Measurement of mixing time in a gas-liquid mixing system stirred by top-blown air using ECT and image analysis

Yang, Kai; Xue, Zhaohui; Li, Meng; Xiao, Qingtai; Wang, Hua

doi:10.1016/j.flowmeasinst.2022.102143

Cited by 14 publications

(8 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the gradient of the electric field strength is zero and thus, the gradient of the sensitivity matrix is zero. As a result, equation (2) becomes ∇λ = S∇g (3) where ∇g is the permittivity gradient.…”

Section: Ect-emm Methodsmentioning

confidence: 99%

Investigation of spatial resolution of electrical capacitance tomography based on the electromagnetic momentum (ECT-EMM)

Yang,

Liu,

Liu

2024

Meas. Sci. Technol.

View full text Add to dashboard Cite

Electrical capacitance tomography (ECT) is a permittivity imaging method widely used in industrial inspection. The equations described by the ECT technique are nonlinear and ill-posed, which results in low image resolution. ECT can be considered an imaging method based on the Green’s reciprocity theorem, an energetic reciprocity theorem. ECT detects scalars, i.e. capacitances. Electromagnetic fields have both "energy" and "momentum." In recent years, the electromagnetic momentum reciprocity theorem has enriched the electromagnetic reciprocity theorem. The electromagnetic momentum reciprocity theorem is an imaging method that detects vectors, i.e. capacitance gradients. Vectors contain richer information than scalars; thus, electrical capacitance tomography based on electromagnetic momentum (ECT-EMM) methods is expected to improve the resolution of permittivity imaging. This paper briefly describes the principle of the ECT-EMM technique for image reconstruction using sensitivity matrix gradient and capacitance gradient. Tikhonov regularisation algorithm is applied. The two methods, with and without capacitance measurements, are used to evaluate imaging resolution. Under different numbers of pixels and electrodes, typical permittivity distributions are used for reconstruction, and correlation coefficients are calculated. Simulations and experiments show that the ECT-EMM technique recognises object boundaries more clearly with high noise immunity. Five quality measures are used to evaluate the performance of the point spread function (PSF) without capacitance measurements. Compared to ECT, the ECT-EMM technique is more sensitive to the central region away from the electrodes, recognises smaller minimum objects, and has smaller shape deformation.

show abstract

Section: Ect-emm Methodsmentioning

confidence: 99%

Investigation of spatial resolution of electrical capacitance tomography based on the electromagnetic momentum (ECT-EMM)

Yang,

Liu,

Liu

2024

Meas. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The cross-sector and cross-scale importance of mixing has driven the development of a wealth of analytical methods through which to quantify it. 27,28 These methods include tomography, 20,29 near-infrared imaging, 30 fluorescence, 31 and acoustics, 32 among others. 27,28 From the range of analytical methods explored in mixing analysis, visible-range imaging and computer vision approaches are attractive on account of being non-contact, spatially resolved (by area), flexible in resolution (to enable study of macro-,meso-, and microscale mixing phenomena), of low cost, and requiring minimal departure from how the reactions would routinely be set-up.…”

Section: Impact Of Mixingmentioning

confidence: 99%

Computer Vision for Kinetic Analysis of Lab- and Process-scale Mixing Phenomena

Barrington,

Dickinson,

McGuire

et al. 2022

Preprint

View full text Add to dashboard Cite

A software platform for the computer vision-enabled analysis of mixing phenomena of relevance to process scale-up is described. By bringing new and known time-resolved mixing metrics under one platform, hitherto unavailable comparisons of pixel-derived mixing metrics are exemplified across non-chemical and chemical processes. The analytical methods described are applicable using any camera and across an appreciable range of reactor scales, from development through to process scale-up. A case study in nucleophilic aromatic substitution run on 5L-scale shows how camera and offline concentration measurements can be correlated. In some cases, it can be shown that camera data holds the power to predict reaction progress.

show abstract

“…Compared with this direct method, the indirect measurement method is more widely used, especially in the industrial production process, which does not require direct observation of flow patterns in most cases. The indirect measurement method obtains signals such as capacitance [ 14 ], pressure [ 15 ], temperature [ 16 ], and capacitance [ 17 ] that can be easily measured, and indicate characteristics of different flow patterns by combining signal-processing technology. Then, the flow pattern or mixing state can be classified and recognized according to these characteristics.…”

Section: Introductionmentioning

confidence: 99%

Identifying Flow Patterns in a Narrow Channel via Feature Extraction of Conductivity Measurements with a Support Vector Machine

Yang

Wang

et al. 2023

Sensors

Self Cite

View full text Add to dashboard Cite

In this work, a visualization experiment for rectangular channels was carried out to explore gas–liquid two-phase flow characteristics. Typical flow patterns, including bubble, elastic and mixed flows, were captured by direct imaging technology and the corresponding measurements with fluctuation characteristics were recorded by using an electrical conductivity sensor. Time-domain and frequency-domain characteristics of the corresponding electrical conductivity measurements of each flow pattern were analyzed with a probability density function and a power spectral density curve. The results showed that the feature vectors can be constructed to reflect the time–frequency characteristics of conductivity measurements successfully by introducing the quantized characteristic parameters, including the maximum power of the frequency, the standard deviation of the power spectral density, and the range of the power distribution. Furthermore, the overall recognition rate of the four flow patterns measured by the method was 93.33% based on the support vector machine, and the intelligent two-phase flow-pattern identification method can provide a new technical support for the online recognition of gas–liquid two-phase flow patterns in rectangular channels. It may thus be concluded that this method should be of great significance to ensure the safe and efficient operation of relevant industrial production systems.

show abstract

Measurement of mixing time in a gas-liquid mixing system stirred by top-blown air using ECT and image analysis

Cited by 14 publications

References 43 publications

Investigation of spatial resolution of electrical capacitance tomography based on the electromagnetic momentum (ECT-EMM)

Investigation of spatial resolution of electrical capacitance tomography based on the electromagnetic momentum (ECT-EMM)

Computer Vision for Kinetic Analysis of Lab- and Process-scale Mixing Phenomena

Identifying Flow Patterns in a Narrow Channel via Feature Extraction of Conductivity Measurements with a Support Vector Machine

Contact Info

Product

Resources

About