Advanced Multi-Phase Flow Laboratory

                       Department of Mechanical and Nuclear Engineering

Current Projects

Small Diameter Horizontal Two-Phase Flow

Research Supported by Bettis Atomic Power Laboratory

    In order to develop and validate Multi-phase Computational Fluid Dynamics (MCFD) codes, an extensive database of two-phase flow information is required for various flow regimes, geometries, and orientations. Many two-phase flow experiments have been performed in vertical flow channel geometries, and thus a substantial number of databases exist to benchmark MCFD approaches in such conditions. However, there are few databases of local two-phase flow parameters acquired in straight horizontal flow channels available that are suitable for comparisons with MCFD and the development of multi-phase closure models. The present work establishes a horizontal, adiabatic, air-water, two-phase flow test facility to: (1) perform detailed flow visualizations, (2) study the interfacial structures and flow regime transitions, and (3) identify gas-phase interactions in air-water horizontal two-phase flow in relation to future interfacial area transport modeling efforts. Figures 1 and 2 highlight two of the bubble interaction mechanisms: turbulence impact breakup and random collision coalescence.
    The test facility is designed to be capable of performing experiments in a comprehensive range of horizontal two-phase flow conditions including bubbly, plug, slug, stratified, stratified-wavy, and annular flow regimes. The test section is desiged to provide an ideal condition for flow visualization and for the application of optical instrumentation. A high speed movie camera capable of capturing images at up to 32,000 frames per second is available and will be employed to perform flow visualization studies. In order to achieve a fully developed horizontal two-phase flow, clear acrylic pipes with 3.81 cm inner diameter are employed as the test section, which provide a total development length of more than 200 diameters.

Figure 1. Time series of bubble breakup by turbulence impact process.
jf=5.00 m/s, jg,atm=0.05 m/s at a development length of 80 diameters.

Figure 2. Time series of bubble coalescence by random collision process.
jf=5.00 m/s, jg,atm=0.10 m/s at a development length of 80 diameters.