Advertisement

Experimental and Computational Multiphase Flow

, Volume 1, Issue 4, pp 300–306 | Cite as

Three-dimensional simulations of liquid waves in isothermal vertical churn flow with OpenFOAM

  • Matej TekavčičEmail author
  • Boštjan Končar
  • Ivo Kljenak
Research Article
  • 38 Downloads

Abstract

Periodic liquid waves of large amplitude are one of characteristic phenomena observed in the churn flow regime of gas–liquid flow in vertical conduits, where the liquid flowing on the wall is entrained upwards by the gas flow in the core. The present work investigates the frequency of these large liquid waves. Three-dimensional simulations of isothermal churn flow of air and water in 19 and 32 mm vertical pipes were performed using the interFoam solver from the OpenFOAM library. Turbulent features in the flow are modelled using the unsteady Reynolds Averaged Navier–Stokes approach with the k–ω SST (shear stress transport) model. Interface sharpening with bounded compression was used to preserve the sharpness of gas–liquid interface by compensating the diffusive fluxes of the numerical scheme. A sensitivity study on the global amount of interface compression was performed for two flow cases taken from the literature. Mesh sensitivity study was performed using four meshes, ranging from a coarse mesh with several hundred thousand cells, to a fine mesh with several million computational cells. Results for the calculated wave frequency and wave maximum amplitude agree with measured values reported in the literature.

Keywords

two-phase flow simulation vertical churn flow wave frequency interface compression 

Notes

Acknowledgements

The authors acknowledge the financial support from the Slovenian Research Agency (research core funding No. P2-0026 “Reactor engineering”).

References

  1. Barbosa Jr., J. R., Govan, A. H., Hewitt, G. F. 2001. Visualisation and modelling studies of churn flow in a vertical pipe. Int J Multiphase Flow, 27: 2105–2127.CrossRefzbMATHGoogle Scholar
  2. Bestion, D. 2014. The difficult challenge of a two-phase CFD modelling for all flow regimes. Nucl Eng Des, 279: 116–125.CrossRefGoogle Scholar
  3. Brackbill, J. U., Kothe, D. B., Zemach, C. 1992. A continuum method for modeling surface tension. J Comput Phys, 100: 335–354.MathSciNetCrossRefzbMATHGoogle Scholar
  4. Deshpande, S. S., Anumolu, L., Trujillo, M. F. 2012. Evaluating the performance of the two-phase flow solver interFoam. Comput Sci Disc, 5: 014016.CrossRefGoogle Scholar
  5. Govan, A. H., Hewitt, G. F., Richter, H. J., Scott, A. 1991. Flooding and churn flow in vertical pipes. Int J Multiphase Flow, 17: 27–44.CrossRefzbMATHGoogle Scholar
  6. Hirt, C. W., Nichols, B. D. 1981. Volume of fluid (VOF) method for the dynamics of free boundaries. J Comput Phys, 39: 201–225.CrossRefzbMATHGoogle Scholar
  7. Klostermann, J., Schaake, K., Schwarze, R. 2013. Numerical simulation of a single rising bubble by VOF with surface compression. Int J Numer Meth Fluids, 71: 960–982.MathSciNetCrossRefGoogle Scholar
  8. Larsen, B. E., Fuhrman, D. R., Roenby, J. 2018. Performance of interFoam on the simulation of progressive waves. Coast Eng J, 61: 380–400.CrossRefGoogle Scholar
  9. Menter, F. R. 1994. Two-equation eddy-viscosity turbulence models for engineering applications. AIAA J, 32: 1598–1605.CrossRefGoogle Scholar
  10. Muzaferija, S., Peric, M. 1997. Computation of free-surface flows using the finite-volume method and moving grids. Numer Heat Tr B: Fund, 32: 369–384.CrossRefGoogle Scholar
  11. Noh, W. F., Woodward, P. 1976. SLIC (simple line interface calculation). In: Proceedings of the 5th International Conference on Numerical Methods in Fluid Dynamics, 330–340.Google Scholar
  12. OpenCFD Ltd. 2015. OpenFOAM: The open source CFD toolbox. Available at http://www.openfoam.com/.
  13. Rusche, H. 2002. Computational fluid dynamics of dispersed two-phase flows at high phase fraction. Ph.D. Thesis. Imperial College of Science, Technology and Medicine, UK.Google Scholar
  14. Tekavcic, M., Koncar, B., Kljenak, I. 2018a. The concept of liquid inlet model and its effect on the flooding wave frequency in vertical air-water churn flow. Chem Eng Sci, 175: 231–242.CrossRefGoogle Scholar
  15. Tekavcic, M., Koncar, B., Kljenak, I. 2018b. The effect of interface compression on the simulated frequency of liquid waves in vertical churn flow. In: Proceedings of the 27th International Conference Nuclear Energy for New Europe.Google Scholar
  16. Ubbink, O. 1997. Numerical prediction of two fluid systems with sharp interfaces. Ph.D. Thesis. Imperial College of Science, Technology and Medicine, UK.Google Scholar
  17. Vierow, K. 2008. Countercurrent flow limitation experiments and modeling for improved reactor safety. Technical Report. Texas A&M University, Texas, USA.Google Scholar
  18. Wang, K., Bai, B. F., Ma, W. M. 2013. Huge wave and drop entrainment mechanism in gas-liquid churn flow. Chem Eng Sci, 104: 638–646.CrossRefGoogle Scholar
  19. Youngs, D. L. 1982. Time-dependent multi-material flow with large fluid distortion. Numerical Methods for Fluid Dynamics, 273–285.Google Scholar

Copyright information

© Tsinghua University Press 2019

Authors and Affiliations

  • Matej Tekavčič
    • 1
    Email author
  • Boštjan Končar
    • 1
  • Ivo Kljenak
    • 1
  1. 1.Reactor Engineering DivisionJožef Stefan InstituteLjubljanaSlovenia

Personalised recommendations