Visualization of Vertical Upward Two-Phase Flow Using Electrical Resistance Tomography (ERT)

Electrical resistance tomography (ERT) is one of the promising techniques in
producing a cross-sectional image showing the distribution of electrical conductivity of a
multiphase flow. 'This technique involves measurement of electrical resistance properties to
image mixtures where the continuous phase is conductive. ERT is suited to monitor gas-liquid
flow, in which the liquid is continuous phase and gas is disperse phase. Few other types of
tomography sensors involving measurement of electrical properties include electromagnetic
tomography (EMT), electrical capacitance tomography (ECT) and electrical impedance
tomography (EIT). These electrical tomography techniques are safe with no radiation hazard
and low cost compared to nuclear techniques. However, ERT stands out among others in its
excellent time resolution arising from the very fast measurements of electrical resistance. 'This
paper covers on the development of ERT for flow visualization where ERT sensor with
circular 8-electrodes is modeled and constructed. A test rig is also build to produce the desired
flow profile of vertical upward liquid-gas flow. Visualization tomogram and data obtained
from the experiment is captured directly by the data acquisition system connected to the ERT
sensor. In analyzing the data, static analysis and dynamic analysis is performed and further
discussion on results is included in this paper.