A FSI Analysis of Unsteady Shock on Last Stage LP Steam Turbine Rotor Blades

In the previous study, we numerically simulated the unsteady forces on the last-stage long-rotor-blade rows in the low pressure steam turbine. The results showed strong shocks generated from the trailing edges of the final-stage stator blades near the hub come into contact with the adjacent rotor-blade noses. Those interactions induced a pressure fluctuation on rotor blade, resulting in torque fluctuation. In this study, a one-way coupled fluid-structure interactions (FSI) analysis is employed to investigate the effect of such unsteady forces on the displacements of the last-stage long-rotor-blade. We compare the time-dependent torque value and the maximum displacements, and discuss how unsteady forces influence the displacements of the blades.