FATIGUE ANALYSIS OF STEAM TURBINE BLADE (STB) CASE STUDY: FINCHAA SUGAR FACTORY

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.