Turbine blade tip shroud

Patent metadata

Field	Value
Publication number	US-9903210-B2
Application number	US-201414891973-A
Country	US
Kind code	B2
Filing date	May 20, 2014
Priority date	May 21, 2013
Publication date	Feb 27, 2018
Grant date	Feb 27, 2018

Abstract

A turbine blade tip shroud ( 22 C, 22 D) with a seal rail ( 32 C, 32 D) oriented in a circumferential direction of rotation ( 29 ) relative to a turbine axis, and extending radially outward from the tip relative to the turbine axis. A first tooth ( 48, 68 ) and a second tooth ( 50, 70 ) form respective downstream and upstream lateral departures or bumps on the seal rail. Each tooth has a sharp top leading edge ( 48, 50, 68, 70 ) and a smoothly curved side surface ( 49, 51, 69, 71 ). A back portion ( 56, 76 ) of the seal rail may span linearly from a lateral peak ( 66, 78 ) of the second tooth to a back end ( 62 ) of the seal rail that is centered on an extended centerline ( 60 ) of a front portion ( 54, 74 ) of the seal rail. The teeth may be disposed proximate or over a stacking axis ( 52 ) of the blade.

First claim

The invention claimed is:

1. A turbine blade tip shroud, comprising
a seal rail oriented in a circumferential direction of rotation relative to a turbine axis, and extending radially outward from a shroud relative to the turbine axis; and
a first tooth and a second tooth extending respectively downstream and upstream from the seal rail with respect to a working gas flow, each tooth comprising a sharp top leading edge and a smoothly curved side surface;
wherein a back portion of the seal rail spans linearly from an upstream peak of the second tooth to a back end of the seal rail that is centered on an extended centerline of a front portion of the seal rail.

2. The turbine blade tip shroud of claim 1 , wherein the back portion of the seal rail forms an angle of 2 to 3 degrees relative to the extended centerline of the front portion of the seal rail.

3. The turbine blade tip shroud of claim 1 , wherein the sharp top leading edge of each tooth comprises an included angle of 90 to 100 degrees between a top surface of the tooth and the side surface thereof as seen in section.

4. The turbine blade tip shroud of claim 1 , wherein the first tooth is proximate a radius of the turbine axis that passes through a center of mass of the blade.

5. A turbine blade tip shroud, comprising:
a plate on a tip of a turbine blade;
a seal rail oriented in a circumferential direction of rotation relative to a turbine axis, the seal rail extending radially outward from the plate relative to the turbine axis;
a first tooth forming a lateral bump on a downstream side of the seal rail with respect to a working gas flow, the first tooth comprising a sharp top leading edge;
a second tooth forming a lateral bump on an upstream side of the seal rail with respect to the working gas flow, the second tooth comprising a sharp top leading edge;
the seal rail comprising a front portion ahead of the first tooth with respect to the direction of rotation and a back portion behind the second tooth with respect to the direction of rotation, wherein the back portion of the seal rail spans linearly from a lateral peak of the second tooth to a back end of the seal rail that is centered on an extended centerline of the front portion of the seal rail.

6. The turbine blade tip shroud of claim 5 , wherein the back portion of the seal rail forms an included angle of 2 to 3 degrees with the extended centerline of the front portion of the seal rail.

7. The turbine blade tip shroud of claim 5 , wherein each of the teeth has a smoothly curved side surface.

8. The turbine blade tip shroud of claim 5 , wherein the sharp top leading edge of each tooth comprises an included angle of 90 to 100 degrees between a top surface of the tooth and a side surface thereof as seen in section.

9. The turbine blade tip shroud of claim 5 , wherein the teeth are proximate or over a radius of the turbine axis that passes through a center of mass of the blade.

10. A turbine blade tip shroud, comprising
a seal rail oriented in a circumferential direction of rotation relative to a turbine axis, and extending radially outward from the shroud relative to the turbine axis; and
a first tooth and a second tooth extending from the seal rail respectively downstream and upstream with respect to a working gas flow, the first and second teeth forming a continuously smooth comma-shaped transition between a front portion of the seal rail and a back portion thereof as viewed from above;
wherein the back portion of the seal rail spans linearly from an upstream peak of the second tooth to a back end of the seal rail that is centered on an extended centerline of the front portion of the seal rail.

Assignees

• Siemens Energy Inc

Inventors

• Evans Charles M
• Narcus Andrew R
• Pula John

Classifications

• F01D5/147

  Construction, i.e. structural features, e.g. of weight-saving hollow blades (F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18) · CPC title

• F01D5/20 Primary

  Specially-shaped blade tips to seal space between tips and stator {(F01D5/225 takes precedence)} · CPC title

• F01D11/127

  with a deformable or crushable structure, e.g. honeycomb · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F01D5/225 Primary

  by shrouding · CPC title