Numerical Investigations of Solid-Liquid Two-Phase Turbulent Flows through Francis Turbine

Abstract:

This work is to investigate solid-liquid flows inside entire passage of a large Francis turbine unit and a modified algebraic model is proposed to take the solid-phase turbulent viscosity into consideration based on realizable turbulence model for the liquid phase and further development of the commercial CFD software. The energy conversion between the pressure and velocity, and the sedimentation distribution characteristics around all the hydraulic parts are simulated. The calculated velocity and sedimentation concentration distributions inside the runner are not uniform due to the effect of the centrifugal and Coriolis force. In addition, the calculated eccentric vortex rope in the draft tube causes vortex cavitation and vibration to the turbine unit, which leads to the eccentric sedimentation distribution. The simulation results (i.e., the mixture pressure, velocity and sedimentation distributions) are in good agreement with the natural rule, suggesting that the simulation strategies are capable to handle two-phase flows over complex geometries. The computational results can provide the useful information for hydraulic turbine designs. Future work will focus on the optimizations of hydraulic impeller designs using simulated results.

• Periodical: Advanced Materials Research (Volume 548)
• Pages: 853-859
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.548.853
• Online since: July 2012
• Authors: Xue Lin Tang, Shang Yu Yang, Fu Jun Wang, Yu Lin Wu
• Keywords: Francis Turbine, Modified Algebraic Model, Solid-Liquid Flows, Turbulence Model

References

[1] C.G. Duan, V.Y. Karelin. Abrasive erosion & corrosion of hydraulic machinery, London: Imperial College Press, (2002).

[2] H. Keck, M. Sick. Thirty years of numerical flow simulation in hydraulic turbomachines. Acta Mechanica, 2008, 201: 211-229.

DOI: 10.1007/s00707-008-0060-4

[3] J. H Gummer. Combating silt erosion in hydraulic turbines. Hydro Review Worldwide, 2009, 17: 28-34.

[4] B. Seven, M. Thomas. Computer aided impeller optimization. World Pumps, 2000, 402: 28-31.

[5] X.L. Tang, F.J. Wang, Y.L. Wu. An improved large eddy simulation of two-phase flows in a pump impeller. Acta Mech Sin, 2007, 23: 635-643.

DOI: 10.1007/s10409-007-0115-0

[6] Y.L. Wu, Y.Y. He, and S.L. Cao. Three dimensional calculation of particle-liquid two-phase turbulent flow in a hydraulic turbine runner. Journal of Engineering Thermophysics, 1998, 19: 17-21.

[7] X.L. Tang, H.F. Tang, Y.L. Wu. Simulation and Erosion Prediction of 3D Two-Phase Flows through a Turbine Runner. Journal of Engineering Thermophysics, 2001, 22: 51-55.

[8] Q.F. Li, R.N. Li, W. Han, et al. Numerical analysis of inner solid-liquid two-phase flow in diversion and guiding apparatus in Francis turbine. Journal of Lanzhou University of Technology, 2008, 34: 47-50.

[9] S.Y. Bergeron, T.C. Vu, A.P. Vincent. Silt Erosion in Hydraulic Turbines: The Need for Real-Time Numerical Simulations. SIMULATION, 2000, 74: 71-74.

DOI: 10.1177/003754970007400201

[10] FLUENT Inc. FLUENT 6. 3 user's guide, 2006 (FLUENT Inc, Lebanon).

[11] X.L. Tang, F.J. Wang Y.J. Li, et al. Numerical investigations of vortex flows and vortex suppression schemes in a large pumping-station sump. Proc. IMechE Part C: J. Mechanical Engineering Science, 2011, 225: 1459-1480.

DOI: 10.1177/2041298310393447

[12] B.P. Leonard. A stable, accurate convective modeling procedure based on quadratic upstream interpolation", Comput. Method Appl. Mech. Eng., 1979, 19: 59-98.

DOI: 10.1016/0045-7825(79)90034-3

[13] J.P. Van Doormaal, G.D. Raithby. Enhancement of the SIMPLE method for predicting incompressible fluid flows. Numer. Heat Transf., 1984, 7: 147-163.

DOI: 10.1080/01495728408961817