Countercurrent two-phase flow regimes and void fraction in vertical and inclined channels
- Georgia Inst. of Technology, Atlanta, GA (United States)
Countercurrent flow limitation (CCFL), or flooding, is one of the most significant aspects of counter-current two-phase flow. The CCFL imposes a limitation on the operational parameters for systems involving countercurrent flow and can have important adverse consequences during the course of various nuclear reactor accidents. Much attention has, therefore, been paid to the CCFL phenomenon. Gravity-driven countercurrent two-phase flow in horizontal and inclined channels, where the flows of both liquid and gas phases are due to the effect of gravity, has recently been studied because of its potential occurrence in the safety cooling systems of advanced reactors. Hydrodynamic characteristics of countercurrent two-phase flow in vertical and inclined channels are investigated. Experiments are performed using air and water at room temperature (25 to 27C) and 160-kPa pressure, in a 208-cm-long, transparent, tubular test section with a 1.9-cm inner diameter. Tests are systematically performed with downward liquid superficial velocities and upward gas superficial velocities covering the 0 to 10 and 0 to 150 cm/s ranges, respectively, with 0-, 8-, 28-, 45-, and 60-deg angles of inclination with respect to the vertical line. Experimental flow regime maps are provided for all the aforementioned angles of inclination. For the vertical channel configuration, the obtained data are compared with existing data and flow regime transition models. Test section average void fractions are found to be sensitive to the channel angle of inclination. For the vertical channel configuration, the data are compared with the previously published data and empirical correlations.
- OSTI ID:
- 46152
- Journal Information:
- Nuclear Science and Engineering, Vol. 119, Issue 3; Other Information: PBD: Mar 1995
- Country of Publication:
- United States
- Language:
- English
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