Displacement Current Phase Tomography (DCPT) is a new modality in electrical tomography that enables measuring and imaging multi-phase flows with a water phase using Capacitance sensors for the first time.
Conventional capacitance tomography (ECT or ECVT) can only measure or image non-conductive two-phase flow regimes. When either of those phases are conductive or highly polar, the linearity between measured capacitance and volume fraction becomes highly distorted. This inhibits the use of electrical capacitance signals for imaging water-based flows.
Displacement Current Phase Tomography solves this problem by using the same ECT or ECVT sensor to measure the dielectric and loss part of the signal and using the electric-phase signal independently for measuring the volume fraction of water. An attractive feature of DCPT is that the relationship between the measured phase and the loss factor inside the sensor domain has a more extended linear range than the relationship between the measured capacitance in ECT or ECVT and the permittivity distribution. DCPT also extends into the 3-D imaging of water-based flows forming volume tomography images.
The image on the left depicts a flow of a water droplet with an Air continuous phase. Using DCPT technology, we are able to resolve 2D and 3D images of the Water droplet. Conventional ECT provides a distorted image of the droplet due to the non-linear relation between Capacitance measurements and water. This non-linearity also increases the ill-posedness of the problem. DCPT is able to resolve accurately the shape and location of the droplet. Using DCPT for measuring and imaging water in flow mixtures provides superior results when compared with capacitance based tomography.