An effective signal processing method for resistivity probe measurements in a two-phase bubbly flow

Liu, Tay-Jian

doi:10.1088/0957-0233/13/2/311

Cited by 9 publications

(2 citation statements)

References 11 publications

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“…Local conductance probes have been widely used in the past to obtain distributions of the local gas velocity and gas volume fraction in multiphase flows (see, e.g., Serizawa et al [1], van der Welle [2], Herringe and Davies [3], Steinemann and Buchholz [4], Liu [5] and Hibiki et al [6]). However virtually all of this previous work was confined to vertical upward gas-liquid flows in which the velocity of the gas bubbles was predominantly axial.…”

Section: Introductionmentioning

confidence: 99%

Measurement of bubble velocity components in a swirling gas–liquid pipe flow using a local four-sensor conductance probe

Lucas

Mishra

2005

Meas. Sci. Technol.

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This paper presents a novel technique for measuring the local axial, radial and azimuthal velocity components of the gas in bubbly gas–liquid flows using a local four-sensor conductance probe. A mathematical model is presented showing how the velocity vector of a gas bubble can be calculated from seven time intervals taken from the output signals from each of the four conductance sensors located within the probe. The paper goes on to describe the construction of a local four-sensor probe and the associated electronic measurement circuitry. Results are presented showing the distributions of the mean local axial, radial and azimuthal gas velocity components in vertical, bubbly gas–liquid flows, both with and without swirl. These results were obtained using the four-sensor probe in a vertical 80 mm diameter pipe into which a swirl generator could be installed. Additional results are presented showing the local gas volume fraction distribution, also obtained from the probe, in bubbly gas–liquid flows with and without swirl. It was found, as expected, that the presence of swirl caused a significant increase in the magnitude of the measured azimuthal velocity of the gas, particularly at the pipe walls. It was also found that, at a comparatively high water flow rate, the presence of swirl caused the gas bubbles to preferentially accumulate at the centre of the pipe.

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Section: Introductionmentioning

confidence: 99%

Measurement of bubble velocity components in a swirling gas–liquid pipe flow using a local four-sensor conductance probe

Lucas

Mishra

2005

Meas. Sci. Technol.

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“…Na literatura são encontrados vários trabalhos que utilizam a variação da condutividade do meio para estimar o tamanho de bolhas em fluxos multifásicos. Exemplos destes sistemas são descritos em Buchholz, Zakrewsky e Schügerl (1981); Dias, França e Rosa (2000); Liu (2002); Lucas e Mishra (2005). Este método de medida utiliza sensores compostos de uma ou mais pontas de provas que medem a variação de condutividade em colunas de borbulhamento.…”

Section: Métodos Intrusivosunclassified

Correlação entre imagens e sinal elétrico para determinação do diâmetro de bolhas em líquidos

Marinho¹

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A distribuição do tamanho de bolhas é uma importante característica em sistemas bifásicos. A área interfacial de bolhas está fortemente relacionada às taxas de reações químicas e de transferência de massa em aplicações industriais como colunas de destilação e fermentação, sistemas biológicos, oxidação, hidrogenação, tratamento de água, e em processos naturais, como dinâmicas de aerossóis e transferência de gás oceano-atmosfera.Pontas de provas intrusivas são largamente usadas para determinar a distribuição do tamanho de bolhas em colunas de borbulhamento bifásicas. Embora o tamanho de bolhas não possa ser obtido diretamente pelo uso de uma simples ponta de prova porque estas medem somente comprimentos perfurados em bolhas, é possível relacionar distribuições de cordas à distribuição de tamanho de bolhas usando análises estatísticas. Este trabalho apresenta a implementação de um sistema capaz de medir distribuição de tamanho de bolhas em uma coluna de borbulhamento composta por água e ar através de uma ponta de prova condutiva.Imagens obtidas por uma câmera de vídeo CCD (Charge-Coupled Devices) monocromática são usadas para validar e calibrar o sistema.Palavras-chave: Escoamento bifásico, tamanho de bolhas, pontas de prova, análise de imagens.

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Bubble Velocity and Size Measurement with a Four‐Point Optical Fiber Probe

Guet

Fortunati

Mudde³

et al. 2003

Part & Part Syst Charact

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The possibility to measure the velocity and size of individual bubbles in a high‐void fraction bubbly flow is investigated by using a four‐point optical fiber probe. The air bubbles have an initial spherical equivalent diameter ranging from 4 to 10 mm and the void fraction is up to 0.3. Firstly, single bubble experiments show that intrusiveness effects, i.e. bubble deformations due to the probe, are negligible provided that the bubble approaches the probe at the axis of the central fiber. A selection criterion is utilized for multiple bubble experiments. A good compromise can be found between the required accuracy, the duration of the measurements and the number of validated bubbles required for reliable statistical averaging. In an air‐water high‐void fraction vertical bubbly pipe flow, the void fraction obtained with the instrument is found to be in good agreement with both local single‐fiber probe measurements, and with the volume average void fraction obtained from pressure gradient measurements. The area average volumetric gas flow rate, based on the bubble velocity and void fraction as measured with the four‐point probe, agree with the measured gas flow rate. Also, the liquid velocity is measured by means of a laser‐Doppler anemometer, to investigate the slip velocity. The results show that reliable and interesting measurements can be obtained by using a four‐point optical fiber probe in high void fraction flows.

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An effective signal processing method for resistivity probe measurements in a two-phase bubbly flow

Cited by 9 publications

References 11 publications

Measurement of bubble velocity components in a swirling gas–liquid pipe flow using a local four-sensor conductance probe

Measurement of bubble velocity components in a swirling gas–liquid pipe flow using a local four-sensor conductance probe

Correlação entre imagens e sinal elétrico para determinação do diâmetro de bolhas em líquidos

Bubble Velocity and Size Measurement with a Four‐Point Optical Fiber Probe

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