An Image Reconstruction Method for Outwards Electrical Impedance Tomography Based on Inversion Mapping

Cavitation is a typical gas-liquid two-phase flow phenomenon that commonly occurs at the fluid-structure interaction interface. Measuring the distribution of internal media within the cavitation clouds is significant for studying the cavitation state and the stability of a rotating body's operation. Due to "soft-field" sensing, electrical impedance tomography (EIT) can recover the media distribution on an object surface by arranging electrodes on the surface and "seeing outwards", i.e., outwards-electrical impedance tomography (Outwards-EIT), which can be employed to evaluate the cavitation state. However, since the outwards-EIT electrode locations and the infinite domain border are independent of each other, it causes computational difficulties in the forward and inverse problems in image reconstruction. To address the reconstruction issue, this article proposes an imaging method based on inversion mapping. Numerical simulations are performed to validate the physical consistency of the reconstruction model after field transformation and the effectiveness of the proposed method. Results show that the proposed method can improve the detection range, eliminate image artifacts near the electrodes, and provide more accurate reconstruction in Outwards-EIT than the conventional Landweber, L1-regularization methods. This manifests its great potential for imaging vacuolar media within cavitation.