Application of Electrical Capacitance Tomography and Differential Pressure Measurement in an Air-Water Bubble Column for Online Analysis of Void Fraction

Among electrical tomography techniques, electrical capacitance tomography (ECT) has been the subject of extensive recent research due to its non intrusive and non-invasive nature. It is used for obtaining information about the distribution of the contents of closed pipes or vessels by measuring variations in the dielectric properties of the material inside the vessel. An experimental study was conducted by producing two-phase bubble flow regime in a
vertical online ECT column. This experimental study measures the void fraction in a two-phase bubble flow
regime by using ECT and differential pressure (ΔP).
Differential pressure is also a simple and reliable
approach. The experiments conducted for this study
used compressed air as the gas phase and deionised
water as a liquid phase. On the variation in superficial
gas velocity from 0.0021 to 0.03 m/sec, and superficial
liquid velocity from 0 to 0.034 m/sec, some different
kinds of sub-bubble flow regimes were observed within
the column. The experimental results show the influence
of gas velocity on the void fraction in an increasing
manner. The raw data obtained from ECT was also
compared with the simulated data which shows a good
agreement to each other.