Stress analysis of a steam turbine blade due to bowing effect

Steam turbine is a prime mover which extracts steam energy and converts it to mechanical energy of rotor having set of blades. Steam turbine blades are designed to get maximum output from steam. Bowing of shaft occurs when the turbine is shut down faster and shaft cooling time is not proper causing the shaft bend at center to any direction. Bowing of the shaft can make the rotor blades striking the casing of turbine causing crack in the blade due to fatigue loading. The aim is to confirm the crack initiation on blade of rotor by bowing of the shaft of a typical steam turbine. In this regard, blade is generated from the blade profile of the typical steam turbine using BladeGen. A fine mesh is generated using TurboGrid, on the modeled blade. CFD of the blade is done using steam as fluid at the specified conditions of the typical steam turbine with the help of CFX. Depending upon the rotor blade stage and location, bowing effect will be different. Hence the blade may strike with casing of the turbine resulting crack initiation either at leading edge or trailing edge or it may be any location along the chord of blade. The effect of this location results in high stresses at different locations of the blade root. Due to these stresses in the blade, the fatigue life of the blade will be very less which can cause the turbine to fail. These effects have been discussed in detail in this paper.