fields and applications, namely, biomedical [25] [26], industrial [27], environmental, wireless networking, etc…The main goal of this research, which is still on the way, is to develop applications and new findings in the field of array of sensors using beamforming. This goal also includes a generalization of the approach in order to be able to design and modeling acoustic system.…”