GAS-IN-LIQUID FLOW DETECTOR USING ELECTRICAL CAPACITANCE TOMOGRAPHY{ECT)

The multiphase flow characterization is a significant task for monitoring,
measuring or controlling industrial processes especially in petroleum industry.
The flow structures are classified in flow regimes, whose precise characteristics
depend on a number of parameters which are velocity of gas and flow rate of the
water. The various flow regimes are formed based on the distribution of the
fluid phases in space and time differs. The objective of this study is to visualize
the flow of gas in liquid phase which is capable in assisting operation which is
flow regime identification. Electrical Capacitance Tomography (ECT) is a
technique 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. 12-electrode ECT sensor is being used in order to
capture the flow structure where the cross section is to be imaged fonned from
simple metal plates. The basic principle of designing ECT sensor including the
number of length of electrodes, earthed screen, stray capacitance effect and the
connection issues must take into account. In this project, the author used inner
pipe diameter of 2.1cm, outer pipe diameter is 2.5cm, electrode length of 5cm,
electrode width of0.4cm and space between the electrodes is 0.3cm The online
ECT sensor measures the voltage and capacitance for the varying flow regime.
From the measurements, the permittivity image can be produced. In this project,
the amount of the air flow is varying while the amount of water is constant. The
author analyzed the results and compared with the physical observation. The
reliability and verification of method is demonstrated by comparison of
deionized water and normal water. By implementing this method, the
visualization of the cross-sectional of the flow will be detem1ined and this
method is important for industrial process monitoring.