Investigation of Electrical Impedance Imaging Relative to Two-Phase, Gas-Liquid Flows

Jones, O.C.; Lin, Jen-Tai; Ovacik, Levent

doi:10.1080/00986449208936100

Cited by 10 publications

(4 citation statements)

References 25 publications

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“…Multiple measurements ofj and Vat the boundary are used to iteratively reconstruct the conductivity distribution within D that yields the measured boundary conditions. More information on EIT theory and the development of EIT systems for the study of multiphase flows may be found in Dickin et al (1993); Jones et al (1992Jones et al ( , 1993Jones et al ( , 1994and Ceccio and George (1996).…”

Section: Electrical-impedance Tomography (Eit)mentioning

confidence: 99%

Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

George¹,

Shollenberger²,

Torczynski³

et al. 2001

International Journal of Multiphase Flow

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---Experiments are presented in which electrical-impedance tomography (EIT) and gammadensitometry tomography (GDT) measurements were combined to simultaneously measure the solid, liqui~and gas radial distributions in a vertical three-phase flow. The experimental testbed was a 19.05-cm diameter bubble column in which gas is injected at the bottom and exits out the top while the liquid and solid phases recirculate. The gas phase was air and the liquid phase was deionized water with added electrolytes. Four different particle classes were investigated for the solid phase: 40-100 pm and 120-200 pm glass beads (2.41 g/cm3), and 170-260pm and 200-700pm polystyrene beads (1.04 g/cm3), Superficial gas velocities of 3 to 30 cmk and solid volume fractions up to 0.30 were examined. For all experimental conditions investigated, the gas distribution showed only a weak dependence on both . particle size and density. Average gas volume fraction as a fimction of supert3cial gas velocity can be described to within &O.04by a curve passing through the center of the data. For most cases the solid particles appeared to be radially uniformly dispersed in the liquid.

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Section: Electrical-impedance Tomography (Eit)mentioning

confidence: 99%

Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

George¹,

Shollenberger²,

Torczynski³

et al. 2001

International Journal of Multiphase Flow

View full text Add to dashboard Cite

show abstract

“…More information on EIT theory and the development of EIT systems for the study of multiphase flows may be found in Dickin et al (1993); Jones et al (1992Jones et al ( , 1993Jones et al ( , 1994and Ceccio and George (1996).…”

Section: Eit Theorymentioning

confidence: 99%

Validation of electrical-impedance tomography for measurements of material distribution in two-phase flows

George

Torczynski

Shollenberger

et al. 2000

International Journal of Multiphase Flow

103

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“…Based on these measurements, an estimate for the 3D distribution of resistivity (or its reciprocal, conductivity) is computed. Previously, ERT has been applied, for example, in process monitoring [23][24][25][26], biomedical imaging [27][28][29][30][31], geology [32][33][34] and some NDT applications [35]. However, only few preliminary studies for applying ERT to non-destructive testing of concrete or other cement based materials have been reported so far [36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

Electrical Resistance Tomography imaging of concrete

Karhunen¹,

Seppänen²,

Lehikoinen³

et al. 2010

Cement and Concrete Research

214

135

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Cracking and deterioration of concrete are the leading causes of a premature failing of reinforced concrete structures. To assess the condition of concrete, a variety of destructive and non-destructive testing methods have been developed. From these two methods, the non-destructive testing (NDT) is a more favorable (albeit more challenging) option since the tested target is left undamaged. The NDT modalities include acoustic, electromagnetic and radiation based techniques. In this thesis, the feasibility of electrical resistance tomography (ERT) for NDT of concrete is studied. In ERT, electric currents are injected into the target through electrodes that are are attached to the boundary of the target. The resulting voltages between the electrodes are measured and this boundary voltage data is then used to reconstruct the internal conductivity distribution of the target. The reconstruction of the internal conductivity distribution of concrete is expected to provide valuable information about the condition of the structure so that appropriate repairs can be taken in time. The difficulty in ERT, as is in any other diffuse tomography modality, is that the problem has a nature of an ill-posed inverse problem. This implies that the solutions of the problem are unstable and nonunique in the classical sense. As a consequence, extra attention must be directed to the mathematical modeling of the measurements as well as to the reconstruction methods. Furthermore, concrete is strongly heterogeneous material composed of cement matrix, aggregate and different chemical compounds that create a challenging target for electrical modalities. Previous studies have shown that ERT is a potential tool for NDT of concrete, but the quality of the reconstruction was not yet sufficient for practical applications. In this thesis, especially localizing reinforcing bars and crack identification are considered. To meet those aims, novel computational methods for the image reconstruction are developed. For the crack identification and localizing reinforcing bars, a novel adaptive meshing approach was developed. In the new approach cracks and reinforcing bars are modeled as internal structures. The results show that by employing accurate mathematical models and statistical inversion techniques based on the Bayesian framework, ERT can become an applicable tool for practical NDT of concrete.

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Investigation of Electrical Impedance Imaging Relative to Two-Phase, Gas-Liquid Flows

Cited by 10 publications

References 25 publications

Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

Three-phase material distribution measurements in a vertical flow using gamma-densitometry tomography and electrical-impedance tomography

Validation of electrical-impedance tomography for measurements of material distribution in two-phase flows

Electrical Resistance Tomography imaging of concrete

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