Two-Phase Flow in Steam Turbines

Garant předmětu:

Lecturer:

Tutor:

Supervisor:

Department of Energy Engineering

Synopsis:

Aims of the course:

Familiarization with the issues of formation, evolution and negative impacts of the wet steam liquid phase in steam turbines.

Content of the course:

Wet steam flow in flow path of the steam turbines is followed by decrease of turbine efficiency and reliability. A physical and mathematical model of nucleation and condensation in expanding steam as well as model of secondary droplets formation are presented as the foundation for the comprehension and grasping of theoretical analyses of two-phase flows in steam turbines. Furthermore, there will be presented the issues of experimental research of wet steam-flow and -structure in turbines.

Basic topics of the course:

Wet steam flow in steam turbines. The effect of wet steam on turbine efficiency and reliability. Formation of fine primary droplets structure by nucleation and condensation in expanding steam. Formation of coarse secondary droplets which are causing braking loss and erosion damage. Additional wet steam energy losses in turbine stage. Instrumentation for research of the two-phase flow in power plant systems. Possibility to reduce negative effects of steam wetness in turbines of fossil-fired, nuclear and renewable power plants.

Requirements:

Basic knowledge on Gas dynamics, Thermodynamics and Steam and Gas Turbines from MS studies.

Syllabus of lectures:

Formation of wet steam during expansion in a convergent-divergent nozzle and in a steam turbine. Homogeneous and heterogeneous nucleation process. Critical droplet size and droplet growth-rate equation. Mathematical model of condensation in the flowing steam. Formation of coarse droplets in steam turbines. Additional energy losses in the wet steam. Causes of blade erosion, erosion-corrosion. Measures for preventing unfavourable effects of the steam moisture occuring in the fossil and nuclear steam turbines.

Syllabus of tutorials:

Study Objective:

Study materials:

Core literature:

Moore, M.J. and Sieverding, C.H.: Two-phase steam flow in turbines and separators: theory,instrumentation, engineering. Hemisphere Publishing corporation, 1976

Recommended literature:

Gyarmathy, G.: Grundlagen einer Theorie der Nassdampfturbine. Dissertation ETH Zürich, Juris Verlag, Zürich, 1962

Note:

Time-table for winter semester 2023/2024:

Time-table is not available yet

Time-table for summer semester 2023/2024:

Time-table is not available yet

The course is a part of the following study plans: