Experimental study for local air/water flow structure of bubbly and slug flow regime

Abstract

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.

A study for local hydraulic characteristics of water and air/steam mixture flow is a very challenging topic for advanced thermal hydraulic analysis code development. Recently, many researchers made efforts in the study of mechanistic feature related to the two phase dynamics such as an interfacial area transport model. The mechanistic study for the interfacial area needs a lot of understanding for the bubble/drop dynamics and flow propagation phenomena. To generate an experimental data base for a modeling, an air/water test was performed in this study. The facility has a cylindrical acryl test section of which the diameter and height are 80 mm and 10m, respectively. The major local parameters to be measured are the void fraction, bubble/liquid velocities, interfacial area concentration and bubble size. To investigate the transport phenomena of the twophase parameters, a local probe and an impedance void meter(IVM) are installed at three axial elevations of the test section. (L/D=12.2, 42.2, 100.7) The test range covers 0.5~2.8 m/s and 0.04~1.2 m/s of the superficial liquid and gas velocity, respectively, which corresponds to the bubbly and slug flow regimes. The system pressure conditions are 0.2~0.3 MPa at the L/D=12.2.