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Time-average drag coefficient and void fraction in gas-liquid two phase flow

Ghanbarzadeh, S ; Sharif University of Technology

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  1. Type of Document: Article
  2. DOI: 10.1115/FEDSM2009-78220
  3. Abstract:
  4. Two-phase flow simulations around a body were not studied before and considering these flows can play a significant role in long-term reliability and safety of industrial systems. In this paper, flow regimes, drag coefficient and void fraction around different cross-section prisms were considered. To achieve this aim, main equations of flow have been developed for investigation of drag coefficient in air-water two phase. Our numerical analyses were performed by a designed and written CFD package which is based on Eulerian-Eulerian approach. Geometries, which have been studied in this article, are: circle, rectangle and triangle, for different aspect ratio (length over width) and leading edge angle, respectively. Other parameters such as two phase Reynolds number, free stream void fraction and bubble size were considered, too. Drag coefficient is closely related to the turbulence and the bubble motion. Since these mechanisms vary over time, we used the time-average value of drag coefficient. Furthermore, some attempts were done to investigate flow field, void fraction distribution and especially wake region around the cylinders by an image processing scheme in an upward air-water bubbly flow. The results showed that drag coefficient strongly dependent upon Reynolds number. Numerical results were compared with available empirical correlations and experimental works of Yokosawa et al [1]. Copyright © 2009 by ASME
  5. Keywords:
  6. Air-water ; Average values ; Bubble motion ; Bubble size ; Bubbly flow ; Empirical correlations ; Eulerian-Eulerian approach ; Flow regimes ; Free stream ; Gas-liquid two-phase flow ; Industrial systems ; Leading edge ; Numerical results ; Two phase ; Void fraction distribution ; Wake region ; Air ; Aspect ratio ; Computational fluid dynamics ; Drag ; Drag coefficient ; Equations of motion ; Image processing ; Numerical analysis ; Reynolds number ; Void fraction ; Two phase flow
  7. Source: Proceedings of the ASME Fluids Engineering Division Summer Conference 2009, FEDSM2009, 2 August 2009 through 6 August 2009, Vail, CO ; Volume 1, Issue PART B , 2009 , Pages 1083-1094 ; 9780791843727 (ISBN)
  8. URL: http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1636956