Gas film cooling structure and rotary detonation engine

Abstract

This invention discloses a film cooling structure and a rotary detonation engine, relating to the field of thermal protection technology for rotary detonation combustion chambers. The film cooling structure includes a film cooling pipe disposed on and connected to the rotary detonation combustion chamber, and a cold air chamber disposed at the end of the film cooling pipe away from the rotary detonation combustion chamber and connected to the film cooling pipe. The connection end of the film cooling pipe to the rotary detonation combustion chamber is provided with a microporous structure, and the interior of the film cooling pipe is provided with a flow guiding device for guiding the fluid in the cold air chamber. By setting the microporous structure and the flow guiding device, a certain effect of suppressing backflow is achieved, and the coolant enters the combustion chamber more quickly, achieving a higher instantaneous cooling effect.

Description

Technical Field

[0001] This invention relates to the field of thermal protection technology for rotating detonation combustion chambers, specifically to a film cooling structure and a rotating detonation engine. Background Technology

[0002] Rotating detonation (RDE) engines are a novel propulsion technology based on the principle of continuous rotating detonation wave propagation. Their core lies in the self-sustaining rotating detonation wave formed within a ring-shaped combustion chamber by a premixed gas of fuel and oxidizer, thereby achieving supersonic combustion and efficient energy release. Compared to traditional isobaric combustion engines, RDEs, thanks to the high-pressure gain characteristics of the detonation wave, theoretically possess higher thermal cycle efficiency and a more compact structure, and are considered a key development direction for future aerospace propulsion systems.

[0003] However, the thermal environment of the RDE (Revolutionary Detonator) is exceptionally complex due to the unique propagation mechanism of the detonation wave. The detonation wave rotates supersonically along the circumference of the combustion chamber, generating intense high-temperature and high-pressure gradients and rapidly changing flow structures, resulting in a highly unsteady thermal load. This transient heat flux distribution poses a severe challenge to the thermal protection design of the combustion chamber.

[0004] Currently, film cooling exhibits good cooling performance in RDE thermal protection. However, when detonation waves erode the film cooling orifices, the backflow of high-temperature combustion gases is severe, potentially even intruding into the cold gas chamber and significantly interfering with coolant injection. This backflow problem is prevalent in both the detonation wave and oblique shock wave regions. While existing film cooling structures can suppress detonation wave intrusion, the coolant flow rate is correspondingly affected, thus reducing the cooling effect.

[0005] Therefore, it is necessary to develop and design film cooling structures and rotary detonation engines, which can not only reduce gas backflow but also increase the outflow rate of coolant and improve cooling efficiency. This is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a film cooling structure and a rotary detonation engine, which can not only reduce gas backflow but also increase the coolant outflow rate and improve cooling efficiency.

[0007] To achieve the above objectives, the present invention provides the following solution: A film cooling structure includes a film cooling tube disposed on and communicating with a rotating detonation combustion chamber, and a cold air chamber disposed at the end of the film cooling tube away from the rotating detonation combustion chamber and communicating with the film cooling tube. The connection end of the film cooling tube to the rotating detonation combustion chamber is provided with a microporous structure, and the interior of the film cooling tube is provided with a flow guiding device for guiding fluid into the cold air chamber.

[0008] Preferably, the microporous structure includes an end plate disposed at the end of the air film tube and through holes formed on the end plate.

[0009] Preferably, the diameter of the through hole is between 100 μm and 600 μm.

[0010] Preferably, the number of through holes is 4 to 10, and they are evenly distributed on the end plate.

[0011] Preferably, the number of gas film tubes is 1 to 10, and the end of the gas film tube away from the cold air chamber extends toward the outlet of the rotating detonation combustion chamber.

[0012] Preferably, the flow guiding device includes at least two flow guiding ribs arranged circumferentially along the air film tube, the flow guiding ribs are inclined, and the end of the flow guiding rib near the cold air chamber is far away from the central axis of the air film tube.

[0013] Preferably, the guide ribs are arranged sequentially along the axial direction of the air film tube.

[0014] Preferably, the drainage device is a spiral groove disposed on the inner wall of the air film tube.

[0015] Preferably, the drainage device includes a pipe communicating with the microporous structure and a limiting plate disposed inside the air film tube for limiting the pipe, wherein the limiting plate is spaced apart from the connection end of the air film tube and the cold air chamber.

[0016] The present invention also discloses a rotary detonation engine, including the above-described film cooling structure, characterized in that it further includes a rotary detonation combustion chamber and a combustion chamber inlet and a combustion chamber outlet respectively opened at both ends of the rotary detonation combustion chamber.

[0017] The present invention achieves the following technical effects compared to the prior art: By incorporating a microporous structure and a flow-guiding device, when the detonation wave passes through the cooling film tube, the coolant enters the cold air chamber through the inlet and flows into the rotating detonation combustion chamber. When the rotating detonation wave passes through the film tube, high-temperature combustion gases may backflow into it. However, when passing through the microporous structure, most of these gases are blocked inside the combustion chamber, with only a small portion entering the film tube, thus achieving a certain degree of suppression of backflow. The coolant, after entering from the cold air chamber inlet, flows into the film tube. Due to the flow-guiding device, the coolant forms an orderly flow path within the film tube, significantly reducing flow losses and eddy mixing. When it enters the combustion chamber through the microporous structure, the reduced channel area provides a certain acceleration effect, allowing the coolant to enter the combustion chamber more quickly and achieving a higher instantaneous cooling effect. Attached Figure Description

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

[0019] Appendix Figure 1 This is a schematic diagram of the overall structure of the film cooling structure and the rotary detonation engine disclosed in this invention. Appendix Figure 2 This is a schematic diagram of the main view structure of the film cooling structure and the rotating detonation engine disclosed in this invention. Appendix Figure 3 This is a diagram showing the flow direction of coolant in a single film cooling pipe in the film cooling structure and rotary detonation engine disclosed in this invention. Appendix Figure 4 This is a schematic diagram of the air film cooling structure and the spiral groove in the rotary detonation engine disclosed in this invention. Appendix Figure 5 This is a schematic diagram of the air film cooling structure and the flow guiding device in the rotary detonation engine disclosed in this invention when the flow guiding device is a flow guiding rib. Appendix Figure 6 This is a schematic diagram of the air film cooling structure and the ductwork in the rotary detonation engine disclosed in this invention. Appendix Figure 7 This is a schematic diagram of the arrangement of five through holes in the film cooling structure and rotary detonation engine disclosed in this invention. Appendix Figure 8 This is a schematic diagram showing the arrangement of 10 through holes in the film cooling structure and rotary detonation engine disclosed in this invention. The arrows in the attached diagram indicate the direction of coolant flow. Among them, 1. Cold air chamber inlet; 2. Cold air chamber; 3. Air film pipe; 4. Combustion chamber inlet; 5. Rotary detonation combustion chamber; 6. Combustion chamber outlet; 7. Through hole; 8. Guide rib; 9. Limiting plate; 10. Pipe. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a film cooling structure and a rotary detonation engine, which can not only reduce the backflow of combustion gases, but also increase the outflow rate of coolant and improve cooling efficiency.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] refer to Figures 1-3 The film cooling structure disclosed in this embodiment of the invention includes at least a film cooling tube 3 and a cooling chamber 2. The film cooling tube 3 is disposed on and communicates with the rotating detonation combustion chamber 5. The end of the film cooling tube 3 away from the rotating detonation combustion chamber 5 is provided with the cooling chamber 2. The end of the cooling chamber 2 near the combustion chamber inlet 4 is provided with a cooling chamber inlet 1. The connection end of the film cooling tube 3 and the rotating detonation combustion chamber 5 is provided with a microporous structure. The interior of the film cooling tube 3 is provided with a flow guiding device for the coolant in the cooling chamber 2. By providing the microporous structure and the flow guiding device, when the detonation wave passes through the cooling film cooling hole, the coolant will enter the interior of the cooling chamber 2 along the cooling chamber inlet 1, and then flow into the rotating detonation combustion chamber 2 after passing through the film cooling tube 3 and the microporous structure. In the combustion chamber 5, when the rotating detonation wave passes through the film membrane tube 3, the high-temperature combustion gas will back-enter the film membrane tube 3. However, when passing through the microporous structure, most of it will be blocked inside the combustion chamber by the microporous surface, and a small portion of the high-temperature combustion gas will enter the film membrane tube 3, achieving a certain effect of suppressing back-entry. After the coolant enters from the cold air chamber inlet 1, it flows into the interior of the film membrane tube 3. Due to the guiding effect of the flow guiding device, the coolant forms an orderly flow path in the film membrane tube 3, which significantly reduces flow loss and eddy mixing. When it enters the combustion chamber through the microporous structure, the reduced channel area will have a certain acceleration effect on the coolant, allowing the coolant to enter the combustion chamber faster and achieve a higher instantaneous cooling effect.

[0024] refer to Figure 3 As one implementation method, the microporous structure includes an end plate set at the end of the film gas tube 3 and through holes 7 opened on the end plate. By setting an end plate and opening precision through holes 7 at the end of the film gas tube 3, on the one hand, the physical barrier effect of the end plate is used to form an effective flow-blocking surface when the detonation wave back-intrudes, blocking most of the high-temperature gas in the combustion chamber, significantly suppressing backfire and hot gas backflow. On the other hand, the densely arranged through holes 7 serve as coolant outlet channels, which not only achieve uniform distribution and jet breaking of coolant along the circumference, but also improve the cold gas jet velocity and penetration depth through the throttling effect of the through holes 7, thereby constructing a uniform and stable film gas covering layer in the near-wall area of ​​the combustion chamber, greatly enhancing the local thermal protection capability and cooling efficiency.

[0025] It should be noted that the cold air chamber inlet 1 can also be set as two, respectively located at both ends of the cold air chamber 2, to achieve bidirectional countercurrent supply of coolant. On the one hand, the dual-inlet structure significantly shortens the flow path of coolant from the inlet to each gas film tube 3, effectively reducing flow resistance and pressure loss along the way, making the pressure distribution in the cold air chamber 2 more uniform, thereby ensuring a high degree of consistency in the outlet flow of each exhaust film tube 3. On the other hand, simultaneous feeding at both ends can form a pressure superposition effect in the middle of the cold air chamber 2, further increasing the driving pressure difference of coolant at the inlet of the gas film tube 3, suppressing the interference of high-frequency pulsation of detonation wave on the stability of the supply flow, and ultimately achieving uniform distribution and long-term stability of the circumferential cooling gas film.

[0026] During the entire rotary detonation process, the coolant enters from the cold air chamber inlet 1, passes through the film gas pipe 3, and enters the rotary detonation combustion chamber 5. The premixed fuel enters the rotary detonation combustion chamber 5 from the combustion chamber inlet 4 for combustion. Finally, both enter through the combustion chamber outlet 6 and exit. refer to Figures 1-3 In one embodiment, the aperture of the through hole 7 is 100 μm to 600 μm.

[0027] refer to Figures 7-8 In one implementation, the number of through holes 7 is 4 to 10, and they are evenly distributed on the end plate. By limiting the number of through holes 7 to 4 to 10 and distributing them evenly on the end plate, the configuration of the coolant outlet channel is optimized. On the one hand, this range avoids the cooling dead zone and insufficient jet coverage caused by too few holes, while also preventing the inability to suppress the backflow of combustion gases and the dispersion of coolant flow caused by too many holes. On the other hand, the uniform distribution ensures that the airflow at the outlet of each through hole 7 is highly consistent in the circumferential direction, so that the coolant jet can form a continuous and stable gas film covering layer in the near-wall area of ​​the combustion chamber, eliminating local hot spots and temperature gradients. At the same time, with the reasonable design of the spacing between holes, the mutual entrainment and superposition effect between adjacent jets is enhanced, thereby maximizing the cooling coverage and thermal protection effect under the premise of limited cooling gas consumption.

[0028] refer to Figure 1As a preferred approach, the number of film cooling pipes 3 is between 1 and 10, and they are evenly distributed on the rotating detonation combustion chamber 5 along the extension direction from the combustion chamber inlet 4 to the combustion chamber outlet 6. By limiting the number of film cooling pipes 3 to between 1 and 10 and distributing them evenly along the combustion chamber axis, a graded and orderly coverage of the cooling film along the flow direction is achieved. On the one hand, this range of numbers takes into account both the cooling coverage density and the need for structural simplification—too few pipes may lead to insufficient downstream cooling capacity, while too many pipes will increase structural complexity and cooling gas consumption. On the other hand, the uniform distribution along the axis allows each exhaust film pipe 3 to form a film protective layer at different axial positions in the combustion chamber, effectively addressing the characteristic of the gradual accumulation of wall heat load during the propagation of the detonation wave from upstream to downstream. This ensures that the wall is under effective thermal protection throughout the entire stroke from the combustion chamber inlet 4 to the combustion chamber outlet 6, significantly improving the durability and thermal reliability of the combustion chamber under long-distance operation conditions.

[0029] refer to Figure 1 In one implementation, the end of the film cooling tube 3 away from the cold air chamber 2 extends toward the outlet of the rotating detonation combustion chamber 5, achieving a high degree of coordination between the cooling jet flow direction and the main combustion gas flow direction. On the one hand, this co-current arrangement allows the coolant to be injected into the combustion chamber along the mainstream direction, significantly reducing the shear mixing loss between the jet and the high-speed rotating detonation mainstream, and avoiding the additional flow resistance and film lifting phenomenon caused by counter-current injection. On the other hand, the coolant flows in the forward direction and adheres to the wall, which can continuously form a stable film covering layer in the downstream area of ​​the combustion chamber, effectively dealing with the heat load accumulated along the path during the propagation of the detonation wave. At the same time, with the help of the flow momentum superposition effect, the wall penetration depth and coverage length of the cooling jet are enhanced, thereby maximizing the thermal protection effect of the downstream wall under the premise of limited cooling gas consumption.

[0030] refer to Figure 5 As a preferred embodiment, the diversion device includes at least two guide ribs 8 arranged circumferentially along the film tube 3. The guide ribs 8 are inclined, with the end of the guide rib 8 near the cold air chamber 2 being away from the central axis of the film tube 3. The inclined design of the near end of the guide rib 8 away from the central axis expands the cold air capture cross section, reduces flow separation and eddy current loss at the inlet, and induces the coolant to flow downstream along the wall. This not only has the effect of diverting the coolant, but the inclined structure can also effectively suppress the backflow tendency of high-temperature combustion gas into the cold air chamber 2 when the detonation wave back-intrudes.

[0031] It should be noted that the adjacent guide ribs 8 are spaced apart. This spacing allows the coolant to be evenly distributed circumferentially into the flow channels between the ribs, avoiding flow interference and local congestion that may be caused by the continuous arrangement of the guide ribs 8, and significantly reducing flow resistance and pressure loss. In another embodiment, the flow guiding device can be a conical orifice plate installed inside the film gas pipe 3, with the orifice diameter on the side closer to the cold air chamber 2 being larger than that on the side farther from the cold air chamber 2. This achieves gradual acceleration and pressure regulation of the coolant flow process: on the one hand, the large-diameter inlet can effectively capture the coolant from the cold air chamber 2, reduce the flow resistance in the inlet section, and ensure sufficient cold air supply; on the other hand, the orifice diameter gradually decreases along the flow direction, generating a continuous throttling and acceleration effect on the coolant, enabling it to obtain a higher jet flow when entering the downstream of the film gas pipe 3, thereby enhancing its ability to penetrate the near-wall region of the combustion chamber; at the same time, the change in the flow cross section of the conical orifice plate forms a stable pressure gradient in the pipe, effectively suppressing the reverse propagation of high-frequency pulsations of detonation waves to the upstream cold air chamber 2, playing a wave-blocking role similar to a "pneumatic diode"; in addition, the conical orifice plate itself, as a solid baffle, can also block some of the backflow of high-temperature combustion gases directly backflowing along the pipe wall, significantly improving the reverse sealing performance and cooling supply stability of the film gas pipe 3 under extreme pulsation conditions.

[0032] refer to Figure 5 As one implementation method, the guide ribs 8 are arranged sequentially along the axial direction of the film gas pipe 3, that is, at least two backflow ribs form a guide mechanism. The guide components are arranged sequentially along the axial direction of the film gas pipe 3. The sequential action of each level of guide ribs 8 can form a multi-layer superimposed swirling boundary layer on the inner wall surface of the film gas pipe 3, which effectively suppresses the reverse diffusion and wall climbing of the high-temperature backflow gas along the axial direction.

[0033] refer to Figure 4 As one implementation method, the flow guiding device is a spiral groove set on the inner wall of the air film tube 3. The spiral groove structure makes the coolant flow smoother and more stable. At the same time, the continuous channel can also induce the coolant to form a persistent swirling flow, so that it maintains a high turbulence intensity and wall adhesion ability before entering the microporous structure, ultimately improving the coverage uniformity and instantaneous cooling response speed of the air film jet.

[0034] refer to Figure 6 As one implementation method, the diversion device includes a pipe 10 connected to the microporous structure and a limiting plate 9 disposed inside the gas film pipe 3 to limit the pipe 10. The limiting plate 9 is spaced apart from the connection end of the gas film pipe 3 and the cold air chamber 2. The space between the limiting plate 9 and the connection end forms a buffer pressure stabilizing chamber, which allows the coolant from the cold air chamber 2 to be fully pressure equalized and rectified before entering the pipe 10, effectively suppressing the reverse propagation of the high-frequency pulsation of the detonation wave upstream. While strengthening the directional flow of the coolant, this structure further blocks the reverse climb of the back-invading high-temperature gas along the wall of the gas film pipe 3 through the physical barrier of the limiting plate 9, realizing the dual function of diversion and prevention of back-invasion.

[0035] refer to Figure 1The present invention also discloses a rotary detonation engine, including the above-described film cooling structure, and further including a rotary detonation combustion chamber 5 and a combustion chamber inlet 4 and a combustion chamber outlet 6 respectively opened at both ends of the rotary detonation combustion chamber 5.

[0036] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A film cooling structure, characterized in that, It includes a gas film tube (3) disposed on and connected to the rotary detonation combustion chamber (5), and a cold air chamber (2) disposed at the end of the gas film tube (3) away from the rotary detonation combustion chamber (5) and connected to the gas film tube (3). The connection end of the gas film tube (3) and the rotary detonation combustion chamber (5) is provided with a microporous structure. The interior of the gas film tube (3) is provided with a flow guiding device for guiding the fluid in the cold air chamber (2).

2. The gas film cooling structure according to claim 1, characterized in that, The microporous structure includes an end plate disposed at the end of the air film tube (3) and a through hole (7) formed on the end plate.

3. The air film cooling structure according to claim 2, characterized in that, The diameter of the through hole (7) is 100μm to 600μm.

4. The air film cooling structure according to claim 2, characterized in that, The number of through holes (7) is 4 to 10, and they are evenly distributed on the end plate.

5. The film cooling structure according to claim 1, characterized in that, The number of the air film tubes (3) is 1 to 10, and the end of the air film tube (3) away from the cold air chamber (2) extends toward the outlet of the rotating detonation combustion chamber (5).

6. The film cooling structure according to claim 1, characterized in that, The drainage device includes at least two guide ribs (8) arranged circumferentially along the air film tube (3). The guide ribs (8) are inclined and the end of the guide rib (8) near the cold air chamber (2) is far away from the central axis of the air film tube (3).

7. The film cooling structure according to claim 1, characterized in that, The guide ribs (8) are arranged sequentially along the axial direction of the air film tube (3).

8. The film cooling structure according to claim 1, characterized in that, The drainage device is a spiral groove set on the inner wall of the air film tube (3).

9. The film cooling structure according to claim 1, characterized in that, The drainage device includes a pipe (10) communicating with the microporous structure and a limiting plate (9) disposed inside the air film tube (3) for limiting the pipe (10). The limiting plate (9) is spaced apart from the connection end of the air film tube (3) and the cold air chamber (2).

10. A rotating detonation engine, comprising the film cooling structure according to any one of claims 1-9, characterized in that, It also includes a rotating detonation combustion chamber (5) and combustion chamber inlets (4) and combustion chamber outlets (6) respectively opened at both ends of the rotating detonation combustion chamber (5).

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