Phase Distribution Characteristics of Bubbly to Slug Flow Transition Region in a 10mm ID Vertical Round Pipe

As a common heat transfer structure, the vertical round pipe is widely used in nuclear energy systems. The phase distribution characteristics of two-phase flow in a vertical round pipe is an important issue. For two-phase flow, combined with the local typical flow phenomenon, the analysis of the phase distribution characteristics such as the void fraction and the interfacial area concentration is helpful to research the two-fluid model and interfacial area transport equation. Based on the completed flow pattern experiment, an air-water two-phase flow characteristic experiment is carried out for the visualized experimental section of 10 mm ID vertical round pipe. In addition, the 5 × 7 total 35 measuring points of bubbly to slug flow transition region are selected, including 5 superficial liquid velocities (0.5, 1.0, 1.5, 2.0, 2.5 m/s) and 7 superficial gas velocities (0.08, 0.11, 0.13, 0.17, 0.21, 0.28, 0.35 m/s). High-speed camera is used to capture the flow patterns of bubbly to slug flow transition region. Four-sensor conductivity probe is used to measure the interfacial parameters such as void fraction and interfacial area concentration. Thus, the phase distribution characteristics of bubbly to slug flow transition region in the round pipe is analyzed. The obtained two-phase flow parameter data can provide data support for the development of two-fluid model and interfacial area transport equation.