The non-stationary two-phase flow evaluation by radioisotopes

Two-phase flows, especially those commonly applied during hydraulic exploitation of minerals, are often characterized by the presence of serious variations of density. The adequate control of such a system produces high discrepancy of the mixture velocity. These flows cannot be examined by traditional impulse injection of a tracer. A solution to these difficulties is proposed based on the application of sealed sources and measuring methods calibrated by radiotracers during steady conditions of the flow. The paper presents the results of a full-scale test in a laboratory installation where the stream of water is transporting upwards naturally dispersed nodules through a Ř150 mm vertical pipe. A specially designed equipment allows the control of mixture density as well as the measurement of water and the velocity of particular nodules. The obtained results illustrate the capabilities of radiotracers and possibilities how they can be applied in different two-phase flows, when both density and velocity of the components significantly vary during observation.