Flow Measurement by Wavelet Packet Analysis of Sound Emissions

Abstract

Fluid, when running through pipes, makes a complex sound emission whose parameters change nonlinearly with respect to flow speed. Especially, in household pipe systems, there may be spraying effects and resonance effects which make the emission more complex. We present a novel approach for predicting flow speed based on wavelet packet analysis of sound emissions rather than traditional time and frequency domain methods. Wavelet packet analysis, by providing arbitrary time-frequency resolution, enables analyzing signals of stationary and non-stationary nature. It has better time representation than Fourier analysis and better high-frequency resolution than wavelet analysis. Wavelet packet analysis subimages are further analyzed to obtain feature vectors of norm entropy. These feature vectors are fed into a multilayer perceptron for prediction. Prediction accuracy of 98.62%, with 3.99E−04 L/s mean absolute error and its corresponding 1.85% relative error is achieved. Time sensitivity is ±0.453 s and is open to improvement by varying window width. The result indicates that the proposed method is a good candidate for flow measurement by acoustic analysis.

Dataset of Flow-Induced Vibrations on a Pipe Conveying Cold Water

“…The vibrations produced in the walls of a pipe when a fluid circulates through it have been studied with a variety of aims, from the general analysis of systems dynamics [1] to more specific applications such as leak detection [2]. One of the specific applications of pipe vibration analysis that has shown potential for future developments is the design of non-intrusive flowrate soft sensors, capable of inferring the value of the flowrate using vibrational signals [3], and it has been addressed using either accelerometers [4][5][6], Laser Doppler Vibrometers (LDV) [7] or acoustic sensors [8,9].…”

Metrological Advantages of Applying Vibration Analysis to Pipelines: A Review

“…There are manly three types of sensors (see Table III) that have been used to acquire signals that capture the vibrational features on a pipe: accelerometers, which are attached to the pipe wall and register the acceleration that affects in in several axes [2] [3] [6] [8] [9] [7]; Laser Doppler Vibrometer (LDV), that use a laser and an interferometer to measure the vibration amplitude and frequency based on the Doppler shift of the laser reflected on the pipe surface [1] [4] [10] [11]; and acoustic sensors, which have been used on works that focus on vibrations associated with acoustic dynamics, where promising results have been accomplished [12] [13] [14] [15].…”

“…In 2018, Göksu propose the use of Wavelet Packet Analysis (WPA), which has the advantage of enabling the analysis of stationary and non-stationary signals [12]. This is an approach that relies on multiple features to represent the system dynamics and includes a relevance analysis, using norm entropy, to obtain an effective representation space.…”