Patent Publication Number: US-2021190320-A1

Title: Turbine engine assembly including a rotating detonation combustor

Description:
BACKGROUND 
     The present disclosure relates generally to rotating detonation combustion systems and, more specifically, to rotating detonation combustion systems that provide increased mixing of fuel and air to more efficiently combust the fuel within the rotating detonation combustor. 
     In rotating detonation engines and, more specifically, in rotating detonation combustors, a mixture of fuel and an oxidizer is ignited such that combustion products are formed. For example, the combustion process begins when the fuel-oxidizer mixture in a tube or a pipe structure is ignited via a spark or another suitable ignition source to generate a compression wave. The compression wave is followed by a chemical reaction that transitions the compression wave to a detonation wave. The detonation wave enters a combustion chamber of the rotating detonation combustor and travels along the combustion chamber. Air and fuel are fed into the rotating detonation combustion chamber and are consumed by the detonation wave. As the detonation wave consumes air and fuel, combustion products traveling along the combustion chamber accelerate and are discharged from the combustion chamber. 
     In at least some known gas turbines including a can-annular combustor arrangement, fuel and air are channeled to the combustion chamber from at least one inlet. More specifically, at least some known fuel and air inlets discharge fluid across a flat surface into the combustion chamber. As such, the fuel and air may not completely intermix before combustion occurs, which may result in less than ideal turbine operating efficiencies. 
     Additionally, in at least some known rotating detonation combustion systems, forces from the detonation wave passing over the air and fuel inlets may expel hot combustion gases through either or both of the air and fuel inlets and into the associated air and fuel plenums. Inhalation of combustion gases into either the air or fuel plenums is undesirable as it may cause operating inefficiencies and/or a decrease in the service lifetime of the combustor. 
     BRIEF DESCRIPTION 
     In one aspect, a rotating detonation combustor is provided. The rotating detonation combustor includes a combustion chamber configured for a rotating detonation process to produce a flow of combustion gas and an air plenum configured to contain a volume of air. The rotating detonation combustor also includes a flow passage coupled in flow communication between the combustion chamber and the air plenum and configured to channel an airflow from the air plenum. The rotating detonation combustor also includes at least one fuel inlet coupled in flow communication with the flow passage and configured to channel a fuel flow into the flow passage. The flow passage includes a plurality of fuel mixing mechanisms configured to mix the airflow and the fuel flow within the combustion chamber. 
     In another aspect, a rotating detonation combustor is provided. The rotating detonation chamber includes a combustion chamber configured for a rotating detonation process to produce a flow of combustion gas and an air plenum configured to contain a volume of air. The rotating detonation chamber also includes a first sidewall and a second sidewall that define a flow passage therebetween such that the flow passage is coupled in flow communication between the combustion chamber and the air plenum and is configured to channel an airflow from the air plenum. The rotating detonation chamber further includes an air flow splitter positioned within the flow passage between the first sidewall and the second sidewall and a plurality of fuel mixing mechanisms coupled to at least one of the splitter and the first and second sidewalls A plurality of fuel inlets are coupled in flow communication with the flow passage and configured to channel a fuel flow into the flow passage, wherein the plurality of fuel mixing mechanisms are configured to mix the airflow and the fuel flow within the combustion chamber. 
     In yet another aspect, a turbine engine assembly is provided. The turbine engine assembly includes a plurality of rotating detonation combustors configured for a rotating detonation process to produce a flow of combustion gas and a turbine coupled downstream from the plurality of rotating detonation combustors and configured to receive the flow of combustion gas. Each rotating detonation combustor includes a combustion chamber, an air plenum configured to contain a volume of air, and a flow passage coupled in flow communication between the combustion chamber and the air plenum. The flow passage includes a plurality of fuel mixing mechanisms and is configured to channel an airflow from the air plenum. Each rotating detonation combustor also includes at least one fuel inlet coupled in flow communication with the flow passage and configured to channel a fuel flow into the flow passage. The plurality of fuel mixing mechanisms are configured to mix the airflow and the fuel flow within the combustion chamber. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic illustration of an exemplary combined cycle power generation system; 
         FIG. 2  is a schematic illustration of an exemplary rotating detonation combustion system that may be used in the combined cycle power generation system shown in  FIG. 1 ; 
         FIG. 3  is a schematic cross-sectional illustration of an exemplary rotating detonation combustor that may be used in the rotating detonation combustion system shown in  FIG. 2 ; and 
         FIG. 4  is an enlarged illustration of the rotating detonation combustor shown in  FIG. 3 . 
         FIG. 5  is another enlarged illustration of the rotating detonation combustor shown in  FIG. 3 . 
         FIG. 6  is a schematic cross-sectional illustration of an alternative rotating detonation combustor that may be used in the rotating detonation combustion system shown in  FIG. 2 . 
         FIG. 7  is an enlarged illustration of the rotating detonation combustor shown in  FIG. 6 . 
         FIG. 8  is another enlarged illustration of the rotating detonation combustor shown in  FIG. 6 . 
         FIG. 9  is a schematic side cross-sectional illustration of another alternative rotating detonation combustor that may be used in the rotating detonation combustion system shown in  FIG. 2 . 
         FIG. 10  is a schematic end cross-sectional illustration of the rotating detonation combustor shown in  FIG. 9 . 
         FIG. 11  is a side cross-sectional illustration of yet another alternative rotating detonation combustor that may be used in the rotating detonation combustion system shown in  FIG. 2 . 
         FIG. 12  is an end cross-sectional illustration of the rotating detonation combustor shown in  FIG. 11 . 
         FIG. 13  is a top illustration of a portion of the rotating detonation combustor shown in  FIG. 11 . 
     
    
    
     Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein. 
     DETAILED DESCRIPTION 
     In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. 
     The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. 
     “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not. 
     Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged. Such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise. 
     As used herein, the terms “axial” and “axially” refer to directions and orientations that extend substantially parallel to a centerline of the turbine engine assembly or the rotating detonation combustor. Moreover, the terms “radial” and “radially” refer to directions and orientations that extend substantially perpendicular to the centerline of the turbine engine assembly or the rotating detonation combustor. In addition, as used herein, the terms “circumferential” and “circumferentially” refer to directions and orientations that extend arcuately about the centerline of the turbine engine assembly or the rotating detonation combustor. In addition, as used herein, the terms “tangential” and “tangentially” refer to directions and orientations that extend substantially perpendicular relative to a radial axis of the turbine engine assembly or the rotating detonation combustor. 
     Embodiments of the present disclosure relate to a turbine engine assembly that efficiently converts the energy of exhaust gas produced by detonative combustion into shaft mechanical work via a turbine. More specifically, the turbine engine assembly described herein includes a rotating detonation combustor that includes a combustion chamber, an air plenum, and a flow passage coupled in flow communication between the combustion chamber and the air plenum and configured to channel an airflow from the air plenum. A fuel inlet channels a fuel flow into the flow passage, and the flow passage includes a plurality of fuel mixing mechanisms configured to mix the airflow and the fuel flow within the combustion chamber. As described herein, the fuel mixing mechanisms include, but are not limited to, corrugations, dimples, protrusions, or obstructions. 
     The flow passage corrugations introduce a more complete and faster mixing of the fuel and air in the combustion chamber, resulting in a shorter mixing distance and stronger detonations. Furthermore, the shape of the air plenum in each RDC is designed such that the pressure wave created by the passing combustion wave reflects off an end wall and reaches the flow passage at the same time as the combustion wave comes back around. As such, the air plenum is designed to create an opposing pressure wave that stiffens the air within the flow passage to prevent the combustion wave from channeling fluid into air plenum and to push unburnt air back into the combustion chamber, resulting in a stronger combustion. 
     As used herein, “detonation” and “quasi-detonation” may be used interchangeably. Typical embodiments of detonation chambers include a means of igniting a fuel/oxidizer mixture, for example a fuel/air mixture, and a confining chamber, in which pressure wave fronts initiated by the ignition process coalesce to produce a detonation wave. Each detonation or quasi-detonation is initiated either by external ignition, such as spark discharge or laser pulse, or by gas dynamic processes, such as shock focusing, autoignition or by another detonation via cross-firing. The geometry of the detonation chamber is such that the pressure rise of the detonation wave expels combustion products out the detonation chamber exhaust to produce a thrust force. In addition, rotating detonation combustors are designed such that a substantially continuous detonation wave is produced and discharged therefrom. As known to those skilled in the art, detonation may be accomplished in a number of types of detonation chambers, including detonation tubes, shock tubes, resonating detonation cavities, and annular detonation chambers. 
       FIG. 1  is a schematic illustration of an exemplary combined cycle power generation system  100 . Power generation system  100  includes a gas turbine engine assembly  102  and a steam turbine engine assembly  104 . Gas turbine engine assembly  102  includes a compressor  106 , a combustor  108 , and a first turbine  110  powered by expanding hot gas produced in combustor  108  for driving an electrical generator  112 . Gas turbine engine assembly  102  may be used in a stand-alone simple cycle configuration for power generation or mechanical drive applications. In the exemplary embodiment, exhaust gas  114  is channeled from first turbine  110  towards a heat recovery steam generator (HRSG)  116  for recovering waste heat from exhaust gas  114 . More specifically, HRSG  116  transfers heat from exhaust gas  114  to water/steam  118  channeled through HRSG  116  to produce steam  120 . Steam turbine engine assembly  104  includes a second turbine  122  that receives steam  120 , which powers second turbine  122  for further driving electrical generator  112 . 
     In operation, air enters gas turbine engine assembly  102  through an intake  121  and is channeled through multiple stages of compressor  106  towards combustor  108 . Compressor  106  compresses the air and the highly compressed air is channeled from compressor  106  towards combustor  108  and mixed with fuel. The fuel-air mixture is combusted within combustor  108 . High temperature combustion gas generated by combustor  108  is channeled towards first turbine  110 . Exhaust gas  114  is subsequently discharged from first turbine  110  through an exhaust  123 . 
       FIG. 2  is a perspective illustration of an exemplary rotating detonation combustion (RDC) system  124  that may be used in combined cycle power generation system  100  (shown in  FIG. 1 ). In the exemplary embodiment, RDC system  124  includes a plurality of rotating detonation combustors  126  and a plurality of flow conduits  128  coupled to the plurality of rotating detonation combustors  126 . As described above, the plurality of rotating detonation combustors  126  combust a fuel-air mixture (not shown in  FIG. 2 ) to produce a flow of combustion gas  130 . The plurality of rotating detonation combustors  126  are oriented such that the flow of combustion gas  130  discharged therefrom flows in a partially circumferential direction relative to an axial centerline  132  of gas turbine engine assembly  102  (shown in  FIG. 1 ). More specifically, each rotating detonation combustor  126  has a longitudinal centerline  134 , and each rotating detonation combustor  126  is oriented such that longitudinal centerline  134  is oriented tangentially relative to a radial axis  136  of gas turbine engine assembly  102 . As such, orienting rotating detonation combustors  126  with a circumferential or tangential component facilitates satisfying turbine inlet flow angle requirements for first turbine  110  (shown in  FIG. 1 ) coupled downstream from the plurality of rotating detonation combustors  126 . As used herein, “flow angle” is defined as a ratio of circumferential or tangential velocity to axial velocity of a flow of fluid. 
     In alternative embodiments, rotating detonation combustors  126  may be oriented at other angles relative to the radial axis  136 . For example, the angle defined between longitudinal centerline  134  and radial axis  136  is defined within a range between about 0 degrees and about 180 degrees, between about 30 degrees and about 150 degrees, between about 60 degrees and about 120 degrees, between about 60 degrees and about 90 degrees, or between about 75 degrees and about 90 degrees. 
       FIG. 3  is a cross-sectional schematic illustration of an exemplary rotating detonation combustor (RDC)  200  that may be used in RDC system  124  (shown in  FIG. 2 ).  FIG. 4  is an enlarged illustration of RDC  200 , and  FIG. 5  is another enlarged illustration of RDC  200 . Rotating detonation combustor  200  is one example of rotating detonation combustor  126  (shown in  FIG. 2 ) that may be used in RDC system  124 . In the exemplary embodiment, RDC  200  includes an air plenum  202  that contains a volume of air and a fuel plenum  204  that contains a volume of fuel. A flow passage  206  couples air plenum  202  and fuel plenum  204  in flow communication with a combustion chamber  208  of RDC  200 . Specifically, flow passage  206  is coupled in flow communication between air plenum  202  and combustion chamber  208  and channels an airflow from air plenum  202  toward combustion chamber  208 . In the exemplary embodiment, air plenum  202  is oriented perpendicular to combustion chamber  208  and flow passage  206  is oriented perpendicular to centerline axis  134 . Alternatively, air plenum  202  is axially aligned with combustion chamber  208  and flow passage  206  is oriented parallel with centerline axis  134 . 
     Additionally, RDC  200  includes a fuel inlet  210  that couples fuel plenum  204  in flow communication with flow passage  206  and channels a fuel flow into flow passage  206 . As described in further detail below, in the exemplary embodiment, flow passage  206  includes a plurality of fuel mixing mechanisms  212  over which the airflow and fuel flow are channeled. Fuel mixing mechanisms  212  cause the air from air plenum  202  and the fuel from fuel inlet  210  to mix within combustion chamber  208 . In the exemplary embodiment, and in subsequently described embodiments, fuel mixing mechanisms  212  include, but are not limited to, corrugations, dimples, protrusions, or obstructions. Generally, fuel mixing mechanisms  212  include any mechanism that facilities mixing of air and fuel to enable operation of the rotating detonation combustors described herein. For simplicity, the fuel mixing mechanisms are shown in the figures and described hereafter as corrugations. Although only shown and described hereafter as corrugations, the fuel mixing mechanisms are not limited embodying only corrugations and may include any type of fuel mixing mechanism. 
     As shown in  FIGS. 3-5 , air plenum  202  includes a first sidewall  214  and a second sidewall  216  that converge to form a throat portion  218  at an inlet of flow passage  206  between air plenum  202  and flow passage  206 . Furthermore, air plenum  202  includes an end wall  220  coupled between sidewalls  214  and  216  opposite throat portion  218 . In the exemplary embodiment, end wall  220  is curved for the entire arc length between sidewalls  214  and  216 . In another embodiment, end wall  220  is substantially flat or planar for at least a partial distance between sidewalls  214  and  216 . Air plenum  202  also includes an air inlet  222  that channels air into air plenum  202 . In the exemplary embodiment, air inlet  222  is oriented parallel to centerline axis  134  and is defined in second sidewall  216 . In other embodiments, air inlet  222  is oriented perpendicular to centerline axis  134  and is defined in end wall  220 . 
     Referring now to  FIG. 5 , flow passage  206  includes a first sidewall  224  and an opposing second sidewall  226  that define flow passage  206  therebetween. In the exemplary embodiment, fuel inlet  210  is defined through second sidewall  226  and is positioned downstream, with respect to fluid flow through RDC  200 , of throat portion  218 . Additionally, second sidewall  226  is a portion of a wall  228  of combustion chamber  208  such that a portion of wall  228  at least partially defines flow passage  206 . In the exemplary embodiment, combustion chamber  208  also includes a sidewall  330  that is oriented perpendicular to first and second sidewalls  224  and  226  of flow passage. Alternatively, as described in further detail below, second sidewall  226  is a portion of sidewall  230  such that a portion of sidewall  230  at least partially defines flow passage  206  and end wall  228  is oriented perpendicular to first and second sidewalls  224  and  226  of flow passage  206 . 
     In the exemplary embodiment, corrugations  212  are positioned downstream from fuel inlet  210  in flow passage  206  and include a first subset of corrugations  232  formed in first sidewall  224  and a second subset of corrugations  234  formed in second sidewall  226 . Alternatively, corrugations  212  are positioned upstream from fuel inlet  210  in flow passage  206 . Generally, corrugations  212  are positioned at any location that facilitates operation of RDC  200  as described herein. 
     In operation, a combustion wave is traveling circumferentially around combustion chamber  208  and is continuously fed by the air and fuel being channeled from plenums  202  and  204  through flow passage  206 . Corrugations  212  at the outlet of flow passage  208  introduce a more complete and faster mixing of the fuel and air in combustion chamber  208 , resulting in a shorter mixing distance and stronger detonations within combustion chamber  208 . Furthermore, corrugations  212  introduce both flow direction variation and flow velocity variation, which enhances the mixing of the fuel and air such that when the mixture exits flow passage  206  into combustion chamber  208 , the flow is already partially mixed and corrugations  212  cause further turbulence in combustion chamber  208  to provide additional mixing. 
     When the combustion wave passes over a point in flow passage  206 , it sends a pressure wave down into air plenum  202  through flow passage  206 . In the exemplary embodiment, the shape of air plenum  202  is designed such that the pressure wave created by the passing combustion wave reflects off end wall  220  and reaches flow passage  206  at the same time as the combustion wave comes back around to the same point in flow passage  206 . As such, air plenum  202  is designed to create an opposing pressure wave that stiffens the air within flow passage  206  to prevent the combustion wave from channeling fluid into air plenum. More specifically, air plenum  202  reflects the pressure wave and uses it to push unburnt air back into combustion chamber  208 , resulting in a stronger combustion. In the exemplary embodiment, the length of end wall  220  includes any length that facilitates operation of RDC  200  as described herein. Additionally, in the exemplary embodiment, air inlet  222  is located approximately midway through air plenum  202  in the radial direction between end wall  220  and flow passage  206 . As such, air inlet  222  is positioned to be in the anti-node of the pressure wave as it travels through air plenum  202 . 
       FIG. 6  is a schematic cross-sectional illustration of an alternative RDC  300  that may be used in the rotating detonation combustion system  124  (shown in  FIG. 2 ).  FIG. 7  is an enlarged illustration of RDC  300 , and  FIG. 8  is another enlarged illustration of RDC  300 . RDC  300  is substantially similar to RDC  200  (shown in  FIGS. 3-5 ) in operation and structure with the exception that RDC  300  includes a splitter  350  positioned in the flow passage between the air plenum and the combustion chamber. As such, components of RDC  300  shown in  FIGS. 6-8  are labeled with similar reference numbers as those used to describe RDC  200  in  FIGS. 3-5  with the exception that the reference numbers are in the  300  series. RDC  300  with splitter  350  may be substituted for RDC  200  without a splitter within rotating detonation combustion system  124 . 
     As shown in  FIGS. 6-8 , splitter  350  is at least partially positioned in flow passage  306  and includes a first end  352  coupled to end wall  320  and a second end  354  positioned in flow passage  306  between sidewalls  324  and  326  of flow passage  306 . Alternatively, first end  352  may be coupled to one or both of sidewalls  314  and  316  of air plenum  302 . First end  352  of splitter  350  is substantially planar and second end  354  of splitter  350  includes a plurality of splitter corrugations  356  that facilitate mixing the airflow from air plenum  302  and the fuel flow from fuel inlet  310  within combustion chamber  308 , as described herein. Furthermore, splitter  350  includes a plurality of openings  358  defined therethrough upstream of flow passage  306  and positioned within air plenum  302 . Openings  358  enable airflow from air inlet  322  to flow through splitter  350  and fill air plenum  302 . 
     As best shown in  FIG. 8 , splitter  350  includes a first sidewall  360  with a first subset  362  of corrugations  356 . Similarly, splitter  350  includes a second sidewall  364  with a second subset  366  of corrugations  356 . First subset  332  of flow passage corrugations  312  and first subset  362  of splitter corrugations  356  combine to form a first wave-shaped slot  368  through which a mixture of air and fuel is channeled and further mixed within combustion chamber  308 . Similarly, second subset  334  of flow passage corrugations  312  and second subset  366  of splitter corrugations  356  combine to form a second wave-shaped slot  370  through which a mixture of air and fuel is channeled and further mixed within combustion chamber  308 . 
     In operation, a combustion wave is traveling circumferentially around combustion chamber  308  and is continuously fed by the air and fuel being channeled from plenums  302  and  304  through flow passage  306 . Flow passage corrugations  312  and splitter corrugations  356  at the outlet of flow passage  306  introduce a more complete and faster mixing of the fuel and air in combustion chamber  308 , resulting in a shorter mixing distance and stronger detonations within combustion chamber  308 . Furthermore, corrugations  312  and  356  introduce both flow direction variation and flow velocity variation, which enhances the mixing of the fuel and air such that when the mixture exits flow passage  306  into combustion chamber  308 , the flow is already partially mixed and corrugations  312  cause further turbulence in combustion chamber  308  to provide additional mixing. 
     When the combustion wave passes over a point in flow passage  306 , it sends a pressure wave down into air plenum  302  through flow passage  306 . In the exemplary embodiment, the shape of air plenum  302  is designed such that the pressure wave created by the passing combustion wave reflects off end wall  320  and reaches flow passage  306  at the same time as the combustion wave comes back around to the same point in flow passage  306 . As such, air plenum  302  is designed to create an opposing pressure wave that stiffens the air within flow passage  306  to prevent the combustion wave from channeling fluid into air plenum. More specifically, air plenum  302  reflects the pressure wave and uses it to push unburnt air back into combustion chamber  308 , resulting in a stronger combustion. In the exemplary embodiment, the length of end wall  320  includes any length that facilitates operation of RDC  300  as described herein. Additionally, in the exemplary embodiment, air inlet  322  is located approximately midway through air plenum  302  in the radial direction between end wall  320  and flow passage  306 . As such, air inlet  322  is positioned to be in the anti-node of the pressure wave as it travels through air plenum  302 . 
       FIG. 9  is a schematic side cross-sectional illustration of another alternative RDC  400  that may be used in rotating detonation combustion system  124  (shown in  FIG. 2 ),  FIG. 10  is a schematic end cross-sectional illustration of RDC  400 . RDC  400  is one example of rotating detonation combustor  126  (shown in  FIG. 2 ) that may be used in RDC system  124 . In the illustrated embodiment, RDC  400  includes an air plenum  402  that contains a volume of air and a fuel plenum (not shown) that contains a volume of fuel. A flow passage  406  couples air plenum  402  and fuel plenum in flow communication with a combustion chamber  408  of RDC  400 . Specifically, flow passage  406  is coupled in flow communication between air plenum  402  and combustion chamber  408  and channels an airflow from air plenum  402  toward combustion chamber  408 . In the illustrated embodiment, air plenum  402  is axially aligned with combustion chamber  408  and flow passage  406  is oriented parallel with centerline axis  134 . 
     Additionally, RDC  400  includes at least one fuel inlet  410  that couples fuel plenum in flow communication with flow passage  406  and channels a fuel flow into flow passage  406 . As described herein, flow passage  406  includes a plurality of corrugations  412  over which the airflow and fuel flow are channeled. Corrugations  412  cause the air from air plenum  402  and the fuel from fuel inlet  410  to mix within combustion chamber  408 . 
     As shown in  FIGS. 9 and 10 , air plenum  402  includes a first sidewall  414  and a second sidewall  416  that converge to form a throat portion  418  at an inlet of flow passage  406  between air plenum  402  and flow passage  406 . Furthermore, air plenum  402  includes an end wall  420  coupled between sidewalls  414  and  416  opposite throat portion  418 . In the exemplary embodiment, end wall  420  is curved for the entire arc length between sidewalls  414  and  416 . In another embodiment, end wall  420  is substantially flat or planar for at least a partial distance between sidewalls  414  and  416 . Air plenum  402  also includes an air inlet  422  that channels air into air plenum  402 . In the exemplary embodiment, air inlet  422  is oriented perpendicular to centerline axis  134  and is defined in first sidewall  414 . In other embodiments, air inlet  422  is oriented parallel with centerline axis  134  and is defined in end wall  420 . 
     Flow passage  406  includes a first sidewall  424  and an opposing second sidewall  426  that define flow passage  406  therebetween. In the illustrated embodiment, at least one fuel inlet  410  is defined through first sidewall  424  and is positioned downstream, with respect to fluid flow through RDC  400 , of throat portion  418 . Furthermore, at least one fuel inlet  410  is defined through second sidewall  426  and is also positioned downstream, with respect to fluid flow through RDC  400 , of throat portion  418 . Although RDC  400  is illustrated as having fuel inlets  410  defined through both sidewalls  424  and  426 , it is contemplated that only one of sidewalls  424  or  426  includes fuel inlets  410 . Additionally, first sidewall  424  is a portion of a first sidewall  428  of combustion chamber  408  such that a portion of sidewall  428  at least partially defines flow passage  406 . Similarly, second sidewall  426  is a portion of a second sidewall  430  of combustion chamber  208  such that a portion of second sidewall  430  at least partially defines flow passage  406 . 
     In the exemplary embodiment, corrugations  412  are positioned downstream from fuel inlet  410  in flow passage  406  and include a first subset of corrugations  432  formed in first sidewall  424  and a second subset of corrugations  434  formed in second sidewall  426 . Alternatively, corrugations  412  are positioned upstream from fuel inlet  410  in flow passage  406 . Generally, corrugations  412  are positioned at any location that facilitates operation of RDC  400  as described herein. 
     In operation, a combustion wave is traveling circumferentially around combustion chamber  408  and is continuously fed by the air and fuel being channeled from plenums  402  and  404  through flow passage  406 . Corrugations  412  at the outlet of flow passage  406  introduce a more complete and faster mixing of the fuel and air in combustion chamber  408 , resulting in a shorter mixing distance and stronger detonations within combustion chamber  408 . Furthermore, corrugations  412  introduce both flow direction variation and flow velocity variation, which enhances the mixing of the fuel and air such that when the mixture exits flow passage  406  into combustion chamber  408 , the flow is already partially mixed and corrugations  412  cause further turbulence in combustion chamber  408  to provide additional mixing. 
     When the combustion wave passes over a point in flow passage  406 , it sends a pressure wave down into air plenum  402  through flow passage  406 . In the exemplary embodiment, the shape of air plenum  402  is designed such that the pressure wave created by the passing combustion wave reflects off end wall  420  and reaches flow passage  406  at the same time as the combustion wave comes back around to the same point in flow passage  406 . As such, air plenum  402  is designed to create an opposing pressure wave that stiffens the air within flow passage  406  to prevent the combustion wave from channeling fluid into air plenum. More specifically, air plenum  402  reflects the pressure wave and uses it to push unburnt air back into combustion chamber  408 , resulting in a stronger combustion. In the exemplary embodiment, the length of end wall  420  includes any length that facilitates operation of RDC  400  as described herein. Additionally, in the exemplary embodiment, air inlet  422  is located approximately midway through air plenum  402  in the axial direction between end wall  420  and flow passage  406 . As such, air inlet  422  is positioned to be in the anti-node of the pressure wave as it travels through air plenum  402 . 
       FIG. 11  is a side cross-sectional illustration of another alternative RDC  500  that may be used in the rotating detonation combustion system  124  (shown in  FIG. 2 ).  FIG. 12  is an end cross-sectional illustration of RDC  500 .  FIG. 13  is a top illustration of a portion of RDC  500 . In the illustrated embodiment, RDC  500  includes an air plenum  502  that contains a volume of air and a fuel plenum (not shown) that contains a volume of fuel. A flow passage  506  couples air plenum  502  and fuel plenum in flow communication with a combustion chamber  508  of RDC  500 . Specifically, flow passage  506  is coupled in flow communication between air plenum  502  and combustion chamber  508  and channels an airflow from air plenum  502  toward combustion chamber  508 . In the illustrated embodiment, air plenum  502  is axially aligned with combustion chamber  508  and flow passage  506  is oriented parallel with centerline axis  134 . 
     Additionally, RDC  500  includes at least one fuel inlet  510  that couples fuel plenum in flow communication with flow passage  506  and channels a fuel flow into flow passage  506 . As described herein, flow passage  506  includes a plurality of corrugations  512  over which the airflow and fuel flow are channeled. Corrugations  512  cause the air from air plenum  502  and the fuel from fuel inlet  510  to mix within combustion chamber  508 . 
     As shown in  FIGS. 11 and 12 , air plenum  502  includes a first sidewall  514  and a second sidewall  516  that converge to form a throat portion  518  at an inlet of flow passage  506  between air plenum  502  and flow passage  506 . Furthermore, air plenum  502  includes an end wall  520  coupled between sidewalls  514  and  516  opposite throat portion  518 . In the exemplary embodiment, end wall  520  is curved for the entire arc length between sidewalls  514  and  516 . In another embodiment, end wall  520  is substantially flat or planar for at least a partial distance between sidewalls  514  and  516 . Air plenum  502  also includes an air inlet  522  that channels air into air plenum  502 . In the exemplary embodiment, air inlet  522  is oriented perpendicular to centerline axis  134  and is defined in first sidewall  514 . In other embodiments, air inlet  522  is oriented parallel with centerline axis  134  and is defined in end wall  520 . 
     Flow passage  506  includes a first sidewall  524  and an opposing second sidewall  526  that define flow passage  506  therebetween. In the illustrated embodiment, at least one fuel inlet  510  is defined through first sidewall  524  and is positioned downstream, with respect to fluid flow through RDC  500 , of throat portion  518 . Furthermore, at least one fuel inlet  510  is defined through second sidewall  526  and is also positioned downstream, with respect to fluid flow through RDC  500 , of throat portion  518 . Although RDC  500  is illustrated as having fuel inlets  510  defined through both sidewalls  524  and  526 , it is contemplated that only one of sidewalls  524  or  526  may include fuel inlets  510 . Additionally, first sidewall  524  is a portion of a first sidewall  528  of combustion chamber  508  such that a portion of sidewall  528  at least partially defines flow passage  506 . Similarly, second sidewall  526  is a portion of a second sidewall  530  of combustion chamber  508  such that a portion of second sidewall  530  at least partially defines flow passage  506 . 
     In the exemplary embodiment, corrugations  512  are positioned downstream from fuel inlet  510  in flow passage  506  and include a first subset of corrugations  532  formed in first sidewall  524  and a second subset of corrugations  534  formed in second sidewall  526 . Alternatively, corrugations  512  are positioned upstream from fuel inlet  410  in flow passage  506 . Generally, corrugations  512  are positioned at any location that facilitates operation of RDC  500  as described herein. 
     RDC  500  also includes a splitter  550  positioned in the flow passage  506  between the air plenum  502  and the combustion chamber  508 . As shown in  FIGS. 11-13 , splitter  550  is at least partially positioned in flow passage  506  and includes a first end  552  coupled to end wall  520  and a second end  554  positioned in flow passage  506  between sidewalls  524  and  526  of flow passage  506 . Alternatively, first end  552  may be coupled to one or both of sidewalls  514  and  516  of air plenum  502 . Furthermore, splitter  550  includes a plurality of openings  558  defined therethrough upstream of flow passage  506  and positioned within air plenum  502 . Openings  558  enable airflow from air inlet  522  to flow through splitter  550  and fill air plenum  502 . 
     Splitter  550  includes a first sidewall  560  and an opposing second sidewall  564  that is substantially parallel to first sidewall  560 . More specifically, sidewalls  560  and  564  are parallel for an entirety of the length of splitter  550  between first end  552  and  554 . Additionally, sidewalls  560  and  564  at second end  554  of splitter  550  are substantially planar, or smooth, such that splitter  550  does not include corrugations or other fuel mixing mechanism. 
     In the illustrated embodiment, fuel inlets  510  in first sidewall  524  are formed radially from the peaks of first subset  532  of corrugations  512 . That is, fuel inlets  650  are formed in sidewall  524  at a point where the distance between sidewall  524  and sidewall  560  is shortest. Similarly, fuel inlets  510  in second sidewall  526  are formed radially from the peaks of second subset  534  of corrugations  512 . That is, fuel inlets  510  are formed in sidewall  526  at a point where the distance between sidewall  526  and sidewall  564  is shortest. Locating fuel inlets  510  at such locations positions fuel inlets  510  at the point of lowest pressure within flow passage  506 . And therefore protects the fuel from the combustion wave that travels around chamber  508 . 
     In the illustrated embodiment, splitter  550  includes a plurality of fuel inlets  511  defined therein. More specifically, splitter fuel inlets  511  are located approximately midway between first sidewall  560  and second sidewall  564 . In one embodiment, splitter fuel inlets  511  are used in combination with fuel inlets  510  to provide fuel in two different locations. In other embodiments, RDC  500  does not include fuel inlets  510 , and splitter fuel inlets  511  provide all of the fuel necessary for combustion. Additionally, as shown in  FIG. 13 , at least one splitter fuel inlet  511  is obliquely oriented with respect to centerline  134  such that at least one splitter fuel inlet  511  discharges fuel at an angle relative to centerline  134 . In the illustrated embodiment, the angle of orientation of splitter fuel inlets  511  changes around the circumference of splitter  550 . Alternatively, each splitter fuel inlet  511  is oriented at the same angle relative to centerline  134  such that fuel is injected into combustion chamber  508  at the same angle relative to centerline  134  about the circumference of splitter  550 . Injecting fuel into combustion chamber  508  at an angle relative to centerline  134  orients the fuel flow in the direction of the traveling combustion wave and also prevents or reduces the likelihood of the pressure wave traveling back down the splitter fuel inlets  511 . 
     In operation, a combustion wave is traveling circumferentially around combustion chamber  508  and is continuously fed by the air and fuel being channeled from plenums  502  and  504  through flow passage  506 . Corrugations  512  at the outlet of flow passage  508  introduce a more complete and faster mixing of the fuel and air in combustion chamber  508 , resulting in a shorter mixing distance and stronger detonations within combustion chamber  508 . Furthermore, corrugations  512  introduce both flow direction variation and flow velocity variation, which enhances the mixing of the fuel and air such that when the mixture exits flow passage  506  into combustion chamber  508 , the flow is already partially mixed. 
     When the combustion wave passes over a point in flow passage  506 , it sends a pressure wave down into air plenum  502  through flow passage  506 . In the exemplary embodiment, the shape of air plenum  502  is designed such that the pressure wave created by the passing combustion wave reflects off end wall  520  and reaches flow passage  506  at the same time as the combustion wave comes back around to the same point in flow passage  506 . As such, air plenum  502  is designed to create an opposing pressure wave that stiffens the air within flow passage  506  to prevent the combustion wave from channeling fluid into air plenum. More specifically, air plenum  502  reflects the pressure wave and uses it to push unburnt air back into combustion chamber  508 , resulting in a stronger combustion. In the exemplary embodiment, the length of end wall  220  includes any length that facilitates operation of RDC  500  as described herein. Additionally, in the exemplary embodiment, air inlet  522  is located approximately midway through air plenum  502  in the radial direction between end wall  520  and flow passage  506 . As such, air inlet  522  is positioned to be in the anti-node of the pressure wave as it travels through air plenum  502 . 
     The systems and methods described herein facilitate efficiently converting the kinetic energy of high velocity RDC combustion products. More specifically, the RDC systems described herein include a plurality of rotating detonation combustors that each include a plurality of corrugations between and air plenum and the combustion chamber. The flow passage corrugations introduce a more complete and faster mixing of the fuel and air in the combustion chamber, resulting in a shorter mixing distance and stronger detonations. Furthermore, the shape of the air plenum in each RDC is designed such that the pressure wave created by the passing combustion wave reflects off an end wall and reaches the flow passage at the same time as the combustion wave comes back around. As such, the air plenum is designed to create an opposing pressure wave that stiffens the air within the flow passage to prevent the combustion wave from channeling fluid into air plenum and to push unburnt air back into the combustion chamber, resulting in a stronger combustion. 
     An exemplary technical effect of the systems and methods described herein includes at least one of: (a) preserving the kinetic energy of high velocity RDC combustion products; and (b) increasing the efficiency of each RDC by both improving fuel and air mixing and by preventing inhalation of combustion products into the air plenum. 
     Exemplary embodiments of RDC systems are provided herein. The systems and methods are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the configuration of components described herein may also be used in combination with other processes, and is not limited to practice with only ground-based, combined cycle power generation systems, as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many applications where a RDC system may be implemented. 
     Although specific features of various embodiments of the present disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of embodiments of the present disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the embodiments of the present disclosure, including the best mode, and also to enable any person skilled in the art to practice embodiments of the present disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.