Empirical correlations and CFD simulations of vertical two-phase gas–liquid (Newtonian and non-Newtonian) slug flow compared against experimental data of void fraction

Ratkovich, Nicolás Ríos; Majumder, Subrata Kumar; Bentzen, Thomas Ruby

doi:10.1016/j.cherd.2012.11.002

Cited by 44 publications

(16 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…They suggested a simplified model for the process of ring-type waves propagation. Ratkovich et al [23] simulated slug flows of Newtonian and non-Newtonian fluids in a 2D axisymmetric domain at different superficial velocities. Results of averaged void fraction in a portion of the domain were compared to correlations of the literature and own experimental data.…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the churn-slug transition dynamics in vertical upward air-water flows

Imada¹,

Saltara²,

Bali˜no³

2013

Computational Methods in Multiphase Flow VII

View full text Add to dashboard Cite

In gas-liquid two-phase flows through vertical ducts, the spatial distribution of phases may assume several configurations, known as flow patterns. Slug and churn patterns are characterized by an unsteady behaviour and their boundary is a subject of interest for many researchers. Different descriptions of mechanisms occurring at churn/slug transition may be found in the literature. One transition process is described by Taitel et al. (Modelling flow pattern transitions for steady upward gas-liquid flow in vertical tubes. AIChE Journal, 26, pp. 345-354, 1980), in which churn flow is an entrance condition observed upstream of a developed slug flow if there is sufficient pipe length for this to happen. In the present work, vertical upward air-water flows through a 2-inch i.d. tube are simulated with the commercial finite-volume-based code FLUENT, aiming to study this churn/slug transition process through spatial and temporal phase distribution visualizations and statistical analyses of void fraction histories at points along the domain. The incompressible Volume of Fluid (VOF) formulation allied to a Piecewise Linear Interface Construction (PLIC) technique is applied to capture the distribution of phases throughout three-dimensional domains. Turbulence effects are accounted through the Realizable k-epsilon model. Three different tube lengths and two sets of superficial velocities are studied in order to understand their influence in liquid slug collapse and bubble coalescence processes. Void fraction histories at points distributed along the duct centerline are stored during a simulation time long enough to provide statistical data with reasonable errors. Fast Fourier Transform analyses are used to verify the transition point and flow characteristic frequencies. Probability distributions of void fraction at cross sections along the tube are also evaluated. The VOF method was able to qualitatively capture the mechanisms of churn/slug transition processes. Results for entrance length and frequencies are

show abstract

Section: Introductionmentioning

confidence: 99%

Numerical study of the churn-slug transition dynamics in vertical upward air-water flows

Imada¹,

Saltara²,

Bali˜no³

2013

Computational Methods in Multiphase Flow VII

View full text Add to dashboard Cite

show abstract

“…Two-phase flow can be considered as the most common class of multiphase flows and includes gas-solid, gas-liquid, and liquid-liquid flows. In spite of its common presence, the understanding is quite limited in comparison to single-phase flow due to its nature [1]. Among two-phase flows the gas-liquid flow is probably the most important due to its existence in many industrial processes and to the comprised characteristics of a deformable interface as well as to the compressibility of one of the co-existing phases.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Premoli et al. Correlation Predictions in Horizontal Stratified-Wavy Two-Phase Flow Encountered at Small Diameter T-Junction

Makrygiannis¹,

Margaris²

2020

International Journal of New Technology and Research

View full text Add to dashboard Cite

“…Modelling two‐phase flow boiling in a vertical tube is complicated for three reasons: the gas‐liquid interface; that the gas flows faster than the liquid (buoyancy and slip between the phase), affecting the void fraction along the tube; and the pressure drop . Few complicated phase change process models have been proposed recently .…”

Section: Introductionmentioning

confidence: 99%

Two‐phase flow boiling in 19 mm tube: Experiments and CFD modelling

2016

View full text Add to dashboard Cite

Boiling flows are encountered in a wide range of industrial applications such as boilers, nuclear reactors, electronic cooling, and various types of chemical reactors. Heat transfer coefficients, flow boiling regimes, flow instabilities, pressure drops, and conditions like dry-out are some of the key issues in every boiling flow study. It is observed that a limited experimental database is available for the 19 mm ID channel diameter, i.e. a typical tube diameter of steam generator. Therefore, in the present work, the experimental setup was designed for studying boiling flows in a 19 mm ID tube in such a way that different flow regimes occurring in a steam generator tube (from pre-heating of sub-cooled water to dry-out) could be investigated by varying inlet conditions. The reported results cover a reasonable range: 8-27 kW/m 2 and 2.9-5.9 kg/m 2 Á s heat and mass flux conditions, respectively. A basic computational flow model was also developed to facilitate interpretation of the obtained data. The presented design of the experimental setup and the approach of mimicking different types of steam generator tubes as well as presented experimental and simulated results are useful for gaining insight into complex boiling flows in tubes, and provide a sound basis for further work in this area.

show abstract

Empirical correlations and CFD simulations of vertical two-phase gas–liquid (Newtonian and non-Newtonian) slug flow compared against experimental data of void fraction

Cited by 44 publications

References 40 publications

Numerical study of the churn-slug transition dynamics in vertical upward air-water flows

Numerical study of the churn-slug transition dynamics in vertical upward air-water flows

Assessment of Premoli et al. Correlation Predictions in Horizontal Stratified-Wavy Two-Phase Flow Encountered at Small Diameter T-Junction

Two‐phase flow boiling in 19 mm tube: Experiments and CFD modelling

Contact Info

Product

Resources

About