International Journal of Fluid Machinery and Systems

Korean Society for Fluid machinery (한국유체기계학회)
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Performance Optimization of High Specific Speed Pump-Turbines by Means of Numerical Flow Simulation (CFD) and Model Testing

  • Accepted : 2010.12.14
  • Published : 2010.12.31
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Abstract

In recent years, the market has shown increasing interest in pump-turbines. The prompt availability of pumped storage plants and the benefits to the power system achieved by peak lopping, providing reserve capacity, and rapid response in frequency control are providing a growing advantage. In this context, there is a need to develop pumpturbines that can reliably withstand dynamic operation modes, fast changes of discharge rate by adjusting the variable diffuser vanes, as well as fast changes from pumping to turbine operation. In the first part of the present study, various flow patterns linked to operation of a pump-turbine system are discussed. In this context, pump and turbine modes are presented separately and different load cases are shown in each operating mode. In order to create modern, competitive pump-turbine designs, this study further explains what design challenges should be considered in defining the geometry of a pump-turbine impeller. The second part of the paper describes an innovative, staggered approach to impeller development, applied to a low head pump-turbine project. The first level of the process consists of optimization strategies based on evolutionary algorithms together with 3D in-viscid flow analysis. In the next stage, the hydraulic behavior of both pump mode and turbine mode is evaluated by solving the full 3D Navier-Stokes equations in combination with a robust turbulence model. Finally, the progress in hydraulic design is demonstrated by model test results that show a significant improvement in hydraulic performance compared to an existing reference design.

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References

  1. Sallaberger, M., Bachmann, P., Michaud, Ch., Sick, M., Dorfler, P., 2003, “Modern hydraulic design of large pump-turbines,” Hydropower & Dams, Issue 5.
  2. Eisele, K., Muggli, F., Zhang, Z., Casey, M., Sallaberger, M. and Sebestyen, A., 1998, “Experimental and Numerical Studies of Flow Instabilities in Pump-Turbine Stages,” 18th IAHR Symp. on Hydr. Machinery and Systems, Valencia, Spain.
  3. Giese, M., Jung, A. and Hassler, P., 2008, “PSP Limberg II – Optimized design for a wide head range application,” HYDRO, Ljubljana, Slovenia.
  4. Spidla, J. and Motycak, L., 2008, “Cavitation characteristics of a high-head pump-turbine,” HYDRO, Ljubljana, Slovenia.
  5. Liang, Q., Keller, M. and Sick, M., 2009, “Rotor-stator interaction during no load operation of pump-turbines,” HYDRO, Lyon , France.
  6. Staubli, Th., Senn, Fl., Sallaberger, M., 2008, “Instability of pump-turbines during start-up in the turbine mode,” HYDRO, Ljubljana, Slovenia.
  7. Stein, P., Sick, M., Doerfler, P., White, P. and Braune, A., 2006, “Numerical simulation of the cavitating draft tube vortex in a Francis turbine,” 15th IAHR Symp. on Hydr. Machinery and Systems, Yokohama, Japan.
  8. Doerfler, P., 2009, “Evaluating 1D models for vortex-induced pulsation in Francis turbines,” 3rd IAHR International Meeting of the Workgroup on Cavitation and Dynamic Problems in Hydraulic Machinery and Systems, Brno, Czech Republic.
  9. Zangeneh, M., 1991 “A compressible three dimensional blade design method for radial and mixed flow turbomachinery blades,” Int. J. Numerical Methods in Fluids, Vol. 13, pp. 599-624. https://doi.org/10.1002/fld.1650130505
  10. Gehrer, A., 1999 “Entwicklung eines 3d-Navier-Stokes Codes zur Berechnung der Turbomaschinenströmung,” PhD Thesis, Technical University Graz, Austria.
  11. Menter, F.R., 1994 “Two-equation eddy-viscosity turbulence models for engineering applications,” AIAA-Journal 32(8). https://doi.org/10.2514/3.12149
  12. Gehrer, A., Benigni, H., Penninger, G., 2004, “Dimensioning and Simulation of Process Pumps,” Karlsruhe Pump Users Technical Forum, Preprints 15-4, VDMA.
  13. Nichtawitz, A., Parkinson, E., Sallaberger, M., Sebestyen, A., 2000, “State of the art review in pump-turbine hydraulic development,” 19th IAHR Symp. on Hydr. Machinery and Systems, Cordoba, Argentina.
  14. Gehrer, A., Schmidl, R., Sadnik, D., 2006, “Kaplan Turbine Runner Optimization by Numerical Flow Simulation (CFD) and an Evolutionary Algorithm,” Proceedings of the 23rd IAHR Symposium - Yokohama, October 2006.

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