Investigation of the riser cross-sectional aspect ratio effect on the flow dynamics in circulating fluidized beds by electrical capacitance tomography

Tu, Qiansi; Wang, Haigang

doi:10.1177/0142331219851913

Cited by 6 publications

(4 citation statements)

References 30 publications

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“…For the measurement of the two-phase fluidized bed, the main ET technologies are electrical capacitance tomography (ECT) and electrical resistance tomography (ERT). ECT is applied to measure the objects with the continuous phase as nonconductive media and is mainly used for reconstructing the holdup distribution and measuring the average holdup for each phase in gas–solid and gas–liquid fluidized beds. − ERT is applied to measure the objects with the continuous phase as conductive media and is mainly used for reconstructing the holdup distribution and measuring the average holdup for each phase in gas–liquid and liquid–solid fluidized beds. − For the measurement of the gas–liquid–solid three-phase fluidized bed, there are currently two main ways. One is to regard two of the three phases as one phase to further obtain the holdup distribution of the remaining two phases.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Three-Phase Holdup Distribution in Gas–Liquid–Solid Fluidized Bed Based on ERT/TMR-EMT

Wang,

Zhang,

Guo

et al. 2023

Ind. Eng. Chem. Res.

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The measurement of three-phase holdup distributions in the gas−liquid−solid fluidized bed has guiding significance for the fluidized bed's characterization, design, and optimization. Aimed at the measurement of three-phase holdup distribution simultaneously, an image reconstruction method for electrical resistance tomography and electromagnetic tomography based on tunnel magnetoresistance (ERT/TMR-EMT) dual-modality system is proposed. The distributions of equivalent conductivity and equivalent permeability are reconstructed by the D-bar algorithm based on ERT and TMR-EMT, respectively. Then, the three-phase holdup distribution is reconstructed through equivalent media theory. From the results of the reconstructed image and threephase average holdup in simulation, the holdup variations of the gas, liquid, and solid are principally consistent with the phantom sets. From the measurement results of the dynamic experiments, clusters with high solid holdup and bubbles with high gas holdup can be accurately reflected and the variation of three-phase holdup distribution and average holdup can correctly reflect changes in experimental states in the fluidized bed.

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Section: Introductionmentioning

confidence: 99%

Measurement of Three-Phase Holdup Distribution in Gas–Liquid–Solid Fluidized Bed Based on ERT/TMR-EMT

Wang,

Zhang,

Guo

et al. 2023

Ind. Eng. Chem. Res.

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“…In the process of solving the sensitivity coefficient, the capacitance measurement data needs to be normalized [17][18][19]. A normalized model is essentially a description of the medium distribution, and the parallel normalization model (PM) is commonly used [20].…”

Section: Introductionmentioning

confidence: 99%

Image reconstruction of ECT based on second-order hybrid sensitivity matrix and fuzzy nonlinear programming

Zhang,

Chen

2023

Meas. Sci. Technol.

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In the derivation of the sensitivity matrix of electrical capacitance tomography, only the linear portion of the sensitivity coefficient is usually retained, while the neglected nonlinear part also contains important imaging information. In order to improve the accuracy of image reconstruction, a second-order hybrid sensitivity matrix is presented based on the capacitance normalization model and second-order item of sensitivity coefficients in this paper. Then, a fuzzy nonlinear programming algorithm based on the second-order hybrid sensitivity matrix (SHS-FNP) is proposed. Simulation and experiments are carried out. Reconstructed images using the presented method are compared with those of the Tikhonov algorithm, first-order hybrid Landweber algorithm, second-order hybrid Landweber algorithm, and fuzzy linear programming algorithm. The experimental results show that the SHS-FNP algorithm considerably enhances the quality of the reconstructed image.

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“…Based on the different electrical features of the object in the sensitivity field, the ET techniques could be divided into electromagnetic tomography (EMT), electrical capacitance tomography (ECT), electrical impedance tomography (EIT), and electrical resistance tomography (ERT). Based on the principle of electromagnetic induction, the EMT can reconstruct the distribution state of the magnetic permeability for the medium in the sensitivity field [1][2][3][4][5][6]; Based on the principle of capacitance sensitivity, the ECT can reconstruct the distribution state of the dielectric constant for the medium in the sensitivity field [7][8][9][10][11][12][13][14][15][16][17]; Based on the principle of impedance sensitivity, the EIT can reconstruct the distribution state of the complex admittance for the medium in the sensitivity field [18][19][20][21][22][23][24]; Based on the principle of resistance sensing, the ERT can reconstruct the distribution state of the dielectric resistivity/conductivity for the medium in the sensitivity field [25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Design and Optimization of a Finite Element Model for Electrical Resistance Tomography of Human Lungs

Xiao¹

2021

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To improve the reconstruction quality of electrical resistance tomography (ERT) images, this paper designs and optimizes the finite element model for human lungs. According to the computer tomography (CT) scan image on human chest, the entire simulation domain was divided into a region of lungs, heart, and spine, and a region of adipose tissue, and the boundary curve equations of each region were derived by the improved particle swarm optimization (PSO). Based on the prior knowledge, a structural model was established for human lungs; the ERT forward problem was solved by the finite element model based on grid reconstruction, and the calculated boundary voltage of sensitivity field was taken as the theoretical value. Next, two optimization goals were set up: improving the calculation accuracy of forward problem, and easing the ill-conditionedness of the sensitivity matrix; two variables were configured: the number of layers of the finite element model in each region, and the polar diameter ratio of the finite element nodes on each layer to the finite element nodes on the boundary of each region corresponding to the same polar angle. On this basis, the finite element model was optimized by the improved PSO to adapt to human lung ERT. Simulation results show that, under the same experimental conditions, the proposed finite element model could solve the forward problem more accurately, improve the ill-conditionedness of the sensitivity matrix and the Hessian matrix, and make the sensitivity distribution more uniformly, thereby enhancing the accuracy of image reconstruction.

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Investigation of the riser cross-sectional aspect ratio effect on the flow dynamics in circulating fluidized beds by electrical capacitance tomography

Cited by 6 publications

References 30 publications

Measurement of Three-Phase Holdup Distribution in Gas–Liquid–Solid Fluidized Bed Based on ERT/TMR-EMT

Measurement of Three-Phase Holdup Distribution in Gas–Liquid–Solid Fluidized Bed Based on ERT/TMR-EMT

Image reconstruction of ECT based on second-order hybrid sensitivity matrix and fuzzy nonlinear programming

Design and Optimization of a Finite Element Model for Electrical Resistance Tomography of Human Lungs

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