A bubble-induced turbulence model for gas-liquid bubbly flows in airlift columns, pipes and bubble columns

Shu, Shuli; Bahraoui, Naoufel El; Bertrand, François; Chaouki, Jamal

doi:10.1016/j.ces.2020.115945

Cited by 15 publications

(6 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Note that bubbly flow with higher bubble density or larger bubble size has a higher probability to affect the void fraction at the data point; this indicates a stronger turbulence and velocity fluctuation (as shown in case 3, case 8 and case 9). Similar results are also reported by Erdogan et al [35] and Shu et al [36]. Additionally, another phenomenon is shown; turbulence kinetic energy increases while the void fraction remains zero.…”

Section: Bubble-induced Turbulencesupporting

confidence: 89%

Numerical Investigation on the Flow Instability of Dispersed Bubbly Flow in a Horizontal Contraction Section

Chen

Fang

et al. 2022

Processes

View full text Add to dashboard Cite

Dispersed bubbly flow is important to understand when working in a wide variety of hydrodynamic engineering areas; the main objective of this work is to numerically study bubble-induced instability. Surface tension and bubble-induced turbulence effects are considered with the momentum and k-ω transport equations. Steady dispersed bubbly flow is generated at the inlet surface using time-step and user-defined functions. In order to track the interface between the liquid and gas phases, the volume of fraction method is used. Several calculation conditions are considered in order to determine the effects of bubble diameter, bubble distribution, bubble velocity and bubble density on flow instability and void fraction. The void fraction of the domain is set to no more than 0.5% under different bubbly (micro/small) flow conditions; and the order of magnitude of the Reynolds number is 106. Results from the simulation indicate that velocity fluctuation induced by bubble swarm increases with increasing bubble diameter. Bubble density and bubble distribution seem to have a complex influence on flow instability. Bubble-induced turbulence results indicate that small bubbles produce a significant disturbance near the boundary region of bubble swarm; this indicates that induced bubble swarm has a potential capability of enhancing heat and mass transfer in the velocity boundary layer. Results from this study are useful for two-phase flow, bubble floatation and other hydrodynamic engineering applications.

show abstract

Section: Bubble-induced Turbulencesupporting

confidence: 89%

Numerical Investigation on the Flow Instability of Dispersed Bubbly Flow in a Horizontal Contraction Section

Chen

Fang

et al. 2022

Processes

View full text Add to dashboard Cite

show abstract

“…In addition, it is noted that the turbulent kinetic energies would increase obviously with the incease of gas flow rate. Shu et al 34 pointed out that the liquid turbulent field could be changed dramatically by the existence of dispersed bubbles. Lindken and Merzkirch 35 presented that in the direction of bubble rising the the turbulent fluctuations would be enhanced remarkably from the results of their PIV experiments, which seems to be consistent with the vatiations of the turbulent kinetic energy in Figure 15A.…”

Section: Resultsmentioning

confidence: 99%

Microbubble generation driven by the oscillation in a self‐excited fluidic oscillator

et al. 2021

View full text Add to dashboard Cite

The oscillation‐driven microbubble generation in a self‐excited fluidic oscillator is explored in this work. By investigating the behaviors of bubbles, it is noted that for relatively low liquid flow rate, bubbles move upward directly and breakup does not occur inside the chamber region. Interestingly, the existence of bubbles could destroy the structure of flow field and even affect the oscillation. Nevertheless, for relatively high liquid flow rate, the bubbles would not be able to change the flow field structure of liquid phase effectually. Meanwhile, binary, shear‐off‐induced and a kind of dynamic erosive breakup of the bubbles could occur for the effects of oscillations of liquid main jet. Abundant microbubbles could be produced mainly by the dynamic erosive breakup. The oscillation is only induced by the Coanda effect without any moving parts. Nevertheless, it is able to supply a robust oscillating turbulent field to enhance the breakup of bubbles dramatically.

show abstract

“…In this work, the model proposed by Launder et al [ 34 ] (LRR) was used to model the Reynolds stress term R l . For more details of the LRR model, readers are referred to Shu et al [ 35 ]…”

Section: Experimental and Simulationmentioning

confidence: 99%

“…The source term for the turbulent dissipation rate, Sε , can be generally written as follows:where C ε ,BIT is a model constant and τ is the characteristic time scale. In this work, C ε ,BIT is set as 1.44 and the τ used in this work is proposed by Shu et al [ 35 ] as follows:

τ = \frac{d}{2 (||, {bold-italicu}_{italicslip}) {ε_{g}}^{n_{0}}}

where n 0 is a model constant and set as 0.75.…”

Section: Experimental and Simulationmentioning

confidence: 99%

Effect of pressure on the hydrodynamics of a pilot‐scale bubble column operating with low and moderate viscosity Newtonian liquids

et al. 2021

Self Cite

View full text Add to dashboard Cite

In a pilot‐scale bubble column operating with low and moderate viscosity hydrocarbons, the effect of pressure on the total and axial gas holdup as well as the regime transition velocity was investigated. Experiments were performed for two air‐Ketrul D100 and air‐Hydroseal G250 HL gas‐liquid hydrocarbon systems. It was found that increasing pressure increased gas holdup at the heterogeneous regime, and this effect was more pronounced for the low‐viscosity liquid. Moreover, increasing pressure further stabilized the homogeneous regime, and again, this stabilizing effect was more significant for the low‐viscosity liquid. Also, as a response to the pressure increasing, the axial gas holdup became more uniform in the case of the low‐viscosity liquid and less uniform in the case of the moderate‐viscosity liquid.

show abstract

A bubble-induced turbulence model for gas-liquid bubbly flows in airlift columns, pipes and bubble columns

Cited by 15 publications

References 50 publications

Numerical Investigation on the Flow Instability of Dispersed Bubbly Flow in a Horizontal Contraction Section

Numerical Investigation on the Flow Instability of Dispersed Bubbly Flow in a Horizontal Contraction Section

Microbubble generation driven by the oscillation in a self‐excited fluidic oscillator

Effect of pressure on the hydrodynamics of a pilot‐scale bubble column operating with low and moderate viscosity Newtonian liquids

Contact Info

Product

Resources

About