Izvestiya vuzov. Yadernaya Energetika

The peer-reviewed scientific and technology journal. ISSN: 0204-3327

Using Computational Fluid Dynamics Tools to Calculate the Diffusion of Gas and Aerosol Emissions in Conditions of a Complex Terrain

11/19/2020 2020 - #04 Environmental aspects

Mehdi M. Panin M.P.

DOI: https://doi.org/10.26583/npe.2020.4.09

UDC: 621.039.75

ANSYS FLUENT tools were used as part of a standard turbulence (kε)-model to simulate the air flow around a number of typical obstructions (a 3D cube, a 3D hemisphere, and a 2D hill) which form a potential terrain in the NPP emission spread area and roughly correspond to the geometry of the buildings and structures within this area. For reproducibility, a non-uniform spatial grid is plotted in the computational region which condenses near the obstruction surface and the outer boundaries. The dimensions and the positions of the obstructions were chosen such that to ensure their best possible coincidence with the conditions of the published experiments. The result of modeling the velocity and direction of the air flow as the whole shows a good agreement with the data from the wind tunnel experiments in the areas in front of and over the obstruction, as well as in its aerodynamic shadow. Typical accelerated flow, vortex, and reverse flow areas are reproduced reliably. There are variances observed only in the local heavy turbulence regions in the obstruction’s aerodynamic shadow near the ground surface. All this indicates that it is possible to model in full scale the spread of the NPP emissions taking into account the features of the plant site terrain and the major onsite structures to determine more accurately the personnel and public exposure dose.

References

  1. Safety Series No. 50-SG-S3. IAEA Safety Guides. Vienna. IAEA, 1980.
  2. Leeloossy A., Lagzi I., Kovacs A., Meszaros R., A review of numerical models to predict the atmospheric dispersion of radionuclides. Journal of Environmental Radioactivity. 2018, no.182, pp.20-33.
  3. Yoshihide T., Akashi M., Ryuichiro Y., Hiroto K., Tsuyoshi N., Masaru Yoshikawa T. AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings. Journal of Wind Engineering and Industrial Aerodynamics. 2008, no. 96, pp.1749-1761.
  4. Gorle C., Beeck J.V., Rambaud P., Tendeloo G.V. CFD modelling of small particle dispersion: The influence of the turbulence kinetic energy in the atmospheric boundary layer. Atmospheric Environment. 2009, no. 43, pp.673-681.
  5. Ai Z.T., Mak C.M. CFD simulation of flow and dispersion around an isolated building: Effect of inhomogeneous ABL and near-wall treatment. Atmospheric Environment. 2013, no. 77, pp. 568-578.
  6. Stupin A.B., Overko V.S. Influence of the form of a relief on distributions of emissions in an atmosphere. DonNTU, 2006. Available at: http://ea.donntu.org/handle/123456789/6268 (accessed Jul 04, 2020) (in Russian).
  7. ANSYS Fluent Theory Guide, ANSYS Inc., 275 Technology Drive Canonsburg, PA 15317, November 2013.
  8. Yu Y., Kwok K.C.S., Liu X.P., Zhang Y. Air pollutant dispersion around high-rise buildings under different angles of wind incidence. Journal of Wind Engineering and Industrial Aerodynamics. 2017, no. 167, pp 51-61.
  9. Zhenqing L., Shuyang C., Heping L., Takeshi I. Large-Eddy Simulations of the Flow over an Isolated Three-Dimensional Hill. Boundary-Layer Meteorology. 2019, no. 170(3), pp. 415-441.
  10. Takeshi I., Kazuki H., Susumu O. A wind tunnel study of turbulent flow over a three-dimensional steep hill. Journal of Wind Engineering and Industrial Aerodynamics. 1999, no. 83, pp. 95-107.
  11. Ferreira A.D., Silva M.C.G., Viegas D.X., Lopes A.M.G. Wind tunnel simulation of the flow around two dimensional hills. Journal of Wind Engineering and Industrial Aerodynamics. 1991, no. 38, pp. 109-122.
  12. Kim H.G., Lee C.M., Lim H.C., Kyong N.H. An experimental and numerical study on the flow over two dimensional hills. Journal of Wind Engineering and Industrial Aerodynamics. 1997, no. 66, pp. 7-33.
  13. Trombetti F., Martano P., Tampieri F. Data Sets for Studies of Flow and Dispersion in Complex Terrain: The «RUSHIL» Wind Tunnel Experiment (Flow Data). Technical Report No. 4, FISBAT-RT-19911.
  14. Martinuzzi R., Tropea C. The flow around surface-mounted, prismatic obstacles in a fully developed channel flow. Journal of Fluids Engineering. 1993, no. 115, pp.85-92.
  15. Tavakol M.M., Yaghoubi M., Masoudi Motlagh M. Air flow aerodynamic on a wall-mounted hemisphere for various turbulent boundary layers. Experimental Thermal and Fluid Science. 2010, no. 34, pp. 538-553.
  16. Juretic F., Hrvoje H., Computational modeling of the neutrally stratified atmospheric boundary layer flow using the standard k-ε turbulence model. Journal of Wind Engineering and Industrial Aerodynamics. 2013, no. 115, pp. 112-120.
  17. Richards P.J., Norris S.E. Appropriate boundary conditions for computational wind engineering models revisited. Journal of Wind Engineering and Industrial Aerodynamics. 2011, no. 99, pp. 257-266.
  18. Xing J., Liu Z.Y., Huang P., Feng C.G., Zhou Y., Zhang, D.P., Wang F. Experimental and numerical study of the dispersion of carbon dioxide plume. Journal of Hazardous Materials. 2013, no. 256, pp. 40-48.
  19. Kisha M., Jelemensky L. CFD Dispersion Modelling for Emergency Preparedness. Journal of Loss Prevention in the Process Industries. 2009, no. 22 (1), pp. 97-104.
  20. Richards P.J., Hoxey R. P. Appropriate boundary conditions for computational wind engineering models using the k-ε model. Journal of Wind Engineering and Industrial Aerodynamics. 1993, no. 46, pp. 145-153.

NPP gas and aerosol emissions turbulent diffusion modeling ANSYS FLUENT