Caracterização experimental da evolução do escoamento líquido-gás em golfadas em uma tubulação vertical

Abstract

Two-phase gas-liquid flow can assume different geometric configurations called flow patterns, one of these is the slug flow, characterized by the intermittency of a structure known as unit cell, which is composed by the Taylor bubble and the liquid slug. Due to the transient and intermittent behavior of the slug flow, a detailed analysis is necessary to describe its characteristics. In this study, an experimental characterization of the slug flow in a vertical pipe of 0.026 m diameter and 14 m long was developed. The experiments were carried out for air and water, with the gas superficial velocity ranging from 0.2 to 1.5 m/s and liquid superficial velocity ranging from 0.2 to 1.5 m/s, totalizing eighteen (18) experimental points. Phase detection was carried out in five measuring stations, used to monitor the structures of the slug flow, where two-wire resistive sensors were installed in four of them and in one station the electrode mesh sensor (wire-mesh) along with a camera of high acquisition of the flow were used. From the experimental data, a phenomenological analysis of the flow was developed as a function of the dimensionless parameters of Froude and Reynolds. The evolution of the statistical distribution of the characteristic parameters of the slug flow was analyzed through the probability density functions along the five measuring stations. Empirical correlations were proposed to estimate the mean and their respective standard deviation values for the bubble velocity, frequency, void fraction of the unit cell, void fraction of the liquid slug and bubble and liquid slug lengths. Thus, the results obtained in this work present information that contribute to the understanding of the slug flow behavior in vertical pipes, provide experimental data and empirical correlations that can be used in industry or academically for the development and verification of mathematical and numerical models.