Modeling of the evolution of bubbly flow along a large vertical pipe


Modeling of the evolution of bubbly flow along a large vertical pipe

Lucas, D.; Krepper, E.; Prasser, H.-M.

A detailed experimental database, obtained for a large pipe with an inner diameter of 195 mm and length of 9 m was used for the validation of models applied in CFD codes for the simulation of bubbly flow. Since the bubbles were injected via holes at the pipe wall, especially very useful information on the bubble migration from the pipe wall towards the pipe center were obtained by measurements at different distances between gas injection and measuring plane. The bubble migration is determined by the forces acting on the bubbles. A simplified model, introduced earlier, but with some new extensions, described in this paper, was used to analyze the data. The comparison of results from a simulation and the experimental findings give the advice, that the turbulent dispersion force according to the FAD model is too strong compared with the radial drag. Up to now no appropriate models for bubble coalescence and break-up are available, which can be applied for a wide range of gas and liquid volume flow rates. Nevertheless for selected combinations of volume flow rates, the calculated bubble size distributions and radial gas volume fraction profiles show an acceptable agreement with the experimental data.

Keywords: bubbly flow; pipe flow; bubble forces; CFD

  • Contribution to proceedings
    The 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-11), 02.-06.10.2005, Avignon, France
    Paper 051
  • Lecture (Conference)
    The 11th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics (NURETH-11), 02.-06.10.2005, Avignon, France
  • Nuclear Technology 158(2007), 291-303

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Publ.-Id: 7001