Electrical impedance imaging of phase boundary in two-phase systems with adaptive mesh regeneration technique

Numerical and experimental works are conducted to develop a visualization technique for the phase distribution in a two-phase system by electrical impedance tomography technique, which reconstructs the resistivity distribution with the electrical responses that are determined by corresponding excitations. In conventional Newton-Raphson method, the flow field is discretized into pixels, each of which has an unknown resistivity value to be determined by the image reconstruction algorithm. The pixels are usually fixed in a predetermined way. In practical cases, such as the impedance imaging of two-phase flow, this model might not be useful. For the two-phase flow system, the impedance of each phase does not change but instead the phase boundary depends on the distribution of dispersed phase. In the present study, a new image reconstruction algorithm employing adaptive mesh regeneration technique is developed for the detection of phase boundary. Numerical works show that the proposed method can treat two-phase systems reasonably even with some errors in measurement data. Also, with an apparatus developed for impedance imaging this study attempts to reconstruct the images of the simulated bubble distributions and the reconstructed images imply the potential possibility of the electrical impedance tomography for the two-phase flow visualization.