Patent Application
20130025283
The subject matter disclosed herein relates to fuel nozzles and more specifically, to mounting systems for sector nozzles.
In general, gas turbines combust a mixture of compressed air and fuel within a combustor to produce hot combustion gases. The hot combustion gases rotate blades of the turbine to rotate a shaft that drives a load, such as an electrical generator. Fuel nozzles within the combustor inject fuel and air into the combustor. In some designs, the fuel nozzles include one or more mixing sections that pre-mix the fuel and air before the fuel and air enters the combustion zone. During operation of the combustor, the mixing sections, as well as other components of the fuel nozzles, may be subjected to vibration and loads.
Certain embodiments commensurate in scope with the originally claimed invention are summarized below. These embodiments are not intended to limit the scope of the claimed invention, but rather these embodiments are intended only to provide a brief summary of possible forms of the invention. Indeed, the invention may encompass a variety of forms that may be similar to or different from the embodiments set forth below.
In a first embodiment, a system includes a sector nozzle for a gas turbine combustor. The sector nozzle is configured to fit with adjacent sector nozzles to form a fuel nozzle assembly. The sector nozzle includes a nozzle portion configured to mix fuel and air to produce a fuel-air mixture, a shell coupled to the nozzle portion, a first longitudinal strut and a second longitudinal strut each coupled to a first surface of the shell on opposite sides of a window within the first surface, and a second longitudinal strut coupled to a second surface of the shell, where the second surface is disposed opposite of the first surface.
In a second embodiment, a system includes a sector nozzle for a gas turbine combustor. The sector nozzle is configured to fit with adjacent sector nozzles to form a fuel nozzle assembly. The sector nozzle includes a nozzle portion configured to mix fuel and air to produce a fuel-air mixture and a shell coupled to the nozzle portion. The shell includes a top panel, a bottom panel, and a pair of side panels extending between the top panel and the bottom panel. The sector nozzle also includes a base coupled to the shell at an end opposite from the nozzle portion, a first longitudinal strut and a second longitudinal strut each coupled to the base and the top panel, and a third longitudinal strut coupled to the base and the bottom panel.
In a third embodiment, a fuel nozzle assembly includes a plurality of sector nozzles disposed adjacent to one another to form a circular cross section within a gas turbine combustor. Each of the plurality of sector nozzles includes a nozzle portion configured to mix fuel and air to produce a fuel-air mixture, a shell coupled to the nozzle portion, a first longitudinal strut and a second longitudinal strut each coupled to a first surface of the shell, and a third longitudinal strut coupled to a second surface of the shell, wherein the second surface is disposed opposite of the first surface.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
The present disclosure is directed to mounting systems for sector nozzles that inject fuel into a combustion chamber, such as a gas turbine combustion chamber. Each sector nozzle may have a segmented shape, such as a wedge shaped cross section, that allows the sector nozzle to fit together with adjacent sector nozzles to form an annular ring of sector nozzles within a combustor. Further, the sector nozzle includes one or more fuel supply passages that extend from the end cover of the combustor to a fuel plenum. A series of mixing tubes extend through the fuel plenum. Air flows through the interior of the mixing tubes, and each tube includes side openings that allow fuel from the plenum to enter the tubes and mix with the air. The fuel-air mixture is then directed through the tubes and into the combustion zone.
Rather then employing a nozzle cap that is disposed near the combustion zone and that mounts all of the nozzles within the liner, the mounting structures described herein can be employed to mount individual sector nozzles to the combustor end cover. The mounting systems can be installed within the combustor as an integral part of the sector nozzle, thus eliminating the need for installment of a separate mounting component, such as a cap. According to certain embodiments, the mounting structures include longitudinal struts and a shell designed to facilitate attachment of the sector nozzle to the combustor end cover. The mounting systems may be designed to provide improved structural stability relative to traditional nozzle cap configurations. For example, the longitudinal struts and shell may be designed to stabilize the sector nozzle against vibrations and loads. Further, in certain embodiments, the mounting systems may be designed to shift the natural frequency of the sector nozzle past the third revolution of the gas turbine. In other words, the mounting systems may enable the sector nozzle to withstand the vibration and loads generated by operating the turbine at a frequency that is at least three times greater than the base frequency of the gas turbine.
Within the combustor 12, the fuel 14 may mix with pressurized air, shown by arrows 16, and ignition may occur, producing hot combustion gases 18 that power the gas turbine system 10. As discussed further below with respect to
The pressurized air 16 includes intake air 20 that enters the gas turbine system 10 through an air intake section 22. The intake air 20 is compressed by a compressor 24 to produce the pressurized air 16 that enters the combustor 12. In certain embodiments, the sector fuel nozzles may direct the fuel 14 and the pressurized air 16 into the combustion zone of the combustor 12. Within the combustion zone, the pressurized air 16 combusts with the fuel 14 to produce the hot combustion gases 18. From the combustor 12, the hot combustion gases 18 may flow through a turbine 26 that drives the compressor 24 via a shaft 28. For example, the combustion gases 18 may apply motive forces to turbine rotor blades within the turbine 26 to rotate the shaft 28. The shaft 28 also may be connected to a load 30, such as a generator, a propeller, a transmission, or a drive system, among others. After flowing through the turbine 26, the hot combustion gases 18 may exit the gas turbine system 10 through an exhaust section 32.
The sector nozzles 34 are arranged adjacent to one another to form a generally circular fuel nozzle assembly 44. According to certain embodiments, each sector nozzle 34 has a wedge-shaped cross section designed to abut a pair of adjacent sector nozzles 34. Further, in certain embodiments, each sector nozzle 34 may be arranged around a center fuel nozzle 46 (
The mounting portion 50 also includes a shell 56 that extends between the base 52 and the nozzle portion 48 in the axial direction 57. The shell 56 extends generally perpendicular to the base 52 and a face 58 of the sector nozzle 34. According to certain embodiments, the shell 56 may be welded to the base 52 and the nozzle portion 48. Longitudinal struts 60 extend along the shell 56 to provide strength and stability. As discussed further below with respect to
In operation, air from the compressor may enter the sector nozzles 34 through windows 66 and 67 (
While the nozzle portion 48 mixes the fuel and the air to direct a fuel-air mixture into the combustion chamber 36, the mounting portion 50 provides mounting and structural support for the nozzle portion 48. In particular, the mounting portion 50 enables the nozzle portion 48 to be supported by the end cover 54 (
The shell 56 is also coupled to the fuel plenum 70 of the nozzle portion 48. According to certain embodiments, the shell 56 may be welded, or otherwise joined, to the exterior of the fuel plenum 70. Further, the shell 56 has a wedge-shaped cross section that is substantially similar to the wedge-shaped cross section of the nozzle portion 48, which facilitates attachment of the shell 56 to the nozzle portion 48. The shell 56 includes panels 78, 80, 82, and 84 that are coupled to one another to enclose the interior volume 77 of the shell 56. According to certain embodiments, the panels 78, 80, 82, and 84 may be separate pieces that are welded, or otherwise joined, to one another. However, in other embodiments, the panels 78, 80, 82, and 84 may be integral components of the shell 56. For example, the shell 56 may be a single piece of sheet metal that is roll-formed to produce panels 78, 80, 82, and 84. In another example, the shell 56 may be formed from a metal tube. The radially outward, top panel 78 and the radially inward, bottom panel 84 are disposed opposite from one another and are curved to follow the corresponding curvatures of the nozzle portion 48. The side panels 80 and 82 are angled towards one another and connect the top and bottom panels 78 and 84. The windows 66 and 67 are disposed in the shell 56 to enable air to enter the shell 56. For example, the window 66 allows air to enter the interior 77 of the shell 56 through the bottom panel 84 and the side panels 80 and 82, while the window 67 allows air to enter the interior 77 of the shell 56 through the top panel 78. According to certain embodiments, the windows 66 and 67 may be formed by cutting, stamping, or punching the shell 56.
The longitudinal struts 60 are coupled to the exterior surface of the top panel 78 and extend along a length 86 of the shell 56. In particular, the struts 60 have a length 88 that is smaller than the length 86 of the shell 56. According to certain embodiments, the length 88 of the longitudinal struts 60 may be approximately 50 to 100%, and all subranges therebetween, of the total length 86 of the shell 56. More specifically, the length 88 of the struts 60 may be approximately 90 to 100% of the total length 86 of the shell 56. Each strut 60 tapers from a first height 90 at a first end 92 to a smaller height 94 at a second end 96, located closest to the nozzle portion 48. The first end 92 is coupled to the base 52 and the second end 96 is located proximate to the fuel plenum 70. According to certain embodiments, the tapered geometry of the struts 60 may be designed to produce an aerodynamic flow of air into the shell 56, while also enabling the struts 60 to have a relatively lightweight construction when compared to struts of a constant cross section. However, in other embodiments, the geometry of the struts 60 may vary. For example, in other embodiments, the struts 60 may have a generally square, rectangular, trapezoidal, and/or curved cross section. Further, in other embodiments, the number of struts 60 may vary. For example, in other embodiments, 1, 2, 3, or more struts 60 may be coupled to the top panel 78.
The longitudinal strut 62 is coupled to the interior surface of the bottom panel 84 and extends along the length 86 of the shell 56. In particular, the longitudinal strut 62 has a length 98 that is smaller than the total length 86 of the shell 56. In certain embodiments, the length 98 may be approximately equal to the length 88 of the top longitudinal struts 60. However, in other embodiments, the length 98 of the bottom longitudinal strut 62 may be shorter or longer than the length 68 of the top longitudinal struts 60. The longitudinal strut 62 includes a straight portion 100 that extends through the window 66 and that is coupled to the base 52. The longitudinal strut 62 also includes a tapered portion 102 that tapers from a height 104 at a first end 106 to a height 108 at a second end 110, located closest to the nozzle portion 48. The first end 106 is coupled to the base 52 and the second end 110 is located proximate to the fuel plenum 70. According to certain embodiments, the tapered geometry of the strut 62 may be designed to produce an aerodynamic flow of air through the interior 77 of the shell 56, while also enabling the struts 62 to have a relatively lightweight construction when compared to struts of a constant cross section. However, in other embodiments, the geometry of the strut 62 may vary. For example, in other embodiments, the strut 62 may have a generally square, rectangular, trapezoidal, and/or curved cross section. Further, in other embodiments, the number of struts 62 may vary. For example, in other embodiments, 1, 2, 3, or more struts 62 may be coupled to the bottom panel 84.
While the bottom strut 62 extends through the window 66, the top struts 60 are disposed on opposite sides of the window 67. Further, a stiffening rib 112 extends generally transverse to and between the top struts 60 to strengthen the shell 56. According to certain embodiments, the stiffening rib 112 may include a curved lip designed to aerodynamically direct air into the shell 56 through the window 67. However, in other embodiments, the stiffening rib 112 may be omitted.
As shown in
The sector nozzle 34 shown in
As discussed above, the mounting systems described herein may be particularly well suited to mounting sector nozzles within a combustor. The mounting systems include a shell and longitudinal struts designed to withstand the vibration and loads generated during operation of a turbine. Further, the shell and longitudinal struts are designed to facilitate attachment of the sector nozzles to an end cover of a combustor. Accordingly, rather than employing a separate end cap that attaches the sector nozzles to the liner, each sector nozzle may be individually mounted to the end cover using an integral part of the sector nozzle.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
