An auxiliary measuring technology of wet gas flow based on the vibration signals of the pipe

Abstract

Flow induced vibration exists commonly in multiphase flow pipelines, and the amplitude, frequency and some other characteristic parameters of pipe vibration are closely correlated with multiphase flow rate and flow regimes. The relationship between the vibration signals and gas mass fraction has been theoretically analyzed. An acceleration sensor was selected and attached to the pipe wall for the measurement of pipe vibration induced by wet gas flow, and a set of experiments has been carried out. One schematic model was put forward for explaining the interactions between two-phase flow and pipe wall. The model is much more like a closed loop control system; the input of the system is a linear combination of random vibration of two-phase flow momentum, two basic fluid–structure coupling mechanics (friction coupling and Poisson coupling) and the force arising from gas–liquid impacting on slotted orifice. The characteristic parameters of the vibration signals have been extracted and analyzed. Both experimental results and theoretical analysis show that there is a certain relationship between the standard deviation value of vibration signal and gas–liquid flow rate, and this relationship could be approximated by a function of gas mass fraction. The characteristic parameters in frequency domain, which include wavelet package energy and wavelet package energy entropy of vibration signal, are varied regularly with different flow regimes, and they are potential classification parameters for wet gas flow regimes.