A more fundamental wall lubrication force from turbulent dispersion regularization for multiphase CFD applications

Lubchenko, Nazar; Magolan, Ben; Sugrue, Rosie; Baglietto, Emilio

doi:10.1016/j.ijmultiphaseflow.2017.09.003

Cited by 70 publications

(40 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…S3) that it essentially creates a region with no gas near the wall, in contrast to the experimental observation. This behavior of the Hosokawa model or other similar models has been previously reported in the literature . On the other hand, the approach by Lubchenko and co‐workers produces more physical results, even though the predicted location of the peak is not in agreement with the experimental data.…”

Section: Resultssupporting

confidence: 75%

“…Their correlation is based on simulations with the wall lubrication model by Lubchenko et al. , explained in the following section, which necessitates the use of a damping function for the lift coefficient, such as that suggested by Shaver and Podowski . Moreover, the model takes into account the effect of local bubble crowding on the lift force.…”

Section: Methods and Modelsmentioning

confidence: 99%

“…Recently, Lubchenko et al. proposed a new approach that imposes a parabolic void fraction profile obtained by considering the physical shape of a bubble near the wall. The proposed wall lubrication force is derived by imposing this void fraction profile and considering the instantaneous equilibrium between the turbulent dispersion force and the wall lubrication force near the wall.…”

Section: Methods and Modelsmentioning

confidence: 99%

“…Recently, Lubchenko et al. developed a new wall lubrication model based on the geometric analysis of a bubble close to the wall. Their model does not yield zero gas volume fraction in the close vicinity of the wall.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Evaluation of Hydrodynamic Closures for Bubbly Regime CFD Simulations in Developing Pipe Flow

et al. 2019

Self Cite

View full text Add to dashboard Cite

The effect of interfacial forces and relevant closures, particularly the lift and wall lubrication forces, on the predictions of Eulerian-Eulerian computational fluid dynamics simulations of bubbly flows was studied. The test case under study was a developing turbulent bubbly pipe flow, simulated by using OpenFOAM. The results show that the geometric approach to consider the wall effect leads to better agreement than a standard relation assuming asymmetric drainage around the bubble near the wall. Furthermore, the results verify the need for employing negative lift coefficients in cases with large bubbles. A sensitivity analysis on the lift coefficient highlighted the importance of investigating spatially developing flows to draw general conclusions on the applicability of closure relations.

show abstract

Section: Resultssupporting

confidence: 75%

Section: Methods and Modelsmentioning

confidence: 99%

Section: Methods and Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Evaluation of Hydrodynamic Closures for Bubbly Regime CFD Simulations in Developing Pipe Flow

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Thus, the apparent repulsive effect is not a hydrodynamic force but a manifestation of the surface tension force coming from the averaging operator and the use of a particle approach. In order to quantify the bubble size-induced repulsive force, Lubchenko et al (2017) have proposed a new closure that is relevant to further investigations based on DNS data. This sort of consideration arises for any variable linked to interfacial position.…”

Section: Surface Tension and Wall Repulsionmentioning

confidence: 99%

Analysis and modelling of Reynolds stresses in turbulent bubbly up-flows from direct numerical simulations

2019

View full text Add to dashboard Cite

Two-phase bubbly flows are found in many industrial applications. These flows involve complex local phenomena that are still poorly understood. For instance, two-phase turbulence modelling is still commonly based on single-phase flow analyses. A direct numerical simulation (DNS) database is described here to improve the understanding of two-phase turbulent channel flow at a parietal Reynolds number of 127. Based on DNS results, a physical interpretation of the Reynolds stress and momentum budgets is proposed. First, surface tension is found to be the strongest force in the direction of migration so that budgets of the momentum equations suggest a significant impact of surface tension in the migration process, whereas most modelling used in industrial application does not include it. Besides, the suitability of the design of our cases to study the interaction between bubble-induced fluctuations (BIF) and single-phase turbulence (SPT) is shown. Budgets of the Reynolds stress transport equation computed from DNS reveal an interaction between SPT and BIF, revealing weaknesses in the classical way in which pseudoturbulence and perturbations to standard single-phase turbulence are modelled. An SPT reduction is shown due to changes in the diffusion because of the presence of bubbles. An increase of the redistribution leading to a more isotropic SPT has been observed as well. BIF is comprised of a turbulent (wake-induced turbulence, WIT) and a non-turbulent (wake-induced fluctuations, WIF) part which are statistically independent. WIF is related to averaged wake and potential flow, whereas WIT appears when wakes become unstable or interact with each other for high-velocity bubbles. In the present low gravity conditions, BIF is reduced to WIF only. A thorough analysis of the transport equations of the Reynolds stresses is performed in order to propose an algebraic closure for the WIF towards an innovative two-phase turbulence model.

show abstract

Computational modeling of microbubble coalescence and breakup using large eddy simulation and Lagrangian tracking

et al. 2020

View full text Add to dashboard Cite

The flow of dispersed microbubbles was studied with an Eulerian-Lagrangian technique using large eddy simulation to predict the continuous liquid flow and Lagrangian tracking to compute bubble trajectories. The model fully accounts for bubble coalescence and breakup and was applied to horizontal and vertical channel flows. With low levels of turbulence, gravity in horizontal, and lift in vertical, channel flows govern the bubble spatial and collision distribution. When turbulence is sufficiently high to, at least partially, oppose bubble preferential concentration, more uniform collision and coalescence distributions are found, although these remain peaked near the wall in both configurations. Almost 100% coalescence efficiency was always found, due to bubbles colliding along similar trajectories, with breakup only recorded in a flow of low surface tension refrigerant R134a. Models like this can provide the required quantitative understanding of the microbubbles complex behavior, as well as supporting the development of more macroscopic modeling closures.

show abstract

A more fundamental wall lubrication force from turbulent dispersion regularization for multiphase CFD applications

Cited by 70 publications

References 24 publications

Evaluation of Hydrodynamic Closures for Bubbly Regime CFD Simulations in Developing Pipe Flow

Evaluation of Hydrodynamic Closures for Bubbly Regime CFD Simulations in Developing Pipe Flow

Analysis and modelling of Reynolds stresses in turbulent bubbly up-flows from direct numerical simulations

Computational modeling of microbubble coalescence and breakup using large eddy simulation and Lagrangian tracking

Contact Info

Product

Resources

About