Flared cone for mixer assembly for gas turbine combustor

Abstract

A flared cone for a mixer assembly includes an annular conical wall extending circumferentially about a mixer assembly centerline, the annular conical wall including a conical inner surface defining a conical opening of the annular conical wall, and an annular axial wall extending in a longitudinal direction relative to the mixer assembly centerline, the annular axial wall being disposed radially outward of the annular conical wall and connected to the annular conical wall. The annular conical wall and the annular axial wall define an annular step circumferentially about the mixer assembly centerline and extending upstream in the longitudinal direction between a downstream end of the annular conical wall and a rear surface of the annular axial wall.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a flare cone of a mixer assembly of a combustor for a gas turbine engine. BACKGROUND

[0002] Some conventional gas turbine engines are known to include rich burn combustors that generally use a swirler integrated with a fuel nozzle to deliver a swirled fuel / air mixture to the combustor. A radial-radial swirler is one example of such a swirler and includes a primary radial swirler, a secondary radial swirler, and a flare cone connected to the secondary swirler. The primary swirler includes a primary swirler venturi in which a primary swirled air stream from the primary swirler mixes with fuel injected through the fuel nozzle into the primary swirler venturi, thereby creating a swirled primary fuel-air mixture. The secondary swirler provides a secondary swirled air stream downstream of the primary swirler in which the secondary swirled air stream mixes with the swirled primary fuel-air mixture, thereby creating a swirled fuel-air mixture. The swirled fuel-air mixture then flows downstream to the flare cone connected to a downstream end of the secondary swirler. The flare cone has a conical inner surface that disperses the swirled secondary fuel-air mixture into a combustion chamber where it is ignited and burned to produce combustion product gases. BRIEF DESCRIPTION OF DRAWINGS

[0003] The features and advantages of the present disclosure will be apparent from the following detailed description of various exemplary embodiments, as illustrated in the accompanying drawings, in which like reference numerals generally represent like, functionally similar, and / or structurally similar elements.

[0004] Figure 1 is a schematic partial cross-sectional side view of an exemplary high-bypass turbofan jet engine in accordance with aspects of the present disclosure.

[0005] Figure 2 is a partial cross-sectional side view of an exemplary combustion section in accordance with aspects of the present disclosure.

[0006] Figure 3 is a partial cross-sectional side view of a front portion of the exemplary combustion section of Figure 2

[0007] Figure 4 is a partial cross-sectional side detail view of a portion of the flare cone taken at detail 4-4 of Figure 3

[0008] Figure 5 is an enlarged detail view of one aspect of the flare cone taken at detail 101 of Figure 4

[0009] Figure 6 ​​​is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure. Figure 4 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure.

[0010] Figure 7 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure. Figure 4 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure.

[0011] Figure 8 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure. Figure 4 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure.

[0012] Figure 9 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure. Figure 4 is a detail view of another aspect of the flared cone taken at detail 101 according to aspects of the present disclosure.DETAILED DESCRIPTION

[0013] Features, advantages, and embodiments of the present disclosure are set forth below with reference to the detailed description and accompanying drawings. Furthermore, the detailed description is exemplary and explanatory only and is not intended to be limiting of the present disclosure as claimed.

[0014] Various embodiments are discussed in detail below. While specific implementations are discussed, this is simply for illustration purposes. One skilled in the relevant art will recognize from the teachings herein how make and use other implementations and configurations.

[0015] As can be used herein, the terms "first," "second," and "third" can be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.

[0016] The terms "upstream" and "downstream" refer to the relative direction with respect to fluid flow in a fluid path. For example, "upstream" refers to the direction from which fluid flows, and "downstream" refers to the direction to which fluid flows.

[0017] In a rich burn combustor including a radial-radial cyclone, air is provided from a pressure plenum of the combustor to a primary cyclone, where swirl is induced in the air by swirl vanes in the primary cyclone as the air flows through the primary cyclone. The primary cyclone further includes a venturi into which a fuel nozzle injects fuel, which mixes with the swirling air flow of the primary cyclone in the venturi to produce a swirling primary fuel-air mixture. A secondary cyclone provides a secondary swirling air flow downstream of the primary cyclone, where the secondary swirling air flow mixes with the swirling primary fuel-air mixture, thereby producing a swirling fuel-air mixture. The swirling fuel-air mixture then flows downstream of the secondary cyclone to a flared cone connected to a downstream end of the secondary cyclone.

[0018] Prior to entering the combustor, the divergent cone causes the swirling fuel-air mixture to expand along the diverging conical inclined surface, where it is ignited and burned to produce combustion product gases in the combustor. Conventional divergent cones utilize a fixed diverging conical inclined surface and include a sharp edge at the exit end of the conical inclined surface. In addition, conventional divergent cones include a backside cooling slot having a fixed angle that generally matches the angle of the conical inclined surface. Due to the fixed conical inclined surface and sharp edge, a defined flow separation occurs from the sharp edge such that the swirling flow expands at an angle equal to or less than the angle of the diverging conical inclined surface of the divergent cone. As a result, the resulting flow is susceptible to combustion instability, which is promoted by the unstable interaction of the flame, corner vortices formed in the flow at the sharp edge, and the cooling flow provided by the dome.

[0019] The present disclosure addresses the above problems by providing aerodynamic turning of the flow on the divergent cone and dome to minimize combustion dynamics, thereby reducing the unstable interaction of the flame with the cooling flow of the dome. According to the present disclosure, in one aspect, an annular step having a defined width and height is provided on the divergent cone outer end instead of a sharp edge. In another aspect, a contoured inner surface of the divergent cone is provided to allow a steeper angle flow closer to the exit end of the divergent cone. Both the annular step and contoured surface provide a smoother transition for the fuel-air mixture flow exiting the divergent cone at the outer edge, thereby reducing unstable flame motion. In addition, the divergent cone shape can influence the flame shape, making the flame more resistant to pressure fluctuations.

[0020] Reference will now be made to the drawings, Figure 1 is a schematic partial cross-sectional side view of an exemplary high-bypass turbofan jet engine 10, referred to herein as "engine 10," which can incorporate various embodiments of the present disclosure. Although described further below with reference to a ducted turbofan engine, the present disclosure is also applicable to general turbomachinery, including turbojet, turboprop, and turboshaft gas turbine engines, including marine and industrial turbine engines and auxiliary power units. Moreover, the present invention is not limited to ducted fan-type turbine engines as shown in Figure 1 but can be implemented in unducted fan (UDF) type turbine engines. As shown in Figure 1 engine 10 has a longitudinal or axial centerline axis 12 that extends from an upstream end 98 to a downstream end 99 for reference purposes. Generally, the engine 10 can include a fan assembly 14 and a core engine 16 disposed downstream of the fan assembly 14.

[0021] The core engine 16 typically includes a housing 18 defining an annular inlet 20. The housing 18 surrounds or at least partially forms, in a series flow relationship, a compressor section having a boost or low-pressure (LP) compressor 22 and a high-pressure (HP) compressor 24, a combustion section 26, a turbine section including a high-pressure (HP) turbine 28 and a low-pressure (LP) turbine 30, and an injection / exhaust nozzle section 32. A high-pressure (HP) rotor shaft 34 drives the HP turbine 28 to the HP compressor 24. A low-pressure (LP) 36 drives the LP turbine 30 to the LP compressor 22. The LP rotor shaft 36 may also be connected to a fan 38 of the fan assembly 14. In a specific embodiment, as... Figure 1 As shown, the LP rotor shaft 36 can be connected to the fan shaft 38 via a reduction gear 40, for example in an indirect drive or gear drive configuration. In other embodiments, although not shown, the engine 10 may also include an intermediate pressure (IP) compressor and a turbine that can rotate with the intermediate pressure shaft.

[0022] like Figure 1 As shown, the fan assembly 14 includes a plurality of fan blades 42 coupled to and extending radially outward from the fan shaft 38. An annular fan housing or nacelle 44 circumferentially surrounds at least a portion of the fan assembly 14 and / or the core engine 16. In one embodiment, the nacelle 44 may be supported relative to the core engine 16 by a plurality of circumferentially spaced outlet guide vanes or struts 46. Furthermore, at least a portion of the nacelle 44 may extend over an external portion of the core engine 16 to define a bypass airflow passage 48 therebetween.

[0023] Figure 2 An exemplary combustion section 26 according to this disclosure is depicted. Figure 2 In this configuration, combustion section 26 includes a mixer assembly 50, a fuel nozzle assembly 52, a dome assembly 54, and an annular combustion bushing 56 within a housing 64. The annular combustion bushing 56 includes an outer annular bushing 58 and an inner annular bushing 60, forming a combustion chamber 62 between them. A pressure chamber 66 is formed within the dome assembly 54. (Return to Reference) Figure 1 During operation, air 73 enters the nacelle 44, and a portion of the air 73 enters the compressor section as compressor inlet airflow 80, where it is compressed. Another portion of the air 73 enters the bypass airflow passage 48, thus providing bypass airflow 78. Figure 2In this configuration, air 82 from the compressor section (22 / 24) enters the combustion section 26 via a diffuser (not shown). A portion of the air 82(a) enters the dome assembly 54 and reaches the pressure chamber 66, while another portion of the air 82(b) is delivered to the external flow passage 68 between the annular combustion bushing 56 and the housing 64. As will be described below, the air 82(a) in the pressure chamber 66 passes through the mixer assembly 50 to mix with the fuel injected by the fuel nozzle assembly 52 and is ignited to produce combustion product gases 86.

[0024] Figure 3 A partial cross-sectional view of the front portion of the burner 27 in combustion section 26, including the mixer assembly 50, is depicted. Figure 3 In the middle, the burner 27 defines itself relative to the engine centerline axis 12 (see...). Figure 1 The mixer assembly 50 is generally symmetrical about the mixer assembly centerline 69, extending in the longitudinal direction L and generally perpendicular to the radial direction R. The mixer assembly 50 is suitably connected to the dome assembly 54, including via a support wall 94. The mixer assembly 50 includes a swirler assembly 51 and a fuel nozzle 76, which are arranged within the swirler assembly 51. The swirler assembly 51 includes a primary swirler 70 having a primary swirler venturi tube 88, a secondary swirler 72, and a swirler bead plate 74. The primary swirler 70 includes a plurality of primary swirler impellers 100 arranged circumferentially in a row such that each primary swirler impeller 100 extends radially inward. The primary swirler 70 further includes a primary swirler venturi tube 88, which extends concentrically about the mixer assembly centerline 69 in the longitudinal direction L. The primary cyclone separator 70 is configured to cause a corresponding portion of the pressurized air 82(a) from the pressure chamber 66 to swirl radially inward within the primary cyclone separator 70 in the primary cyclone direction (i.e., to rotate clockwise or counterclockwise about the center line 69 of the mixer assembly).

[0025] The secondary cyclone 72 similarly includes secondary cyclone impellers 102 arranged in a circumferential row, such that each secondary cyclone impeller 102 extends radially inward. The secondary cyclone 72 is configured to cause another corresponding portion of the pressurized air 82(a) from the pressure chamber 66 to swirl radially inward. The cyclone assembly 51 further includes a flared cone 90 connected downstream of the secondary cyclone 72.

[0026] It can be seen that the fuel nozzle assembly 52 includes a fuel nozzle 76 disposed within the swirler collar plate 74 of the swirler assembly 51. The fuel nozzle 76 injects fuel 84 into the primary swirler venturi 88 where it mixes with air 82(a) from the primary swirler 70. The fuel and air mixture in the primary swirler venturi 88 is further mixed downstream in the conical opening 122 of the flared cone 90 with air 82(a) from the secondary swirler 72. The fuel and air mixture from the flared cone 90 diverges from the flared cone 90 into the combustion chamber 62 at a divergence angle where it is ignited and burned to produce the combustion product gases 86.

[0027] The flow guide wall 92 extends radially outwardly from the annular axial wall outer surface 132 of the flared cone 90. The flow guide wall is a generally annular wall that extends circumferentially about the mixer assembly centerline 69. The flow guide wall 92 is also seen to be connected to the support wall 94 of the dome assembly 54 at a radially outward portion of the support wall 94. The support wall 94 is also seen to be connected to the annular axial wall outer surface 132 of the flared cone 90. A flow guide wall cavity 96 is formed between the support wall 94, the flow guide wall 92, and the annular axial wall outer surface 132 of the flared cone 90. It can be seen that the support wall 94 includes a plurality of support wall cooling passages 108 therethrough, and it can be seen that the flow guide wall 92 includes a plurality of flow guide wall cooling passages 106 therethrough. A portion of the air 82(a) from the pressure plenum 66 flows through the support wall cooling passages 108 into the flow guide wall cavity 96, and then through the flow guide wall cooling passages 106 to provide film cooling of the flow guide wall aft surface 138 of the flow guide wall 92.

[0028] The flared cone 90 includes a flared cone cavity 104 formed therein. As will be described in more detail below with respect to Figure 7 In brief summary, however, a portion of the air 82(a) from the flow guide wall cavity 96 enters the flared cone cavity 104 through a plurality of flared cone cooling holes 152 (see Figure 7 ) in the flared cone 90. The air 82(a) entering the flared cone cavity 104 then enters the slotted cooling passage 154 at an inlet 170 (see Figure 7 ) and exits the slotted cooling passage 154 of the flared cone 90 at an outlet 172.

[0029] Figure 4 is an enlarged detail view taken at detail 4-4 shown in Figure 3 . Figure 4 A more detailed view of the flared cone 90, the flow guide wall 92, and the support wall 94 is depicted. In Figure 4In the middle, it can be seen that the flare cone 90 includes an upstream end 126 and a downstream end 128. The support wall 94 includes support wall cooling passages 108 that provide air flow 82(a) from the pressure chamber 66 through the support wall 94 into the flow guide wall cavity 96. The support wall cooling passages 108 can be axially aligned (i.e., parallel to the mixer assembly centerline 69) or can be angled, such as the support wall cooling passages 112. The flow guide wall 92 includes flow guide wall cooling passages 106. As shown, the flow guide wall cooling passages 106 can be arranged radially outwardly, such that air flow from the flow guide wall cavity 96 is directed radially outwardly along a flow guide wall back surface 138 of the flow guide wall 92. Of course, the flow guide wall cooling passages 106 can also be axially arranged (i.e., parallel to the mixer assembly centerline 69) or have a compound angle with radial, axial, and tangential components. In addition, flow guide wall cooling passages 110 can be included to provide air flow from the flow guide wall cavity 96 radially inwardly along the flow guide wall back surface 138. Figure 4

[0030] Figures 5 to 7 Figure 4 is an enlarged detail view at detail 101, and depicts various different aspects of the flare cone 90. In Figure 5 , it can be seen that the flare cone 90 includes an annular tapered wall 114, an annular axial wall 124, and an annular inner axial wall 150. Each of the annular tapered wall 114, the annular axial wall 124, and the annular inner axial wall 150 extends circumferentially around the mixer assembly centerline 69 (see Figure 3 ). The mixer assembly centerline 69 can also be referred to as a flare cone centerline when referring to the flare cone itself, as opposed to the flare cone as part of the cyclone assembly 51. The annular tapered wall 114 includes an annular tapered wall inner surface 142 arranged at a tapered wall angle 116, and defines a tapered opening 122 therethrough. The tapered wall angle 116 can be, for example, forty-five degrees, or can be an angle in the range of from thirty to sixty degrees. The annular axial wall 124 is disposed at a radially outer portion 117 of the annular tapered wall 114 and is connected to the annular tapered wall 114. The annular axial wall 124 extends upstream in the longitudinal direction L (see Figure 3 ) from the annular tapered wall 114 to the upstream end 126 of the flare cone 90 (see Figure 4 ), with the annular axial wall 124 being connected to the secondary cyclone 72 (see Figure 4 ).

[0031] The annular inner axial wall 150 is connected to the annular tapered wall 114 at an annular tapered wall upstream end 118 of the annular tapered wall 114, and extends upstream in the longitudinal direction L from the annular tapered wall upstream end 118 of the annular tapered wall 114. The annular inner axial wall 150 can extend to the upstream end 126 of the flare cone 90, or as shown in Figure 4 ​​As shown, it may extend partially between the upstream end 118 of the annular conical wall 114 and the upstream end 126 of the flared cone 90. The annular inner axial wall 150 is also connected to the secondary cyclone separator 72. The annular inner axial wall 150 is radially spaced from the annular axial wall 124 to define a flared cone cavity 104 between the annular axial wall 124 and the annular inner axial wall 150. The flared cone cavity 104 may be an annular cavity extending circumferentially around the mixer assembly centerline 69. Flared cone cooling holes 152 (see...) Figure 7 The airflow 82(a) is considered to pass through the annular axial wall 124 and is provided from the guide wall cavity 96 to the flared cone cavity 104. (Refer to below...) Figure 7 The airflow to the flared cone cavity 104 is described in more detail.

[0032] At the 90° flaring cone Figure 5 In this aspect, the annular conical wall 114 includes a rear surface 140 of the annular conical wall extending radially outward from the downstream end 120 of the annular conical wall on the inner surface 142 of the annular conical wall. The rear surface 140 of the annular conical wall extends circumferentially around the centerline 69 of the mixer assembly and forms the downstream end 128 of the flared cone 90. The transition between the rear surface 140 of the annular conical wall and the inner surface 142 of the annular conical wall may include a circular portion (or mixing portion) 146 to allow for a smoother transition of the airflow exiting the flared cone. Figure 5 As shown, the rear surface 160 of the annular axial wall 124 extends radially outward from the radially outer portion 117 of the annular conical wall 114. The rear surface 160 of the annular axial wall also extends circumferentially around the mixer assembly centerline 69. Therefore, the annular conical wall rear surface 140 of the annular conical wall 114 and the rear surface 160 of the annular axial wall 124 can be substantially parallel to each other in the radial direction R (see Figure 124). Figure 3 However, the rear surface 160 of the annular axial wall 124 is longitudinally offset upstream of the rear surface 140 of the annular conical wall 114 to define an annular step 134 therebetween. The annular step 134, formed by a portion of the annular conical wall 114, extends circumferentially around the centerline 69 of the mixer assembly. The length of the annular step 134 in the longitudinal direction L can range from 0.03 inches to 0.08 inches (or approximately 0.76 mm to 2.0 mm). Of course, the length of the annular step 134 is not limited to the above range, and annular steps 134 that are longer or shorter than the above range can also be used. Therefore, the annular step 134 provides a smoother transition flow for the fuel-air mixture as it exits the flare cone at the downstream end of the flare cone and enters the combustion chamber, thereby reducing unstable flame movement at the exit end of the flare cone and thus better controlling combustion instability. This is at least in part due to the recirculation bubbles 161 formed in the flow field at the annular step 134 during operation.

[0033] The flow guide wall 92 is connected to the annular axial wall 124 at a downstream end 130 of the annular axial wall outer surface 132. It can be seen that the flow guide wall rear surface 138 of the flow guide wall 92 is radially aligned with the rear surface 160 of the annular axial wall 124. The flow guide wall 92, while shown as a separate element, can instead be integrally formed with the flared cone 90.

[0034] Figure 6 Another aspect of the flared cone 90 according to the present disclosure is depicted, again in cross-section 101, taken at a detail 102. Figure 4 Figure 6 The flared cone aspect of Figure 5 the flared cone aspect of Figure 6 all other aspects of the flared cone 90 are the same as the flared cone 90 of Figure 5 described again are not repeated. In the flared cone 90 of Figure 6 ​In aspects, the annular conical wall inner surface 142 is a continuously curved conical inner surface 143. The continuously curved conical inner surface 143 begins at a first conical wall angle 144 and transitions from the first conical wall angle 144 to end at a second conical wall angle 148, forming a smoothly curved surface therebetween. A beginning portion 162 of the continuously curved conical inner surface 143, beginning at the upstream end 119 of the continuously curved conical inner surface 143, can be disposed at the first conical wall angle 144. For example, the first conical wall angle 144 can be forty-five degrees relative to the mixer assembly centerline 69, taken at a tangent to the continuously curved conical inner surface 143 at the beginning portion 162. The continuously curved conical inner surface 143 then angularly transitions along its length from the first conical wall angle 144 to a steeper angle through an intermediate portion 163. For example, the intermediate portion 163 can be disposed at a conical wall intermediate angle 145 of fifty-two or fifty-three degrees, taken at a tangent to the continuously curved inner surface 143 at the intermediate portion 163. The continuously curved conical inner surface 143 continues to angularly transition along its length to an even steeper angle at an ending portion 164 proximate the downstream end 121 of the continuously curved conical inner surface 143. The ending portion 164 can be disposed at the second conical wall angle 148, which can be, for example, sixty degrees relative to the mixer assembly centerline 69, taken at a tangent to the continuously curved conical inner surface 143 at the ending portion 164. Thus, the portions of the continuously curved conical inner surface 143 between the beginning portion 162 and the ending portion 164 transition from the forty-five degree first conical wall angle 144 to the sixty degree second conical wall angle 148. Alternatively, the first conical wall angle 144 can be thirty degrees and the second conical wall angle 148 can be forty-five degrees. In yet another aspect, the first conical wall angle 144 can be sixty degrees and the second conical wall angle 148 can be seventy-five degrees. Other angles can be alternatively implemented than those described above, but as can be seen from the foregoing examples, the first conical wall angle 144 is less than the second conical wall angle 148, such that a steeper flow field is achieved as the surface transitions toward the exit end of the flared cone. Thus, Figure 6 Aspects of the arrangement of the flared cone can cause the flow along the surface of the annular conical wall of the flared cone to transition more steeply into the combustion chamber in order to provide improved combustor dynamics.

[0035] Figure 7 Yet another aspect of a flared cone 90 according to the present disclosure is depicted, also at Figure 4 taken at detail 101. Figure 7 The depicted flared cone aspect in Figure 5 The depicted flared cone aspect in Figure 5In this respect, the downstream end 128 of the flared cone 90 includes a rear surface 140 of an annular conical wall, which provides a smooth transition between the inner surface 142 of the annular conical wall and the annular step 134. However, in Figure 7 In this design, the inner surface 142 of the annular conical wall and the annular step 156 form an acute angle 168 to define the sharp edge 166 of the flared cone 90. The acute angle 168 is generally the same as the conical wall angle 116, provided that the annular step 156 is approximately parallel to the centerline 69 of the mixer assembly. Therefore, the annular step 156 can be more perpendicular to the centerline 69 of the mixer assembly in the longitudinal direction than... Figure 5 The annular step 134 is longer. The longer length of the annular step 156 can also be used to allow slotted cooling channel outlets 172 to be provided through the surface of the annular step 156.

[0036] in this regard, Figure 7 The flared cone includes multiple slotted cooling channels 154. The slotted cooling channels 154 include an inlet 170 at the flared cone cavity 104 and a slotted cooling channel outlet 172 at the annular step 156. A portion of the air 82(a) from the pressure chamber 66 flows through the support wall 94 (see...). Figure 4 The cooling channels (108 / 112) enter the guide wall cavity 96, then through the flared cone cooling holes 152 into the flared cone cavity 104, and then through the slotted cooling channels 154 to provide thin-film cooling at the annular step 156. Multiple slotted cooling channels 154 may be arranged circumferentially around the centerline 69 of the mixer assembly, and they may be spaced apart from each other in the circumferential direction. Therefore, while the flared cone cavity 104 may be an annular cavity, it may include slotted cooling channels 154 to provide fluid communication between various portions of the flared cone cavity 104 and the annular step 156, in which outlets 172 are arranged to pass through the surface of the annular step 156. The number and circumferential spacing of the slotted cooling channels 154, as well as the actual dimensions (e.g., height, width) of the slotted cooling channels, may vary to provide the required amount of cooling to the annular step 156.

[0037] Figure 8 Another aspect of the flared cone according to this disclosure is depicted, in Figure 4 Details were captured at point 101. Figure 8 The flared cone 90 is similar in aspect to Figure 7 aspect. Figure 8 aspect and Figure 7 One difference between the two is that Figure 8 The aspects include a continuously curved conical inner surface 143, similar to the aspects regarding Figure 6 As shown and described. Therefore, the above refers to Figure 6 The element with the described continuous curved conical inner surface 143 is suitable for Figure 8 The details regarding this aspect will not be elaborated upon here. Figure 8 All other aspects andFigure 7 The same, whose description is not repeated.

[0038] Figure 9 Another aspect of a flared cone in accordance with the present disclosure is depicted, in Figure 4 taken at detail 101. In Figure 9 In aspects of the flared cone 100, the annular conical wall 114 includes a continuously curved conical inner surface 143. Figure 9 The continuously curved conical inner surface 143 of the flared cone 100 is similar to those depicted in Figure 6 and includes the same elements. Therefore, its description will not be repeated. However, Figure 9 The annular conical wall 114 of the flared cone 100 includes a backside cooling channel 174. The backside cooling channel 174 can generally begin near the annular conical wall upstream end 118 of the annular conical wall 114 and extend radially outwardly and downstream therefrom through an annular step 180. The backside cooling channel 174 can also include a continuously curved profile similar to the continuously curved conical inner surface 143. Therefore, a backside cooling channel back surface 182 of the backside cooling channel 174 can have a continuously curved profile consistent with the continuously curved profile conical inner surface 143. A backside cooling channel front surface 184 of the backside cooling channel 174 can also have a continuously curved profile that is generally consistent with the back surface 182 of the backside cooling channel 174. The backside cooling channel 174 can also extend circumferentially around the mixer assembly centerline 69.

[0039] With the implementation of the backside cooling channel 174, a flared cone flange 178 is defined. The flared cone flange 178 is defined between the continuously curved conical inner surface 143 and the back surface 182 of the backside cooling channel 174. The flared cone flange 178 includes a sharp edge 166. The flared cone flange 178 further includes an annular step 180 that extends generally in the longitudinal direction and generally corresponds to the annular step 134 (see Figure 5 and Figure 6 ).

[0040] Figure 9 The annular conical wall 114 of the flared cone 100 further includes a plurality of impingement cooling holes 176. The impingement cooling holes 176 extend from the flow guide wall cavity 96 through the annular conical wall 114 to the backside cooling channel 174. In Figure 9 In aspects of the flared cone 100, the impingement cooling holes 176 are shown as angled, but they can instead be arranged perpendicular to the mixer assembly centerline 69 (see Figure 3). The plurality of impingement cooling holes 176 can be arranged circumferentially around the annular conical wall 114 and can be spaced apart from each other in the circumferential direction. The number of impingement cooling holes 176, as well as the size, shape, and spacing, can be based on a particular impingement cooling amount to be provided to the flared cone flange 178. In operation, cooling air from the flow guide wall cavity 96 flows through the plurality of impingement cooling holes 176 into the aft cooling passage 174, and then out of the aft cooling passage 174 at the annular step 180. As a result, impingement cooling can be provided to the flared cone flange 178. Moreover, the continuous curved conical inner surface 143, particularly the more steeply angled ending portion 164, provides better transitional flow of the fuel and air mixture from the flared cone into the combustor, thereby improving flame stability as well as durability of the flared cone. The continuous curved aft cooling passage 174 also provides a cooling air flow directed in substantially the same angular direction as the fuel-air mixture to improve combustion dynamics.

[0041] While the foregoing description generally relates to a gas turbine engine, it can be readily appreciated that the gas turbine engine can be implemented in various environments. For example, the engine can be implemented in an aircraft, but can also be implemented in non-aircraft applications, such as power generation stations, marine applications, or oil and gas production applications. Accordingly, the present disclosure is not limited to use in an aircraft.

[0042] Further aspects of the present disclosure are provided by the subject matter of the following clauses.

[0043] A mixer assembly of a combustor defining a mixer assembly centerline therethrough, the mixer assembly comprising a swirler assembly including a primary swirler and a secondary swirler arranged downstream of the primary swirler; and a flared cone arranged at a downstream end of the secondary swirler, the flared cone comprising: (a) an annular conical wall extending circumferentially around the mixer assembly centerline, the annular conical wall including a conical inner surface defining a conical opening of the annular conical wall, and (b) an annular axial wall extending in a longitudinal direction relative to the mixer assembly centerline, the annular axial wall being arranged radially outward of the annular conical wall and connected to the annular conical wall, wherein the annular conical wall and the annular axial wall define an annular step circumferentially around the mixer assembly centerline and extending upstream in the longitudinal direction between a downstream end of the annular conical wall and an aft surface of the annular axial wall.

[0044] The mixer assembly of any of the preceding clauses, wherein the downstream end of the annular conical wall comprises an annular conical wall aft surface extending radially outward from the downstream end of the conical inner surface of the annular conical wall to the annular step.

[0045] The mixer assembly of any of the preceding clauses, wherein the tapered inner surface of the annular tapered wall comprises a continuously curved tapered inner surface extending from an upstream end of the continuously curved tapered inner surface to a downstream end of the continuously curved tapered inner surface.

[0046] The mixer assembly of any of the preceding clauses, wherein (a) a starting portion of the continuously curved tapered inner surface at the upstream end of the continuously curved tapered inner surface is disposed at a first tapered wall angle relative to the mixer assembly centerline, (b) an ending portion of the continuously curved tapered inner surface at the downstream end of the continuously curved tapered inner surface is disposed at a second tapered wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved tapered inner surface between the starting portion and the ending portion transitions from the first tapered wall angle to the second tapered wall angle.

[0047] The mixer assembly of any of the preceding clauses, wherein the first tapered wall angle is forty-five degrees and the second tapered wall angle is sixty degrees.

[0048] The mixer assembly of any of the preceding clauses, wherein the flared cone further comprises an annular inner axial wall extending upstream in the longitudinal direction from an upstream end of the annular tapered wall, wherein an annular cavity is defined between the annular axial wall and the annular inner axial wall.

[0049] The mixer assembly of any of the preceding clauses, wherein the flared cone comprises a plurality of slotted cooling channels, each slotted cooling channel having an inlet at the annular cavity and an outlet at a surface of the annular step.

[0050] The mixer assembly of any of the preceding clauses, wherein the surface of the annular step intersects the tapered inner surface of the annular tapered wall at the downstream end of the annular tapered wall and forms an acute angle therebetween.

[0051] The mixer assembly of any of the preceding clauses, wherein the tapered inner surface of the annular tapered wall comprises a continuously curved tapered inner surface extending from an upstream end of the continuously curved tapered inner surface to a downstream end of the continuously curved tapered inner surface.

[0052] The mixer assembly of any of the preceding clauses, wherein (a) a starting portion of the continuously curved conical inner surface at the upstream end of the continuously curved conical inner surface is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) an ending portion of the continuously curved conical inner surface at the downstream end of the continuously curved conical inner surface is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

[0053] The mixer assembly of any of the preceding clauses, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

[0054] The mixer assembly of any of the preceding clauses, further comprising a flow- directing wall connected to the annular axial wall at a downstream end of the annular axial wall and extending radially outward from an outer surface of the annular axial wall, wherein the flow-directing wall is integrally formed with the flared cone.

[0055] The mixer assembly of any of the preceding clauses, wherein the flow-directing wall comprises a plurality of cooling channels therethrough.

[0056] The mixer assembly of any of the preceding clauses, wherein the annular conical wall further comprises a backside cooling channel, wherein a flared cone flange is defined between the backside cooling channel and the conical inner surface of the annular conical wall, wherein the conical inner surface of the annular conical wall comprises a continuously curved conical inner surface extending from an upstream end of the continuously curved conical inner surface to a downstream end of the continuously curved conical inner surface, and wherein (a) a starting portion of the continuously curved conical inner surface at the upstream end of the continuously curved conical inner surface is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) an ending portion of the continuously curved conical inner surface at the downstream end of the continuously curved conical inner surface is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

[0057] The mixer assembly of any of the preceding clauses, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

[0058] The mixer assembly of any of the preceding clauses, wherein the backside cooling channel comprises a backside cooling channel back surface that is a continuously curved surface that conforms with the continuously curved conical inner surface.

[0059] A flared cone for a mixer assembly, the flared cone defining a flared cone centerline therethrough, the flared cone comprising: an annular conical wall extending circumferentially about the flared cone centerline, the annular conical wall comprising a conical inner surface defining a conical opening of the annular conical wall; and an annular axial wall extending in a longitudinal direction relative to the flared cone centerline, the annular axial wall being disposed radially outward of a radially outward portion of the annular conical wall and connected to the annular conical wall, wherein the annular conical wall and the annular axial wall define an annular step that circumferentially surrounds the flared cone centerline and extends upstream in the longitudinal direction between a downstream end of the annular conical wall and a back surface of the annular axial wall.

[0060] The flared cone of any of the preceding clauses, wherein the downstream end of the annular conical wall comprises an annular conical wall back surface extending radially outward from a back end of the conical inner surface of the annular conical wall to the annular step.

[0061] The flared cone of any of the preceding clauses, wherein the conical inner surface of the annular conical wall comprises a continuously curved conical inner surface extending from an upstream end of the continuously curved conical inner surface to a downstream end of the continuously curved conical inner surface.

[0062] The flared cone of any of the preceding clauses, wherein (a) a starting portion of the continuously curved conical inner surface at the upstream end of the continuously curved conical inner surface is disposed at a first conical wall angle relative to the flared cone centerline, (b) an ending portion of the continuously curved conical inner surface at the downstream end of the continuously curved conical inner surface is disposed at a second conical wall angle relative to the flared cone centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

[0063] The flared cone of any of the preceding clauses, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

[0064] The flare cone of any of the preceding clauses, wherein the flare cone further comprises an annular inner axial wall extending upstream in the longitudinal direction from an upstream end of the annular conical wall, wherein an annular cavity is defined between the annular axial wall and the annular inner axial wall.

[0065] The flare cone of any of the preceding clauses, wherein the flare cone comprises a plurality of slotted cooling channels, each slotted cooling channel having an inlet at the annular cavity and an outlet at a surface of the annular step.

[0066] The flare cone of any of the preceding clauses, wherein the surface of the annular step intersects the conical inner surface of the annular conical wall at the downstream end of the annular conical wall and forms an acute angle therebetween.

[0067] The flare cone of any of the preceding clauses, wherein the conical inner surface of the annular conical wall comprises a continuously curved conical inner surface extending from an upstream end of the continuously curved conical inner surface to a downstream end of the continuously curved conical inner surface.

[0068] The flare cone of any of the preceding clauses, wherein (a) a starting portion of the continuously curved conical inner surface at the upstream end of the continuously curved conical inner surface is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) an ending portion of the continuously curved conical inner surface at the downstream end of the continuously curved conical inner surface is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

[0069] The flare cone of any of the preceding clauses, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

[0070] The flare cone of any of the preceding clauses, further comprising a flow guide wall connected to the annular axial wall at a downstream end of the annular axial wall and extending radially outward from an outer surface of the annular axial wall, wherein the flow guide wall is integrally formed with the flare cone.

[0071] The flare cone of any of the preceding clauses, wherein the flow guide wall comprises a plurality of cooling channels therethrough.

[0072] The flare cone according to any of the preceding clauses, wherein the annular conical wall further comprises a backside cooling channel, wherein a flare cone flange is defined between the backside cooling channel and the conical inner surface of the annular conical wall, wherein the conical inner surface of the annular conical wall comprises a continuously curved conical inner surface extending from an upstream end of the continuously curved conical inner surface to a downstream end of the continuously curved conical inner surface, and wherein (a) a starting portion of the continuously curved conical inner surface at the upstream end of the continuously curved conical inner surface is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) the continuously curved conical inner surface at the downstream end of the continuously curved conical inner surface is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

[0073] The flare cone according to any of the preceding clauses, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

[0074] The flare cone according to any of the preceding clauses, wherein the backside cooling channel comprises a backside cooling channel back surface that is a continuously curved surface coincident with the continuously curved conical inner surface.

[0075] While the foregoing description has been directed to some exemplary embodiments of the present disclosure, other variations and modifications will be apparent to those skilled in the art and can be made without departing from the spirit or scope of the present disclosure. Further, features described in conjunction with one embodiment can be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A mixer assembly for a burner, the mixer assembly defining a centerline passing through it, characterized in that, The mixer assembly includes: a cyclone assembly including a primary cyclone and a secondary cyclone arranged downstream of the primary cyclone; and a flared cone arranged at a downstream end of the secondary cyclone, the flared cone including (a) an annular conical wall extending circumferentially about the mixer assembly centerline, the annular conical wall including a conical inner surface defining a conical opening of the annular conical wall, and (b) an annular axial wall extending in a longitudinal direction relative to the mixer assembly centerline, the annular axial wall being arranged radially outward of the annular conical wall and connected to the annular conical wall, wherein the annular conical wall and the annular axial wall define an annular step circumferentially about the mixer assembly centerline and extending upstream in the longitudinal direction between a downstream end of the annular conical wall and a rear surface of the annular axial wall, wherein the flared cone further includes an annular inner axial wall extending upstream in the longitudinal direction from an upstream end of the annular conical wall, wherein an annular cavity is defined between the annular axial wall and the annular inner axial wall, and wherein the flared cone includes a plurality of slotted cooling passages each having an inlet at the annular cavity and an outlet at a surface of the annular step.

2. The mixer assembly of claim 1, wherein, wherein the downstream end of the annular conical wall includes an annular conical wall rear surface extending radially outward from a downstream end of the conical inner surface of the annular conical wall to the annular step.

3. The mixer assembly of claim 1, wherein, wherein the conical inner surface of the annular conical wall includes a continuous curved conical inner surface extending from an upstream end of the continuous curved conical inner surface to a downstream end of the continuous curved conical inner surface.

4. The mixer assembly of claim 3, wherein, wherein (a) a starting portion of the continuous curved conical inner surface at the upstream end of the continuous curved conical inner surface is arranged at a first conical wall angle relative to the mixer assembly centerline, (b) an ending portion of the continuous curved conical inner surface at the downstream end of the continuous curved conical inner surface is arranged at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuous curved conical inner surface between the starting portion and the ending portion transitions from the first conical wall angle to the second conical wall angle.

5. The mixer assembly of claim 4, wherein, wherein the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

6. The mixer assembly of claim 1, wherein, wherein the surface of the annular step intersects the conical inner surface of the annular conical wall at the downstream end of the annular conical wall and forms an acute angle therebetween.

7. The mixer assembly of claim 6, wherein, wherein the conical inner surface of the annular conical wall includes a continuous curved conical inner surface extending from an upstream end of the continuous curved conical inner surface to a downstream end of the continuous curved conical inner surface.

8. The mixer assembly of claim 7, wherein, wherein (a) a start portion of the continuously curved conical inner surface at the upstream end thereof is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) an end portion of the continuously curved conical inner surface at the downstream end thereof is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the start portion and the end portion transitions from the first conical wall angle to the second conical wall angle.

9. The mixer assembly of claim 8, wherein, wherein, the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

10. The mixer assembly of claim 1, wherein, further comprising a flow guide wall connected to the annular axial wall at a downstream end of the annular axial wall and extending radially outward from an outer surface of the annular axial wall, wherein the flow guide wall is integrally formed with the flared cone.

11. The mixer assembly of claim 10, wherein, wherein, the flow guide wall includes a plurality of cooling passages therethrough.

12. The mixer assembly of claim 1, wherein, wherein, the annular conical wall further comprises a backside cooling passage, wherein a flared cone flange is defined between the backside cooling passage and the conical inner surface of the annular conical wall, wherein the conical inner surface of the annular conical wall comprises a continuously curved conical inner surface extending from an upstream end of the continuously curved conical inner surface to a downstream end of the continuously curved conical inner surface, and wherein (a) a start portion of the continuously curved conical inner surface at the upstream end thereof is disposed at a first conical wall angle relative to the mixer assembly centerline, (b) an end portion of the continuously curved conical inner surface at the downstream end thereof is disposed at a second conical wall angle relative to the mixer assembly centerline, and (c) an intermediate portion of the continuously curved conical inner surface between the start portion and the end portion transitions from the first conical wall angle to the second conical wall angle.

13. The mixer assembly of claim 12, wherein, wherein, the first conical wall angle is forty-five degrees and the second conical wall angle is sixty degrees.

14. The mixer assembly of claim 12, wherein, wherein, the backside cooling passage comprises a backside cooling passage back surface that is a continuously curved surface coincident with the continuously curved conical inner surface.

15. A flared cone for a mixer assembly, the flared cone defining a flared cone centerline therethrough, characterized by, the flared cone comprises: an annular conical wall extending circumferentially about the flared cone centerline, the annular conical wall comprising a conical inner surface defining a conical opening of the annular conical wall; and an annular axial wall extending in a longitudinal direction relative to the flared cone centerline, the annular axial wall disposed at a radially outward portion of the annular conical wall and connected to the annular conical wall, wherein the annular conical wall and the annular axial wall define an annular step circumferentially about the flared cone centerline and extending upstream in the longitudinal direction between a downstream end of the annular conical wall and a back surface of the annular axial wall, wherein the flared cone further comprises an annular inner axial wall extending upstream in the longitudinal direction from an upstream end of the annular tapered wall, wherein an annular cavity is defined between the annular axial wall and the annular inner axial wall, and wherein the flared cone comprises a plurality of slotted cooling passages, each slotted cooling passage having an inlet at the annular cavity and an outlet at a surface of the annular step.

16. The flared cone of claim 15, wherein, wherein, the downstream end of the annular tapered wall comprises an annular tapered wall back surface extending radially outward from a back end of the tapered inner surface of the annular tapered wall to the annular step.

17. The flared cone of claim 15, wherein, wherein, the tapered inner surface of the annular tapered wall comprises a continuous curved tapered inner surface extending from an upstream end of the continuous curved tapered inner surface to a downstream end of the continuous curved tapered inner surface.

18. The flared cone of claim 17, wherein, wherein, (a) a starting portion of the continuous curved tapered inner surface at the upstream end of the continuous curved tapered inner surface is disposed at a first tapered wall angle relative to the flared cone centerline, (b) an ending portion of the continuous curved tapered inner surface at the downstream end of the continuous curved tapered inner surface is disposed at a second tapered wall angle relative to the flared cone centerline, and (c) an intermediate portion of the continuous curved tapered inner surface between the starting portion and the ending portion transitions from the first tapered wall angle to the second tapered wall angle.

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