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Proceedings Paper

Sensitivity analysis of different sensing strategies for electrical impedance imaging of two-phase flows
Author(s): T. P. Figueiroa; Paulo Seleghim
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Paper Abstract

The basic motivation of this work comes from the fact that most of the numerical reconstruction algorithms were developed for hard sensing fields, i.e. they have the underlying assumption that the sensing field is two-dimensional and parallel. When using soft sensing fields, such as in electrical impedance tomography, these conditions are barely satisfied, unless in the situation of a low contrast between the electrical properties of the flowing phases, for which the ill-conditioned nature of the problem will be much more critical anyway. The development of a less restrictive method can be achieved by refining the qualitative images of a direct imaging probe, through the minimization of a conveniently defined error functional reflecting the difference between experimental and numerical values taken at the boundary of the sensing volume. However, in order to do this, these boundary values must be sufficiently sensitive to changes in the distribution of the electrical properties of the flow. This paper addresses this problem and presents a sensitivity analysis of different excitation strategies and their applicability in a reconstruction algorithm such as described above. Classical Dirac excitation is compared to an alternative excitation profile with regards to the capability of producing significant changes in boundary measurements when the internal organization of the sensed media is altered. Results confirm that classical strategies suffer from a major lack of sensitivity and that new ones must be developed, possibly based on the optimization of the excitation profiles or on multisensing strategies.

Paper Details

Date Published: 2 February 2001
PDF: 9 pages
Proc. SPIE 4188, Process Imaging for Automatic Control, (2 February 2001); doi: 10.1117/12.417161
Show Author Affiliations
T. P. Figueiroa, Univ. de Sao Paulo (Brazil)
Paulo Seleghim, Univ. de Sao Paulo (Brazil)

Published in SPIE Proceedings Vol. 4188:
Process Imaging for Automatic Control
Hugh McCann; David M. Scott, Editor(s)

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