Theoretical study of vertical slug flow measurement by data fusion from electromagnetic flowmeter and electrical resistance tomography

Electrical resistance tomography (ERT) can be used to obtain the conductivity distribution or the phase distribution of gas/liquid flows (e.g. slug flow). Using proper parameter models and flow regime identification models, the measurement of phase size, void fraction, and pattern recognition can be realized. Electromagnetic flowmeters have been used to measure conductive single-phase liquid flows. However, neither ERT nor electromagnetic flowmeters (EMF) can provide accurate measurement of gas/liquid two-phase flows. This paper presents an approach to fuse the information from ERT and an electromagnetic flowmeter. A model for the measurement signal from the electromagnetic flowmeter has been developed based on the flow pattern and the phase distributions, which are obtained from the reconstructed images of ERT, aiming to reduce the measurement error of the electromagnetic flowmeter and enhance the measurement accuracy. Through the simulation research of virtual current density distribution, the feasibility of fusion of electromagnetic flowmeter and ERT to measure gas/liquid two-phase vertical slug flow is verified. By theoretical analysis, the relationship between the output of electromagnetic flowmeter and flow parameters is established. The electrical potential difference of the electromagnetic flowmeter, average velocity, volume flow rate and gas void fraction between the bubble size and location are also investigated. The fusion approach can be used to measure vertical slug flows.

A new method for gas/liquid two-phase vertical slug flow measurement based on the fusion of electromagnetic flowmeter (EMF) and electrical resistance tomography (ERT) is proposed. The feasibility of EMF to measure vertical slug flow is verified by the simulation research. The fusion equations of electromagnetic flowmeter and ERT have been established and verified theoretically. Figure optionsDownload as PowerPoint slideHighlights
► A new method for gas/liquid two-phase vertical slug flow measurement is proposed.
► The fusion equations between EMF and ERT are established and verified.
► Conditions and affecting factors to the fusion of EMF and ERT are investigated.