Investigation of the vapour–liquid two-phase flow in the low-pressure cylinder of a 1000 MW nuclear power steam turbine

Abstract

The vapour–liquid two-phase flow in the low-pressure cylinder of a 1000 MW nuclear steam turbine has been investigated. Firstly, a comparative study of the flows with equilibrium and non-equilibrium condensation is described. The vapour extraction and moisture removal processes are included in the calculations to simulate the actual operating conditions in the low-pressure cylinder. Differences in the thermodynamic expansion lines, and in the distributions of wetness and degree of reaction, for equilibrium and non-equilibrium flow calculations are discussed. Secondly, the deposition of the fog and coarse water droplets in the last stage stator is investigated computationally. An empirical approach, together with the predictions of the non-equilibrium flow calculation, is used to redistribute the spanwise profile of the wetness at inlet to the last stage of the turbine. The movement and deposition of the water droplets are tracked in a Lagrangian frame. The variations of the fog and coarse water deposition rates are obtained in both the spanwise and axial-chordwise directions.

Keywords

Vapour–liquid two-phase flow low-pressure cylinder nuclear power steam turbine

Get full access to this article

View all access options for this article.

References

Moore

Sieverding

. Two-phase steam flow in turbines and separators, London: Hemisphere Publishing Corporation, 1976.

Moses

Stein

. On the growth of steam droplets formed in a Laval nozzle using both static and light scattering measurements. J Fluid Eng 1978; 100(3): 311–322.

Bakhtar

Ebrahimi

Webb

. On the performance of a cascade of turbine rotor tip section blading in nucleating steam. Part 1: Surface pressure distributions. J Mech Eng Sci 1995; 209(2): 115–124.

White

Young

Walters

. Experimental validation of condensing flow theory for a stationary cascade of steam turbine blades. Phil Trans Roy Soc 1996; A354(1704): 59–88.

Guha A and Young JB. Time-marching prediction of unsteady condensation phenomena due to supercritical heat addition. In: Proceedings of IMechE conference on turbomachinery: Latest developments in a changing scene, London, UK, 1991, pp. 167–177.

Sejna

. Numerical modeling of unsteady wet steam flow. Z Angew Math Mech 1993; 73(6): 578–581.

Bakhtar

Mahpeykar

. On the performance of a cascade of turbine rotor tip section blading in nucleating steam. Part 3: Theoretical treatment. J Mech Eng Sci 1997; 211(3): 195–210.

Haller BR, Unsworth RG, Walters PT, et al. Wetness measurements in a model multistage low pressure steam turbine. In: Proceedings of the international conference on technology of turbine plant operating with wet steam, London, 11–13 October 1988, pp. 137–145.

Hirabayashi T, Ohji A, Suzuki A, et al. Advanced nuclear turbines for large output. In: Proceedings of the international conference on technology of turbine plant operating with wet steam, London, 11–13 October 1988, pp. 63–68.

10.

Kreitmeier

Greim

Congiu

. Experimental and numerical analyses of relaxation process in LP steam turbines. J Mech Eng Sci 2005; 219(12): 1411–1436.

11.

Bohn

Funcke

Ren

. Numerical and experimental investigation of the wetness in the fron stages of a low-pressure steam turbine. VGB Power Tech 2004; 84: 80–85.

12.

Cai

Niu

. Investigation of wet steam flow in a 300 MW direct air-cooling steam turbine. Part 2: Flow field and windage. J Power Energy 2010; 224(1): 129–137.

13.

Winkler

Schnerr

. Nucleating unsteady flows in low pressure steam turbine stages. J Power Energy 2001; 215(6): 773–781.

14.

Gerber

Sigg

Völker

. Predictions of non-equilibrium phase transition in a model low-pressure steam turbine. J Power Energy 2007; 221(6): 735–744.

15.

Gerber

. Inhomogeneous multi-fluid model for prediction of non-equilibrium phase transition and droplet dynamics. J Fluid Eng 2008; 130(3): 031402–1–11.

16.

Li L, Li Y, Wu LW, et al. Numerical study on condensing flow in low pressure cylinder of a 300 MW steam turbine. In: Proceedings of the ASME turbo expo, Glasgow, UK, 14–18 June 2010, pp. 2289–2296.

17.

Tanuma T and Sakamoto T. The removal of water from steam turbine stationary blades by suction slots. In: Proceedings of IMechE conference on turbomachinery: Latest developments in a changing scene, London, UK, 1991, pp. 179–189.

18.

Parker

Lee

. Studies of the deposition of sub-micron particles on turbine blades. Proc Instn Mech Engrs 1972; 186(1): 519–526.

19.

Crane

. Deposition of fog drops on low pressure steam turbine blades. Int J Mech Sci 1973; 15(8): 613–631.

20.

Yau

Young

. The deposition of Fog droplets on steam turbine blade by turbulent diffusion. J Turbomachinery 1987; 109(3): 429–435.

21.

Young

Yau

. The inertial deposition of fog droplets on steam turbine blades. J. Turbomachinery 1988; 110(2): 155–162.

22.

Philips HW and Deakin AW. Measurements of the collection efficiency of various demister devices. In: Proceedings of the fourth annual meeting of the aerosol society, Loughborough, UK, 1990.

23.

Troyanovskii BM, Filipov GA and Bulkn AE. Steam and gas turbine for nuclear power plants (in Russian). Moscow: Energoatomizdat, 1985.