Two phase flow 1D turbulence model for poly-disperse upward flow in a vertical pipe

Issa, S. Al; Lucas, Dirk

doi:10.1016/j.nucengdes.2009.04.009

Cited by 7 publications

(8 citation statements)

References 17 publications

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“…As can be seen in Figure 9(d), the ratio C W /C L is larger and smaller than those models depicted in Figure 9(a) and (b), respectively. From Figures 9(d) and 3, it is interesting to note that our ratio C W /C L value is quite close to those of Frank et al's [11] and Al Issa and Lucas's [15] studies. In their studies, a good agreement in the void fraction profile between the predicted results and the experiment data have also been obtained by applying Frank et al's [11] and Tomiyama's [6] wall lubrication force models.…”

Section: Grid Sensitivity Studysupporting

confidence: 88%

“…However, the coefficient C BIT should be adjusted for different pipe diameters as mentioned in [15]. The reason is not clearly explained yet and more investigation is needed regarding this point.…”

Section: As Can Be Seen Inmentioning

confidence: 99%

“…Many investigations using a Eulerian-Eulerian two-fluid model have been done concerning the distribution of radial gas profiles in a simple vertical pipe flow in the regime of turbulent bubbly flows [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. For bubbly flows, the equation of momentum conservation includes the terms of forces acting on bubbles reflecting the interaction between the phases.…”

Section: Introductionmentioning

confidence: 99%

“…The implementation of the wall lubrication force together with the lift force is indispensable for reproducing the void fraction peak near the wall, while the turbulent dispersion force tends to flatten this radial void fraction profile. The original formulation of wall lubrication force model of Antal et al [18] has been widely used in a CFD simulation of a bubbly flow even though its coefficients were adjusted case by case to balance with the lift force coefficient under a higher liquid velocity condition [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. By pointing out that the wall lubrication force is too small to balance strong lift forces under certain flow conditions, Tomiyama [6] and Hosokawa and Tomiyama [10] modified the wall lubrication force formulation and coefficients of Antal et al [18], based on the results of experiments with the flow of air bubbles in glycerin in a pipe.…”

Section: Introductionmentioning

confidence: 99%

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The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

Nguyen

Song

Bae

et al. 2013

Journal of Nuclear Science and Technology

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Based on the significance of a computational fluid dynamics (CFD) simulation of dispersed two-phase flow systems in many engineering fields, especially in nuclear energy systems, extensive analytical and numerical studies of wall lubrication force for vertical upward turbulent bubbly two-phase flow are presented. An analytical expression of the wall lubrication force considering the effect of liquid velocity is developed and analyzed. A numerical methodology for evaluating the wall lubrication force coefficients is proposed, which is based on the assumption that the balance of the forces acting on a bubble perpendicularly to the flow direction determines the establishment of radial void fraction profiles. Wall lubrication force coefficients are determined based on a reasonable agreement in radial void fraction profiles between numerical results predicted by the CFD EAGLE (elaborated analysis of gas-liquid flows evolution) code and extensive experimental database in the open literature as well as experiments performed at the Korea Atomic Energy Research Institute-vertical air-water loop test facility. Liquid velocity dependence of wall lubrication force is clearly shown in both analytical and numerical ways in the present study, and new correlations are then proposed for the wall lubrication force coefficients.

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Section: Grid Sensitivity Studysupporting

confidence: 88%

Section: As Can Be Seen Inmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

Nguyen

Song

Bae

et al. 2013

Journal of Nuclear Science and Technology

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“…In bubbly flows without phase changes, the development of physical models for bubble breakup and coalescence requires the consideration of bubble size distribution as well as the dynamic interaction between bubbles or bubble and liquid turbulence. Open literature researches have shown unsatisfying results regarding the simulation of the bubble coalescence and breakup [4][5][6][7]. One of the reasons may come from the shortcoming on the modelling of the local turbulent kinetic energy k and its dissipation rate ε, as local bubble coalescence and break-up rates strongly depend upon these parameters.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Bubble-Induced Turbulence on the Interfacial Area Transport in Gas-Liquid Two-Phase Flow

Nguyen

Bae

Euh

et al. 2012

The Journal of Computational Multiphase Flows

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In the present work, two common modelling concepts taking into account the influence of bubbles on the turbulence of the liquid phase with available models in open literature were implemented in the EAGLE (Elaborated Analysis of Gas-Liquid flow Evolution) code and assessed against experimental data of Hibiki et al. (2001). The EAGLE code has been developed at KAERI based on the two-fluid model for a multi-dimensional analysis of two-phase flow with the implementation of non-drag force, standard k-ε turbulence model, and the interfacial area transport equation. In order to investigate the bubble size effect on two-phase flow evolution and to provide a data set for developing the physical models to describe the bubble-induced turbulence effect and also for validating the EAGLE code, a series of local parameter measurements as well as visualization tests were conducted in air-water vertical-upward flow condition in which the initial bubble size is controlled by a specially designed bubble generator. The numerical results and experimental data were compared, analysed and discussed in this paper.

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Theoretical Analysis of Culture Growth in Flat‐Plate Bioreactors: The Essential Role of Timescales

Zarmi

Bel

Aflalo

2013

Handbook of Microalgal Culture

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Qualitative characteristics of biomass production in ultrahigh density algal bioreactors with a small optical path (specifically, thin flat-plate reactors) are analyzed and explained in terms of models, which combine the random motion of cells across the optical path with simple models for the photosynthetic process. Characteristics of different models at extreme densities are compared with existing data. An analogy between flashing light illumination and the light regime experienced by the randomly moving cells provides basic insight into the important role of timescales in reactor performance. The emergence of an optimal culture density (OCD), at which the volumetric and areal production rates are maximal, is understood in simple terms. While higher density implies an increase in the number of photosynthesizing cells, it leads to narrowing of the illuminated (photic) zone, hence to a decrease in the time spent by these cells in the photic zone. When the time spent by cells in the photic zone is longer than the time needed to collect the photons required for the photosynthetic process, the addition of cells increases the volumetric production rate. When the time spent by cells in the illuminated zone falls below the time needed for the collection of photons, the volumetric production rate is decreased. The combined effects of changes in density are the cause of the emergence of an OCD. At the OCD, the time spent by cells in the thin illuminated layer of the culture and the time needed for the collection of the photons required for the photosynthetic process coincide.

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Two phase flow 1D turbulence model for poly-disperse upward flow in a vertical pipe

Cited by 7 publications

References 17 publications

The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

The Effect of Bubble-Induced Turbulence on the Interfacial Area Transport in Gas-Liquid Two-Phase Flow

Theoretical Analysis of Culture Growth in Flat‐Plate Bioreactors: The Essential Role of Timescales

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