A turbine is provided with a seal device. The seal device includes: at least one step surface disposed in a region of an outer peripheral surface of a rotor facing a shroud of a stationary vane in the radial direction of the rotor, the at least one step surface facing upstream in a flow direction of the fluid and dividing the region of the outer peripheral surface into at least two sections in an axial direction of the rotor: at least two seal fins protruding toward the at least two sections from the stationary vane and facing the at least two sections via a seal gap; and a swirling-component application portion disposed on an end side of the shroud of the stationary vane with respect to the axial direction of the rotor and configured to be capable of applying a swirling component to the fluid flowing toward the seal gap.
1. A turbine, comprising:
a casing;
a rotor extending inside the casing;
a plurality of rotor blades fixed to the rotor and arranged in a circumferential direction of the rotor:
a plurality of stationary vanes fixed to the casing and arranged in the circumferential direction of the rotor, each of the stationary vanes having a vane body and a shroud which is connected to the vane body and which faces an outer peripheral surface of the rotor via a clearance in a radial direction of the rotor; and
a seal device capable of restricting a flow of a fluid iii the clearance,
wherein the seal device comprises:
at least one step surface disposed in a region of the outer peripheral surface of the rotor facing the shroud of the stationary vane in the radial direction of the rotor, the at least one step surface facing upstream in a flow direction of the fluid and dividing the region of the outer peripheral surface into at least two sections in an axial direction of the rotor;
at least two seal fins protruding toward the at least two sections from the stationary vane and facing the at least two sections via a seal gap; and
a swirling-component application portion disposed on an end side of the shroud of the stationary vane with respect to the axial direction of the rotor and configured to be capable of applying a swirling component to the fluid flowing toward the seal gap.
2. The turbine according to claim 1 ,
wherein the swirling-component application portion comprises a plurality of grooves formed on the end side of the shroud and arranged in the circumferential direction of the rotor,
wherein each of the plurality of grooves has an outer end portion disposed on an outer side in the radial direction of the rotor and an inner end portion disposed on an inner side in the radial direction of the rotor, and
wherein at least the inner end portion of each of the plurality of grooves extends inclined with respect to the radial direction of the rotor.
3. The turbine according to claim 2 ,
wherein, in each of the plurality of grooves, the inner end portion is disposed in front of the outer end portion in a rotational direction of the rotor.
4. The turbine according to claim 2 ,
wherein, in each of the plurality of grooves, an inclination angle of the inner end portion with respect to the radial direction of the rotor is greater than an inclination angle of the outer end portion with respect to the radial direction of the rotor.
5. The turbine according to claim 2 ,
wherein each of the plurality of grooves extends linearly and inclined with respect to the radial direction.
6. The turbine according to claim 2 ,
wherein each of the plurality of grooves extends curved so as to deviate gradually from the radial direction of the rotor from outside toward inside in the radial direction of the rotor.
7. The turbine according to claim 2 ,
wherein each of the plurality of grooves has a constant width.
8. The turbine according to claim 2 ,
wherein each of the plurality of grooves has portions with different widths from one another.
9. The turbine according to claim 2 ,
wherein the plurality of grooves are formed by a plurality of blade portions formed on the end side of the shroud and arranged M the circumferential direction of the rotor.
10. The turbine according to claim 9 ,
wherein the blade portion has a leading edge portion disposed on an outer side in the radial direction of the rotor, and a trailing edge portion disposed, on an inner side in the radial direction of the rotor, and
wherein the trailing edge portion is disposed in front of the leading edge portion in a rotational direction of the rotor.
11. The turbine according to claim 9 ,
wherein the blade portion has a leading edge portion disposed on an outer side in the radial direction of the rotor and a trailing edge portion disposed on an inner side in the radial direction of the rotor, and
wherein an inclination angle of the trailing edge portion with respect to the radial direction of the rotor is greater than an inclination angle of the leading edge portion with respect to the radial direction of the rotor.
12. The turbine according to claim 2 ,
wherein each of the plurality of grooves has portions with different depths from one another.
13. The turbine according to claim 1 ,
wherein an end surface of the end side of the shroud is inclined with respect to the radial direction of the rotor.