Initial test and design of a soft sensor for flow estimation using vibration measurements

This article presents results of an experimental study that indicates a correlation between the flow of the fluid in a pipe and the resulting vibrations. The main idea is to investigate the possibility of developing a low-cost, nonintrusive, flow rate estimation technique with a simple soft-sensor based on the dependency of flow rate on the vibration levels. In this work, the pipe vibrations were measured using a capacitive microphone installed on the pipe. Microphone time domain data were recorded at different flow rate values and then transformed to the frequency domain for further analysis. Empirical results indicate that there is a relationship between the output signal of microphone in frequency domain and the flow rate in the pipe. In other words, investigations show that pipe vibration levels are proportional to the fluid flow rate. Also, to study the effect of microphone installation location, the experiments were repeated for different microphone locations.