Abstract:
T
he steam turbine handles the maximum power demand among all stationary prime
movers that are used for electric power generation. A steam turbine is a constant
volume machine. There are two basic types of steam turbines. The impulse stage
is best suited for high-pressure region and for small steam quantities. The reaction stage is ad vantageous at the lower pressure region, where a large volume of steam must be handled. Both
type of steam turbine is used in Finchaa Sugar Factory in four units; two impulses and two reac tions. This study is focused on impulse steam turbine blade because it works for a twenty-one
years ago. The main failure of steam turbine blade is due to corrosion fatigue failure, fritting
fatigue failure and thermal fatigue failure. The main problem occurred on steam turbine blade
in Finchaa Sugar Factory is due to thermal load which is depend on thermal properties of steam.
The aim of this study is to predict the life of steam turbine blade through analysis of its thermal
fatigue using computational fluid dynamics software packages. In Fluid-Structure Interaction
method of analysis, both transient computational fluid dynamics and structural dynamics are
mathematically modeled. To analyze the approximate solutions for transient state for both fluid
and solid fourth ordered Runge Kutta initial value problem method is derived. The blade was
then analyzed for the temperature and pressure distribution. After containing thermal load dis tribution, the blade was then analyzed for static structure. Results shows that the maximum total
deformation is 5.755 mm and the maximum equivalent stress is 1983.8 MPa. Generally, steam
turbine blade with given typical parameter here is operating for minimum of 19.42 years. This
predicted fatigue life is due to the cause of thermal fatigue only.
