Application of the phase method in radioisotope measurements of the liquid - solid particles flow in the vertical pipeline

Abstract

Abstract. The paper presents idea and an application of the gamma-absorption method to a two-phase flow investigation in a vertical pipeline, where the flow of solid particles transported by water was examined by a set of two 241 Am radioactive sources and probes with NaI(Tl) scintillation crystals. In the described experiments as solid phase the ceramic models representing natural polymetallic ocean nodules were used. For advanced analysis of electrical signals obtained from detectors the phase of cross-spectral density function has been applied. Results of the average solid-phase velocity measurements were compared with one obtained by application of the classical cross-correlation. It was found that the combined uncertainties of the velocity of solid particles evaluation in the presented experiment did not exceed 0.6% in phase method and 3.2% in crosscorrelation method.

Improvement of radiotracers experiments in mass transfer processes

“…The presented methods and described experiment, as well as attached literature, allow to formulate the following proposals: -radioisotopes may profitably supplement traditional method of multiphase flow analysis [15][16][17], -reduction of the necessary assumption demanded for radiotracer experiments allows applying easier measuring procedures and extending their range of application [18][19][20][21][22][23][24][25], -huge development in radiotracer methods, especially in flow velocity measurements, allows both reduction of the radioactivity and increase of the measurements' accuracy [20,[26][27][28][29], -in many cases, application of radioisotopes may bring smaller hazard due to mass of radioisotopes reduction [30][31][32][33], -in some measurements radiotracers may be replaced by sealed radioactive sources [10,16,26] -equipment based on a pair of sealed radioactive sources appeared to be convenient for two-phase flow control [34][35][36], -simultaneous application of tracers and sealed sources gives possibility of more detailed analysis of complex flows [37][38][39][40].…”

Application of nuclear techniques in two-phase liquid-solid particles hydrotransport investigations

“…The basic principle of gamma-ray absorption measurement is based on fact that the intensity of a collimated gamma beam decreases as it passes through matter [5][6][7][10][11][12][13][14][15][16][17].…”

“…These probes record the radiation intensity I v and I z from the marked particle (6). Velocity of the marked particle can be determined as before by determining time delay between signals.…”

“…The mining of nodules using the hydraulic method requires nodules vertical transport by water to sea level in extremely hard and varying environment. Determination of the velocity of nodules of various sizes in the vibrating pipeline at a significant depth is a very difficult task and requires the use noninvasive measurement techniques [5,6].…”

Possibilities of radioisotope measuring in control of an unstable solid particles hydrotransport

“…where T is approximation time sufficient for grains' transport evaluation, s; IJ time delay, s [9][10][11][12][13][14].…”