Local gas and liquid phase velocity measurement in a miniature stirred vessel using PIV combined with a new image processing algorithm

Chung, Kenneth; Simmons, Mark; Barigou, Mostafa

doi:10.1016/j.expthermflusci.2009.01.010

Cited by 23 publications

(20 citation statements)

References 16 publications

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“…Chung et al also reported average gas phase velocities in the range of 0.03-0.2 U TIP in the radial direction, and 0.02-0.11 U TIP in the axial direction [68]. The velocities were also higher within the impeller region, reaching a maximum value around the tip of the impeller, and decreases towards the axis of rotation of the impeller and the reactor wall [66][67][68][69]. The gas hold-up in the impeller region was as high as 0.1-0.2, but decreased as we moved from the impeller in the radial direction to almost zero near the reactor wall.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…The average liquid phase velocity in the radial direction was about 0.25 U TIP , in the axial direction it was about 0.07 U TIP , while that of the gas phase velocity in the radial direction was about 0.2 U TIP . Chung et al also reported average gas phase velocities in the range of 0.03-0.2 U TIP in the radial direction, and 0.02-0.11 U TIP in the axial direction [68]. The velocities were also higher within the impeller region, reaching a maximum value around the tip of the impeller, and decreases towards the axis of rotation of the impeller and the reactor wall [66][67][68][69].…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…It is reasonable to expect errors in measurements using this technique due to fluctuations in the liquid surface from varying flow patterns and turbulence during stirring. A number of optical imaging techniques as well as computational fluid dynamics (CFD) simulations have also been used for estimating the gas hold-up, mean bubble diameter, and the gas and liquid phase velocities [66][67][68][69]. Yang et al [66] performed gas-liquid-solid dispersion studies using CFD simulations and compared with experimental measurements in a stirred reactor.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

See 2 more Smart Citations

Gas Hydrate Growth Kinetics: A Parametric Study

Meindinyo

Svartaas

2016

Energies

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Gas hydrate growth kinetics was studied at a pressure of 90 bars to investigate the effect of temperature, initial water content, stirring rate, and reactor size in stirred semi-batch autoclave reactors. The mixing energy during hydrate growth was estimated by logging the power consumed. The theoretical model by Garcia-Ochoa and Gomez for estimation of the mass transfer parameters in stirred tanks has been used to evaluate the dispersion parameters of the system. The mean bubble size, impeller power input per unit volume, and impeller Reynold's number/tip velocity were used for analyzing observed trends from the gas hydrate growth data. The growth behavior was analyzed based on the gas consumption and the growth rate per unit initial water content. The results showed that the growth rate strongly depended on the flow pattern in the cell, the gas-liquid mass transfer characteristics, and the mixing efficiency from stirring. Scale-up effects indicate that maintaining the growth rate per unit volume of reactants upon scale-up with geometric similarity does not depend only on gas dispersion in the liquid phase but may rather be a function of the specific thermal conductance, and heat and mass transfer limitations created by the limit to the degree of the liquid phase dispersion is batched and semi-batched stirred tank reactors.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

See 1 more Smart Citation

Gas Hydrate Growth Kinetics: A Parametric Study

Meindinyo

Svartaas

2016

Energies

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“…This allows us to separately analyze the movement of objects which reflect laser radiation and these which emit radiation generated during fluorescence. This measuring system enables a simultaneous measurement of phase velocities but requires the use of two synchronized cameras (Bröder and Sommerfeld, 2000;Chung et al, 2009;Honkanen and Saarenrinne, 2002;Kosiwczuk et al, 2005). Further analysis of this issue leads to a conclusion that in this method a problem may be time intervals between laser pulses, due to which in two frames the shifts of flow tracers are recorded.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous velocity measurement of phases in a liquid-gas system

Musoski

Stelmach

2017

Chemical and Process Engineering

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Results of velocity measurements of liquid and gas bubbles in a tank with a self-aspirating disk impeller are analysed. Studies were carried out using a fluorescent dye tracer in the measuring system with two cameras (simultaneous phase velocity measurement) and with one camera (sequential measurement of phase velocity). Based on a comparative analysis of the acquired data it was found that when differences in the phase velocities were small the simultaneous velocity measurement gave good results. However, sequential measurement gives greater possibilities for setting the measuring system and if the analysis of instantaneous velocities is not necessary, it seems to be a better solution.

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“…Snakes [4], [5], [6], contour based models [7], principal component analysis [8], gradient based thresholding methods [9], [10] were utilized by different groups. Even if these methods would give accurate detection results in single frames, they would cause big time delays in videos.…”

Section: Introductionmentioning

confidence: 99%

Automatic Bubble Detection in Cardiac Video Imaging

Parlak¹,

Ademoğlu²,

Egi³

et al. 2011

Polibits

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Abstract-Bubble recognition is a challenging problem in a broad range from mechanics to medicine. These gas-filled structures whose pattern and morphology alter in their surrounding environment would be counted either manually or with computational recognition procedures. In cardiology, user dependent bubble detection and temporal counting in videos require special trainings and experience due to ultra fast movement, inherent noise and video quality. In this study, we propose an efficient recognition routine to increase the objectivity of emboli detection. Firstly, we started to compare five different methods on two synthetic data sets emulating cardiac chamber environment with increasing speckle noise levels. Secondly, real echocardiographic video records were segmented by variational active contours and Left Atria (LA) were extracted. Finally, three successful methods in simulation were applied to LAs in order to reveal candidate bubbles on video frames. Our detection rate of proposed method was 95.7% and the others were 86.2% and 88.3%. We conclude that our approach would be useful in long lasting video processing and would be applied in other disciplines.

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Local gas and liquid phase velocity measurement in a miniature stirred vessel using PIV combined with a new image processing algorithm

Cited by 23 publications

References 16 publications

Gas Hydrate Growth Kinetics: A Parametric Study

Gas Hydrate Growth Kinetics: A Parametric Study

Simultaneous velocity measurement of phases in a liquid-gas system

Automatic Bubble Detection in Cardiac Video Imaging

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