Predictions of non-equilibrium phase transition in a model low-pressure steam turbine

Abstract

An Eulerian-Eulerian multi-phase computational fluid dynamics model for predicting phase transition under non-equilibrium conditions in the low-pressure stages of a steam turbine is presented. In a novel way the model introduces dispersed liquid phases into the solution according to phase transition type and location in the turbine. Such an approach provides added information on the location and extent of phase transition regions, including associated droplet size, number, and wetness distributions. The model provides a mass weighted size distribution throughout the turbine with a resolution depending on the number of phases chosen. The study presents examples of the models usefulness in isolating phase transition activity and growth at design and off-design conditions. Comparison against results based on equilibrium phase transition in the turbine is provided for verification and discussion. Validation against measured droplet and flow data from the model turbine is also discussed.

Keywords

computational fluid dynamics modelling steam turbine

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References

Gyarmathy

Grundlagen einer Theorie der Nassdampf-strömung. Dissertation ETH Zürich, Prom. Nr. 3221, Juris Verlag Zürich, 1962.

Bakhtar

Special issue on wet steam - Part 2. Proc. IMech, Part C: J. Mechanical Engineering Science, 2005, 219, 1301–1436.

Stastny

Sejna

Numerical analysis of hetero-homogeneous condensation of the steam flowing in turbine cascade. IMechE Conf. Transactions, vol. B, London, UK, 1999, paper C557/082/99, ETC-3 1999.

Bakhtar

White

A. J.

Mashmoushy

Theoretical treatments of two-dimensional two-phase flows of steam and comparison with cascade measurement. Proc. IMechE, Part C: J. Mechanical Engineeering Science, 2005, 219, 1335–1355.

Wet steam measurement in the model steam turbine. Internal Technical report, ITSM, Stuttgart, Germany, August 2003.

Völker

Casey

Neef

Stüer

The flow field and performance of a model low pressure steam turbine. AFT-022_05 / 43, ETC-6 2005, Lille, France, 2005.

Gerber

A. G.

Inhomogeneous multi-fluid model for non-equilibrium phase transition and droplet dynamics. ASME, J. Fluids Eng., 2007, in press.

McDonald

J. E.

Homogeneous nucleation of water vapor condensation. I. Thermodynamic aspects. Am. J. Phys., 1962 30, 870–877.

Bakhtar

Piran

Thermodynamic properties of supercooled steam. Int. J. Heat Fluid Flow, 1979, 1(2), 53–62.

10.

Menter

F. R.

Two-equation eddy-viscosity turbulence models for engineering applications. AIAAJ., 1994, 32(8), 1598–1605.

11.

Mousavi

Gerber

A. G.

Kermani

M. J.

Representing polydispersed droplet behavior in nucleating steam flow with the quadrature method of moments. FEDSM2006, Miami, FL, 17-20 July 2006, paper no. 98459.

12.

Bohn

Funke

Ren

Sürken

Sell

Osterhage

Th.

Numerical and experimental investigation of the wetness in the front stages of a low-pressure steam turbine. VGB PowerTech 11/2004, 2004, 80–85.