11th World Congress on Industrial Process Tomography
Evaluation of Iterative Absolute Value implemented into High-temperature Electrical Resistance Tomography for High-accurate Visualization Molten Salt Solidification
S. Segawa1, A. A. Luthfie1,2, Y. A. K. Prayitno1,3*, N. Saito4, M. Takei1
1Department of Mechanical Engineering, Division of Fundamental Engineering, Graduate School of Engineering, Chiba University, Chiba, Japan
2Department of Mechanical Engineering, Faculty of Engineering, Mercu Buana University, Jakarta, Indonesia
3Department of Mechanical Engineering, Vocational College, Universitas Gadjah Mada, Yogyakarta, Indonesia
4Department of Material Science and Engineering, Faculty of Engineering, Kyushu University, Fukuoka, Japan
*Email: yosephus.ardean@ugm.ac.id
ABSTRACT
Iterative absolute value implemented into high-temperature electrical resistance tomography (ERT) has been evaluated to visualize molten salt solidification. The iterative absolute value of conductivity σ^i estimates solid volume fraction φ based on the number of ERT iterations i. In order to derive the σi, absolute reconstruction algorithm is applied into ERT. The algorithm treats the ERT as a nonlinear problem, which prevents the extended linear approximation by Jacobian matrix to adapt to large conductivity difference distributions due to molten salt solidification. σ^i generates simulated voltage dataset Vi by node-based finite element method (FEM) as Vi=FEM(σi) to take the difference with the measured voltage dataset Vexp, measured during high-temperature molten salt solidification. σi is updated by Gauss-Newton method using Jacobian matrix directly calculated by FEM in the i-th simulation. In the experiment, the application of alternating current and the measurement of voltage are performed in adjacent method with platinum-wire electrodes. The composition of LiCl-KCl molten salt was LiCl 85mol%–KCl 15 mol%. The initial temperature was set at 700˚C and was lowered at a rate of 4.44˚C/min. σi was developed into solid volume fraction φ by referring to known conductivity values. As the results, comparing the correction amount in iteration, the appropriate number of iterations was determined as i≥6.
Keywords: Molten salt solidification, high temperature, electrical resistance tomography.
Industrial Application: Thermal energy storage.
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