The paper presents the design of an experimental apparatus aimed at observing isothermal two-phase flows within a vertical pipe. The construction of the apparatus allows for the continuous or discontinuous injection of gas into the system, with the gas being introduced from beneath the test section, while water is supplied from above as a counter-current with respect to the gas. The test section of the experimental apparatus comprises two tubes with different diameters, enabling detailed observation of two-phase flow under laminar and turbulent flow conditions. The instrumentation of the apparatus includes sensors for measuring pressure, temperature, and liquid flow rate. High-speed cameras are primarily employed for flow observation, facilitating image capture of the test section at high frequencies. Measurements can be conducted under normal illumination or illumination with a laser plane.
In this work, the apparatus was utilized for studying a stationary Taylor bubble, where buoyancy is balanced by the counter-current flow of water. Measurements encompass the analysis of Taylor bubble breakup, dynamics of the bubble interface, and the reconstruction of the velocity field in the vicinity of the bubble. Measurements were carried out over a range of temperatures (from 20°C to 50°C) and pressures (from 1 bar to 2.5 bar). The experiments were carried out for Eötvös numbers ranging from 20 to 100, Morton numbers from 0.1 · 10-12 to 25 · 10-12, and Reynolds numbers of the liquid phase ranging from 1000 to 10000. The acquired data offers a better understanding of the dynamics of the two-phase slug flow in a vertical pipe. The data has also been used for the development and validation of computer models of slug flow.
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