COMBUSTOR BASKET COOLING RING

Abstract

A cooling ring (102) of a combustor basket system (110) has a transition zone 108 that extends to a cooling channel (106) at a cooling channel entrance (104). The transition zone (108) has the substantially the same material strength throughout the length of the transition zone (108). By having the same material strength throughout the length of the transition zone (108), the cooling ring (102) is able to withstand greater stresses than previously used cooling rings. One way in which this is accomplished is by having a uniform thickness.

Claims

1. A combustor basket system comprising: a cooling ring comprising a transition zone, wherein the transition zone extends from a transition zone start to a cooling channel entrance; and wherein the transition zone comprises a cross-section profile configured to provide a substantially uniform material strength.

2. The system of claim 1, wherein the transition zone has a uniform thickness.

3. The system of claim 1, wherein the cooling ring is conical shaped.

4. The system of claim 3, wherein the cooling ring can withstand temperatures substantially above 700 C. without failure.

5. The system of claim 4, wherein an outer diameter of the cooling ring is larger at a first location of the transition zone than at another location of the transition zone.

6. The system of claim 5, wherein the outer diameter of the cooling ring is greatest closest to the cooling channel entrance.

7. The system of claim 1, wherein the basket cooling system has a transition zone that is 75% of an active combustion length.

8. The system of claim 1, wherein the transition zone has a step-like feature at the cooling channel entrance.

9. The system of claim 1, wherein there is an angle that is between about 3 to 10.

10. The system of claim 9, wherein the thickness of the transition zone (108) is between 5-8 mm.

11. A cooling ring for use with a basket cooling system comprising: a wall having an outer surface and an inner surface; wherein the wall forms a transition zone that extends to a cooling channel entrance of the basket cooling system; wherein the wall has a thickness which is the distance between the outer surface and the inner surface, and wherein the material strength of the wall is substantially uniform throughout the transition zone.

12. The cooling ring of claim 11, wherein the wall has a uniform thickness.

13. The cooling ring of claim 11, wherein the cooling ring (102) is conical shaped.

14. The cooling ring of claim 11, wherein the cooling ring can withstand temperatures substantially above 700 C. without failure.

15. The cooling ring of claim 11, wherein an outer diameter of the cooling ring is larger at a transition zone end than at transition zone start.

16. The cooling ring of claim 15, wherein the outer diameter of the cooling ring is greatest closest to a cooling channel entrance.

17. The cooling ring of claim 11, wherein the basket cooling system has a transition zone that is 75% of an active combustion length.

18. The cooling ring of claim 11, wherein the transition zone has a step-like feature located proximate to a cooling channel entrance.

19. The cooling ring of claim 11, wherein there is an angle that is between about 3 to 10.

20. The cooling ring of claim 11, wherein the thickness of the transition zone is between 5-8 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is cross-sectional side view of a combustor basket system that uses a prior art cooling ring.

[0011] FIG. 2A shows a diagram illustrating the temperatures that affect the cooling ring shown in FIG. 1.

[0012] FIG. 2B shows a diagram illustrating the Von Mises stresses that occur with the cooling ring shown in FIG. 1.

[0013] FIG. 3 is a cross-sectional side view of a combustor basket system that uses a cooling ring in accordance with an embodiment of the present disclosure.

[0014] FIG. 4A shows a diagram illustrating the temperatures that affect the cooling ring shown in FIG. 3.

[0015] FIG. 4B shows a diagram illustrating the Von Mises stresses that occur with the cooling ring show in FIG. 3.

DETAILED DESCRIPTION

[0016] To facilitate an understanding of embodiments, principles, and features of the present disclosure, they are explained hereinafter with reference to implementation in illustrative embodiments. Embodiments of the present disclosure, however, are not limited to use in the described systems or methods.

[0017] The components and materials described hereinafter as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components and materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of embodiments of the present disclosure.

[0018] To ameliorate the problems that occur due to the reduction in the thickness of the cooling ring 2 shown in FIG. 1, an embodiment of the present disclosure has the location of the entrance to cooling channels not at a cylindrical section of a combustor, but instead locates the entrance to the cooling channels at a conical section of a combustor basket system. By moving the transition zone and entrance to a conical section of the of the combustor basket system, the machined feature of the cooling ring 2 that results in a weakness is eliminated and the thickness of the cooling ring can be maintained throughout its length. This also provides the benefit of being able to use fewer liners than in previous combustor basket systems.

[0019] Referring to FIG. 3, wherein an embodiment of the present invention shown, a cooling ring 102 is shown used in combustor basket system 110. The combustor basket system 110 shown in FIG. 3 is colloquially referred to as a G-type basket style system. By G-type basket style it is meant the basket is used with a G-frame combustor. With a G-type basket style the active combustion length is split between 25% being the combustor basket and 75% the transition zone. In other words, the transition zone is longer than the combustor basket. In other types of combustor basket systems, the active combustion length is generally split between the combustor basket and the transition zone so that it is 50% combustor basket and 50% transition zone. While, the combustor basket system 110 shown in FIG. 3 is a G-type basket style, it is contemplated that other types of styles may be employed. For example, the cooling ring 102 may be employed with baskets colloquially referred to as D-type, E-type, F-type, H-type baskets and J-type baskets.

[0020] Still referring to FIG. 3, the cooling ring 102 is formed by a wall 103 that has an inner surface 105 and an outer surface 107 and forms transition zone 108. In the embodiment shown in FIG. 3, the cooling ring 102 is conically shaped. However it should be understood that other shapes may be accommodated provided that the cooling ring 102 is able to maintain its material strength at the transition zone 108. By material strength it is meant that that the stresses that the material is able to withstand due to environmental factors, such as forces impacting the material or temperatures that the material can withstand without failure. The limiting factor of cooling rings is low cycle fatigue life which is impacted by material properties and the temperature.

[0021] The transition zone 108 is the portion of the cooling ring 102 that begins at transition zone start 111 and ends at transition zone end 113. Transition zone start 111 may be the area where the cooling ring 102 begins, or alternatively an area proximate to where the cooling ring 102 begins. The transition zone start 111 may also begin prior to the hot section of the combustor basket system 110, however the transition zone start 111 may be located after another cooling feature of the combustor basket system 110. Transition zone end 113 is that area of the transition zone 108 where the cooling channel entrance 104 begins. The transition zone 108 may be 75% of the length of the active combustion length, which is defined as the length of the combustor in which combustion occurs.

[0022] The cooling ring 102 may be made of nickel alloys with high nickel concentrations, or other materials capable of withstanding temperatures found within combustor basket system 110. Generally speaking the temperatures that the cooling ring 102 can withstand in the transition zone 108 are temperatures within the range of 500 to 1000 C., more preferably the cooling ring 102 can withstand temperatures greater than 700 C.

[0023] The transition zone 108 of the cooling ring 102 is able to withstand temperatures greater than 750 C. without having to provide additional measures to cool the area in the transition zone 108, such as those required in typical combustor basket systems. In some embodiments this means that the number of air holes 117 located in the combustor basket system 110 may be reduced. For example the number of air holes used in previous combustor basket systems may be greater than 180. In combustor basket system 110 the number of air holes 117 may be less than 180 and may be as low as 90, or less.

[0024] Still referring to FIG. 3, the combustor basket system 110 has a cooling channel entrance 104 that permits access of cooling air into a cooling channel 106. In an embodiment of the present invention, the outer diameter D.sub.3 of the cooling ring 102 gradually increases, to the diameter D.sub.4 as it approaches cooling channel entrance 104. The gradual increase may be accomplished by having an angle that is less than about 10 but greater than 3, and more preferably from between about 4-6. The angle is an angle that is formed between a point on the horizontal line formed by the central axis of the cooling basket system 110 and a point on the inner surface 105 of the wall 103.

[0025] While the outer diameter of the cooling ring 102 gradually increases, the thickness T.sub.2 of the cooling ring 102 may remain substantially constant, that is within appropriate manufacturing tolerances. The thickness T.sub.2 is the distance between the outer surface 107 and the inner surface 105 of the wall 103 of the cooling ring 102. Thus the transition zone 108 has substantially the same thickness T.sub.2 throughout. Preferably the thickness T.sub.2 is between 4 to 12 mm and more preferably between 5-8 mm, while it is contemplated that a uniform thickness extends throughout the transition zone 108, it should be understood that preferably the thickness is such that the integrity of the cooling ring 102 is not compromised during use due to material weaknesses, or that the Von Mises stresses that affect the cooling ring 102 are such that they do not adversely impact the cooling ring 102 in a particular location. In other words, maintaining the thickness T.sub.2 constant throughout the transition zone 108 is one way in which material weaknesses do not adversely impact one particular area of the cooling ring 102. Other features of the cooling ring 2, discussed herein, may also provide ways in which the material strength of the cooling ring 2 may remain constant throughout the transition zone 108.

[0026] In an embodiment of the present disclosure, the transition zone 108 is integrally formed as part of the cooling ring 102. However, the transition zone 108 may also be formed from sheet metal and welded to the cooling ring 102. By maintaining the thickness T.sub.2 substantially constant the weakness exhibited by typical cooling rings is avoided because there is no change in the material thickness of the transition zone 108 thereby maintaining a uniform material strength.

[0027] Additionally, the transition zone 108 approaches the cooling channel entrance 104 with a step-like feature having a having a height of Hi. The height Hi is the distance the cooling channel entrance 104 is above the outer surface 103. Hi may be between the ranges of 3 to 15 mm. The height Hi plays a beneficial role in the flow of air through the combustor basket system 110.

[0028] FIGS. 4A and 4B illustrate representative stresses that may occur with the cooling ring 102. FIG. 4A depicts the temperatures that impact the cooling ring 102. FIG. 4B illustrates representative Von Mises stresses that occur within the cooling ring 102 due to the impact of the temperature on the cooling ring 102. As shown in FIG. 4B, the Von Mises stresses are reduced at the cooling channel entrance 104, as compared with the cylindrical cooling ring 2, because there is no reduction in the thickness T.sub.2 of the cooling ring 102 at the cooling channel entrance 104. Further, the angle and direction at which the transition zone 108 meets the cooling channel entrance 104 permits there to be smooth flow of air. Further, as opposed to typical combustor basket systems, the number of liners 119 used in the system may be reduced.

[0029] While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.