Influence of Liquid Viscosity and Geometry on Vertical Gas/Liquid Two-Phase Annular-Duct Flow

Colmanetti, Alex Roger Almeida; Castro, Marcelo Souza de; Barbosa, Marcel Cavallini; Rodriguez, Oscar Maurício Hernandez

doi:10.2118/200491-pa

Cited by 5 publications

(2 citation statements)

References 33 publications

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“…( 2) and (3) to enhance the robustness of the algorithm. This paper uses formula (6) to calculate the local density, defined as follows:…”

Section: Clusteringmentioning

confidence: 99%

Flow regimes identification of air water counter current flow in vertical annulus using differential pressure signals and machine learning

Cao,

Dang,

Dang

et al. 2024

Sci Rep

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This study investigates the gas–liquid two-phase counter-current flow through a vertical annulus, a phenomenon prevalent across numerous industrial fields. The presence of an inner pipe and varying degrees of eccentricity between the inner and outer pipes often blur the clear demarcation of flow regime boundaries. To address this, we designed a vertical annulus with adjustable eccentricity (outer and inner diameters of 125 mm and 75 mm, respectively). We conducted gas–liquid counter-current flow experiments under specific conditions: gas superficial velocity ranging from 0.06 to 5.04 m/s, liquid superficial velocity from 0.01 to 0.25 m/s, and five levels of eccentricity (e = 0, 0.25, 0.5, 0.75, 1). We collected differential pressure data at two distinct height distances (DP1: 50 mm and DP2: 1000 mm). We used vectors, composed of both the probability density functions (PDFs) of the differential pressure signals and the power spectral density (PSD) reduced via Principal Component Analysis, as features. Using the CFDP clustering algorithm—based on local density—we clustered the flow regimes of the experimental data, thereby achieving an objective and consistent identification of the flow regime of gas–liquid two-phase counter-current flow in a vertical annulus. Our analysis reveals that for DP1, the main differences in the PSD of various flow regimes occur within the 0.5–1 Hz range. Among the three flow regimes involved, the slug flow exhibits the highest power intensity, followed by the bubbly flow, with the churn flow having the least. In terms of differential pressure distribution, the bubbly and churn flows have a concentrated distribution, while the slug flow is more dispersed. For DP2, the PSD differences primarily exist within the 0.5–2 Hz range. The churn flow has the highest power intensity, followed by the slug flow, with the bubbly flow being the weakest. Here, the bubbly flow's differential pressure distribution is concentrated, while the slug and churn flows are more dispersed. Based on the results of the flow regime classification, we generated a flow regime map and analyzed the influence of annulus eccentricity on the flow regime. We found that in most cases, pipe eccentricity does not significantly affect the flow regime. However, in the transition region—such as the bubbly to slug flow transition zone—flows with medium eccentricity values (e = 0.5, 0.75) are more likely to transition to slug flow. We compared the visual recognition results of flow regimes with the clustering results. 4.04% of the total samples showed different results from visual recognition and clustering, primarily located in the flow regime transition area. Since visually distinguishing flow regimes in these areas is typically challenging, our methodology offers an objective classification approach for gas–liquid two-phase counter-current flow in a vertical annulus.

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“…( 2) and (3) to enhance the robustness of the algorithm. This paper uses formula (6) to calculate the local density, defined as follows:…”

Section: Clusteringmentioning

confidence: 99%

Flow regimes identification of air water counter current flow in vertical annulus using differential pressure signals and machine learning

Cao,

Dang,

Dang

et al. 2024

Sci Rep

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“…In the annular space formed by tubing and casing, the region where the gas-water phase co-exists is in a two-phase counter-current flow state [1] . Accurate identification of air-water two-phase flow regime in CBM wellbore is extremely important to predict the production performance of coal bed [2,3] , However, the flow regime of air-water two-phase in vertical annulus is controlled by many factors, such as fluids physical properties [4,5] , flow rate [6] , annulus structure [7][8][9] etc. among them, there are few literatures on annulus structure, especially the influence of eccentricity of inner and outer pipes on flow regime, which needs further study.…”

Section: Introductionmentioning

confidence: 99%

Flow regime identification of air-water two-phase counter-current flow in vertical annulus and eccentricity effect analysis：a machine learning approach

Cao,

Dang,

Dang

et al. 2023

Preprint

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Gas-liquid two-phase counter-current flow has been involved in many industrial fields, due to the existence of the inner pipe and the variation of the eccentricity of the inner and outer pipes, the flow regimes are difficult to be visual identification. To solve this problem, a vertical annulus with adjustable eccentricity was designed. Experiments were carried out under different combination of gas-liquid flowrate and eccentricity. The feature vector was formed by PDF and principal components of PSD of two differential pressure signals. The clustering algorithm CFDP based on local density was used to cluster the experimental data, results show that this method can realize the identification of flow regimes without prior information, and the flow regime transition boundary agrees with the experimental results. The influence of pipe eccentricity on the flow regime transition is analyzed. The results show that, in most cases, pipe eccentricity has no obvious influence on the flow regimes. However, in the flow regime transition region, such as the bubbly flow to slug flow transition region, when the eccentricity is at a medium value, that is, e = 0.25,0.5,0.75, the flow is more likely to transit to slug flow, however, when e = 0,1. The flow tends to remain bubbly flow.

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Research on flow of sour gas mixture in deep well annulus

Tang

Kong

2021

Journal of Dispersion Science and Technology

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Influence of Liquid Viscosity and Geometry on Vertical Gas/Liquid Two-Phase Annular-Duct Flow

Cited by 5 publications

References 33 publications

Flow regimes identification of air water counter current flow in vertical annulus using differential pressure signals and machine learning

Flow regimes identification of air water counter current flow in vertical annulus using differential pressure signals and machine learning

Flow regime identification of air-water two-phase counter-current flow in vertical annulus and eccentricity effect analysis：a machine learning approach

Research on flow of sour gas mixture in deep well annulus

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