Abstract: Ultrasonic measurement techniques for velocity estimation are currently widely used in fluid flow studies and applications. An accurate determination of interfacial position in gas-liquid two-phase flows is still an open problem. The quality of this information directly reflects on the accuracy of void fraction measurement, and it provides a means of discriminating velocity information of both phases. The algorithm known as Velocity Matched Spectrum (VM Spectrum) is a velocity estimator that stands out from other methods by returning a spectrum of velocities for each interrogated volume sample. Interface detection of free-rising bubbles in quiescent liquid presents some difficulties for interface detection due to abrupt changes in interface inclination. In this work a method based on velocity spectrum curve shape is used to generate a spatial-temporal mapping, which, after spatial filtering, yields an accurate contour of the air-water interface. It is shown that the proposed technique yields a RMS error between 1.71 and 3.39 and a probability of detection failure and false detection between 0.89% and 11.9% in determining the spatial-temporal gas-liquid interface position in the flow of free rising bubbles in stagnant liquid. This result is valid for both free path and with transducer emitting through a metallic plate or a Plexiglas pipe.
Keywords: ultrasound; Doppler method; multiphase flow; gas liquid two-phase flow
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Coutinho, F.R.; Ofuchi, C.Y.; de Arruda, L.V.R.; Jr., F.N.; Morales, R.E.M. A New Method for Ultrasound Detection of Interfacial Position in Gas-Liquid Two-Phase Flow. Sensors 2014, 14, 9093-9116.
Coutinho FR, Ofuchi CY, de Arruda LVR, Jr. FN, Morales REM. A New Method for Ultrasound Detection of Interfacial Position in Gas-Liquid Two-Phase Flow. Sensors. 2014; 14(5):9093-9116.
Coutinho, Fábio R.; Ofuchi, César Y.; de Arruda, Lúcia V.R.; Jr., Flávio N.; Morales, Rigoberto E.M. 2014. "A New Method for Ultrasound Detection of Interfacial Position in Gas-Liquid Two-Phase Flow." Sensors 14, no. 5: 9093-9116.