Session: 21-02: Wet Steam

Paper Number: 153115

Modelling of Water Film and Secondary Droplet Formation in a Steam Turbine 

Low and temporally unstable steam parameters at the inlets and outlets of steam turbines, particularly in waste-to-energy (WtE) facilities and heating plants, place increased and often extreme demands on the flexibility and operational control range of steam turbines. This necessitates accurate predictions of machine behaviour across various operating modes during the turbine design phase.

This paper focuses on the contribution to a more comprehensive computational treatment of the last stage blade erosion problem. Erosion rate is significantly influenced by the dispersion of the coarse water phase, specifically the size and quantity of coarse water droplets generated by the breakup of water films on the blade surface.

The Czech Technical University in Prague (CTU) and steam turbine manufacturer Doosan Škoda Power (DSPW) are currently developing a novel in-house approach for predicting the dispersion of coarse water droplets based on empirical relationships. A commercial CFD solver, Ansys, is employed in key stages to refine several parameters incorporated into these empirical models.

By simulating non-equilibrium steam condensation in turbine stages and calculating the transport of primary droplets near the blade surface, boundary conditions for the in-house code are established. This tool is utilized to model the formation and movement of the water film on turbine blades.

The outcome from the computational in-house code is the distribution of of the coarse water phase dispersion particularly on the trailing edge of the last-stage stator blade. Results obtained for a 34 MW Doosan Škoda Power steam turbine designed for a WtE facility are presented in this paper.

Presenting Author: Guk Chol Jun Czech technical university in Prague

Presenting Author Biography: In 2018 - Ph.D. degree at the Faculty of Mechanical engineering Czech technical university in Prague
Since 2018 - Academic researcher in the field of Wet steam

Authors:

Guk Chol Jun Czech technical university in Prague
Michal Kolovratnik Czech technical university in Prague
Vaclav Petr Czech technical university in Prague
Michal Hoznedl Doosan Skoda Power
Jakub Vlasak Doosan Skoda Power