Investigations of Bubbly Flows using Direct Numerical Simulations

Technical Report · Wed Apr 30 04:00:00 EDT 2014

OSTI ID:1090888

Tryggvason, Gretar ^[1]

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1. Worcester Polytechnic Institute, MA (United States); Worcester Polytechnic Institute

Direct numerical simulations are used to examine the behavior of relatively high void fraction bubbly flows. The full Navier-Stokes equations are solved for both the bubbles and the ambient liquid and the flow near the moving and deforming phase boundaries is resolved fully. This yields detailed data for the evolution of the system that can be used to extract information about the basic bubble-bubble and bubble-flow interactions as well as about the averaged properties of the system. Such information are critical for the generation of averaged engineering models of industrial size systems as well as for novel applications of bubbly flows where experiments are difficult. The project has yielded detailed information about many aspects of bubbly flows. The results for flows in vertical channels are particularly significant and have yielded an essentially complete understanding of many aspects of the flows. The important insight is that the flow has a particularly simple structure, consisting of a homogeneous core in hydrostatic balance and a wall layer whose composition depends of whether the liquid is flowing upward or downward. These results hold for both laminar and turbulent flows and have allowed us to derive an analytical model to predict the flow. We have also shown that bubble deformability results in a completely different flow structure, but also giving rise to relatively simple predictive models. Preliminary studies of transient migration of a non-homogeneous bubble distribution and coalescence induced flow regime transitions in vertical channels were also done.

• Research Organization: Worcester Polytechnic Institute, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: FG02-03ER46083
• OSTI ID: 1090888
• Report Number(s): DOE-ER--46083-4
• Country of Publication: United States
• Language: English

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