Image processing techniques for high-speed videometry in horizontal two-phase slug flows

Amaral, Carlos E. F. do; Alves, Rafael Fabricio; Silva, Marco J. da; Arruda, Lúcia Valéria Ramos de; Dorini, Leyza Baldo; Morales, Rigoberto E. M.; Pipa, Daniel Rodrigues

doi:10.1016/j.flowmeasinst.2013.07.006

Cited by 74 publications

(17 citation statements)

References 25 publications

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“…The optical image analyses have been used recently for quantifying the bubble size distribution. [63][64][65][66] Luo et al 67 utilized the visualization technique to study the bubble characteristics and bubble formation behavior. A number of studies have been recently conducted using this approach with different algorithms for image analysis.…”

Section: Non-intrusive Techniquesmentioning

confidence: 99%

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2017

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Abbreviations BSD, bubble size distribution; PET, positron emission tomography; PIV, particle image velocimetry, RPT; radioactive particle tracking; NMR, nuclear magnetic resonance imaging IntroductionMultiphase flow systems have been applied extensively in chemical, physical, petrochemical and biochemical processing industries.1-3 Among different multiphase flow systems, bubbly flow is a two phase flow where small bubbles are dispersed or suspended in a liquid continuum. Typical features of this flow are moving and deformable interfaces of bubbles in time and space domains and complex interactions between the interfaces, and also between the bubbles and the liquid flow. Bubbly flows occur frequently in natural systems and are also used for different applications in energy-producing and chemical and petroleum industries. Some of the common applications involve bubble columns which are used as reactors in a variety of chemical and biochemical processes, e.g. the Fischer-Tropsch process for hydrocarbon synthesis, hydrogenation of unsaturated oil, coal liquefaction, fermentation, waste water treatment etc. 4,5 Bubbly flows are also ubiquitously found in flotation cells 6 and spargers 7 and have recently been investigated extensively for aeration studies. [8][9][10][11][12] Concentration, size and velocity distributions of solid or liquid particles suspended in gas or liquid are important in many processes such as meteorological research, biology, environmental protection, chemistry, medicine and agricultural engineering. Further, commercial activities such as conversion of natural gas to fuels and chemicals have prompted further fundamental research in fluid and bubble dynamics, transport phenomena and the effects due to scale up of three-phase fluidization systems.The prediction of pressure drop and wall heat transfer is necessary in many of these processes and these are strongly dependent upon the concentration, morphology and spatial distribution of the bubbles. 13 Similarly, in many liquid-gas systems, gases are dispersed in liquids to obtain large interfacial area for chemical reactions, heat and mass transfer processes. The rate of these processes is determined by bubble surface area flux which is closely linked to the bubble size distribution. 14 DiscussionDifferent techniques have been employed to measure bubble size distributions. Broadly, it can be divided into two categoriesintrusive and non-intrusive techniques.15 Both these methods have been extensively reported in the literature and a brief description of different intrusive and non-intrusive techniques is provided below, Intrusive techniquesConsiderable intrusive techniques have been developed to study bubble behavior in gas-liquid and gas-liquid-solid fluidized systems. These intrusive techniques include impedance (conductivity or resistivity) probes, capillary suction probes, 16 optical fiber probes, ultrasound probes, endoscopic probes, wire-mesh sensors 17 and hot film anemometry.The impedance probe has been applied to measure the bubble volume f...

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Section: Non-intrusive Techniquesmentioning

confidence: 99%

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2017

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“…What is more, image processing may give information about the dynamic character of the flow [14]. In the field of image analysis, coefficients or thresholds are often introduced in order to classify the observed flow patterns [1,15]. 2 of 9 In this paper, the synchronization of boiling in two parallel minichannels was determined using image analysis.…”

Section: Introductionmentioning

confidence: 99%

Boiling Synchronization in Two Parallel Minichannels—Image Analysis

et al. 2020

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In this paper, the boiling synchronization of two-phase flow patterns in two parallel minichannels of 1 mm in diameter with connected compressible volumes was analyzed. The analysis was performed using images recorded with a high-speed camera. The degree of synchronization between channels was evaluated by assessing the presence of liquid flow in the small part of the minichannels. It can be concluded that boiling is synchronized when small bubble flow or wavy annular flow occur in neighboring channels. The occurrence of slug flow in one channel causes the boiling in neighboring channels to become unsynchronized. The result of the image analysis shows that the correlation coefficient based on the evaluation of the presence of liquid flow in the small part of the minichannels over a long enough time period allows for the detection of boiling synchronization.

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“…Ahmed [2] used capacitance probes, hot-film anemometer, and image processing techniques to determine slug length and velocity; the results were in good agreement with existing models and correlations of slug flow. Amaral et al [17] used an image processing technique to measure bubble velocity and detect bubble contours. They then compared their results with theoretical predictions and achieved a good agreement; however, they suggested that future work should focus on reducing processing time.…”

Section: Introductionmentioning

confidence: 99%

“…Several studies have developed image processing techniques to investigate slug flow characteristics; however, image processing time is lengthy and needs improvement [17]. In …”

Section: Introductionmentioning

confidence: 99%