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ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
DETAILED ANALYSIS OF THE DIAMETER INFLUENCE ON AIR-WATER SLUG FLOW CHARACTERISTICS IN UPWARD VERTICAL FLOW
Submission Author:
Paúl Delgado , PR , Brazil
Co-Authors:
Paúl Delgado, Carolina Cimarelli Rodrigues, Eduardo Nunes dos Santos, Moisés Marcelino Neto, Marco Jose Da Silva, Rigoberto Morales
Presenter: Carolina Cimarelli Rodrigues
doi://10.26678/ABCM.ENCIT2022.CIT22-0420
Abstract
Multiphase slug flow is found in pipes and process equipment in the oil & gas industry. Air-water slug flow is usually defined as the alternate passage of two structures: a liquid slug and a Taylor bubble, which is an elongated, bullet-shaped bubble. This type of flow occurs intermittently and the passage of all bubbles and liquid slugs have different lengths and velocities. The gas expansion in vertical multiphase flow is highly relevant, as it affects all the characteristic parameters. Therefore, the knowledge of the flow evolution and not only of its average behavior is essential to the design of separator equipment as well as pipelines. In this sense, this work aims to evaluate the influence of the internal diameter on the evolution of the characteristic parameters of slug flow such as the Taylor bubble velocity, the length of the elongated bubble and the liquid slug, the void fraction in bubble and slug regions, and the slug frequency. The experimental study was done in the Multilab experimental loop of the Multiphase Flow Center at UTFPR/NUEM with three different internal diameters (26, 40.8 and 50 mm). The entry section has a 10 m horizontal tube for flow development connected to a 90°-curve that directs the flow to the vertical test section with approximately 14 m of height. Fifty different combinations of air-water superficial velocities were used, of which twenty were for ID = 26 mm, twelve for ID = 40.8mm and eighteen for ID = 50 mm. To evaluate the flow, five measuring stations were used: four two-wire resistive sensors and one wire-mesh capacitive sensor. The pressure was measured at the five measuring stations with differential/gauge pressure transmitters and an atmospheric pressure transmitter was used. High image acquisition camera were used to analyze the flow qualitatively in three different heights in order to acquire the largest number of relevant images from the slug flow. The results obtained provided valuable information for the development of models/simulators and engineering correlations that allow an accurate prediction of the evolution of slug flow in vertical pipes.
Keywords
Vertical Slug Flow, Flow assurance, Slug Flow
