Mass fraction measurements in multiphase flows using a clamp-on PVDF array

In this paper we present a method for the measurement of mass fractions of iron ore in two-phase flows consisting of water and iron ore particles. The proposed method uses a clamp-on PVDF transmitter and a 12-element PVDF receiver array to measure the excess attenuation of pulsed ultrasound due to the presence of particles. From the measured data we are able to extract a quantity that varies linearly with particle mass fraction in the range from 0 to 13%. With the proposed method we can measure the mass fraction in whole percent, at a 95% confidence level. Using an array of receivers we are also able to calculate an attenuation profile over a cross section of the flow, which indicates how the particles are distributed within the flow. This is used to examine how the particle distribution is affected by flow speed, flow meter position, and mass fraction, respectively.