A diverging pulse detonation combustor head structure

Abstract

This application provides a gradually expanding pulse detonation combustor head structure, belonging to the technical field of turbine engines. Specifically, it includes a connected intake and fuel supply section and a mixing section. The mixing section includes a mixing annular shell, a central cone, and a swirler. One end of the mixing annular shell is fixedly connected to the intake and fuel supply section. The central cone is installed inside the mixing annular shell via the swirler, and several fuel nozzles surround the outer periphery of the large-diameter end of the central cone. The inner wall of the mixing annular shell at the end away from the intake annular shell has an annular protrusion structure. The inner diameter of the annular protrusion structure gradually decreases and then gradually increases from the side closest to the intake annular shell towards the ignition section of the detonation combustor. The portion of the annular protrusion structure with gradually decreasing inner diameter is the contraction section, and the portion with gradually increasing inner diameter is the expansion section. This application's solution improves the uniformity of the air-fuel mixture in the detonation combustor.

Description

Technical Field

[0001] This application relates to the field of turbine engines, and in particular to a gradually expanding pulse detonation combustion chamber head structure. Background Technology

[0002] The pulse detonation turbine engine is a new type of turbine engine that replaces the isobaric combustion chamber in a traditional turbine engine with a pulse detonation combustion chamber, which features self-pressurization and low entropy increase. Compared with traditional aero-turbine engines, the pulse detonation turbine engine has advantages such as high thermal cycle efficiency, high specific thrust, low fuel consumption, and a wide operating range, and has broad application prospects.

[0003] In practical applications, direct ignition of combustible mixtures requires significant ignition energy, and direct ignition is very difficult for gas-liquid two-phase mixtures. Therefore, indirect ignition, i.e., the method of transitioning from combustion to detonation, is closer to practical engineering applications. To avoid the dynamic problems of the rotor system and the increase in engine weight caused by excessively long axial distance of the combustion chamber, the fuel-air distribution in the detonation combustion chamber needs to be as uniform as possible to shorten the distance from slow combustion to detonation. Therefore, high design requirements are placed on the head intake mixing structure of the detonation combustion chamber.

[0004] Currently, to facilitate the formation of detonation waves and the back-transmission of detonation pressure upstream within the pulse detonation combustion chamber, an intake cone is required at the head of the chamber. The bottom of the intake cone forms a thrust wall, which is beneficial for detonation wave generation. However, this structure causes the airflow to suddenly expand after passing through the intake cone, creating a large recirculation zone at the head. The presence of this recirculation zone causes fuel to become stationary, resulting in stationary combustion. The flame cannot propagate and accelerate backward, thus hindering the formation of detonation waves. Summary of the Invention

[0005] In view of this, this application provides a gradually expanding pulse detonation combustion chamber head structure, which solves the problems in the prior art and improves the uniformity of oil-gas mixing in the detonation combustion chamber.

[0006] The technical solution for the gradually expanding pulse detonation combustion chamber head structure provided in this application is as follows:

[0007] A gradually expanding pulse detonation combustion chamber head structure includes a connected intake and fuel supply section and a mixing section; The intake and fuel supply section includes an intake annular housing, an intake cone, and mounting bases. One end of the intake annular housing is connected to the detonation combustion chamber pressure back-transmission isolation section, and the other end of the intake annular housing is connected to the mixing section. The intake annular housing and the intake cone are coaxially arranged, and the tip of the intake cone faces the detonation combustion chamber pressure back-transmission isolation section. The intake cone is installed inside the intake annular housing through several spaced mounting bases. The several mounting bases are distributed circumferentially around the intake annular housing. Each mounting base has a fuel nozzle on the side facing the mixing section. The fuel delivery pipe of the fuel nozzle passes through the interior of the mounting base and the side wall of the intake annular housing and extends out of the intake annular housing. The gap between the several mounting bases serves as the intake passage of the mixing section. The blending section includes a blending annular shell, a central cone, and a cyclone separator. One end of the blending annular shell is fixedly connected to the intake annular shell, and the other end of the blending annular shell is connected to the detonation combustion chamber ignition section. The intake annular shell, intake cone, blending annular shell, and central cone are coaxially arranged. The tip of the central cone faces the detonation combustion chamber ignition section. The central cone is installed inside the blending annular shell through a cyclone separator. The cyclone separator includes several swirl blades spaced apart circumferentially along the blending annular shell. Several fuel nozzles surround the outer periphery of the large-diameter end of the central cone. The inner wall of the end of the mixing annular shell away from the intake annular shell is provided with an annular protrusion structure. The inner diameter of the annular protrusion structure gradually decreases and then gradually increases from the side near the intake annular shell towards the side of the detonation combustion chamber ignition section. The part of the annular protrusion structure with the gradually decreasing inner diameter is the tapering section, and the part of the annular protrusion structure with the gradually increasing inner diameter is the expanding section. The end of the tapering section away from the expanding section surrounds the outer periphery of the tip of the central cone.

[0008] Optionally, the large-diameter end of the central cone and the large-diameter end of the intake cone are connected to each other.

[0009] Optionally, the large-diameter end of the intake cone is provided with a groove, and the large-diameter end of the central cone is provided with a boss that engages with the groove.

[0010] Optionally, the central cone has a cavity inside, and the outer wall of the central cone has a plurality of openings communicating with the cavity.

[0011] Optionally, the outer wall of the central cone is provided with several rings of openings. At least one ring of openings is provided on both the side of the cyclone separator facing the air intake annular housing and the side facing away from the air intake annular housing. Multiple openings in the same ring are located at the same axial position of the mixing annular housing, and the openings in the same ring are circumferentially and evenly spaced around the axis of the mixing annular housing.

[0012] Optionally, the area of ​​the opening is calculated using the following formula: ; in, Design frequency for detonation combustion chamber For the local speed of sound, The area of ​​the opening is... For cavity volume, For the depth of the hole, This is a correction factor.

[0013] Optionally, the intake annular housing, intake cone, and mounting base are integrated into one unit.

[0014] Optionally, the mixing annular shell, central cone, cyclone separator, and annular protrusion structure are integrally formed.

[0015] In summary, this application includes the following beneficial technical effects: This application employs a ring-cavity distributed fuel nozzle for fuel supply combined with two-stage mixing, which can enhance the fuel-air mixing effect at the head of the knock combustion chamber, making the fuel-air distribution in the knock combustion chamber more uniform and conducive to the formation of knock waves.

[0016] The mixing section of this application adopts a gradually expanding channel, which can act as a thrust wall while avoiding a large backflow zone at the head of the detonation combustion chamber, thus preventing flame stationary combustion and facilitating high-frequency operation of the detonation combustion chamber.

[0017] The cavity and opening of the central cone form a Helmholtz cavity. Utilizing the Helmholtz principle, it effectively reduces reverse pressure pulsation, which helps to shorten the length of the reverse pressure isolation section in the knock combustion chamber and reduce the weight of the engine. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the overall structure of the head structure of the gradually expanding pulse detonation combustion chamber; Figure 2 A schematic diagram of the cross-sectional structure of the head structure of a gradually expanding pulse detonation combustion chamber; Figure 3 This is a schematic diagram of the assembly structure of the intake cone and the center cone.

[0020] Explanation of reference numerals in the attached drawings: 1. Intake and fuel supply section; 11. Intake annular housing; 12. Intake cone; 13. Mounting base; 14. Fuel nozzle; 2. Mixing section; 21. Mixing annular housing; 22. Central cone; 23. Swirl; 24. Annular protrusion structure; 25. Recessed section; 26. Expanding section; 3. Groove; 31. Boss; 4. Cavity; 41. Opening. Detailed Implementation

[0021] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0022] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0024] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0025] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0026] This application provides a gradually expanding pulse detonation combustion chamber head structure.

[0027] like Figures 1 to 3 As shown, a gradually expanding pulse detonation combustion chamber head structure includes a connected intake and fuel supply section 1 and a mixing section 2.

[0028] The intake and fuel supply section 1 includes an intake annular housing 11, an intake cone 12, and mounting bases 13. One end of the intake annular housing 11 is connected to the detonation combustion chamber pressure back-transmission isolation section, and the other end of the intake annular housing 11 is connected to the mixing section 2. The intake annular housing 11 and the intake cone 12 are coaxially arranged, and the tip of the intake cone 12 faces the detonation combustion chamber pressure back-transmission isolation section. The intake cone 12 is installed inside the intake annular housing 11 through several spaced mounting bases 13. The several mounting bases 13 are distributed circumferentially along the intake annular housing 11. Each mounting base 13 has a fuel nozzle 14 on the side facing the mixing section 2. The fuel supply pipe of the fuel nozzle 14 passes through the interior of the mounting base 13 and the side wall of the intake annular housing 11 and extends out of the intake annular housing 11. The gap between the several mounting bases 13 serves as the intake passage of the mixing section 2.

[0029] The blending section 2 includes a blending annular shell 21, a central cone 22, and a cyclone separator 23. One end of the blending annular shell 21 is fixedly connected to the intake annular shell 11, and the other end of the blending annular shell 21 is connected to the detonation combustion chamber ignition section. The intake annular shell 11, the intake cone 12, the blending annular shell 21, and the central cone 22 are coaxially arranged. The tip of the central cone 22 faces the detonation combustion chamber ignition section. The central cone 22 is installed inside the blending annular shell 21 through the cyclone separator 23. The cyclone separator 23 includes several swirl blades that are spaced apart circumferentially along the blending annular shell 21. Several fuel nozzles 14 surround the outer periphery of the large-diameter end of the central cone 22.

[0030] The inner wall of the end of the mixing annular shell 21 away from the intake annular shell 11 is provided with an annular protrusion structure 24. The inner diameter of the annular protrusion structure 24 gradually decreases and then gradually increases from the side near the intake annular shell 11 toward the side of the detonation combustion chamber ignition section. The part of the annular protrusion structure 24 with the gradually decreasing inner diameter is the tapered section 25, and the part of the annular protrusion structure 24 with the gradually increasing inner diameter is the expanding section 26. The end of the tapered section 25 away from the expanding section 26 surrounds the outer periphery of the tip of the central cone 22.

[0031] In this application, the cyclone separator 23 forms the first-stage mixing structure, and the central cone 22, the converging section 25, and the expanding section 26 form a Venturi mixer as the second-stage mixing structure. During operation, the airflow from upstream reaches the mounting base 13 via the intake cone 12 and mixes with fuel injected from multiple circumferentially distributed fuel nozzles 14. The fuel and air undergo first-stage mixing via the cyclone separator 23 between the mixing annular shell 21 and the central cone 22, followed by second-stage mixing via the Venturi mixer after convergence and expansion. This two-stage mixing facilitates the breakup and evaporation of fuel droplets and thorough mixing with air. The front end of the mixing annular shell 21 and the central cone 22 form a expanding channel, allowing the fuel and air to gradually expand within the mixing section 2. This prevents a backflow zone from forming at the head of the detonation combustion chamber, thus avoiding stagnant combustion and promoting the formation of detonation waves.

[0032] In one embodiment, the intake annular housing 11 and the detonation combustion chamber pressure back-transmission isolation section are fixedly connected by a flange and bolts, the intake annular housing 11 and the mixing annular housing 21 are fixedly connected by a flange and bolts, and the mixing annular housing 21 and the detonation combustion chamber ignition section are fixedly connected by a flange and bolts.

[0033] In one embodiment, the intake annular housing 11, intake cone 12, and mounting base 13 are integrally formed. The mixing annular housing 21, central cone 22, cyclone separator 23, and annular protrusion structure 24 are integrally formed. The cone angle of the central cone 22 ranges from 5 to 20°, making it difficult for the airflow to escape from the wall of the central cone 22. The blockage ratio of the Venturi mixer is between 0.4 and 0.6.

[0034] In one embodiment, a plurality of fuel nozzles 14 are evenly spaced along the circumference of the intake annular housing 11, and the number of fuel nozzles 14 is four.

[0035] The large-diameter end of the central cone 22 and the large-diameter end of the intake cone 12 are connected to each other. A groove 3 is provided on the end face of the large-diameter end of the intake cone 12, and a boss 31 is provided on the end face of the large-diameter end of the central cone 22, which engages with the groove 3. Both the groove 3 and the boss 31 are circular and coaxially arranged with the intake annular housing 11. The cooperation between the central cone 22 and the intake cone 12 can, on the one hand, prevent gaps at the joint surface of the central cone 22 and the intake cone 12 from causing flow field disorder, and on the other hand, prevent the central cone 22 from becoming a cantilever structure. It also serves to center the structure during installation.

[0036] The central cone 22 has an internal cavity 4, and its outer wall has several openings 41 communicating with the cavity 4. The cavity 4 is located on the side of the annular protrusion 24 facing the intake cone 12. The design of the cavity 4 and openings 41 reduces the mass of the central cone 22, contributing to engine weight reduction. Furthermore, the cavity 4 and openings 41 form a Helmholtz chamber. When the reverse pressure generated by the detonation wave passes through the central cone 22, the gas column inside the opening acts like a piston. The friction between gas molecules and between the gas and the orifice wall generates a huge damping force. The greater the gas velocity inside the orifice, the greater the damping force, ultimately converting mechanical energy into heat energy. According to the Helmholtz principle, when the gas approaches resonance, the viscous friction between gas molecules and between gas molecules and the orifice is stronger, resulting in a more significant reduction in reverse pressure pulsation. Therefore, this helps to shorten the length of the pressure reverse transmission isolation section in the detonation combustion chamber, thereby reducing the engine weight.

[0037] The outer wall of the central cone 22 is provided with several rings of openings 41. At least one ring of openings 41 is provided on both the side of the cyclone separator 23 facing the air intake annular housing 11 and the side facing away from the air intake annular housing 11. Multiple openings 41 in the same ring are located at the same axial position of the mixing annular housing 21, and the openings 41 in the same ring are evenly spaced around the axis of the mixing annular housing 21 in a circumferential direction.

[0038] The area of ​​the opening 41 is calculated using the following formula: ; in, Design frequency for detonation combustion chamber For the local speed of sound, For an opening area of ​​41, The cavity has a volume of 4. The hole depth is 41. This is a correction factor.

[0039] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A gradually expanding pulse detonation combustion chamber head structure, characterized in that, It includes a connected intake and fuel supply section (1) and a mixing section (2); The intake and fuel supply section (1) includes an intake annular housing (11), an intake cone (12), and mounting bases (13). One end of the intake annular housing (11) is connected to the detonation combustion chamber pressure back-transmission isolation section, and the other end of the intake annular housing (11) is connected to the mixing section (2). The intake annular housing (11) and the intake cone (12) are coaxially arranged, and the tip of the intake cone (12) faces the detonation combustion chamber pressure back-transmission isolation section. The intake cone (12) is connected to a plurality of spaced mounting bases. (13) Installed inside the intake annular housing (11), a plurality of the mounting seats (13) are distributed circumferentially along the intake annular housing (11), each mounting seat (13) is provided with a fuel nozzle (14) on the side facing the mixing section (2), the fuel supply pipe of the fuel nozzle (14) passes through the interior of the mounting seat (13) and the side wall of the intake annular housing (11) and extends out of the intake annular housing (11), the gap between the plurality of mounting seats (13) serves as the intake passage of the mixing section (2); The mixing section (2) includes a mixing annular shell (21), a central cone (22), and a swirler (23). One end of the mixing annular shell (21) is fixedly connected to the intake annular shell (11), and the other end of the mixing annular shell (21) is connected to the detonation combustion chamber ignition section. The intake annular shell (11), intake cone (12), mixing annular shell (21), and central cone (22) are coaxially arranged. The tip of the central cone (22) faces the detonation combustion chamber ignition section. The central cone (22) is installed inside the mixing annular shell (21) through the swirler (23). The swirler (23) includes several swirling blades that are spaced apart along the circumference of the mixing annular shell (21). Several fuel nozzles (14) surround the outer periphery of the large-diameter end of the central cone (22). The inner wall of the end of the mixing annular shell (21) away from the intake annular shell (11) is provided with an annular protrusion structure (24). The inner diameter of the annular protrusion structure (24) gradually decreases and then gradually increases from the side near the intake annular shell (11) towards the side of the detonation combustion chamber ignition section. The part of the annular protrusion structure (24) with the gradually decreasing inner diameter is the tapered section (25), and the part of the annular protrusion structure (24) with the gradually increasing inner diameter is the expanding section (26). The end of the tapered section (25) away from the expanding section (26) surrounds the outer periphery of the tip of the central cone (22).

2. The gradually expanding pulse detonation combustion chamber head structure according to claim 1, characterized in that, The large-diameter end of the central cone (22) and the large-diameter end of the intake cone (12) are connected to each other.

3. The gradually expanding pulse detonation combustion chamber head structure according to claim 2, characterized in that, The large-diameter end of the intake cone (12) is provided with a groove (3), and the large-diameter end of the central cone (22) is provided with a boss (31) that engages with the groove (3).

4. The gradually expanding pulse detonation combustion chamber head structure according to claim 1, characterized in that, The central cone (22) has a cavity (4) inside, and the outer wall of the central cone (22) has a number of openings (41) that communicate with the cavity (4).

5. The gradually expanding pulse detonation combustion chamber head structure according to claim 4, characterized in that, The outer wall of the central cone (22) is provided with several rings of openings (41). At least one ring of openings (41) is provided on both the side of the cyclone separator (23) facing the air intake annular housing (11) and the side facing away from the air intake annular housing (11). Multiple openings (41) in the same ring are located at the same axial position of the mixing annular housing (21), and the openings (41) in the same ring are evenly spaced around the axis of the mixing annular housing (21).

6. The gradually expanding pulse detonation combustion chamber head structure according to claim 4, characterized in that, The area of ​​the opening (41) is calculated using the following formula: ； in, Design frequency for detonation combustion chamber For the local speed of sound, For the area of ​​the opening (41), For the volume of cavity (4), The depth of the opening (41) This is a correction factor.

7. The gradually expanding pulse detonation combustion chamber head structure according to claim 1, characterized in that, The intake annular housing (11), intake cone (12), and mounting base (13) are integrally formed.

8. The gradually expanding pulse detonation combustion chamber head structure according to claim 1, characterized in that, The mixed annular shell (21), central cone (22), cyclone separator (23) and annular protrusion structure (24) are integrally formed.

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