Local Measurement in Annular Flows Using a Two-Sensor Droplet-Capable Conductivity Probe
Two-sensor electrical conductivity probes have been widely used for detailed local measurement in two-phase flow systems. However application of conductivity probes in liquid-dispersed flows has been limited. In the churn-turbulent to annular transition and annular flow regimes, the liquid phase exists as a continuous phase in the film and ligaments, and as a dispersed phase in the droplets. The conventional design of a conductivity probe is not valid because it cannot distinguish the dispersed liquid phase from the gas phase. In this paper, the Two-Sensor Droplet-Capable Conductivity Probe (DCCP-2) is designed in order to extend measurement capability to liquid-dispersed flows. The liquid phase is classified into droplets and ligaments. The interface velocity, volume fraction, interfacial area concentration, as well as the chord length of liquid droplets and ligaments, can be calculated from the raw signal. The radial distribution of these parameters and the probability distribution of chord length and velocity are obtained for downwards flow in a vertical pipe. The results show that although the average volume fraction of droplets is only on the order of 1%, droplets contribute to around 20%-30% to the entrained liquid phase in the gas core, the remainder as ligaments. The interfacial area concentration from droplets and ligaments are in the order of 300 m-1.
Q. Zhu et al., "Local Measurement in Annular Flows Using a Two-Sensor Droplet-Capable Conductivity Probe," Transactions of the American Nuclear Society, vol. 115, pp. 1503-1506, American Nuclear Society (ANS), Nov 2016.
2016 ANS Winter Meeting and Nuclear Technology Expo (2016, Nov. 6-10, Las Vegas, NV)
Nuclear Engineering and Radiation Science
Keywords and Phrases
Drops; Liquids; Phase interfaces; Probability distributions; Probes; Volume fraction; Conductivity probe; Conventional design; Dispersed liquid phase; Electrical conductivity; Interface velocity; Interfacial area concentrations; Local measurement; Radial distributions; Two phase flow
International Standard Serial Number (ISSN)
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01 Nov 2016