Gas injection in a yield stress fluid

Hojeij, Ali; Jossic, Laurent; Magnin, Albert; Blésès, Didier; Hattou, Stéphane

doi:10.1002/aic.16878

Cited by 5 publications

(12 citation statements)

References 22 publications

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“…The present study focuses on numerical simulation of the raising toward the free surface of gas inclusions in a yield stress fluid. It is in line with a previous study by Hojeij et al, 3 which focused on the fluid dynamics in the vicinity of the injection point. The present study brings new experimental results about the bubbles generated.…”

supporting

confidence: 92%

“…The pilot reactor used to perform experiments has already been presented in Hojeij et al 3 It is schematically represented in Figure 1 with the main injection parameters and briefly reminded here. The yield stress fluid is stored in a transparent tank of cuboid shape, with length and width equal to 60 cm and height equal to 50 cm.…”

Section: Experimental Set-up and Materialsmentioning

confidence: 99%

“…It is worth mentioning that F b can be predicted using a correlation by Hojeij et al 3 based on the injection parameters.…”

Section: Nondimensional Numbersmentioning

confidence: 99%

“…In order to maximize the fluid recirculation, the air is injected at a given flow rate toward the bottom of a tank. A dedicated experimental study on the cavity's dynamics generated at the injection point can be found in Hojeij et al 3 The experimental set-up considered is schematically represented in Figure 1. The gap between the outlet of the nozzle and the bottom of the tank is small in comparison with the tank dimensions.…”

mentioning

confidence: 99%

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Experimental study and numerical modeling of mixing by air injection in yield stress fluids using the OpenFOAM software

et al. 2021

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Mixing by gas injection is an operation used in industrial processes such as wastewater treatment, metallurgy, or methanization in which pressurized gas is injected into a fluid in order to reduce concentrations and temperatures gradients. This study demonstrates how the CFD toolbox OpenFOAM can be used to simulate such flows.Experimental measurements and observations have been performed on a pilot-scale reactor where pressurized air is injected in a yield stress fluid. The volume of fluid method and an adaptive mesh with refinement at the interface have been used to track the gas inclusions. The numerical model accuracy has been assessed by comparing experimental and numerical results related to the bubble's frequency, dimensions, and rising velocities as well as the fluid recirculation, yielded, and unyielded regions in the tank. The influence of injection parameters such as the injection flow rate and the fluid rheological parameters has been quantified.

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supporting

confidence: 92%

Section: Experimental Set-up and Materialsmentioning

confidence: 99%

“…It is worth mentioning that F b can be predicted using a correlation by Hojeij et al 3 based on the injection parameters.…”

Section: Nondimensional Numbersmentioning

confidence: 99%

mentioning

confidence: 99%

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Experimental study and numerical modeling of mixing by air injection in yield stress fluids using the OpenFOAM software

et al. 2021

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“…Bubble formation and coalescence are widely encountered in the chemical process industry, petrochemical industry and mineral processing 1‐3 . As the bubble size decreases, its surface area for a given gas volume increases and its residence time in liquid becomes longer.…”

Section: Introductionmentioning

confidence: 99%

Continuous formation of microbubbles during partial coalescence of bubbles from a submerged capillary nozzle

et al. 2020

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Bubble formation from a downward‐pointing capillary nozzle was investigated in this study. The experiments were conducted at gas flow rate of 40–5,400 ml/h and inner nozzle radius of 0.030–0.255 mm. Experimental results show that microbubbles are formed continuously at moderate Weber number, which was not reported in pervious investigations with injecting gas through an upward‐pointing capillary nozzle. High‐speed visualization indicates that the formation of microbubbles arises from the convergence of the capillary waves induced by the partial coalescence of larger bubbles. A bubbling regime map is given to identify the critical conditions for the formation of microbubbles. In the present air‐water experiments, the generated microbubbles are 20–170 μm in diameter. From experimental data, a scaling law for microbubble size is proposed as a function of Weber and Bond numbers.

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Agitation of yield stress fluids by gas injection

et al. 2022

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This study is in line with two previous studies by the same authors on gas injection in yield stress fluids. Gas is injected toward the bottom wall of a prismatic tank containing a yield stress fluid. When rising toward the free surface, trains of bubbles generate fluid recirculation in the tank. Two experimental colorimetric methods are introduced and validated in order to quantify the recirculation liquid flow rate as well as the time evolution of the extent and shape of the mixed volume. The influences of the injection flow rate, fluid rheology, and reactor size have been quantified. Correlations based on the characteristic nondimensional numbers of the flow have been developed to predict the downward liquid flow rate as well as the mixed volume. A model for estimating the mixing time is also developed and compared to experimental results.

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Gas injection in a yield stress fluid

Cited by 5 publications

References 22 publications

Experimental study and numerical modeling of mixing by air injection in yield stress fluids using the OpenFOAM software

Experimental study and numerical modeling of mixing by air injection in yield stress fluids using the OpenFOAM software

Continuous formation of microbubbles during partial coalescence of bubbles from a submerged capillary nozzle

Agitation of yield stress fluids by gas injection

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