Patent Application
20110239652
The present application is hereby cross-referenced with co-pending application entitled “Annular Ring-Manifold Quaternary Fuel Distributor,” the entire contents of which are incorporated herein by reference.
The subject matter disclosed herein relates to gas turbine combustors, and particularly to an annular ring-manifold quaternary fuel distributor, which is used to mitigate combustor instability, to provide better fuel/air mixing and improve flame holding margin of downstream fuel nozzles by accommodating up to 30%, by mass, of total combustor fuel.
Existing quaternary fuel pegs of a combustor are installed through the flow sleeve casing inner wall of, for example, combustors of gas turbine engines and are located in the annulus between the flow sleeve and cap barrel, which are upstream of combustor fuel nozzles. Their main function is to inject fuel into the flow of air or a fuel/air mixture and to mitigate combustion dynamics in and through the combustor during combustion operations.
The existing quaternary peg design is susceptible, however, to instances of flame-holding, which refers to the phenomena of unexpected flame occurrence immediately downstream of the quaternary pegs within combustors. Flame-holding can lead to damage to combustor hardware. The existing design also tends to generate relatively unsatisfactory quaternary fuel air mixing, which limits the capability to accommodate high quaternary fuel mass fraction, leading to unsatisfactory or limited quaternary fuel-air pre-mixing upstream combustor fuel nozzles.
According to one aspect of the invention, a combustor section is provided and includes a segmented annular manifold mounted upstream from a fuel nozzle support in a section of a passage through which an oxidizer flows, each segment of the manifold being substantially axially aligned and including a body to accommodate fuel internally that is formed to define injection holes through which the fuel is injected into the passage through which the oxidizer flows upstream of the fuel nozzle support.
According to another aspect of the invention, a combustor is provided and includes a casing, and a cap assembly disposed within the casing to define an annular passage along which oxidizer flows upstream from a fuel nozzle support, the annular fuel manifold including a segmented annular body, each body segment being substantially axially aligned, formed to accommodate fuel therein and formed to define fuel injection holes by which the fuel is injected into a section of the passage upstream from the fuel nozzle support.
According to yet another aspect of the invention, an annular fuel manifold of a combustor is provided and includes a casing, and a cap assembly disposed within the casing to define an annular passage along which oxidizer flows upstream from a fuel nozzle support, the annular fuel manifold including a segmented annular body, each body segment being substantially axially aligned, formed to accommodate fuel therein and formed to define fuel injection holes by which the fuel is injected into a section of the passage upstream from the fuel nozzle support.
According to yet another aspect of the invention, a combustor section is provided and includes a segmented manifold mounted upstream from a fuel nozzle support in a section of a passage through which an oxidizer flows, each segment of the manifold being substantially axially aligned and including a body to accommodate fuel internally, each of the bodies having a shape reflective of an axial shape of the passage section and being formed to define injection holes through which the fuel is injected into the passage through which the oxidizer flows upstream of the fuel nozzle support.
According to yet another aspect of the invention, a combustor section is provided and includes a casing, a cap assembly, having a fuel nozzle support formed therein, the cap assembly being disposed within the casing to define a passage between the casing and the cap assembly along which oxidizer flows upstream from the fuel nozzle support and a segmented manifold mounted within a section of the passage at which the oxidizer flows upstream from the fuel nozzle support, each of the segments being substantially axially aligned and including a body in which fuel is accommodated, each of the bodies having a shape reflective of an axial shape of the passage section and injection holes through which the fuel is injected into the passage section.
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.
In accordance with aspects of the invention, one or more concentric annular ring-shaped manifolds may be installed within, for example, a combustor of a gas turbine engine, upstream of combustor fuel nozzles, for promoting and structurally supporting substantially uniform distribution of quaternary fuel injection locations to thus improve fuel and air mixing. Such manifolds may be able to handle relatively large quaternary fuel mass fractions (i.e., about >30% of total system fuel on a mass basis), reduce flame-holding occurrence downstream including the quaternary fuel injection region and areas near the downstream combustor fuel nozzles, and may contribute to reducing NOx emissions and combustion instabilities.
With reference to
In accordance with embodiments, the body segments 201, 202, 203 and 204 are substantially axially aligned with one another although it is understood that this is merely exemplary and that body segments may be axially staggered with respect to one another as well. The annular manifold 20 may be segmented into two or more body segments, with each having a substantially uniform circumferential length and each one being separated from an adjacent one by substantially uniform spacing. Again, it is understood that this configuration is merely exemplary and that longer and shorter body segments may be employed and that they may be separated from one another by uniform or variable length spaces.
With reference to
The annular body 21 of each body segment 201, 202, 203 and 204 includes a segment of a ring-shaped casing 24 that is formed to define an interior therein with first and second opposing sides 25 and 26, at least one of which is tapered in accordance with a predominant direction of incoming fuel to reduce the trailing edge flow separation (recirculation) and, in some cases, so as to thereby reduce a likelihood of an occurrence of reduce local flame-holding. The interior serves as a fuel accommodating space 22, which is sufficiently large enough such that the sum total volume of the space 22 of each of the body segments 201, 202, 203 and 204 accommodates a predefined quantity of fuel. In some cases, this quantity may be up to about 30% by mass of total combustor fuel with an amount accommodated within each of the body segments 201, 202, 203 and 204 being one of fixed and actively controlled. Each annular body 21 is further formed to define injection holes 23 through which fuel is injected from the corresponding fuel accommodating space 22 and into a section 31 of the passage 30. The injection holes 23 are perimetrically arrayed around each body segment 201, 202, 203 and 204 and may be, therefore, able to substantially uniformly distribute quaternary fuel into the passage 30.
The taper of the casing 24 is defined in a direction corresponding to a predominant flow direction of the oxidizer through the passage 30 at the section 31. Thus, a relatively blunt side 26 faces the oncoming flow with the tapered side 25 pointing downstream. The fuel injection holes 23 may be arrayed at various locations on the casing 24 and with varying non-uniform or substantially uniform spacing from one another. In accordance with further embodiments, the fuel injection holes 23 may be formed proximate to the tapered side 25 and on radially inward and radially outward facing surfaces such that the fuel is injected into the section 31 in substantially radially inward and radially outward directions.
In accordance with still further embodiments, the fuel injection holes 23 may be disposed at radial maximum and radial minimum sections of the annular body 21.
The section 31 of the passage 30 is defined as a portion of the passage 30 at which the oxidizer flows upstream from the fuel nozzle supports 60. The section 31 may be further defined as a portion of the passage 30 at which the oxidizer flows at a relatively high local velocity measured relative to relatively low but non-zero flow velocities at other sections of the passage 30. In accordance with embodiments, the high flow velocities may be caused by various factors including, but not limited to, the width of the passage 30 being relatively narrow in some areas as compared with other areas, other aerodynamic considerations and the possible presence of additional flows.
In accordance with embodiments, the section 31 may be radially interposed between the casing 40 and the cap assembly 50. In accordance with further embodiments, the cap assembly 50 may include a baffle 70, which extends axially from an edge of the cap assembly 50. In these embodiments, the section 31 may be radially interposed between the casing 40 and the baffle 70.
The passage 30 is defined with a first leg 33 that is radially aligned with the fuel nozzle support 60 and a second leg 34 that is positioned radially outward of the fuel nozzle support 60. The second leg 34 is upstream from the first leg 33 such that the passage 30 is generally hooked inwardly with the oxidizer flowing in opposite directions along the first and second legs 33 and 34. The section 31 of the passage 30, at which the oxidizer flows at the relatively high local velocity, may be disposed along at least one of the first leg 33 and the second leg 34 or within a region between the legs 33 and 34 where the passage 30 is hooked.
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Referring to
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As an example, fuel transmission pathways 210 and 211 may be defined from fuel line flanges 80 along supply lines 90 to body segments 201 and 202, respectively. In this case, the fuel line flange 80, components of the supply line 90 and the corresponding body segments 201, 202 would be generally circumferentially aligned with one another although this is not required. As an alternate example, the fuel transmission pathway 212 may deliver fuel to both body segments 203 and 204.
With reference to
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
