Sage Journals: Discover world-class research

Abstract

During the runaway process of a Pelton turbine, the runner bears huge amounts of water pressure pulsations and centrifugal forces, which is different from the steady-state condition. In this work, a fine 3D CFD simulation of the runaway process of a Pelton turbine is performed. Both the macro-parameter changing patterns of rotational speed, torque and efficiency, and the micro-flow features of pressure pulsations and flow patterns are intensively studied and analyzed. It is found that the maximum runaway speed is 1.78 times of the rated speed, acceleration is the main feature in the early stage of runaway, and the jet fragment breaks away and strikes once again on the lip region and backside of the buckets in the middle and late stages. The multiple strikes make the frequency of pressure pulsations increase, and the cavitation occurs on the backside mold line. This successful 3D simulation shows that it is possible to simulate other transient processes of Pelton turbines and conduct fluid–structure interaction analysis of the runner.

Keywords

Pelton turbine runaway transient process pressure pulsations 3D CFD simulation

Get full access to this article

View all access options for this article.

References

Zhong Q.S. Analysis of characteristic curves and transient process of Pelton turbine. Master Thesis, Wuhan University, China, 2012.

Hana M. Numerical analysis of non-stationary free surface flow in a Pelton bucket. PhD Thesis, Norwegian University of Science and Technology, Department of Thermal Energy and Hydropower, Norway, 1999.

Monique T., Pierre L., Zoppe B. et al. Numerical study of Pelton bucket flow comparison of FLUENT and CFX results. In: Proceedings of 21st IAHR Symposium, Lausanne, Switzerland, Sep 2002.

Kvicinsky S., Longatte F., Avellan F. et al. Free surface flow: experimental verification of the Volume of Fluid (VOF) method in the plane wall case. In: Proceedings of 3 rd ASME/JSME, 8-23 July 1999, San Francisco, CA.

Gotfred S. B. Numerical analysis of the two-phase Pelton jet flow using a single-phase model and analytical discussions of the Pelton jet surface break-up phenomenon. PhD Thesis, Department of Energy and Process Engineering, Norwegian University of Science and Technology, Norway, 2003.

Nakanishi Y., Kubota T. and Shin T. Numerical simulation of flows on Pelton bucket by particle method (flow on a stationary/rotating flat plate). In: Proceedings of 21st IAHR Symposium, Lausanne, Switzerland, Sep 2002.

Kvicinsky S., Kueny J., Avellan L. Experimental and numerical analysis of free surface flow in a rotating bucket. In: Proceedings of 21st IAHR Symposium, Lausanne, Switzerland, Sep 2002.

Liu J., Han F. Q., Kubota T. Effect of free jet enlargement on the bucket flow in Pelton turbine. In: Proceedings of 21st IAHR Symposium, Lausanne, Switzerland, Sep 2002.

Matthias H. B., Promper O. Numerical simulation of the free surface flow in Pelton turbines. In: The 6th International Conference on Hydraulic Machinery and Hydrodynamics. Timisoara, Romania, October 21-22, 2004, p. 119–124.

10.

Liu J. Study on internal flow simulation and performance of Pelton turbine. PhD Thesis, Huazhong University of Science and Technology, China, 2005.

11.

Perrig A. Hydrodynamics of the free surface Flow in Pelton turbine buckets. PhD Thesis, University of Lausanne, Switzerland, 2007.

12.

Klemetsen L. E. An experimental and numerical study of the free surface Pelton bucket flow. Master Thesis, Norwegian University of Science and Technology, Norway, 2010.

13.

Barstad L. F. CFD analysis of a Pelton turbine. Master Thesis, Norwegian University of Science and Technology, Norway, 2012.

14.

Xiao Y. X., Cui T., Wang Z. W. and Yan Z. G. Numerical simulation of unsteady free surface flow and dynamic performance for a Pelton turbine. In: The 26th IAHR Symposiumon Hydraulic Machinery and Systems, Beijing, China, 19 Aug-23 Aug 2012.

15.

J.W.

Liu

S.H.

Zhou

D.Q.

. Three-dimensional unsteady simulation of the runaway transient of the Francis turbine. Journal of Hydroelectric Engineering 2009; 28(1): 178–183.

16.

Zhou

D.Q.

Y.L.

Liu

S.H

. Three-dimensional CFD simulation of the runaway transients of a propeller turbine model. Journal of Hydraulic Engineering 2010; 42(2): 233–238.

17.

Liu

J.T.

Liu

S.H.

Sun

Y.K.

. Three dimensional flow simulation of load rejection of a prototype pump-turbine. Engineering with Computers 2013; 29: 417–4426.

18.

Xia

L.S.

Cheng

Y.G.

Zhang

X.X.

Zhang

C.Z.

3D CFD simulation of the runaway transients of Buld turbine. Journal of Sichuan University (Engineering Science Edition) Engineering 2014; 46(5): 35–41.

19.

Zhou

W.T.

Zhou

X.Q

. Pelton Turbine Basic Theory and Design, 1st ed. Beijing: China Water Power Press, 2007.