Void fraction measurement using impedance method

Yang, Hee Chan; Kim, D.K.; Kim, M.H.

doi:10.1016/s0955-5986(03)00020-7

Cited by 39 publications

(21 citation statements)

References 11 publications

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“…In the experimental results, Maxwell's estimation was in good agreement with the measured results. These estimations were applied in order to investigate the relationship between void fraction and volume-averaged impedance in water-air mixtures, too [13]. Gas volume fractions measured by the electric resistance tomography was also estimated by Maxwell's estimation [3].…”

Section: Introductionmentioning

confidence: 99%

Measurement of void fraction in bubbly-slug flow with a constant electric current method

Uesawa

Kaneko

Abe

2015

Journal of Nuclear Science and Technology

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In several void fraction measurement methods, a constant electric current method which is one of conductance methods is focused in the present study. By using this method, void fraction can be measured with higher temporal resolution. However, it has been mainly applied to annular flow in previous studies. In the present study, Maxwell's estimation, Bruggemann's estimation, low void fraction approximation and new estimations which consider the bubble shape are applied in order to measure more accurately void fraction of dispersed bubbly flow and slug flow. To understand the effect of bubble shapes and flow patterns, void fraction was measured by the constant electric current method for a rising single spherical bubble and a rising single slug bubble without a forced convection. In addition, void fraction was also measured in bubbly flow and bubbly-slug flow with a forced convection. Then, effects of flow patterns on the proposed estimations of void fraction and the accuracy of their estimations were discussed with the measurement results. From the result, the new estimations which consider a bubble shape are more accurate than the previous estimation in a slug bubble and bubbly-slug flow.

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Section: Introductionmentioning

confidence: 99%

Measurement of void fraction in bubbly-slug flow with a constant electric current method

Uesawa

Kaneko

Abe

2015

Journal of Nuclear Science and Technology

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“…That is, the electric resistance or the capacitance is corresponding to the void fraction in a measuring section. There are all kinds of electric sensing methods such as conductance proves methods [10][11][12][13], wire mesh methods [14][15][16], electric resistance tomography (ERT) [17,18], capacitance method [19][20][21][22][23][24], electric capacitance tomography (ECT) [25] and electric capacitance volume tomography (ECVT) [26]. These electric sensing methods need large systems required complex algorism to reconstruct void value and they need large reconstructing time to obtain the void value.…”

Section: Introductionmentioning

confidence: 99%

“…However, the method cannot be applied to three dimensional bubbly flow because the existing algorithm cannot treat the bubbles distributed in three dimensions. In previous studies, Maxwell's theory [33] was applied to bubbly flow for calculations of void fraction from electric signals by using probes [10,22] and an electric resistance tomography [18]. However, the theory is not applied to the constant electric current method.…”

Section: Introductionmentioning

confidence: 99%

Measurement of void fraction in dispersed bubbly flow containing micro-bubbles with the constant electric current method

Uesawa¹,

Kaneko²,

Abe³

2012

Flow Measurement and Instrumentation

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Void fraction is one of the dominant parameter of gas-liquid two-phase flow in industrial equipment. An electric sensing method based on the difference of electric conductivity and permittivity between liquid and gas is one of online measurement methods of void faction. However, previous constant electric current method is not applicable to dispersed bubbly flow because bubbles are dispersed in three dimensions. In the present study, new constant electric current method available to the three dimensional dispersed bubbly flow with tiny bubbles (micro-bubbles) is developed. The proposed method to estimate the void fraction is based on Maxwell's theory and polarization of tiny bubbles. The method makes it possible to measure the void fraction of three dimensional dispersed bubbly flow. It is experimentally clarified that the present proposed method with constant electric current method can be applicable to measure the void fraction of three dimensional bubbly flow more accurately than previous constant electric current method. It is also clarified that the Maxwell's theory and the present proposed method with polarization are compatible with drift flux model although void fraction estimated with the previous method is higher than the drift flux model for three dimensional dispersed bubbly flow.

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“…Lucas et al (2000) designed and constructed a local six-electrode conductivity probe to simultaneously measure the local solids volume fraction and the local solids axial velocity with high precision in solids-water pipe flows. To investigate the relationship between void fraction and volume-averaged impedance in air-water mixtures, Yang et al (2003) had used styrofoam spheres, whose relative permittivity was negligible compared to that of water to simulate the gas bubble, they got the measurement result whose deviation maintained within 0.5% when the void fraction range is from 0 to 0.1.…”

Section: Introductionmentioning

confidence: 99%

Gas–liquid two phase flow measurement method based on combination instrument of turbine flowmeter and conductance sensor

Guibo

Jin

Jia

et al. 2008

International Journal of Multiphase Flow

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Void fraction measurement using impedance method

Cited by 39 publications

References 11 publications

Measurement of void fraction in bubbly-slug flow with a constant electric current method

Measurement of void fraction in bubbly-slug flow with a constant electric current method

Measurement of void fraction in dispersed bubbly flow containing micro-bubbles with the constant electric current method

Gas–liquid two phase flow measurement method based on combination instrument of turbine flowmeter and conductance sensor

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