Turbine Packing Deflector
A turbine includes a rotor being rotatable about an axis, a circumferential array of nozzles having circumferentially spaced airfoils and inner and outer bands disposed at opposite ends thereof, the inner band having a leading portion and a trailing portion, and an array of directors arranged on the inner band, the array of directors operative to direct a flow path of fluid, the flow path of fluid partially defined by the rotor and the inner band.
Latest General Electric Patents:
The subject matter disclosed herein relates to turbine engines.
The flowpath through a turbine along the root radius is defined in part by the inner bands or rings of the nozzles and flow surfaces along the platforms at the roots of the buckets on the rotor. Any fluid flow leakage exiting the flowpath along the root radii bypasses the buckets and nozzles, and directly decreases the performance of the turbine stage. Teeth arranged on the rotor adjacent to the fluid flow leakage increase the swirl of the fluid flow leakage. A typical nozzle and bucket design of, for example, a steam turbine stage, includes a nozzle root diameter equal to the bucket root diameter, resulting in a significant probability of an upstream facing step, which disturbs the streamline characteristics of the fluid flow in the flowpath. Radial reentry flows cause fluid flow random mixing along the flowpath with consequent aerodynamic efficiency losses.
BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, a turbo machine includes a rotor being rotatable about an axis, a circumferential array of nozzles having circumferentially spaced airfoils and inner and outer bands disposed at opposite ends thereof, the inner band having a leading portion and a trailing portion, and an array of directors arranged on the inner band, the array of directors operative to direct a flow path of fluid, the flow path of fluid partially defined by the rotor and the inner band.
According to another aspect of the invention, an inner band of turbine nozzle array includes a leading portion and a trailing portion, and an array of directors arranged on the inner band, the array of directors operative to direct a flow path of fluid, the flow path of fluid partially defined by a rotor and the inner band.
According to yet another aspect of the invention, an array of directors includes a plurality of fins extending from a guide surface of an inner band portion of a turbine, the inner band portion arranged at an end portion of an array of nozzles, the plurality of fins being operative to direct a flow path of a fluid, the flow path partially defined by the inner band portion and a portion of a rotor having an axis of rotation.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTIONIn this regard, a plurality of directors (diverters) 126 are arranged at the trailing portions 204 of the inner bands 114 and in the leakage flow path. The directors 126 in the illustrated embodiment are operative to direct the leakage flow into the root region of the main flow path while reducing the aerodynamic inefficiency of the introduction of the leakage flow path into the root region of the flow path. The directors 126 may include fins or other similar structures extending from the inner bands 114. The directors 126 may include fins having opposing planar profiled sides or fins having arcuate shaped opposing sides.
The embodiments described above increase the efficiency of a turbine machine by reducing the mixing losses and randomness of the introduction of leakage flows into root regions of the main flow path. The increased efficiency is realized by the use of diverters arranged on inner rings proximate to the trailing edges of the turbine nozzles. The diverters reduce the aerodynamic inefficiency of the introduction of the leakage flow into the root region of the main flow path.
Claims
1. A turbo machine comprising:
- a rotor being rotatable about an axis;
- a circumferential array of nozzles having circumferentially spaced airfoils and inner and outer bands disposed at opposite ends thereof, the inner band having a leading portion and a trailing portion; and
- an array of directors arranged on the inner band, the array of directors operative to direct a flow path of fluid, the flow path of fluid partially defined by the rotor and the inner band.
2. The machine of claim 1, wherein the rotor includes a tooth arranged on the rotor, the tooth and the inner band defining a gap therebetween.
3. The machine of claim 2, wherein the gap further defines the flow path of fluid.
4. The machine of claim 2, wherein the array of directors is arranged a distance x from the tooth, and the inner band is arranged a distance y from the rotor, where a ratio x:y is between 0.3 and 1.
5. The machine of claim 1, wherein the trailing portion of the inner band includes a guide surface portion having a surface arranged at an oblique angle relative to the axis.
6. The machine of claim 1, wherein the array of directors is arranged on a guide surface portion of the inner band.
7. The machine of claim 1, wherein the trailing portion of the inner band includes a guide surface portion having a surface arranged substantially parallel to the axis, and the array of directors is arranged on the guide surface portion.
8. The machine of claim 1, wherein each director of the array of directors defines a linear axis, the linear axis of each of the directors are arranged substantially in parallel to each other.
9. The machine of claim 1, wherein each directors of the array of directors has an arcuate shape that defines a chord line, wherein the chord line of each of the directors are arranged substantially parallel to each other.
10. The machine of claim 1, wherein the machine includes a turbine.
11. The machine of claim 1, wherein the machine includes a compressor.
12. An inner band of a turbine machine, the inner band comprising:
- a leading portion and a trailing portion; and
- an array of directors arranged on the inner band, the array of directors operative to direct a flow path of fluid, the flow path of fluid partially defined by a rotor and the inner band.
13. The inner band of claim 12, wherein the array of directors are arranged proximate to the trailing portion of the inner band.
14. The inner band of claim 12, wherein the trailing portion of the inner band includes a guide surface portion having a surface arranged at an oblique angle relative to an axis intersecting a plane defined by the inner band, the axis normal to the plane.
15. The inner band of claim 12, wherein the array of directors is arranged on a guide surface portion of the inner band.
16. The inner band of claim 12, wherein the trailing portion of the inner band includes a guide surface portion having a surface arranged substantially parallel to an axis intersecting a plane defined by the inner band, the axis normal to the plane, and the array of directors is arranged on the guide surface portion.
17. The inner band of claim 12, wherein each director of the array of directors defines a linear axis, the linear axis of each of the directors are arranged substantially in parallel to each other.
18. The inner band of claim 12, wherein each directors of the array of directors has an arcuate shape that defines a chord line, wherein the chord line of each of the directors are arranged substantially parallel to each other.
19. An array of directors comprising a plurality of fins extending from a guide surface of an inner band portion of a turbine, the inner band portion arranged at an end portion of an array of nozzles, the plurality of fins being operative to direct a flow path of a fluid, the flow path partially defined by the inner band portion and a portion of a rotor having an axis of rotation.
20. The array of directors of claim 19, wherein the fins of the plurality of fins include opposing planar sides arranged at an oblique angle relative to the axis of rotation of the rotor.
Type: Application
Filed: Jan 24, 2012
Publication Date: Jul 25, 2013
Applicant: GENERAL ELECTRIC COMPANY (Schenectady, NY)
Inventors: Prabakaran Modachur Krishnan (Bangalore), Moorthi Subramaniyan (Bangalore)
Application Number: 13/356,840
International Classification: F01D 5/22 (20060101);