PRE-MIXING BASED FUEL NOZZLE FOR USE IN A COMBUSTION TURBINE ENGINE
A pre-mixing type of fuel nozzle (10) for use in a combustion turbine engine is provided. The nozzle includes an array of pre-mixing conduits (20) that extends between an inlet end (14) and an outlet end (16) of a body 12 of the nozzle. The nozzle may further include an array of air flow conduits (22) disposed radially inwardly relative to the array of pre-mixing conduits. The nozzle may include an inter-conduit passageway 24 arranged to aerodynamically reduce flow recirculation in the array of pre-mixing conduits. A fuel-directing structure (26) may include non-swirl elements (28) to direct fuel flow along a radial direction, each non-swirl element including at least one orifice (32) to inject the fuel flow directed along the radial direction into a respective pre-mixing conduit to pre-mix air and fuel.
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Development for this invention was supported in part by Contract No. DE-FC26-05NT42644, awarded by the United States Department of Energy. Accordingly, the United States Government may have certain rights in this invention.
BACKGROUND 1. FieldDisclosed embodiments are generally related to a fuel nozzle for use in a combustion turbine engine, such as a gas turbine engine and, more particularly, to a pre-mixing type of fuel nozzle that in one non-limiting application may be used in a distributed combustion system (DCS) injection system.
2. Description of the Related ArtIn gas turbine engines, fuel is delivered from a fuel source to a combustion section where the fuel is mixed with air and ignited to generate hot combustion products defining working gases. The working gases are directed to a turbine section. The combustion section may comprise one or more stages, each stage supplying fuel to be ignited. See U.S. Pat. Nos. 8,281,594 and 8,752,386 in connection with fuel nozzles involving pre-mixing of air and fuel.
The inventors of the present invention have recognized certain issues that can arise in the context of certain prior art fuel nozzles involving pre-mixing of air and fuel, also referred in the art as micro-mixing. These prior art fuel nozzles generally involve a large number of point injection arrays having a relatively small diameter, and the fabrication of such injection arrays may involve costly fabrication techniques. In view of such a recognition, the present inventors propose an improved fuel nozzle that can benefit from more economical fabrication techniques while providing appropriate levels of NOx emissions and enabling practically a flashback-free operation, even on applications involving a relatively high-content of hydrogen fuel.
In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that embodiments of the present invention may be practiced without these specific details, that the present invention is not limited to the depicted embodiments, and that the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well-understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation.
Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.
The terms “comprising”, “including”, “having”, and the like, as used in the present application, are intended to be synonymous unless otherwise indicated. Lastly, as used herein, the phrases “configured to” or “arranged to” embrace the concept that the feature preceding the phrases “configured to” or “arranged to” is intentionally and specifically designed or made to act or function in a specific way and should not be construed to mean that the feature just has a capability or suitability to act or function in the specified way, unless so indicated.
As may be appreciated in
In one non-limiting embodiment, fuel nozzle 10 further includes an array of air flow conduits 22 disposed radially inwardly relative to the array of pre-mixing conduits 20. In one non-limiting embodiment, fuel nozzle 10 may include means to aerodynamically reduce flow recirculation (flow separation) in the array of pre-mixing conduits 20. It will be appreciated that the reduction of flow recirculation need not be limited to within the array of pre-mixing conduits 20, since zones beyond outlet end 16 can also benefit from such flow recirculation reduction. As may be appreciated in
As may be appreciated in
In one non-limiting embodiment, the array of pre-mixing conduits 20 each comprises at least a respective pre-mixing conduit segment (schematically represented by line 40 (
In one non-limiting embodiment, the array of air flow conduits 22 each comprises at least a respective air flow conduit segment (schematically represented by line 44 (
In operation and without limitation, disclosed embodiments are expected to provide a cost-effective fuel nozzle including arrays of fluid flow conduits that produce a substantially homogenous mixture of fuel and air at the outlet end of the nozzle and thus effective to produce appropriate pre-mixing of fuel and air conducive to ultra-low levels of NOx emissions. Additionally, disclosed embodiments need not involve swirler elements, and thus flashback resistance is substantially high, even for fuel blends comprising a high hydrogen content (e.g., at least 50% hydrogen content by volume).
Without limitation, practical embodiments of the disclosed the nozzle may comprise fluid flow conduits having a minimum diameter in a range from about 0.75 mm to about 1 mm and thus capable of benefiting from relatively low-cost manufacturing technologies, such as, without limitation, three-dimensional (3D) printing, direct metal laser sintering (DLMS), etc., in lieu of presently costlier manufacturing technologies.
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.
Claims
21. A fuel nozzle comprising:
- a body having an inlet end and an outlet end and defining a central axis that extends between the inlet end and the outlet end along an axial direction of the fuel nozzle;
- an array of pre-mixing conduits extending between the inlet end and the outlet end of the body, the array of pre-mixing conduits circumferentially disposed about the central axis of the body, each pre-mixing conduit fluidly coupled to receive air at a respective inlet;
- an array of air flow conduits disposed radially inwardly relative to the array of pre-mixing conduits;
- means to aerodynamically reduce flow recirculation in the array of air/fuel pre-mixing conduits, wherein the means to aerodynamically reduce the flow recirculation in a respective pre-mixing conduit comprises an inter-conduit passageway arranged to provide fluid communication between the respective pre-mixing conduit and a corresponding air flow conduit; and
- a fuel-directing structure in the body comprising a plurality of non-swirl elements, each non-swirl element including a radially-extending passageway to direct fuel flow along a radial direction, each non-swirl element including at least one orifice to inject the fuel flow directed along the radial direction into a respective pre-mixing conduit.
22. The fuel nozzle of claim 21, wherein the array of pre-mixing conduits each comprises at least a respective pre-mixing conduit segment having a cross-sectional area that increases as the respective pre-mixing conduit segment extends from a location between the inlet end and the outlet end towards a respective outlet of the respective pre-mixing conduit.
23. The fuel nozzle of claim 22, wherein the respective pre-mixing conduit segment includes at least one surface tilted radially inwardly relative to the central axis as the segment extends towards the respective outlet of the respective pre-mixing conduit.
24. The fuel nozzle of claim 21, wherein the array of air flow conduits each comprises at least a respective air flow conduit segment having a cross-sectional area that decreases as the respective air flow conduit segment extends from a respective inlet towards a location between the inlet end and the outlet end.
25. The fuel nozzle of claim 21, wherein the array of air flow conduits each comprises an outlet arranged radially inwardly relative to the central axis.
26. The fuel nozzle of claim 25, wherein the fuel-directing structure further comprises a central passageway arranged to direct fuel along the axial direction.
27. The fuel nozzle of claim 26, wherein the fuel-directing structure comprises a central outlet that in combination with the respective outlets of the array of air flow conduits forms a jet-assisted mixing stage.
28. A combustor in a combustion turbine engine comprising the fuel nozzle of claim 21.
29. A fuel nozzle comprising:
- a body having an inlet end and an outlet end and defining a central axis that extends between the inlet end and the outlet end along an axial direction of the fuel nozzle;
- an array of pre-mixing conduits circumferentially disposed about the central axis of the body, each pre-mixing conduit fluidly coupled to receive air at a respective inlet, wherein the array of pre-mixing conduits each comprises at least a respective pre-mixing conduit segment having a cross-sectional area that increases as the respective pre-mixing conduit segment extends from a location between the inlet end and the outlet end towards a respective outlet of the respective pre-mixing conduit;
- an array of air flow conduits disposed radially inwardly relative to the array of pre-mixing conduits, wherein the array of air flow conduits each comprises at least a respective air flow conduit segment having a cross-sectional area that decreases as the respective air flow conduit segment extends from a respective inlet towards a location between the inlet end and the outlet end; and
- a fuel-directing structure in the body, the fuel-directing structure comprising a plurality of non-swirl elements each including a radially-extending passageway to direct fuel flow along a radial direction, each non-swirl element including at least one orifice to inject the fuel flow directed along the radial direction into a respective pre-mixing conduit.
30. The fuel nozzle of claim 29, further comprising means to aerodynamically reduce flow recirculation in the array of pre-mixing conduits.
31. The fuel nozzle of claim 31, wherein the means to aerodynamically reduce the flow recirculation in a respective pre-mixing conduit comprises an inter-conduit passageway arranged to provide fluid communication between the respective pre-mixing conduit and a corresponding air flow channel.
32. The fuel nozzle of claim 29, wherein the respective pre-mixing conduit segment includes at least one surface tilted radially inwardly relative to the central axis, as the segment extends towards the respective outlet of the respective pre-mixing conduit.
33. The fuel nozzle of claim 29, wherein the array of air flow conduits each comprises an outlet arranged radially inwardly relative to the central axis.
34. The fuel nozzle of claim 33, wherein the fuel-directing structure further comprises a central passageway arranged to direct fuel along the axial direction.
35. The fuel nozzle of claim 34, wherein the fuel-directing structure comprises a central outlet that in combination with the respective outlets of the array of air flow conduits forms a jet-assisted mixing stage.
36. A combustor in a combustion turbine engine comprising the fuel nozzle of claim 29.
37. A fuel nozzle comprising:
- a body having an inlet end and an outlet end and defining a central axis that extends between the inlet end and the outlet end along an axial direction of the fuel nozzle;
- an array of pre-mixing conduits extending between the inlet end and the outlet end of the body, the array of pre-mixing conduits circumferentially disposed about the central axis of the body, each pre-mixing conduit fluidly coupled to receive air at a respective inlet, wherein the array of pre-mixing conduits each comprises at least a respective pre-mixing conduit segment having a cross-sectional area that increases as the respective pre-mixing conduit segment extends from a location between the inlet end and the outlet end towards a respective outlet of the respective pre-mixing conduit;
- an array of air flow conduits disposed radially inwardly relative to the array of pre-mixing conduits;
- an inter-conduit passageway arranged to provide fluid communication between a respective pre-mixing conduit and a corresponding air flow conduit; and
- a fuel-directing structure in the body comprising a plurality of non-swirl elements, each non-swirl element including a radially-extending passageway to direct fuel flow along a radial direction, each non-swirl element including at least one orifice to inject the fuel flow directed along the radial direction into a respective pre-mixing conduit.
Type: Application
Filed: Apr 1, 2015
Publication Date: Feb 22, 2018
Applicant: SIEMENS ENERGY, INC. (Orlando, FL)
Inventors: Joseph Meadows (Charlotte, NC), Chunyang Wu (Charlotte, NC)
Application Number: 15/555,188