Separated two-phase flow regime parameter measurement by a high speed ultrasonic pulse-echo system

Abstract

In this work, a high speed ultrasonic multitransducer pulse-echo system using a four transducer method was used for the dynamic characterization of gas-liquid two-phase separated flow regimes. The ultrasonic system consists of an ultrasonic pulse signal generator, multiplexer, 10 MHz (0.64 cm) ultrasonic transducers, and a data acquisition system. Four transducers are mounted on a horizontal 2.1 cm inner diameter circular pipe. The system uses a pulse-echo method sampled every 0.5 ms for a 1 s duration. A peak detection algorithm (the C-scan mode) is developed to extract the location of the gas-liquid interface after signal processing. Using the measured instantaneous location of the gas/liquid interface, two-phase flow interfacial parameters in separated flow regimes are determined such as liquid level and void fraction for stratified wavy and annular flow. The shape of the gas-liquid interface and, hence, the instantaneous and cross-sectional averaged void fraction is also determined. The results show that the high speed ultrasonic pulse-echo system provides accurate results for the determination of the liquid level within +/-1.5%, and the time averaged liquid level measurements performed in the present work agree within +/-10% with the theoretical models. The results also show that the time averaged void fraction measurements for a stratified smooth flow, stratified wavy flow, and annular flow qualitatively agree with the theoretical predictions.

Experimental and Numerical Investigation of Stratified Gas–Liquid Flow in Downward-Inclined Pipes

“…The transit time between the ultrasonic pulse and echo signals provides an accurate measurement of the liquid layer height. This technique was employed successful by Chang and Morala [19] and Masala et al [20]. The uncertainty of the measurements was estimated to be around ±0.03 mm according to the previous calibration procedure.…”

Icone19-43184 Transient Two-Phase Interfacial Parameter Measurements Using Ultrasonic Pulse-Echo Methods in a Natural Circulation Loop

“…Chang et al (Chang et al, 1982) developed a single transducer time-averaged ultrasonic pulse echo method (time averaging A-Scan method) to determine flow regime, liquid level, and location of liquidsolid interfaces in metal pipes and gas-liquid two-phase flow. This work was further extended by Masala et al in horizontal flows, where separated flows were measured (Masala et al 2007) and intermittent flows were studied (Masala et al 2010). Specific parameters such as interfacial area were obtained by Morala and Chang in 1993. In this work, two-phase parameters such as flow regime, bubble velocity, and void fraction for a vertical leg, and liquid level in a separation tank are studied using a two transducer pulse-echo system.…”

Measuring the Level of Liquid in a Partially-Filled Pipe Via the Ultrasonic Pulse-Echo Method Using Acoustic Modeling

“…Devices built on this principle have been built and utilized in varied environments [3][4][5]. The pulse-echo approach has been refined during the years with more accurate modeling of the propagation times [6], and extended to multi-phase flows [7][8]. However, most of these approaches assume large containers and/or a flat fluid interface from which the acoustic pulse is reflected.…”