Rotating brush seal
A brush seal for use between a rotating component and a stationary component in a turbomachine is disclosed. The brush seal according to embodiments of this invention includes a set of bristles having a fixed end and a free end, wherein the fixed end is attached to the rotating component with a mechanical clamping element and the free end extends towards the stationary component, and wherein the set of bristles are angled axially at an axial angle with respect to the rotating component. In one embodiment, the fixed end of the set of bristles are wrapped at least partially around a core element and the clamping element partially surrounds the core element and the fixed end of the set of bristles, wherein the clamping element secures the fixed end of the set of bristles within a circumferential groove in the rotating component.
1. A brush seal for use between a rotating component and a stationary component in a turbomachine, the brush seal comprising:
a set of flexible bristles having a fixed end and a free end;
a circumferential groove in the rotating component, the circumferential groove having a downstream side and an upstream side;
a conical retaining plate, wherein the conical retaining plate is attached to the downstream side of the circumferential groove;
wherein the fixed end is attached to the rotating component with a mechanical clamping element, the mechanical clamping element partially surrounds the core element and the fixed end of the set of flexible bristles, and the mechanical clamping element is friction fitted between and contacts both an inner surface of the conical retaining plate and the upstream side of the circumferential groove to secure the fixed end of the set of flexible bristles within the circumferential groove in the rotating component;
wherein the conical retaining plate extends at least partially along a length of the set of flexible bristles, such that the conical retaining plate is configured to at least partially support the set of flexible bristles on the inner surface of the conical retaining plate from centrifugal loading in an operative state of the turbomachine; and
wherein the set of flexible bristles are angled axially at an axial angle with respect to the rotating component.
2. The brush seal of claim 1 , wherein the set of flexible bristles is bent such that the fixed end of the set of flexible bristles is axially displaced with respect to the free end of the set of flexible bristles.
3. The brush seal of claim 1 , wherein the set of flexible bristles comprise either metal or plastic wires.
4. The brush seal of claim 1 , wherein the brush seal comprises a series of arcuate segments forming a ring when assembled into the rotating component.
5. The brush seal of claim 1 , wherein the axial angle is approximately 15 degrees to approximately 75 degrees.
6. The brush seal of claim 1 , wherein the axial angle is approximately 45 degrees to approximately 60 degrees.
7. the brush seal of claim 1 , wherein the set of flexible bristles are angled circumferentially at an angle substantially less than the axial angle.
8. A turbomachine comprising:
a rotating component having a circumferential groove therein, the circumferential groove having an upstream side and a downstream side;
a stationary component; and
a brush seal for use between the rotating component and the stationary component, the brush seal comprising:
a set of flexible bristles having a fixed end and a free end;
a conical retaining plate extending at least partially along a length of the set of flexible bristles, such that the conical retaining plate is configured to at least partially support the set of flexible bristles on an inner surface of the conical retaining plate from centrifugal loading in an operative state of the turbomachine, wherein the conical retaining plate is attached to the downstream side of the circumferential groove;
wherein the fixed end is wrapped at least partially around a core element and the free end extends towards the stationary component, and wherein the set of flexible bristles are angled axially at an axial angle with respect to the rotating component; and
a clamping element partially surrounding the core element and the fixed end of the set of flexible bristles, wherein the clamping element is friction fitted between and contacts both the inner surface of the conical retaining plate and the upstream side of the circumferential groove to secure the fixed end of the set of flexible bristles within the circumferential groove in the rotating component.
9. The brush seal of claim 8 , wherein the axial angle is approximately 15 degrees to approximately 75 degrees.
10. The turbomachine of claim 8 , wherein the set of flexible bristles are angled circumferentially at an angle substantially less than the axial angle.
11. The turbomachine of claim 8 , wherein the set of flexible bristles is bent such that the fixed end of the set of flexible bristles is axially displaced with respect to the free end of the set of flexible bristles.
12. The turbomachine of claim 8 , wherein the rotating component includes at least one seal tooth extending radially outward from the rotating component toward the stationary component.
13. The turbomachine of claim 8 , wherein the stationary component includes at least one seal tooth extending radially inward from the stationary component toward the rotating component.
14. The turbomachine of claim 8 , wherein the stationary component comprises a nozzle which directs a main flow through the turbomachine into a rotational direction of the turbomachine; and wherein the brush seal directs a leakage flow through the turbomachine into the rotational direction.
15. The turbomachine of claim 14 , wherein a swirl ratio of the main flow at an exit nozzle and a swirl ratio of the leakage flow downstream from the brush seal is approximately 1.0.