抄録
Labyrinth seals have the potential to cause rotordynamic instability induced by the fluid force of seal flows. We conducted a computational fluid dynamics (CFD) study to investigate the rotordynamic characteristics of the turbine blade shroud seal of a steam turbine. The effect of swirl brake on the fluid force and turbine cascade performance was investigated. The predicted fluid force (stiffness coefficients) decreased with increasing the number of swirl brakes installed at the seal inlet, but the cascade performance degraded at the same time. When the swirling flow flowing into the seal portion strikes the swirl brakes, the flow is turned to the inner peripheral side and goes back into the cascade side, which may degrade cascade performance.
