Void Fraction Measurement in a Gas-Liquid Swirling Flow Using an Ultrasonic Sensor

Cesar Yutaka Ofuchi,Rigoberto E M Morales,Marco Jose Da Silva,Flavio Neves,Henrique Krainer Eidt,Dalton Bertoldi

doi:10.1109/access.2020.3033425

Cesar Yutaka Ofuchi, Rigoberto E M Morales + Show 4 more

Open Access

https://doi.org/10.1109/access.2020.3033425

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Abstract

In this article, we propose a novel ultrasonic technique to measure the gas void fraction in a liquid-gas intermittent swirling flow. The method converts the liquid film thickness measurement to a gas void fraction value considering a symmetrical flow pattern. We propose the use of the first echo peak instead of the standard maximum echo peak to estimate the liquid film thickness. The results are compared with a wire-mesh sensor, a reference for gas void fraction measurement, in a 1-inch inner-diameter vertical flow loop. A Root-Mean-Square-Deviation (RMSD) of 2.87% was observed between the proposed ultrasonic method and the reference sensor. An improvement of 6.06% if compared to the standard film thickness method (8.93%). The studied cases show that our method improves the use of ultrasound for gas void fraction measurement in a gas-liquid swirling flow.

Highlights

Multiphase flow can be found in nature and several engineering applications such as nuclear power generation, chemical process and oil, and gas extraction
The flow pattern depends on the combination of superficial gas and liquid velocities, which are responsible for the different lengths of the gas structures in the figure
In this paper, we propose the use of an ultrasound sensor to measure the void fraction in a water-air intermittent swirling flow

Summary

Introduction

Multiphase flow can be found in nature and several engineering applications such as nuclear power generation, chemical process and oil, and gas extraction. A flow-conditioning swirl device is used to modify a two-phase upward vertical gas-liquid flow into a gas-liquid swirling flow This type of flow is characterized by a swirling liquid film on the pipe wall and a swirling gas flow at the center of the pipe. This condition is explored in applications such as heat exchangers [2], steam separators [3], gas-liquid separators [4]–[7], and multiphase flow distribution systems [8][9]. Multiphase flow metering techniques on swirling flow may be simpler than on nonswirling flow

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