A flowmeter for measuring the dispersed phase velocity in multiphase flow with non-uniform velocity profile

This study aims to introduce a new technique to measure
the velocity distribution of the dispersed component of a
vertical, upward, water continuous two-phase pipe flow.
Here, it is proposed that measurements of the variation in
the local conductance of the mixture can be cross
correlated to determine the local velocity distribution of,
for example, gas bubbles in water.
The measurements were conducted by using arrays of
axially separated conductance sensors placed normal to the
flow. Each array contained eight electrodes distributed
over the internal circumference of the pipe carrying the
flow. The arrays, were mounted at a known distance from
each other along the pipe. Within each array, individual
electrodes could be configured as either ‘excitation’,
‘measurement’ or ‘earth’. By changing the electrode
configuration of an array the electric field sensitivity
distribution associated with the array could be altered, thus
changing the region of the flow ‘interrogated’ by the
system. By cross correlating the output signals from these
arrays, in various combinations, the velocity of the
dispersed phase can be obtained at different regions within
the flow, thereby enabling the velocity profile of the
dispersed phase to be measured.
The sensitivity distribution associated with given electrode
configurations has been investigated in a bench test. First
the flow meter was filled with water, and then nonconducting
rods were inserted into the flow meter at
various spatial locations parallel to the pipe, the resulting
change in conductance was measured.. The sensitivity
distribution has also been simulated using COMSOL
software. Agreement between experiment and theory was
close to 1 %.