An approximate formula for the capacitance–void fraction relationship for annular flows

Kim, Sin; Lee, Jeong Seong; Kim, Kyung Youn; Kang, Kyung Ho; Yun, Byung Jo

doi:10.1088/0957-0233/20/12/125404

Cited by 5 publications

(3 citation statements)

References 18 publications

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“…The correlations (Srisomba et al [9]) are different for the three flow patterns above. Kim et al [10] proposed a capacitance method to measure the space-averaged void fraction in concentric annular flows, derived the expression for the capacitance in terms of a given void fraction, and developed a closed-form formula to predict the void fraction from capacitance measurements. Uesawa et al [11] proposed a void fraction estimation method for three-dimensional dispersed bubbly flow based on Maxwell's theory and polarization of tiny bubbles whereas Jassim and Newell [12] developed probabilistic two-phase flow map models to predict void fraction and pressure drop for R134a, R410A and air-water in 6-port microchannels.…”

Section: Introductionmentioning

confidence: 99%

Void Fraction Measurement of Gas-Liquid Two-Phase Flow Based on Empirical Mode Decomposition and Artificial Neural Networks

Wang

Sefiane

Duursma

et al. 2018

Heat Transfer Engineering

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Phone Number: 0 (+44) 131 650 4868, Fax Number: 0 (+44) 131 650 6551 2 ABSTRACT A new void fraction estimation method for gas-liquid two-phase flow combining two differential pressure (DP) signals acquired from a single Venturi tube and based on Empirical Mode Decomposition (EMD) and Artificial Neural Networks (ANN) was experimentally investigated. In order to study gas-liquid distribution in horizontal pipes, two DP signals from the top and bottom sections of the Venturi tube are acquired and EMD is adopted to extract stable and fluctuating components of the DP signals. Experimental data revealed that fluctuating index increases nearly linearly with increasing void fraction when void fraction is less than 0.4. When void fraction is larger than 0.4, this near-linearity ceases. A combination of ANN method and the fluctuating index of DP signals is developed to estimate void fraction. Experimental results show that void fraction based on DP signal from top section of Venturi tube is overestimated because of clustering of bubbles and the scarcity of liquid information when gas-liquid mixture velocity is low. Void fraction is underestimated when the mixture velocity is high. A high gas-liquid slip ratio results in void fraction underestimation. Void fraction prediction performance is satisfactory when void fraction is less than 0.4 and fluctuating index of DP signal less than 1.2. ll f ll kk p            (1)

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Section: Introductionmentioning

confidence: 99%

Void Fraction Measurement of Gas-Liquid Two-Phase Flow Based on Empirical Mode Decomposition and Artificial Neural Networks

Wang

Sefiane

Duursma

et al. 2018

Heat Transfer Engineering

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“…Shu et al (1982) derived a solution to the Laplace equation for the concentric annular geometry in a plate-type capacitance sensor, and conducted sensitivity analyses with respect to the thickness of the dielectric pipe. Kim et al (2009b) developed a closed-form of expression suggesting a relationship between the normalized capacitance and the void fraction in the concentric annular flow. Tsochatzidis et al (1992) derived a conductance response to stratified and annular flow in ring sensor geometry.…”

Section: Introductionmentioning

confidence: 99%

“…Tsochatzidis et al (1992) derived a conductance response to stratified and annular flow in ring sensor geometry. Also, Kim et al (2009b) suggested an expression of the conductance response to slug flow in a three-ring sensor in a simplified manner and compared it with experiments using an acryl rod simulating a Taylor bubble.…”

Section: Introductionmentioning

confidence: 99%

An electrical impedance sensor for water level measurements in air–water two-phase stratified flows

Ko¹,

Lee²,

Lee³

et al. 2013

Meas. Sci. Technol.

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We report a design of an optimized ring-type impedance sensor for water level measurements in air–water stratified flows through horizontal pipes. The ring-type sensor is optimized in view of the sensor linearity. In order to determine an optimal electrode and gap size of a ring-type sensor which generates a linear relationship between the impedance (resistance and/or reactance) and the water level, systematic numerical calculations are performed, and a ring-type impedance sensor of electrode width-to-diameter ratio 0.25 and gap-to-diameter ratio 0.2 has been selected as optimal. Lab-scale static experiments have been conducted to verify the sensor performance in terms of the linearity. Finally, this proposed sensor is installed in a horizontal loop 40 mm in diameter and roughly 5200 mm in length and measures water levels for various stratified flow conditions. The comparisons of water level measurements between the proposed sensor and the high-speed camera images post-processed by the edge detection scheme show that the maximum deviation in dimensionless water level is roughly 0.037, which corresponds to 1.5 mm over the range 40 mm.

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Capacitance-based liquid holdup measurement of cryogenic two-phase flow in a nearly-horizontal tube

et al. 2017

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An approximate formula for the capacitance–void fraction relationship for annular flows

Cited by 5 publications

References 18 publications

Void Fraction Measurement of Gas-Liquid Two-Phase Flow Based on Empirical Mode Decomposition and Artificial Neural Networks

Void Fraction Measurement of Gas-Liquid Two-Phase Flow Based on Empirical Mode Decomposition and Artificial Neural Networks

An electrical impedance sensor for water level measurements in air–water two-phase stratified flows

Capacitance-based liquid holdup measurement of cryogenic two-phase flow in a nearly-horizontal tube

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