Abstract:
A supersonic combustor containing an injector module, a combustor core and an outer shell. The injector module houses both fuel and oxidizer nozzles. The combustor core contains grooves within which the combustion process takes place. The outer shell holds both the injector module and the combustor core and allows for other cooling, mounting and structural mechanisms required for operation.

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
       [0001]    Embodiments of the invention relates to the field of propulsion. More specifically, the invention relates to combustors based on detonation combustion for gas turbine or other engine based application. 
       Description of the Related Art 
       [0002]    A combustor of an engine is a component that houses the burning process of fuel-oxidizer (F/O) mixture or some combination thereof. The combustion process in majority of the engines in operation is subsonic i.e. the rate at which the F/O mixture burns is slower than the local speed of sound. This is a constant pressure combustion process also known as deflagration. 
         [0003]    A detonation combustor houses a similar burning process, however the rate at which the F/O mixture is burnt is faster than the local speed of sound. This a constant volume process also known as detonation. A detonation process is thermodynamically superior to the deflagration process. 
         [0004]    The challenge with existing detonation combustors and detonation based engines are the valves and ignition system required to maintain the pulsed regime of the detonation waves and its unsteady flow characteristics. The present invention aims to address this issue with a unique new technique. 
         [0005]    Where other detonation combustor technologies rely on spark or flame as the source of ignition, the present invention utilizes shock compression and/or shock reflection to carry out the ignition process. The present invention also allows for comparably more uniform and steady flow at the end of the combustion chamber in order to reduce the fatiguing from the pulsed or unsteady nature of other concepts and technologies. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    One or more embodiments of the invention comprises of an injector module supporting both fuel and oxidizer, a combustion core with grooves wherein the detonation occurs and propagates towards the exit and an outer shell that envelopes the injector module and the combustion core. 
         [0007]    A select mass flow of fuel is injected into to the corresponding groove of the combustion core from the fuel nozzle located at the injection module. In the case of a liquid fuel, the said fuel nozzle would be an atomizer. Accurately timed, the oxidizer line ejects a micro shock wave into the same groove of the combustion core. The shock wave compresses the injected fuel against a wall of the groove until the critical pressure, dictated by the Chapman-Jouguet detonation theory, is achieved upon which deflagration to detonation transition (DDT) or direct detonation combustion is initiated. The detonation waves and the reflected Mach waves then propagate out of the combustion section of the combustor core to the mixing section where it then becomes periodic with respect to the reactive flow from the other grooves before exiting the combustor completely. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The above and other aspects, features and advantages of the invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
           [0009]      FIG. 1  is an exploded isometric view of the supersonic combustor in accordance with one or more embodiments of the present invention. 
           [0010]      FIG. 2  is a downstream exploded view of the supersonic combustor illustrating the main components comprising the injector module, combustor core and the outer shell, in accordance with one or more embodiments of the present invention. 
           [0011]      FIG. 3A  is an isometric view of the injector module in accordance with one or more embodiments of the present invention. 
           [0012]      FIG. 3B  is an isometric view of the injector module internals detailing the oxidizer and fuel lines therein in accordance with one or more embodiments of the present invention. 
           [0013]      FIG. 4A  is a front cross-sectional view of the injector module in accordance with one or more embodiments of the present invention. 
           [0014]      FIG. 4B  is a close-up view of a set of fuel and oxidizer injector ports in accordance with one or more embodiments of the present invention. 
           [0015]      FIG. 5  is an upstream cross-sectional view of the combustor core in accordance with one or more embodiments of the present invention. 
           [0016]      FIG. 6  is a side profile view of the combustor core in accordance with one or more embodiments of the present invention. 
           [0017]      FIG. 7  is an upstream cross-sectional view of the combustor core in accordance with one or more embodiments of the present invention. 
           [0018]      FIG. 8  is an isometric view of the outer shell in accordance with one or more embodiments of the present invention. 
           [0019]      FIG. 9  is a side profile view of the injector module geometrically mated to the combustor core and partially depicting the combustion process in accordance with one or more embodiments of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The present invention comprising shock compression based supersonic combustor will now be described. In the following exemplary description numerous specific details are set forth in order to provide a more thorough understanding of embodiments of the invention. It will be apparent, however, to an artisan of ordinary skill that the present invention may be practiced without incorporating all aspects of the specific details described herein. Furthermore, although steps or processes are set forth in an exemplary order to provide an understanding of one or more systems and methods, the exemplary order is not meant to be limiting. One of ordinary skill in the art would recognize that the steps or processes may be performed in a different order, and that one or more steps or processes may be performed simultaneously or in multiple process flows without departing from the spirit or the scope of the invention. In other instances, specific features, quantities, or measurements well known to those of ordinary skill in the art have not been described in detail so as not to obscure the invention. It should be noted that although examples of the invention are set forth herein, the claims, and the full scope of any equivalents, are what define the metes and bounds of the invention. 
         [0021]    For a better understanding of the disclosed embodiment, its operating advantages, and the specified object attained by its uses, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated exemplary disclosed embodiments. The disclosed embodiments are not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation. 
         [0022]    Those of skill in the art would appreciate that the dimensions, geometric parameters and the components detailed in the drawings of the present invention are subjected to change based on the device application, scale, and/or related flow characteristics in order to ensure optimal efficiency and performance. 
         [0023]    The term “first”, “second” and the like, herein do not denote any order, quantity or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
         [0024]    One or more embodiments of the present invention will now be described with references to  FIGS. 1-9 . 
         [0025]    Illustrated in  FIG. 1  is an exploded isometric view of an exemplary embodiment of the supersonic combustor  100  of the present invention. As illustrated, the supersonic combustor  100  comprises injector module  110 , combustor core  120  and the outer shell  130 . One or more embodiments of the present invention may include alignment keys, e.g.  114  on the injector module  110  and keys  124  on combustor core  120 . As illustrated, the down-stream front-side face  113  of the injector module  110  is coupled (coincident) with the upstream back-side face  123  of the combustor core  120 , and the keys  114  of the injector module  110  are aligned with the keys  124  of the combustor core. The alignment of the injector module  110  and combustor core  120  ensures proper placement of the oxidizer line injector port  118  and fuel line injector port  119  within the entrance  125  of the corresponding grooves  121  of the combustor core  120 . The aligned keys  114  and  124  slide into the corresponding slots  134  of the outer shell  130 , locking the various components into position. The sets of fuel lines  116  and oxidizer lines  115  are also illustrated in  FIG. 3A . The pressurized oxidizer from the compressor (usually air) moves into a plenum which then channels the required amount into the oxidizer lines  115  through oxidizer inlet ports  111  of the injector module  110  as well as any cooling systems utilized by the device and/or engine. 
         [0026]    Illustrated in  FIG. 2 , is a downstream exploded isometric view of the exemplary embodiment of supersonic combustor  100  detailing the assembly of the injector module  110 , combustor core  120  and the outer shell  130 . This illustration provides an example of the positioning of the line injector ports  119  and  118  of the fuel line  116  and oxidizer line  115 , respectively, at their corresponding entrances  125  (see  FIG. 6 ) to grooves  121  of the combustor core  120 . The direction of the fuel line  116  is in the z-axis of the supersonic combustor  100  and is coupled through fuel inlet ports  112 , whereas the downstream injector port  118  of the oxidizer line  115  and in turn any valve mechanism that would be attached is at an angle θ to the opposite sidewall  122  of the corresponding groove  121  belonging to the combustor core  120 . 
         [0027]    Illustrated in  FIGS. 3A and 3B  are exemplary illustrations of the downstream isometric views of the injector module  110  and its internals in accordance with one or more embodiments of the present invention. These illustrations detail the keys  114  and the front-side face  113  of the injector module  110  that mate with the rear-side face  123  and the keys  124  of the combustor core  120 . Each set of the fuel lines  116  and oxidizer lines  115  of the injector module  110  correspond to a groove  121  of the combustor core. The fuel system (storage, pump and pipes outside of the present invention) delivers the fuel to the fuel line  116  through the fuel inlet ports  112 . The fuel line  116  may be configured to transport the fluid (e.g. fuel or fuel/air mixture) to the corresponding groove  121  of the combustor core  120  or it can act as a retainer for a different pipe and nozzle/injector depending on the type of fluid and the application. Delivered from the compressor and plenum of the engine, the oxidizer line  115  is filled with oxidizer. Upon achieving critical mass and pressure, a valve located at the downstream injector port  118  of the oxidizer line  115  forms a quick circular opening, analogous to that of a diaphragm burst in a conventional shock tube. This results in production of a micro-shock wave of a specific strength. The length, internal diameter, and cross-sectional area of the oxidizer lines  115  and fuel lines  116  may vary based on the scale, performance, efficiency, flow characteristics and/or any other desired parameter. 
         [0028]    Illustrated in  FIGS. 4A and 4B  are a front cross-sectional view and a close-up of a set of fuel injector ports  119  and oxidizer injector ports  118  in accordance with one or more embodiments of the injector module of the present invention. As illustrated, there are one or more, preferably a plurality (e.g. eight (8)), sets of fuel lines  116  and oxidizer lines  115  on the injector module  110 . The number of sets of fuel lines  116  and oxidizer lines  115  correspond to the number of grooves  121 , e.g. eight (8), in the combustor core  120 . The number of fuel lines  116  and oxidizer lines  115  as well as the corresponding grooves  121  of the combustor core  120  can be varied based on the scale of the present invention and its application. The injector port  118  of the oxidizer line  115  is at an acute angle θ with respect to the front-side cross-section face  113  of the injector module  110  and the axial direction (z-axis) of the combustor  100 . This angle may vary based on the combustion requirements and/or any other parameters that might contribute to the operation of the device. The linear and circumferential spacing between the fuel lines  116  and oxidizer lines  115 , and the thickness of the injector module  110  may also vary due to the device scale, flow characteristics and any other optimization parameters. 
         [0029]    Illustrated in  FIGS. 5, 6 and 7  are exemplary embodiments of the combustor core  120  of the present invention. These drawings illustrate the upstream cross-section, side profile and the upstream isometric views of the combustor core  120  respectively. In  FIG. 5 , an exemplary configuration of the keys  124  of the combustor core  120  are illustrated. In the illustrative embodiment present herein, keys  124  are configured to align with the keys  114  of the injector module  110 . The location of the keys  114  and  124  may change based on the device scale and other design criteria, however, alignment of the keys  114 ,  124  are used to ensure the correct placement of the fuel injector ports  119  and oxidizer injector ports  118  of the injector module  110 , within the corresponding entrance  125  of the grooves  121 . The rear face  123  of the combustor core  120  is shown, which mates with the front face  113  of the injector module  110  allowing the keys  114  and  124  to align. A center hole  127  is present along the entire axial length of the combustor core  120 . The center hole  127  may house the shaft and bearings of an engine to which the present invention is fitted.  FIG. 5  also shows the entrance of the grooves  125  where the corresponding fuel injector ports  119  and oxidizer injector ports  118  are positioned to enable the device operation. 
         [0030]    As illustrated in  FIG. 6 , the combustor core comprises a combustion section  128  and a mixing section  129 . A configuration for grooves  121  along the axial and circumferential direction of combustion section  128  of the combustor core  120  are illustrated. In the present exemplary embodiment of the combustor core  120 , the path of the grooves  121  turns along with the circumference of the combustor core  120 , i.e. spiral, to add a component of rotation to the reactive flow. Those of skill in the art would appreciate that the configuration and path of the grooves  121  may be different, e.g. straight, linear and/or follow a complex curve based on the device optimization requirements. The dimension of the walls  122  can vary based on the shock compression and detonation requirements. The axial and circumferential lengths of the grooves  121  and its walls  122  may vary in order to condition the reactive flow for the entrance of the turbine section downstream of the present invention. 
         [0031]    The mixing section  129  of the combustor core  120 , downstream of the grooves  121 , are illustrated in  FIGS. 6 and 7 . The mixing section  129  allows the periodic reactive flow from each groove  121  to merge and create a more uniform flow downstream. The axial length of the mixing section  129  can vary in order to ensure proper mixing of the reactive flows. 
         [0032]    Illustrated in  FIG. 8  is an illustration of the outer shell  130  of the exemplary embodiment of the present invention. This drawing details the general configuration of the outer shell  130  of the supersonic combustor  100  from an upstream isometric view. The slots  134  can be seen, into which the keys  114  and  124  of injector module  110  and combustor core  120  respectively, slide in. This ensures that the mated and aligned injector module  110  and combustor core  120  are locked into their appropriate positions, allowing the supersonic combustor  100  to be installed and operated with an engine. Although the design of the outer shell  130  is illustrated as a simple hollow cylinder, those of skill in the art would appreciate that it could take other configurations to accommodate other systems, such as cooling, mounting or control systems based on the device and/or engine operation. Similarly, the inner configuration of the outer shell  130 , may be of different design, for example, dictated by combustion and flow regime requirements as well as the compatibility to an engine&#39;s turbine section. 
         [0033]    Alignment, locking and mounting techniques for the present invention and its components may change as required. Additional components may be added to the present invention in order to refine its design and function based on its application. For example, those of skill in the arts would appreciate that cooling, mounting and control systems may change the general design of the components of the supersonic combustor detailed herein. The actuation of the valves at the downstream oxidizer injector ports  118  of the oxidizer lines  115  and the fuel injection from the fuel lines  116  will be governed by a control system. The key parameters of the present invention responsible for the throttling of the device are mass flow of fuel injected from each fuel line  116  into its corresponding grooves  121 ; strength and mass flow of the micro shock wave generated by the oxidizer line  115  and its valve system; and the frequency of fuel  116  and oxidizer  115  fired within their corresponding grooves  121 . 
         [0034]      FIG. 9  is a side profile view of the injector module geometrically mated to the combustor core and partially depicting the combustion process in accordance with one or more embodiments of the present invention. The mated injector module  110  and combustor core  120  are configured to fit inside the outer shell  130 . 
         [0035]    During the combustion process, as the fuel is injected into the groove  121  via the fuel line  116 , a valve, e.g. an iris valve, or any other suitable mechanism placed at the downstream injector port  118  of the oxidizer line  115  forms a circular opening to mimic a diaphragm burst of a conventional shock-tube, thereby creating a micro shock wave. The oxidizer line injector port aperture, timing and other operational parameters may be governed by a control system. As the generated micro shock wave enters the grove  121 , it compresses the injected fuel mass against the sidewall  122  of the groove  121  opposite to the location of the oxidizer line injector port  118 . Detonation combustion occurs as the critical Chapman-Jouguet (CJ) conditions are achieved during the compression process. The detonation waves and reflected Mach waves then propagate down the groove  121 . The downstream cross section  126  of the grooves  121  can be tailored to change the regime of the propagating reactive flow between subsonic and supersonic based on the application of the present invention (e.g. supersonic regime for thrust and subsonic regime for power generation applications). As the reactive flow exits the combustion section  128  and enters the mixing section  129  of the combustor core  120 , it merges with the periodic reactive flow from other grooves  121 , resulting in a uniform flow at the exit  139  of supersonic combustor  100 . 
         [0036]    While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.