Comparison of various flow visualisation techniques in a gas-liquid mixed tank

Miettinen, Tatu; Laakhonen, Marko; Aittamaa, Juhani

doi:10.1016/s1570-7946(03)80210-9

Cited by 8 publications

(4 citation statements)

References 9 publications

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“…[34], [35]). ERT was also applied to the mixing and storage vessels varying from 15-40 cm in diameter ( [36], [37]) to find out mixing characteristics. Some of the notable research works on the study of two phase flow behavior in bubble columns with help of ERT were summarized Table.1.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Vadlakonda

Mangadoddy

2017

Separation and Purification Technology

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Section: Introductionmentioning

confidence: 99%

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Vadlakonda

Mangadoddy

2017

Separation and Purification Technology

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“…Miettien et al 13 have presented a short review of the experimental flow visualization techniques for the characterization of gas-liquid flow in a mixed tank. In what concerns bubble size distribution measurements, only phase doppler anemometry (PDA) and particle image velocimetry (PIV) are indeed noninvasive techniques.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Breakage and Coalescence Model Parameters in a Steady-State Batch Agitated Dispersion

Ribeiro¹,

Regueiras

Guimarães

et al. 2011

Ind. Eng. Chem. Res.

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The highly dynamic behavior of liquid−liquid dispersions in reaction and separation operations still defies accurate and experimentally validated modeling. This behavior is characterized by simultaneous dropsize and operating conditions dependent drop breakage and coalescence, which strongly influence both the hydrodynamics and the reaction yield and selectivity, or separation performance, of such systems. This dynamic character of the behavior is present and of critical importance even at steady state, and not just during the transient evolution toward it or during disturbances in the operating conditions. This work addresses the measurement (by a noninvasive technique) and the optimization of kinetic liquid drop interaction parameters, duly taking into account the full and real complexity of the behavior, which is shown to require the inclusion and quantification of drop coalescence frequencies, no matter how lean and strongly agitated the dispersion may be. The analysis in this paper is limited to batch perfectly agitated vessels with lean dispersions at steady state and uses carefully collected experimental drop size distribution data and a very precise (with 50 logarithmic drop volume classes, to ensure uniform precision of drop size assignment) and fast coupled numerical dynamic simulation and nonlinear optimization algorithm, to quantify the drop breakage and coalescence kinetic parameters of drop interaction models. Significant physical insight has been gained on the interdependence of two (one for breakage and the other for coalescence) of the parameters and on the values of the others, in addition to an excellent agreement of the predicted and experimental drop size distributions at steady state. Further, and as expected, the need to always fully account for interdrop coalescence (in addition to breakage), whatever the operating conditions, by contrast to oversimplified modeling approaches, has also been clearly demonstrated.

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“…With the sensor immersed in the liquid in the tank and using the most common strategy in conventional ERT (due to minimal hardware requirements and fast image reconstruction), alternating current (AC) was injected from the DAS to the electrodes (15 mA current was used as the injection current in this study) using a pair of neighboring electrodes, and the resulting voltage was measured through all other neighboring electrodes. The AC drive current then went to the next electrode pair and the process of injecting current to neighboring electrodes was repeated until all independent pairs were covered 58–60 . When the sensor rod was inserted vertically inside the tank, the image reconstruction algorithms embedded in the software generated 2D images of the conductivity distribution inside the tank on a vertical plane through the rod, extending about 1/3 of the length of the rod in the direction perpendicular to the electrodes, that is, radially toward the impeller shaft.…”

Section: Experimental Apparatus Materials and Methodsmentioning

confidence: 99%

Determination of the just‐suspended speed, N_js, in stirred tanks using electrical resistance tomography (ERT)

et al. 2021

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Njs, the minimum agitation speed to just‐suspend dispersed solids in liquids in stirred tanks, is a critical parameter to operate industrial processes. The focus of this work was to develop a novel observer‐independent method to experimentally obtain Njs in tanks that cannot be visually inspected internally using electrical resistance tomography (ERT). The mean bulk resistivity was measured across electrodes mounted on an ERT linear sensing probe placed inside a stirred tank containing water and glass beads. As the agitation speed increased, more solids became suspended and the resistivity measured by the probe changed. Plots of resistivity variation vs. agitation speed resulted in an S‐shaped curve that could be analyzed to determine Njs. The Njs values obtained with this novel approach compared very favorably with those obtained using other methods requiring transparent tanks. It is expected that the ERT method proposed here could find applications in many industrial solid–liquid mixing processes.

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Comparison of various flow visualisation techniques in a gas-liquid mixed tank

Cited by 8 publications

References 9 publications

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Optimization of Breakage and Coalescence Model Parameters in a Steady-State Batch Agitated Dispersion

Determination of the just‐suspended speed, N_js, in stirred tanks using electrical resistance tomography (ERT)

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Comparison of various flow visualisation techniques in a gas-liquid mixed tank

Cited by 8 publications

References 9 publications

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Hydrodynamic study of two phase flow of column flotation using electrical resistance tomography and pressure probe techniques

Optimization of Breakage and Coalescence Model Parameters in a Steady-State Batch Agitated Dispersion

Determination of the just‐suspended speed, Njs, in stirred tanks using electrical resistance tomography (ERT)

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Determination of the just‐suspended speed, N_js, in stirred tanks using electrical resistance tomography (ERT)