Ultrasound tomography measurements in multiphase flows

Abstract: In many industrial applications, non-invasive measurements of different flows
play an important role. For flows consisting of only one phase, such as water
or gas, there are several methods available. Most of these methods, however,
are not applicable to multiphase flows, such as paper fiber suspensions or
iron ore slurries.

The overall goal of this project was to investigate the use of ultrasound
tomography for measuring particle distributions and particle mass fractions
in multiphase flows.

We use a custom-made ultrasound transmitter and receiver array manufactured
from PVDF (polyvinylidene fluoride) film.

The first part gives an overview of two tomography methods, the filter back
projection and the Fourier
reconstruction. Then we show with experiments how the reconstructed image can
be used to extract information about particle mass fraction as well as
particle distribution in a multiphase flow consisting of iron ore powder and
water. The results are compared with those obtained from conventional
attenuation measurements, and show that we can extract additional information
with this technique