DOI QR코드

DOI QR Code

A study on the working mechanism of internal pressure of super-large cooling towers based on two-way coupling between wind and rain

  • Ke, Shitang (Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics) ;
  • Yu, Wenlin (Jiangsu Power Design Institute Co., LTD, China Energy Engineering Group) ;
  • Ge, Yaojun (State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University)
  • Received : 2017.09.02
  • Accepted : 2019.03.01
  • Published : 2019.05.25

Abstract

In the current code design, the use of a uniform internal pressure coefficient of cooling towers as internal suction cannot reflect the 3D characteristics of flow field inside the tower body with different ventilation rate of shutters. Moreover, extreme weather such as heavy rain also has a direct impact on aerodynamic force on the internal surface and changes the turbulence effect of pulsating wind. In this study, the world's tallest cooling tower under construction, which stands 210m, is taken as the research object. The algorithm for two-way coupling between wind and rain is adopted. Simulation of wind field and raindrops is performed iteratively using continuous phase and discrete phase models, respectively, under the general principles of computational fluid dynamics (CFD). Firstly, the rule of influence of 9 combinations of wind speed and rainfall intensity on the volume of wind-driven rain, additional action force of raindrops and equivalent internal pressure coefficient of the tower body is analyzed. The combination of wind velocity and rainfall intensity that is most unfavorable to the cooling tower in terms of distribution of internal pressure coefficient is identified. On this basis, the wind/rain loads, distribution of aerodynamic force and working mechanism of internal pressures of the cooling tower under the most unfavorable working condition are compared between the four ventilation rates of shutters (0%, 15%, 30% and 100%). The results show that the amount of raindrops captured by the internal surface of the tower decreases as the wind velocity increases, and increases along with the rainfall intensity and ventilation rate of the shutters. The maximum value of rain-induced pressure coefficient is 0.013. The research findings lay the basis for determining the precise values of internal surface loads of cooling tower under extreme weather conditions.

Keywords

Acknowledgement

Supported by : National Natural Science Foundation

References

  1. ANSYS (2011), Ansys Fluent Theory Guide, ANSYS Inc., PA, USA.
  2. Bennett, M., Kodakalla, V. and Gupta, V. (2011), "Vibration mitigation measures in cable stayed bridges", J. Molecular Struct., 996(1-3), 64-68. https://doi.org/10.1016/j.molstruc.2011.04.017
  3. Blocken, B., Dezso, G., Beeck, J.V. and Carmeliet, J. (2010), "Comparison of calculation models for wind-driven rain deposition on building facades", Atmospheric Environ., 44(14), 1714-1725. https://doi.org/10.1016/j.atmosenv.2010.02.011.
  4. Chen, B.W. (2009), "Numerical simulation of wind and rain pressure on low building surface", Postgraduate Dissertation, Harbin Institute of Technology, Harbin.
  5. Chen, X., Zhao, L., Cao, S.Y. and Ge, Y.J. (2016), "Extreme wind loads on super-large cooling towers", J. Int. Assoc. Shell Spatial Struct., 57(1), 49-58. https://doi.org/10.20898/j.iass.2016.187.772.
  6. DL/T 5339-2006 (2006), Code for hydraulic design of fossil fuel power plants, The Ministry of Construction of China; Beijing, China.
  7. Douvi, E. and Margaris, D. (2012), "Aerodynamic performance investigation under the influence of heavy rain of a NACA 0012 airfoil for wind turbine applications", Int. Rev. Mech. Eng., 6(6), 1-8.
  8. Fu, X., Li, H.N. and Li, G. (2016), "Fragility analysis and estimation of collapse status for transmission tower subjected to wind and rain loads", Struct. Safety, 58, 1-10. https://doi.org/10.1016/j.strusafe.2015.08.002.
  9. GB 50009-2012 (2012), Load code for the design of building structures, The Ministry of Structure of the People's Republic of China; Beijing, China.
  10. GB/T 50102-2014 (2014), Code for design of cooling for industrial recirculating water, The Ministry of Construction of China; Beijing, China.
  11. Goudarzi, M.A. and Sabbagh-Yazdi, S.R. (2011), "Effects of modeling strategy on computational wind pressure distribution around the cooling towers", Wind Struct., 14(1), 81-84. https://doi.org/10.12989/was.2011.14.1.081
  12. Gunn, R. and Kinzer, G.D. (1949), "The terminal fall velocity for water droplets in stagnant air", J. Atmospheric Sci., 6(4), 243-248.
  13. Hodson, M.C. (1986), "Raindrop size distribution", J. Appl. Meteorology, 25(7), 1070-1074. https://doi.org/10.1175/1520-0450(1986)025<1070:RSD>2.0.CO;2
  14. Jiang, F. (2008), Fluent Advanced Application And Case Analysis, Tsinghua University Press, Beijing, China.
  15. Ke, S.T. and Ge, Y.J. (2014), "The influence of self-excited forces on wind loads and wind effects for super-large cooling towers", J. Wind Eng. Industrial Aerodynam., 132, 125-135. https://doi.org/10.1016/j.jweia.2014.07.003.
  16. Ke, S.T., Ge, Y.J., Zhao, L. and Tamura, Y. (2015), "Stability and reinforcement analysis of super large exhaust cooling towers based on a wind tunnel test", J. Struct. Eng., 141(12), 04015066. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001309
  17. Ke, S.T., Liang, J., Zhao, L. and Ge, Y.J. (2015), "Influence of ventilation rate on the aerodynamic interference for two IDCTs by CFD", Wind Struct., 20(3), 449-468. https://doi.org/10.12989/was.2015.20.3.449.
  18. Ke, S.T., Du, L.Y. and Hou, X.A. (2018), "Study on the absorption wind vibration coefficient of super-large cooling tower considering the ventilation rate of Venetian blinds", J. Building Struct., 39(8), 36-44.
  19. Liu, S., Huang, S.H. and Li, Q.S. (2017), "3D numerical simulation of wind-driven rain on bridge deck sections based on eulerian multiphase model", Eng. Mech., 34(4), 63-71.
  20. Li, H.N. and Bai, H.F. (2008), "Study on wind (rain) induced vibration response and stability of transmission tower system", China Civil Eng. J., 41(11), 31-38. https://doi.org/10.3321/j.issn:1000-131X.2008.11.006
  21. Marshall, J.S. and Palmer, W.M. (1948), "The distribution of raindrops with size", J. Meteorology, 5(4), 165-166. https://doi.org/10.1002/qj.49707632704.
  22. Mcfarquhar, G.M. and List, R. (2010), "The raindrop mean free path and collision rate dependence on rainrate for three-peak equilibrium and Marshall-Palmer distributions", J. Atmospheric Sci., 48(48), 1999-2004. https://doi.org/10.1175/1520-0469(1991)048<1999:TRMFPA>2.0.CO;2
  23. Mcfarquhar, G.M. (2016), "Raindrop size distribution and evolution", Geophysical Monograph, 191, 49-60.
  24. Niemann, H.J. and Kopper, H.D. (1998), "Influence of adjacent buildings on wind effects on cooling towers", Eng. Struct., 20(10), 874-880. https://doi.org/10.1016/S0141-0296(97)00131-4
  25. Rigby, E.C., Marshall, J.S. and Hitschfeld, W. (2010), "The development of the size distribution of raindrops during their fall", J. Atmospheric Sci., 11(5), 362-372.
  26. Shen, G.H., Zhang, C.S. and Sun, B.N. (2011), "Numerical simulation of wind load on inner surface of large hyperbolic cooling tower", J. Harbin Institute of Technol., 43(4), 104-108.
  27. Sun, T.F. and Zhou, L.M. (1983), "Without ribs the elliptic wind pressure distribution of the cooling tower full size measurement and wind tunnel study", J. Air Dynam., 12(4), 12-17.
  28. VGB-R610Ue (2005), VGB-Guideline: Structural Design of Cooling Tower - Technical Guideline for the Structural Design, Computation and Execution of Cooling Towers, VGB Power Tech, Essen, Germany.
  29. Wang, L.Y. and Xu, Y.L. (2010), "Active stiffness control of wind-rain-induced vibration of prototype stay cable", Int. J. Numerical Methods Eng., 74(1), 80-100. https://doi.org/10.1002/nme.2152.
  30. Wang, Z.Y., Zhao, Y., Li, F.Q. and Jiang, J.Q. (2013), "Extreme dynamic responses of mw-level wind turbine tower in the strong typhoon considering wind-rain loads", Math. Problems Eng., 3, 133-174. http://doi.org/10.1155/2013/512530.
  31. Wu, J.K. (1996), "Review and prospect of structural analysis of large cooling towers", Mech. Practices, 18(6), 1-5.
  32. Xin, D.B., Zhang, M.J., Wang, L., Ou, J.P. and Li, H. (2011), "Experimental study on wind-induced vortex-induced vibration of girders of long-span Bridges", J. Harbin Eng. U., 32(9), 1168-1172. https://doi.org/10.3969/j.issn.1006-7043.2011.09.013
  33. Xin, D.B., Li, H., Wang, L. and Ou, J.P. (2012), "Experimental study on static characteristics of the bridge deck section under simultaneous actions of wind and rain", J. Wind Eng. Industrial Aerodynam., s(107-108), 17-27. https://doi.org/10.1016/j.jweia.2012.03.002.
  34. Yang, J.T. and Lou, W.J. (2011), "CFD simulation of wind-driven rain and calculation method of average rain load", Acta Aerodynamica Sinica, 29(5), 600-606. https://doi.org/10.3969/j.issn.0258-1825.2011.05.011
  35. Zou, Y.F., Niu, H.W. and Chen, Z.Q. (2015), "Three-dimensional effect of wind load on the single tower of the special large cooling tower, and its design value", J. Hunan U, 32(1), 76-82.
  36. Zhang, Q.C. (2010), "Static bifurcation of rain-wind-induced vibration of stay cable", Acta Physica Sinica, 59(2), 729-734. https://doi.org/10.7498/aps.59.729
  37. Zhang, J.F., Ge, Y.J. and Zhao, L. (2013), "Influence of latitude wind pressure distribution on the responses of hyperbolodial cooling tower shell", Wind Struct., 16(6), 579-601. http://dx.doi.org/10.12989/was.2013.16.6.579.