Radiometric methods in the measurement of particle-laden flows

The article discusses a study on hydrotransport of solid particles (ceramic models of polymetallic nodules) in a vertical pipeline using two different radioisotope methods: tracer and gamma-ray absorption. The radiotracer method makes it possible to determine the velocity of selected solid particles representing specified size fractions while the absorption method enables measurement of mean transport velocity of the entire dispersed phase. The measurements were performed with the use of NaI(Tl) scintillation detectors, sealed linear sources of radiation Am-241 with the energy of 59.54 keV and isotope Tc-99m with gamma radiation energy of 140.51 keV. The experiments were carried out in a pipeline with an internal diameter of 150 mm, for three different water velocities in the range of 1.5-3.6 m/s and three different sizes of ceramic models with size up to 60 mm. Analyses of the detector signals, in measurements based on both tracer and absorption technique, applied cross-correlation function (CCF). It was shown that with the same water velocity different fractions of solid particles have moved with different velocities and the lowest velocities were obtained for the particles with the largest diameters. This enabled interpretation of the CCF in absorption measurements as a distribution of possible interval times for the specific fractions of conveyed particles. (C) 2017 Elsevier B.V. All rights reserved.