Combustor nozzle and method for fabricating the combustor nozzle

A combustor nozzle includes a single-piece swirler. The single-piece swirler includes a center body extending axially along the single-piece swirler, a first fuel passage inside the center body, and a plurality of vanes extending radially from the center body. A method for fabricating a combustor nozzle includes casting a single-piece swirler having a center body and a plurality of vanes extending radially from the center body.

FIELD OF THE INVENTION

The present invention generally involves a combustor nozzle and method for fabricating the combustor nozzle.

BACKGROUND OF THE INVENTION

Combustors are known in the art for igniting fuel with air to produce combustion gases having a high temperature and pressure. For example, gas turbine systems, aircraft engines, and numerous other combustion-based systems include one or more combustors that mix a working fluid, such as air, with fuel and ignite the mixture to produce high temperature and pressure combustion gases. Each combustor generally includes one or more nozzles that mix the working fluid with the fuel prior to combustion. If the fuel and air are not evenly mixed prior to combustion, localized hot spots may form in the combustor. The localized hot spots may increase the production of undesirable NOx emissions and may increase the chance for the flame in the combustor to flash back into the nozzles and/or become attached inside the nozzles which may damage the nozzles. Although flame flash back and flame holding may occur with any fuel, they occur more readily with high reactive fuels, such as hydrogen, that have a higher burning rate and a wider flammability range.

It is widely known that the thermodynamic efficiency of a combustion-based system generally increases as the operating temperature, namely the combustion gas temperature, increases. A variety of techniques exist to allow higher operating temperatures while minimizing NOx emissions, flash back, and flame holding. Many of these techniques seek to reduce localized hot spots to reduce the production of NOx and/or reduce low flow zones to reduce and/or prevent the occurrence of flash back or flame holding. For example, continuous improvements in nozzle designs result in more uniform mixing of the fuel and air prior to combustion to reduce or prevent localized hot spots from forming in the combustor. Alternately, or in addition, nozzles have been designed to ensure a minimum flow rate of fuel and/or air through the nozzle to cool the nozzle surfaces and/or prevent the combustor flame from flashing back into the nozzle.

Improved nozzle designs, however, may result in increased manufacturing, maintenance, and repair costs. For example, improved nozzle designs that incorporate multiple fuel channels, swirlers, and fuel injectors typically increase the number of braze and/or weld joints in the nozzle. These joints are relatively expensive to produce and require increased inspections and repairs. Therefore, an improved nozzle design that reduces or eliminates braze joints in the nozzle would be useful.

BRIEF DESCRIPTION OF THE INVENTION

One embodiment of the present invention is a combustor nozzle that includes a single-piece swirler. The single-piece swirler includes a center body extending axially along the single-piece swirler, a first fuel passage inside the center body, and a plurality of vanes extending radially from the center body.

Another embodiment is a combustor nozzle that includes a single-piece swirler. The single-piece swirler includes a center body configured to receive a flow of fuel, a plurality of vanes extending radially from the center body, and a shroud circumferentially surrounding at least a portion of the plurality of vanes.

Embodiments of the present invention may also include a method for fabricating a combustor nozzle. The method includes casting a single-piece swirler having a center body and a plurality of vanes extending radially from the center body.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a simplified cross-section of a combustor10according to one embodiment of the present invention. As shown, the combustor10may include one or more nozzles12radially arranged in a top cap14. A casing16may surround the combustor10to contain the air or compressed working fluid exiting the compressor (not shown). An end cap18and a liner20generally surround a combustion chamber22downstream of the nozzles12. A flow sleeve24with flow holes26may surround the liner20to define an annular passage28between the flow sleeve24and the liner20. As used herein, the terms “holes”, “apertures”, “ports”, and “passages” are intended to be substantially identical in meaning and may be used as synonyms for one another. The compressed working fluid may pass through the flow holes26in the flow sleeve24to flow along the outside of the liner20to provide film or convective cooling to the liner20. The compressed working fluid then reverses direction to flow through the one or more nozzles12where it mixes with fuel before igniting in the combustion chamber22to produce combustion gases having a high temperature and pressure.

FIG. 2shows a perspective cut-away view andFIG. 3shows a side cross-section view of the nozzle12according to one embodiment of the present invention. As shown inFIGS. 2 and 3, the nozzle12may comprise a flange30, an inlet flow conditioner32, a single-piece swirler34, a burner tube36, and a diffusion nozzle38. The flange30may be bolted or otherwise attached to the end cap18at one end and welded, bolted, or otherwise connected upstream of the single-piece swirler34at the other end. Internal passages40inside the flange30provide fluid communication between the end cap18and the single-piece swirler34. The flange30may be constructed from steel or steel alloys capable of withstanding the expected temperatures and may be annularly or conically shaped to reduce the flow resistance as the compressed working fluid flows around the flange30and into the inlet flow conditioner32.

The inlet flow conditioner32may circumferentially surround at least a portion of the flange30and/or single-piece swirler34to improve the velocity distribution of the compressed working fluid as it flows through or across the single-piece swirler34. The inlet flow conditioner32may comprise a perforated screen and/or one or more flow guides. Alternately, or in addition, as shown inFIGS. 2 and 3, the inlet flow conditioner32may comprise an annular sleeve32with a bell mouth opening42, and the annular sleeve32may define a flow passage44between the flange30and/or the single-piece swirler34and the annular sleeve32.

FIG. 4provides a perspective cut-away of the single-piece swirler34shown inFIGS. 2 and 3. As shown, the single-piece swirler34is a unitary or one-piece component that may be forged or cast from steel or steel alloys capable of withstanding the expected temperatures. The single-piece swirler34generally comprises a center body46, a plurality of vanes48, and/or a shroud50. The center body46generally comprises a plenum or annular tube46aligned with and extending along an axial centerline52of the nozzle12to provide fluid communication through the single-piece swirler34. As shown inFIGS. 2-4, the single-piece swirler34may further include a tube54inside at least a portion of the center body46and at least one support56(not shown inFIG. 4) extending radially between the tube54and the center body46. In this manner, the tube54defines an annular space58between the tube54and the center body46to allow a fluid, such as fuel, a diluent, or the compressed working fluid, to readily flow through the single-piece swirler34.

The plurality of vanes48may extend radially from the center body46and may comprise curved or angled blades that impart tangential velocity to the fuel and/or compressed working fluid flowing over the vanes48. As further shown inFIGS. 2-4, fuel passages60through the center body46and the vanes48may provide fluid communication for fuel to be distributed through metering ports62in the vanes48. The metering ports62may be on one or both sides of the vanes48and/or at the tip of the vanes48. Fuel may thus be supplied through the internal passages40in the flange30, through the annular space58in the center body46, through the fuel passages60, and out of the metering ports62in the vanes48. In this manner, the compressed working fluid may flow through the flow passage44and mix with fuel injected into the flow passage44from the metering ports62in the vanes48.

The shroud50circumferentially surrounds at least a portion of the center body46and/or vanes48so that the flow passage44may extend axially through the single-piece swirler34. As a result, the shroud50may contain and guide the mixture of fuel and compressed working fluid flowing through the flow passage44and over the vanes48.

As shown inFIGS. 2 and 3, the burner tube36circumferentially surrounds at least a portion of the diffusion nozzle38and/or single-piece swirler34to contain and guide the mixture of fuel and compressed working fluid flowing through the nozzle12. The burner tube36may be welded, bolted, or otherwise connected to the single-piece swirler34and may extend axially downstream of the single-piece swirler34.

The diffusion nozzle38provides fluid communication for fuel and/or compressed working fluid to flow from the single-piece swirler34through the nozzle12. As shown inFIGS. 2 and 3, the diffusion nozzle38may comprise a plenum or annular tube38with fuel ports64at the downstream end. The diffusion nozzle38may be centrally located within the burner tube36and may be connected to and extend downstream from the single-piece swirler34. Specifically, the diffusion nozzle38may be welded, bolted, or otherwise connected to the tube54and/or center body46, as shown inFIGS. 2 and 3. Fuel may thus flow through the flange30, through the tube54inside the center body46, and through the fuel ports64in the diffusion nozzle38. In addition, a continuous passage66through the shroud50, vanes48, and center body46may allow the compressed working fluid to flow through the single-piece swirler34to dilute fuel flowing through the tube54in the center body46before flowing out of the diffusion nozzle38.

FIG. 5shows a side cross-section view of a nozzle70according to an alternate embodiment of the present invention. In this particular embodiment, the nozzle70generally comprises a flange72, a single-piece swirler74, a shroud76, and a diffusion nozzle78. The flange72may be bolted or otherwise attached to the end cap18at one end and welded, bolted, or otherwise connected upstream of the single-piece swirler74at the other end. Internal passages80inside the flange72again provide fluid communication between the end cap18and the single-piece swirler74. The flange72may be constructed from steel or steel alloys capable of withstanding the expected temperatures and may be annularly or conically shaped to reduce the flow resistance as the compressed working fluid flows around the flange72and into the shroud76.

FIG. 6provides a perspective cut-away of the single-piece swirler74shown inFIG. 5. As shown, the single-piece swirler74is again a unitary or one-piece component that may be forged or cast from steel or steel alloys capable of withstanding the expected temperatures. In this particular embodiment, the single-piece swirler74generally comprises a center body82and a plurality of vanes84, as previously described with respect to the embodiment shown inFIG. 4. Specifically, the center body82generally comprises a plenum or annular tube82aligned with and extending along an axial centerline86of the nozzle70to provide fluid communication through the single-piece swirler74. As shown inFIGS. 5 and 6, the single-piece swirler74may further include a tube88inside at least a portion of the center body82and at least one support90(not shown inFIG. 6) extending radially between the tube88and the center body82. In this manner, the tube88defines an annular space92between the tube88and the center body82to allow a fluid, such as fuel, a diluent, or the compressed working fluid, to readily flow through the single-piece swirler74.

The plurality of vanes84may extend radially from the center body82and may comprise curved or angled blades that impart tangential velocity to fuel and/or compressed working fluid flowing over the vanes84. As further shown inFIGS. 5 and 6, fuel passages94through the center body82and the vanes84may provide fluid communication for fuel to be distributed through metering ports96in the vanes84. The metering ports96may be on one or both sides of the vanes84and/or at the tip of the vanes84. Fuel may thus be supplied through the internal passages80in the flange72, through the annular space92in the center body82, through the fuel passages94, and out of the metering ports96in the vanes84.

In the embodiment shown inFIGS. 5 and 6, the shroud76is a separate component from the single-piece swirler74, and the shroud76performs the functions provided by the inlet flow channel32, shroud50, and burner tube36previously described with respect to the embodiment shown inFIGS. 2-4. Specifically, the shroud76may be welded, bolted, or otherwise connected to the single-piece swirler74and may extend upstream and/or downstream of the single-piece swirler74. Upstream of the single-piece swirler74, the shroud76may comprise an annular sleeve76with a bell mouth opening98that circumferentially surrounds at least a portion of the flange72and/or single-piece swirler74to improve the velocity distribution of the compressed working fluid as it flows through or across the single-piece swirler74. The annular sleeve76may define a flow passage100between the flange72and/or the single-piece swirler74and the annular sleeve76, and the compressed working fluid may flow through the flow passage100and mix with fuel injected into the flow passage100from the metering ports96in the vanes84.

Along the axial length of the single-piece swirler74, the shroud76may circumferentially surround at least a portion of the center body82and/or vanes84so that the flow passage100may extend axially through the single-piece swirler74. As a result, the shroud76may contain and guide the mixture of fuel and compressed working fluid flowing through the flow passage100and over the vanes84. Downstream of the single-piece swirler74, the shroud76may circumferentially surround at least a portion of the diffusion nozzle78and/or single-piece swirler74to contain and guide the mixture of fuel and compressed working fluid flowing through the nozzle70.

The diffusion nozzle78provides fluid communication for fuel and/or compressed working fluid to flow from the single-piece swirler74through the nozzle70. As shown inFIG. 5, the diffusion nozzle78may comprise a plenum or annular tube78with fuel ports102at the downstream end. The diffusion nozzle78may be centrally located within the shroud76and may be connected to and extend downstream from the single-piece swirler74. Specifically, the diffusion nozzle78may be welded, bolted, or otherwise connected to the tube88and/or center body82, as shown inFIG. 5. Fuel may thus flow through the flange72, through the tube88inside the center body82, and through the fuel ports102in the diffusion nozzle78. In addition, a continuous passage104through the shroud76, vanes84, and center body82may allow compressed working fluid to flow through the single-piece swirler74to dilute the fuel flow through the nozzle70before exiting the diffusion nozzle78through the fuel ports102.

The embodiments previously described and illustrated inFIGS. 2-6may provide a method for fabricating a combustor nozzle12,70. Specifically, the method may comprise casting the single-piece swirler34,74having the center body46,82and the plurality of vanes48,84extending radially from the center body46,82. In particular embodiments, the single-piece swirler48may also include the shroud50, as shown inFIG. 4. The method may further include connecting the annular flange30,72to the single-piece swirler34,74upstream of the center body46,82and/or connecting the shroud76and/or burner tube36circumferentially around at least a portion of the plurality of vanes48,84. In this manner, the method eliminates braze joints from the single-piece swirler34,74, improving durability and reducing the complexity of the combustor nozzle12,70design.