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ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
EXPERIMENTAL STUDY OF THE INFLUENCE OF GAS DENSITY ON TWO-PHASE FLOW IN A ROCKING-FLOW CELL
Submission Author:
Bruna Patricia Naidek , PR
Co-Authors:
Bruna Patricia Naidek, Marco Germano Conte, Rigoberto Morales
Presenter: Bruna Patricia Naidek
doi://10.26678/ABCM.ENCIT2022.CIT22-0444
Abstract
Although two-phase flows have been extensively investigated over the last decades, most of the studies analyze the flow of fluids at ambient conditions or high liquid-gas density ratios. In deep water offshore oil and gas production, where pressures are considerably high, the fluid densities are similar to each other or even of the same order of magnitude. Reproducing such conditions in lab scale can be a quite challenging and risky enterprise because of the high-pressure levels involved. One of the options to reproduce those conditions is to reduce the pressure and use heavy gases, instead of light gases at high pressure. In this work, we will analyze the influence of gas density on stratified and slug flows by using fluid models, SF6 and mineral oil. Experiments were performed by using a 51-mm I.D., 500-mm long rocking-flow cell that was pressurized up to 35 bar at temperatures between 5ºC and 45ºC. The gas density ranged from 6 kg/m³ to 388 kg/m³, resulting in liquid-gas density ratios from 142 to 2.3. Liquid loadings of 0.4, 0.7 and 0.9 and rotational speeds between 0.5 and 1.5 rad/s were tested. The maximum inclination of the rocking-flow cell was 17º. Mixing rules were used to predict the influence of dissolved SF6 on liquid properties. Recorded images of the experiments show the gas-liquid interface transition from a smooth surface to a wavy one as the gas density and the rotation speed increases. Differences in the contact angle were also observed. An elongated bubble similar to that of slug flow pattern is observed for the highest liquid loading. For the liquid loading of 0.7, the influence of the gas density on the transition between the stratified and slug flow was observed.
Keywords
Two-phase Flow, Rocking-flow cell, influence of gas density, instabilities of gas-liquid interface
