Patent Publication Number: US-11662096-B2

Title: Combustor swirler to pseudo-dome attachment and interface with a CMC dome

Description:
TECHNICAL FIELD 
     The present disclosure relates to connecting a combustor swirler in a combustor so as to interface with a CMC (Ceramic Matrix Composite) dome in a gas turbine engine. 
     BACKGROUND 
     Some conventional gas turbine engines are known to include rich-burn combustors that typically use a swirler assembly that is connected with a dome structure. The swirler assembly and the dome structure are both generally metallic and are connected to one another. The metallic dome structure has been known to include a deflector wall on a combustion chamber side of the dome, where the deflector wall deflects heat generated in the combustor during combustion. Cooling holes are generally included through the dome structure so as to provide some surface cooling of the dome and deflector wall. The metallic swirler assembly is generally brazed to, or welded to, the dome structure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features and advantages of the present disclosure will be apparent from the following description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. 
         FIG.  1    is a schematic partial cross-sectional side view of an exemplary high by-pass turbofan jet engine, according to an aspect of the present disclosure. 
         FIG.  2    is a partial cross-sectional side view of an exemplary combustor, according to an aspect of the present disclosure. 
         FIG.  3    is a partial cross-sectional aft forward-looking view of an exemplary combustor, taken at plane  3 - 3  of  FIG.  1   , according to an aspect of the present disclosure. 
         FIG.  4    is a partial cross-sectional side view swirler to pseudo-dome connection, and a CMC dome interface, taken at detail view  114  of  FIG.  2   , according to an aspect of the present disclosure. 
         FIG.  5    is a partial cross-sectional side view of a CMC dome and pseudo-dome structure connection to a cowl, taken at detail view  114  of  FIG.  2   , according to an aspect of the present disclosure. 
         FIG.  6    is an enlarged partial cross-sectional side view swirler to pseudo-dome connection, and a CMC dome interface, taken at detail view  114  of  FIG.  2   , according to an aspect of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Features, advantages, and embodiments of the present disclosure are set forth or apparent from a consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that the following detailed description is exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed. 
     Various embodiments are discussed in detail below. While specific embodiments are discussed, this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure. 
     As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. 
     The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. 
     The implementation of non-metallic materials in combustors is becoming more prevalent. In particular, the implementation of Ceramic Matrix Composite (CMC) materials can be used to form the dome structure, rather than utilizing the conventional metallic dome structures. The CMC materials have better thermal capabilities than the conventional metallic materials, and, as a result, less cooling is required for a CMC dome than is required for the conventional metallic dome. The less cooling needed for the dome means that more air is available for other purposes, including being used as dilution air. In addition, the CMC dome structure does not require a deflector wall, thereby reducing the overall axial length of the dome, which also reduces the length of the combustor module. The implementation of the CMC dome with a metallic swirler, however, presents a challenge as to the ability to connect the metallic swirler to the CMC dome, and to provide for a thermal decoupling between the metallic swirler and the CMC dome. The present disclosure provides a technique to separately mount the metallic swirler to a cowl using a metallic pseudo-dome structure, and to also separately mount the CMC dome to the cowl. The swirler assembly, being connected to the pseudo-dome structure apart from the CMC dome, can nonetheless interface with the CMC dome. 
     Referring now to the drawings,  FIG.  1    is a schematic partial cross-sectional side view of an exemplary high by-pass turbofan jet engine  10 , herein referred to as “engine  10 ,” as may incorporate various embodiments of the present disclosure. Although further described below with reference to a ducted turbofan engine, the present disclosure is also applicable to turbomachinery in general, including turbojet, turboprop, and turboshaft gas turbine engines, including marine and industrial turbine engines and auxiliary power units. In addition, the present disclosure is not limited to ducted fan type turbine engines such as that shown in  FIG.  1   , but can be implemented in unducted fan (UDF) type turbine engines. As shown in  FIG.  1   , engine  10  has a centerline axis  12  that extends therethrough from an upstream end  98  to a downstream end  99  for reference purposes. In general, engine  10  may include a fan assembly  14  and a core engine  16  disposed downstream from the fan assembly  14 . 
     The core engine  16  may generally include an outer casing  18  that defines an annular inlet  20 . The outer casing  18  encases, or at least partially forms, in serial flow relationship, a compressor section ( 22 / 24 ) having a booster or low pressure (LP) compressor  22 , a high pressure (HP) compressor  24 , a combustor  26 , a turbine section ( 28 / 30 ) including a high pressure (HP) turbine  28  and a low pressure (LP) turbine  30 , and a jet exhaust nozzle section  32 . A high pressure (HP) rotor shaft  34  drivingly connects the HP turbine  28  to the HP compressor  24 . A low pressure (LP) rotor shaft  36  drivingly connects the LP turbine  30  to the LP compressor  22 . The LP rotor shaft  36  may also be connected to a fan shaft  38  of the fan assembly  14 . In particular embodiments, as shown in  FIG.  1   , the LP rotor shaft  36  may be connected to the fan shaft  38  by way of a reduction gear  40 , such as in an indirect-drive or a geared-drive configuration. In other embodiments, although not illustrated, the engine  10  may further include an intermediate pressure (IP) compressor and a turbine rotatable with an intermediate pressure shaft. 
     As shown in  FIG.  1   , the fan assembly  14  includes a plurality of fan blades  42  that are coupled to, and extend radially outwardly from, the fan shaft  38 . An annular fan casing or nacelle  44  circumferentially surrounds the fan assembly  14  and/or at least a portion of 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 . Moreover, at least a portion of the nacelle  44  may extend over an outer portion of the core engine  16  so as to define a bypass airflow passage  48  therebetween. 
       FIG.  2    is a cross-sectional side view of an exemplary combustor  26  of the core engine  16  as shown in  FIG.  1   .  FIG.  2    depicts a combustor axial centerline  112  that may generally correspond to the centerline axis  12 . Thus, the combustor  26  of  FIG.  2    defines a combustor longitudinal direction (Lc) corresponding to the combustor axial centerline  112 , a combustor radial direction (Rc) extending outward from the combustor axial centerline  112 , and a combustor circumferential direction (Cc) extending circumferentially about the combustor axial centerline  112 . As shown in  FIG.  2   , the combustor  26  may generally include a cowl structure  60 , and a combustor liner  50 , having an inner liner  52  and an outer liner  54 , each of which are connected with the cowl structure  60 . The cowl structure  60  extends in the circumferential direction with respect to the combustor axial centerline  112 , and as will be described below, may be comprised of a plurality of cowl segments that, together, extend circumferentially about the combustor axial centerline  112 . Each of the inner liner  52  and the outer liner  54  are annular liners that extend circumferentially about the combustor axial centerline  112 . A Ceramic Matrix Composite (CMC) dome  56  extends in the combustor radial direction Rc between the inner liner  52  and the outer liner  54  and is connected with the cowl structure  60  at a cowl radially outer portion  57  and a cowl radially inner portion  59 . The CMC dome  56  also extends circumferentially about the combustor axial centerline  112 . Together, the inner liner  52 , the outer liner  54 , and the CMC dome  56  define a combustion chamber  62  therebetween. 
     The combustor  26  also includes a swirler assembly  58  that is mounted to a pseudo-dome structure  61 . The pseudo-dome structure  61  is connected to the cowl structure  60  at the cowl radially outer portion  57  and the cowl radially inner portion  59 . The pseudo-dome structure  61  may extend circumferentially about the combustor axial centerline  112 , or, as will be described below, may include multiple segments that extend about the circumference of the combustor  26 . The swirler assembly  58  is mounted to the pseudo-dome structure  61  and extends through the CMC dome  56 . The swirler assembly  58  is connected with a fuel nozzle assembly  70 , which injects fuel into the swirler assembly  58 . In the combustion chamber  62 , an initial chemical reaction of an ignited fuel-oxidizer mixture injected into the combustion chamber  62  by the swirler assembly  58  occurs to generate combustion gases  86 . The combustion gases  86  then flow further downstream into the HP turbine  28  and the LP turbine  30 . While  FIG.  2    depicts a single swirler assembly  58 , as will be described below, it can be appreciated that a plurality of the swirler assemblies  58  are present in the combustor  26 , where the respective swirler assemblies  58  are circumferentially spaced apart from one another about the combustor axial centerline  112 . 
     The combustor  26  further includes an outer casing  64  that extends circumferentially about the combustor axial centerline  112 , and an inner casing  65  that also extends circumferentially about the combustor axial centerline  112 . An outer flow passage  88  is defined between the outer casing  64  and the outer liner  54 , and an inner flow passage  90  is defined between the inner casing  65  and the inner liner  52 . The outer liner  54  may also include a plurality of outer liner dilution openings  68  that are circumferentially spaced around the outer liner  54 . Similarly, the inner liner  52  may include a plurality of inner liner dilution openings  69  that are circumferentially spaced around the inner liner  52 . 
     Referring back to  FIG.  1   , in operation, air  73  enters the nacelle  44  at a nacelle inlet  76 , and a portion of the air  73  enters the compressor section ( 22 / 24 ) as compressor inlet air flow  80 , where it is compressed. Another portion of the air  73  enters the bypass airflow passage  48 , thereby providing a bypass airflow  78 . In  FIG.  2   , compressed air  82  from the compressor section ( 22 / 24 ) enters the combustor  26  via a diffuser (not shown). A portion of the compressed air  82 ( a ) enters a cowl structure  60  into a pressure plenum  66 , while another portion of the compressed air  82 ( b ) passes to the outer flow passage  88  and to the inner flow passage  90 . The compressed air  82 ( a ) in the pressure plenum  66  passes through the swirler assembly  58  to mix with fuel injected by the fuel nozzle assembly  70  and is ignited to generate the combustion gases  86 . A portion of the compressed air  82 ( b ) in the outer flow passage  88  may be used as dilution air provided to the combustion chamber  62  through the plurality of outer liner dilution openings  68 , and another portion of the compressed air  82 ( b ) in the inner flow passage  90  may also be used as dilution air provided to the combustion chamber  62  through the plurality of inner liner dilution openings  69 . 
       FIG.  3    is a partial cross-sectional view of a combustor  26  taken at plane  3 - 3  shown in  FIG.  1   . As seen in  FIG.  3   , the combustor  26  has a generally annular combustor liner  50  that extends circumferentially about the centerline axis  12  of the engine  10 . As it may relate to the combustor  26 , the centerline axis  12  may also correspond to the combustor axial centerline  112 . The combustor liner  50  includes the outer liner  54  and the inner liner  52 , each of which extends circumferentially about the combustor axial centerline  112 . The CMC dome  56  also extends circumferentially about the combustor axial centerline  112 . The cross-sectional view of  FIG.  2    may be taken at, for example, plane  2 - 2  of  FIG.  3   , and while the cross section of  FIG.  2    depicts a single swirler assembly  58 , a plurality of representative swirler assemblies  58 ( a ),  58 ( b ), etc., are shown in  FIG.  3    as being circumferentially spaced about the combustor axial centerline  112 . With respect to each swirler assembly  58 ( a ),  58 ( b ), a portion of the combustor  26  may be considered to be a segment of the combustor  26 . That is, the combustor  26 , although it may extend circumferentially about the combustor axial centerline  112 , may be considered to include multiple segments corresponding to each swirler assembly  58 . For example, a first segment  100  corresponding to the swirler assembly  58 ( a ) and extending in the circumferential direction between a segment boundary end  104  and a segment boundary end  106  may be included among the segments. A second segment  102  corresponding to swirler assembly  58 ( b ) and extending in the circumferential direction between the segment boundary end  106  and a segment boundary end  108  may be included among the plurality of segments. As can be readily understood, additional segments (not labeled) and swirler assemblies (not labeled) are provided about the entire circumference of the combustor  26 . As mentioned above, the pseudo-dome structure  61  may be implemented as multiple segments. In this case, rather than the pseudo-dome structure  61  extending circumferentially about the combustor axial centerline  112 , a first segment pseudo-dome structure  61 ( a ) may be implemented in the first segment  100 , a second pseudo-dome structure  61 ( b ) may be implemented in the second segment  102 , etc. Thus, each pseudo-dome segment ( 61 ( a ),  61 ( b )) may be included to mount the respective segment swirler assembly ( 58 ( a ),  58 ( b )). 
       FIG.  4    depicts a partial cross-sectional view of a swirler and dome connection taken at detail view  114  of  FIG.  2   . In  FIG.  4   , the fuel nozzle assembly  70  has been removed. As seen in  FIG.  4   , the cowl structure  60  includes the cowl radially outer portion  57  and the cowl radially inner portion  59 . The cowl radially outer portion  57  may comprise a cowl outer clevis  116  having a first outer clevis portion  118  on a radially outer side of the cowl outer clevis  116 , and a second outer clevis portion  120  on a radially inner side of the cowl outer clevis  116 . Similarly, the cowl radially inner portion  59  may comprise a cowl inner clevis  122  having a first inner clevis portion  124  on a radially inner side of the cowl inner clevis  122 , and a second inner clevis portion  126  on a radially outer side of the cowl inner clevis  122 . The pseudo-dome structure  61  is connected to the cowl structure  60  at the cowl radially outer portion  57  and the cowl radially inner portion  59 . This connection will be described in more detail below. The CMC dome  56  and the outer liner  54  are connected to the cowl structure  60  within the cowl outer clevis  116  via mechanical connecting members  128 , such a bolted joint. Similarly, the inner liner  52  and the CMC dome  56  are connected to the cowl structure  60  within the cowl inner clevis  122  via connecting members  128 . The swirler assembly  58  is connected to the pseudo-dome structure  61  and extends through the CMC dome  56 . This connection will also be described in more detail below. 
       FIG.  5    depicts a cross-sectional view of the CMC dome  56  and pseudo-dome structure  61  connection with the cowl structure  60 , taken at detail view  114  of  FIG.  2   , according to an aspect of the present disclosure. In  FIG.  5   , the connecting members  128  are not shown, and the swirler  58  has been removed, but the swirler centerline axis  110  is depicted therein for reference purposes, and an upstream direction  146  and a downstream direction  148  are defined with respect to the swirler centerline axis  110 . The pseudo-dome structure  61  is connected to the cowl outer clevis  116 . More specifically, a radially outer end  130  of the pseudo-dome structure  61  may extend in the upstream direction  146  and is connected (e.g., via brazing or a bolted joint) to a radially inner surface  132  of the outer clevis second portion  120 . The pseudo-dome structure  61  is also connected to the cowl inner clevis  122 , where a radially inner end  134  of the pseudo-dome structure  61  may extend in the upstream direction  146  and is connected (e.g., via brazing or a bolted joint) to a radially outer surface  136  of the inner clevis second portion  126 . The pseudo-dome structure  61  also includes a pseudo-dome swirler opening  138  therethrough for mounting the swirler assembly  58 , as will be described below. The pseudo-dome swirler opening  138  may be a cylindrical opening that, as will be described below, has a pseudo-dome swirler opening diameter  152  that is sized to match an annular outer axial wall diameter  162  ( FIG.  6   ) of the swirler assembly  58  for mounting the swirler assembly  58  to the pseudo-dome structure  61 . Thus, the swirler centerline axis  110  ( FIG.  4   ) may also be considered to correspond to a centerline through the pseudo-dome swirler opening  138 . 
     The CMC dome  56 , as was mentioned above, extends circumferentially about the combustor axial centerline  112  and also extends in the combustor radial direction (Rc). It is noted that, while  FIG.  5    may appear to depict the CMC dome  56  as extending parallel with the combustor radial direction Rc, as shown in  FIG.  4   , the CMC dome  56 , and correspondingly, the pseudo-dome structure  61 , may be arranged at a dome angle  144  with respect to the combustor radial direction Rc. When the CMC dome  56  is arranged at the dome angle  144 , the CMC dome  56 , and the pseudo-dome structure  61 , are nonetheless considered to extend in the combustor radial direction Rc. A radially outer end  140  of the CMC dome  56  may extend in the upstream direction  146  and extend into the cowl outer clevis  116 , and a radially inner end  142  of the CMC dome  56  may extend in the upstream direction  146  and extend into the cowl inner clevis  122 . The outer liner  54  also extends into the cowl outer clevis  116  and, as was shown in  FIG.  4   , the radially outer end  140  of the CMC dome  56  and the outer liner  54  are suitably connected to the cowl outer clevis  116  via connecting members  128 . As was also shown in  FIG.  4   , the CMC dome  56  and the outer liner  54  are connected to the cowl outer clevis  116  via connecting members  128 , and the CMC dome  56  and the inner liner  52  are connected to the cowl inner clevis  122  via the connecting members  128 . 
     The CMC dome  56  includes a CMC dome swirler opening  150  through the CMC dome  56 . The CMC dome swirler opening  150  may be a cylindrical opening having a CMC dome swirler opening diameter  154  that, as will be described below, may be greater than a diameter  160  of a swirler outlet end  161  ( FIG.  4   ) of the swirler assembly  58  so as to provide a circumferential gap  156  ( FIG.  4   ) between an inner surface  158  of the CMC dome swirler opening  150  and the swirler outlet end  161  of the swirler assembly  58 . The CMC dome swirler opening  150  is arranged such that it is generally centered about the swirler centerline axis  110 , and is generally axially aligned with the pseudo-dome swirler opening  138 . Of course, with the CMC dome swirler opening diameter  154  being greater than the diameter  160  of the swirler outlet end  161  of the swirler assembly  58  so as to form the circumferential gap  156 , the CMC dome swirler opening  150  and the pseudo-dome swirler opening  138  may be somewhat axially offset from one another with respect to the swirler centerline axis  110 . The CMC dome  56  may optionally include a plurality of dome cooling passages  164  through the CMC dome  56 . 
       FIG.  6    depicts an example of a swirler assembly  58  with the CMC dome  56  and the pseudo-dome structure  61  connected thereto, according to an aspect of the present disclosure. In  FIG.  6   , the swirler assembly  58  can be seen to define the swirler centerline axis  110  that extends in a swirler longitudinal direction (Ls), and defines a swirler upstream direction  166  and a swirler downstream direction  168 . A swirler radial direction (Rs) extends outward from the swirler centerline axis  110 , and a swirler assembly circumferential direction (Cs) extends circumferentially about the swirler centerline axis  110 . The swirler assembly  58  is generally formed of metallic materials, as compared with the ceramic matrix composite material of the CMC dome  56 . That is, various component parts of the swirler assembly  58  are constructed of metal alloy materials that are more conducive to structural expansion due to increased temperatures within the combustor than is the CMC material of the CMC dome  56 . 
     The swirler assembly  58  includes a primary swirler  170  and a secondary swirler  172  connected to a downstream side  174  of the primary swirler  170 . The primary swirler  170  induces a radially inward swirl to compressed air  82 ( a ) from the pressure plenum  66  ( FIG.  2   ) passing through the primary swirler  170 . The secondary swirler  172  induces a radially inward swirl to the compressed air  82 ( a ) passing through the secondary swirler  172  from the pressure plenum  66 . The swirler assembly  58  further includes a flare  176  connected to a downstream end  178  of the secondary swirler  172 . The flare  176  and its connection with the pseudo-dome structure  61  and its interface with the CMC dome  56  will now be described in more detail. 
     The flare  176  extends circumferentially about the swirler centerline axis  110 . The flare  176  is seen to include an annular inner axial wall  180  that extends circumferentially about the swirler centerline axis  110 , and also extends in the swirler longitudinal direction Ls. The annular inner axial wall  180  is connected to the downstream end  178  of the secondary swirler, such as by being brazed. The flare  176  also includes an annular outer axial wall  182  that extends circumferentially about the swirler centerline axis  110 , and also extends in the flare longitudinal direction Ls. The annular outer axial wall  182  is radially outward of the annular inner axial wall  180 , and a cavity  184  may be formed therebetween. The flare  176  further includes an annular conical wall  186  that extends circumferentially about the swirler centerline axis  110 , and also extends radially outward and downstream from a downstream end  188  of the annular inner axial wall  180 . A swirler downstream end  190  of the annular conical wall  186  comprises a swirler outlet  192 . 
     The annular outer axial wall  182  includes a swirler mounting wall  194  extending radially outward from an annular outer axial wall outer surface  196  of the annular outer axial wall  182 . The swirler mounting wall  194  may also extend circumferentially about the swirler centerline axis  110 , although the swirler mounting wall  194  need not extend about the entire circumference and may instead be comprised of various mounting wall segments (not shown) about the circumference of the annular outer axial wall outer surface  196 . The annular outer axial wall diameter  162  is sized so as to be slightly less than the pseudo-dome swirler opening diameter  152  of the pseudo-dome swirler opening  138  ( FIG.  5   ) so that the flare  176  can be inserted through the pseudo-dome swirler opening  138 . The flare  176  is thus inserted through the pseudo-dome swirler opening  138  so that an upstream side  198  of the swirler mounting wall  194  engages with a downstream side  200  of the pseudo-dome structure  61 . A swirler mounting ring  204  may be installed on a downstream side  202  of the pseudo-dome structure  61 . The swirler mounting ring  204  may extend circumferentially about the swirler centerline axis  110  and may extend radially outward from the annular outer axial wall outer surface  196 . The flare  176  may be connected to the pseudo-dome structure  61  by, for example, brazing the swirler mounting ring  204 , the pseudo-dome structure  61 , and the swirler mounting wall  194  together with each other. Of course, other connecting mechanisms could be employed instead, such as bolted joints, to join the flare  176  to the pseudo-dome structure  61 . The connection between the flare  176 , the swirler mounting wall  194 , and the swirler mounting ring  204  prevents the flare  176 , and, consequently, the swirler assembly  58 , from rotating about the swirler centerline axis  110 . 
     The flare  176  further includes a swirler dome interface wall  206  that extends radially outward from the annular outer axial wall outer surface  196 , and extends circumferentially about the swirler centerline axis  110 . An outer diameter  208  of the swirler dome interface wall  206  is greater than the CMC dome swirler opening diameter  154  ( FIG.  5   ). When the swirler assembly  58  is connected to the pseudo-dome structure  61  as described above, a downstream surface  218  of the swirler dome interface wall  206  interfaces with a CMC dome upstream surface  210  surrounding the CMC dome swirler opening  150  of the CMC dome  56 . The swirler dome interface wall  206  may provide a slight axial force against the CMC dome  56 , but allow the swirler assembly  58  to move radially during operation. 
     A downstream end  212  of the annular outer axial wall  182  extends circumferentially about the swirler centerline axis  110 , and defines the swirler outlet end  161  of the swirler assembly  58 . As was mentioned above, the diameter  160  of the swirler outlet end  161  is less than the CMC dome swirler opening diameter  154  of the CMC dome swirler opening  150 , such that the circumferential gap  156  is defined between the inner surface  158  of the CMC dome swirler opening  150  and the annular outer axial wall outer surface  196  of the swirler outlet end  161 . The swirler outlet end  161 , and the swirler downstream end  190  extend through the CMC dome swirler opening  150  and may extend beyond a downstream surface  216  of the CMC dome  56  into the combustion chamber  62 . The swirler dome interface wall  206  may also include a plurality of purge orifices  214  extending through the swirler dome interface wall  206  into the circumferential gap  156  so as to provide a purge flow of an oxidizer through the purge orifices  214 . 
     While the foregoing description relates generally to a gas turbine engine, it can readily be understood that the gas turbine engine may be implemented in various environments. For example, the engine may be implemented in an aircraft, but may also be implemented in non-aircraft applications, such as power generating stations, marine applications, or oil and gas production applications. Thus, the present disclosure is not limited to use in aircraft. 
     Further aspects of the present disclosure are provided by the subject matter of the following clauses. 
     A combustor for a gas turbine, the combustor comprising: a cowl structure; a pseudo-dome structure including a pseudo-dome swirler opening therethrough, the pseudo-dome structure being connected to the cowl structure; a ceramic matrix composite (CMC) dome including a CMC dome swirler opening therethrough, and having a CMC dome upstream surface surrounding the CMC dome swirler opening, the CMC dome being connected to the cowl structure; and a swirler including a swirler dome interface wall, the swirler being connected to the pseudo-dome structure through the pseudo-dome swirler opening, and extending through the CMC dome swirler opening with the swirler dome interface wall interfacing with the CMC dome upstream surface. 
     The combustor according to any preceding clause, wherein the combustor defines a combustor axial centerline along a combustor longitudinal direction, a combustor radial direction extending outward from the combustor axial centerline, and a combustor circumferential direction extending circumferentially about the combustor axial centerline, the cowl structure extends in the combustor circumferential direction and the combustor longitudinal direction, and has a cowl radially outer portion and a cowl radially inner portion, the pseudo-dome structure extends in the combustor circumferential direction, and extends in the combustor radial direction and is connected to the cowl radially outer portion and the cowl radially inner portion, the CMC dome extends circumferentially about the combustor axial centerline, and extends in the combustor radial direction, the CMC dome being connected to the cowl radially outer portion and to the cowl radially inner portion, the CMC dome, and the swirler defines a swirler centerline axis therethrough that defines a swirler longitudinal direction, the swirler including (a) a swirler outlet on a downstream side of the swirler, (b) the swirler dome interface wall extending radially outward in a swirler radial direction with respect to the swirler centerline axis, the swirler dome interface wall being disposed upstream from a swirler outlet end, and (c) a swirler mounting wall extending radially outward with respect to the swirler centerline axis, the swirler mounting wall being arranged upstream of the swirler dome interface wall, and the swirler extends through the pseudo-dome swirler opening and the swirler mounting wall is connected to the pseudo-dome structure, such that a downstream surface of the swirler dome interface wall interfaces with the CMC dome upstream surface and the swirler outlet extends through the CMC dome swirler opening. 
     The combustor according to any preceding clause, wherein the combustor comprises a plurality of segments arranged circumferentially about the combustor axial centerline, each segment including a respective cowl structure, a respective CMC dome swirler opening through the CMC dome, a respective pseudo-dome structure, and a respective swirler mounted to the pseudo-dome structure. 
     The combustor according to any preceding clause, further comprising a swirler mounting ring, wherein the pseudo-dome structure is mounted to an upstream side of the swirler mounting wall, and the swirler mounting ring is connected to the swirler and to an upstream side of the pseudo-dome structure. 
     The combustor according to any preceding clause, wherein the swirler is connected to the pseudo-dome structure and the swirler mounting ring via brazing or welding. 
     The combustor according to any preceding clause, wherein the cowl radially outer portion comprises an outer clevis having a first outer clevis portion on a radially outer side of the outer clevis, and a second outer clevis portion on a radially inner side of the outer clevis, and the pseudo-dome structure is connected to a radially inner surface of the second outer clevis portion. 
     The combustor according to any preceding clause, wherein the pseudo-dome structure is connected to the second outer clevis portion via brazing or welding. 
     The combustor according to any preceding clause, wherein the CMC dome is connected to the cowl structure within the outer clevis between the first outer clevis portion and the second outer clevis portion. 
     The combustor according to any preceding clause, wherein the CMC dome is connected to the outer clevis via a mechanical connecting member. 
     The combustor according to any preceding clause, further comprising an outer liner extending circumferentially about the combustor axial centerline and extending in the combustor longitudinal direction, the outer liner being connected to the cowl structure within the outer clevis, between the first outer clevis portion and the CMC dome. 
     The combustor according to any preceding clause, wherein a circumferential gap is provided between an inner surface of the CMC dome swirler opening and an outer surface of the swirler outlet end. 
     The combustor according to any preceding clause, wherein the swirler dome interface wall includes a plurality of purge orifices therethrough, the plurality of purge orifices being arranged to provide a purge flow of an oxidizer to the circumferential gap. 
     The combustor according to any preceding clause, wherein the pseudo-dome structure extends circumferentially about the combustor axial centerline. 
     The combustor according to any preceding clause, wherein the combustor comprises a plurality of segments arranged circumferentially about the combustor axial centerline, each segment including a respective cowl structure, a respective CMC dome swirler opening through the CMC dome, a respective pseudo-dome swirler opening, and a respective swirler mounted to the pseudo-dome structure. 
     The combustor according to any preceding clause, wherein the cowl radially inner portion comprises an inner clevis having a first inner clevis portion on a radially inner side of the inner clevis, and a second inner clevis portion on a radially outer side of the inner clevis, and the pseudo-dome structure is connected to a radially outer surface of the second inner clevis portion. 
     The combustor according to any preceding clause, wherein the CMC dome is connected to the cowl structure within the inner clevis between the first inner clevis portion and the second inner clevis portion. 
     The combustor according to any preceding clause, further comprising an inner liner extending circumferentially about the combustor axial centerline and extending in the combustor longitudinal direction, the inner liner being connected to the cowl structure within the inner clevis, between the first inner clevis portion and the CMC dome. 
     The combustor according to any preceding clause, wherein the swirler comprises (a) a primary swirler, (b) a secondary swirler connected to a downstream side of the primary swirler, and (c) a flare connected to a downstream end of the secondary swirler, the flare having (i) an annular inner axial wall extending circumferentially about the swirler centerline axis and in the swirler longitudinal direction, the annular inner axial wall being connected with the secondary swirler, (ii) an annular outer axial wall extending circumferentially about the swirler centerline axis and in the swirler longitudinal direction, the annular outer axial wall being radially outward of the annular inner axial wall, and (iii) an annular conical wall extending circumferentially about the swirler centerline axis, and extending radially outward and downstream from a downstream end of the annular inner axial wall, a downstream end of the annular conical wall comprising the swirler outlet. 
     The combustor according to any preceding clause, wherein the swirler mounting wall extends radially outward from an outer surface of the annular outer axial wall, and extends circumferentially about the swirler centerline axis. 
     The combustor according to any preceding clause, wherein the swirler dome interface wall extends radially outward from the outer surface of the annular outer axial wall, and extends circumferentially about the swirler centerline axis. 
     Although the foregoing description is directed to some exemplary embodiments of the present disclosure, other variations and modifications will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the disclosure. Moreover, features described in connection with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.