Measurement of Oil–Water Two-Phase Flow Phase Fraction With Ultrasound Attenuation

Phase fraction of oil-water two-phase flow is important to the process control and optimization. In this paper, a prediction model based on the mechanism of ultrasound attenuations in oil-water mixture is presented to estimate the phase fraction. This model consists of physical parameters of the two-phase flow and ultrasound frequency, by incorporating the scattering and attenuation of ultrasound in different flow patterns of the oil-water two-phase flow. The nonlinear relationship between ultrasound attenuation coefficient and phase fraction is corrected. An array of 16 ultrasonic transducers with 1-MHz center frequency and 20-Vpp sine acoustic signal is presented to implement this method, and a measuring system was designed and tested on a multiphase flow loop with actual flow experiments. The proposed prediction model showed a good agreement with the online phase fraction calibration in the flow experiments. The average error is 2.3% in water continuous flow, while in 2.8% in oil continuous flow. These findings and the mechanism prediction model provide basic foundations for the phase fraction estimation of oil-water two-phase flow by using the ultrasound attenuation technique.