On the life and habits of gas-core slugs: characterisation of an intermittent horizontal two-phase flow

Arellano, Yessica; Hunt, Andrew; Haas, Olivier; Ma, Lu

doi:10.1016/j.jngse.2020.103475

Cited by 9 publications

(8 citation statements)

References 29 publications

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“…When selecting a zonal configuration, the size of the zones needed to improve signal strength must be weighed against the spatial resolution ensuring that necessary information is not lost [3]. Different zonal configurations have been assessed in the past, where particular configurations allow obtaining velocity profiles along certain symmetrical axis depending on the flow structure [2].…”

Section: Combining Grt and Ectmentioning

confidence: 99%

“…A further way of analysing flow structural effects, on the computed structural velocities at gas rates where errors are greater, is through identification of the predominant flow structures in the vicinity of the region of interest. This was done by identifying the flow regimes from the temporal changes in the cross-section phases based on the density distribution from GRT and the permittivity distribution of ECT, combined with a flow characterisation of the dominant structures from the ECT transient measurements according to the classification parameters listed in [3]. The flow pattern characterisation of test points of interest overlaps the gas cross-spectrum velocity relative error in Fig.…”

Section: Fluid Dynamics Correlationsmentioning

confidence: 99%

“…In this regard, Industrial Process Tomography (IPT) has experienced large interest and development in the past decades due to its non-invasive characteristics, low costs, speed, and size flexibility [1]. IPT technologies have the ability to measure the cross-sectional phase distribution and to identify flow patterns [2] [3], which could potentially be used in conjunction to develop a generalised approach to multiphase metering.…”

Section: Introductionmentioning

confidence: 99%

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Multimodal Two-Phase Flow Measurement Using Dual Plane ECT and GRT

Stavland

Arellano

Hunt³

et al. 2021

IEEE Trans. Instrum. Meas.

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The present work assesses the accuracy two phase flow measurement, based on cross-correlation and cross-spectrum velocity computation, using dual plane non-intrusive Electrical Capacitance Tomography (ECT), over a broad spectrum of horizontal flow configurations, combined with fraction distribution measurements from Gamma-ray Tomography (GRT). The measurement of two-phase flow encompasses the measurement of both the velocity and the phase concentration of the flow components. The accuracy of the flow velocity is still an open discussion and remains a key challenge in the field of multiphase flow measurement. The velocities of the two-phase components vary, both in between them, and across the pipe crosssection. This study assesses the use of cross-correlation techniques as methods for calculating the cross-sectional velocity distribution by deriving the transit time of the fluid flowing through two parallel ECT sensor arrays mounted on the perimeter of a pipe. The spectral distribution of the velocities is assessed for improved accuracy of individual component velocities. A dual-plane ECT is adopted for the velocity measurements and are combined with state-of-the-art density-based cross-sectional phase fraction distribution from a GRT system to measure the volumetric flow rates of the two phases. The results show that the cross-spectrum method provides enhanced velocity estimation for both flow phases over the conventional cross-correlation technique. Further improvement was reported using a simple predictive correction model resulting in flowrate estimation accuracy of ±10%.The method for two-phase flow measurement suggested in this work leverages the accuracy of the tomography systems on accurate fraction measurement and fast data acquisition to lead to potential enhancement in process control by enabling a more accurate prediction of components velocities.

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Section: Combining Grt and Ectmentioning

confidence: 99%

Section: Fluid Dynamics Correlationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multimodal Two-Phase Flow Measurement Using Dual Plane ECT and GRT

Stavland

Arellano

Hunt³

et al. 2021

IEEE Trans. Instrum. Meas.

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“…For technical applications of macro-tube flows, it is essential to know the pressure drop [14], the presence or absence of a slug flow pattern, and the frequency of the slugs. This problem has not been adequately solved for straight pipes [10,15,16], although there is research on the more complex case of air-water two-phase flows in horizontal U-bend pipes [17][18][19][20]. The slug regime in a two-phase gas-liquid flow in horizontal round pipes was experimentally investigated with different methods [10,[21][22][23][24].…”

Section: Experimental Investigation Of Slug Regime Of Gas-liquid Flow...mentioning

confidence: 99%

“…The visual patterns of horizontal gas-liquid flow modes are presented in [10]. The velocity difference between the two phases increases at a higher gas quantity [11].…”

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confidence: 99%

Slug Regime Transitions in a Two-Phase Flow in Horizontal Round Pipe. CFD Simulations

et al. 2020

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The main objective of the study is to propose a technical solution integrated into the pipeline for the transition of the flow regime from slug to bubbly two-phase flow. The object of research is isothermal two-phase gas–Newtonian-liquid flow in a horizontal circular pipeline. There is local resistance in the pipe in the form of a streamlined transverse mesh partition. The mesh partition ensures the transition of the flow from the slug regime to the bubbly regime. The purpose of the study is to propose a technical solution integrated into the pipeline for changing the flow regime of a two-phase flow from slug to bubbly flow. The method of research is a simulation using computational fluid dynamics (CFD) numerical simulation. The Navier–Stokes equations averaged by Reynolds describes the fluid motion. The k-ε models were used to close the Reynolds-averaged Navier–Stokes (RANS) equations. The computing cluster «Polytechnic—RSK Tornado» was used to solve the tasks. The results of simulation show that pressure drop on the grid did not exceed 10% of the pressure drop along the length of the pipeline. The mesh partition transits the flow regime from slug to layered one, which will help to increase the service life and operational safety of a real pipeline at insignificant energy costs to overcome the additional resistance integrated into the pipeline.

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