A subsonic ramjet engine based on counter-rotating rotary detonation flame stabilization ignition

Abstract

This invention discloses a subsonic ramjet engine based on counter-rotating rotary detonation flame stabilization ignition, belonging to the field of subsonic ramjet engine flame stabilization ignition technology. It includes an intake cooling channel, an integrated fuel supply device, and a symmetrical rotary detonation flame stabilization device. The intake cooling channel cools the engine wall temperature; the integrated fuel supply device achieves high system integration, low flow resistance loss, and lightweight and convenient design; the symmetrical rotary detonation flame stabilization device uses a counter-rotating jet to assist in creating a stable low-speed recirculation zone in the main combustion chamber, thereby achieving flame stabilization. Furthermore, the continuously operating rotary detonation generator acts as a pre-combustion tube, providing forced ignition to the main combustion chamber. This highly integrated invention effectively cools the combustion chamber wall temperature of the subsonic ramjet engine, improves combustion stability, and significantly increases the ignition success rate of the main combustion chamber, thus providing an effective technical approach for subsonic ramjet engines to operate within a wide range of conditions.

Description

Technical Field

[0001] This invention relates to the field of flame stabilization technology for subsonic ramjet engines, and more specifically, to a subsonic ramjet engine based on counter-rotating detonation flame stabilization ignition. Background Technology

[0002] A ramjet engine is an air-breathing engine that utilizes the high-speed airflow encountered during high-speed flight. The airflow is decelerated and pressurized in the intake before entering the combustion chamber, where it mixes and burns with fuel. The mixture is then expanded and accelerated out of the exhaust nozzle, generating thrust. Compared to turbocharged aero engines, it can operate at higher Mach numbers and boasts advantages such as simpler structure, higher specific impulse, and greater thrust. Based on the Mach number of the incoming flow within the combustion chamber, ramjet engines are classified into subsonic ramjet engines and scramjet engines. Subsonic ramjet technology is relatively mature, but its performance heavily relies on the stability and efficiency of combustion within the combustion chamber. Even when the incoming flow in a subsonic ramjet engine is subsonic, the mixing degree between the fuel and the fuel, which has a very short residence time, remains low. Achieving rapid mixing of fuel with the high-speed incoming flow and maintaining stable combustion within the combustion chamber remains a long-standing technological bottleneck.

[0003] Traditional flame stabilization technologies, such as V-type flame stabilizers, require a large blockage ratio to achieve the desired flame stabilization effect, resulting in significant dynamic pressure loss. Therefore, under low blockage ratio conditions, the backflow zone strength may be insufficient, leading to problems such as flame blowout, severely limiting the stable operating boundary and performance improvement of subsonic combustion ramjet engines. In addition, rotary detonation engines have attracted widespread attention in recent years. Their working principle involves combustible gas being injected from one end of the combustion chamber, where one or more detonation waves rotate and propagate to consume the freshly injected combustible gas. High-temperature, high-pressure detonation products are then discharged at high speed from the other end of the combustion chamber, generating thrust. They possess advantages such as simple and compact structure and high operating frequency.

[0004] Based on this, in response to the problems of poor flame stability, narrow flame stabilization boundary, and high combustion chamber wall temperature in existing subsonic ramjet engines, this invention proposes a subsonic ramjet engine equipped with symmetrical oblique injection rotating detonation flame stabilization, providing a new technical approach for efficient combustion organization in the combustion chamber of existing subsonic ramjet engines. Summary of the Invention

[0005] 1. The problem to be solved The purpose of this invention is to overcome the problems of easy flame extinguishing, poor combustion stability, and high combustion chamber wall temperature in existing subsonic ramjet engines. This invention proposes a subsonic ramjet engine based on counter-rotating detonation flame stabilization ignition. By installing two symmetrical rotating detonation generators at a specific angle on both sides of the main combustion chamber of the subsonic ramjet engine, the high-energy, periodic oblique counter-rotating detonation jets generated by these devices create a large-scale low-speed recirculation zone at the front end of the combustion chamber, thereby anchoring the flame in the main combustion chamber. Simultaneously, the continuously operating rotating detonation generator acts as a pre-combustion tube, providing forced ignition to the main combustion chamber, effectively solving the problem of the flame in the main combustion chamber of the subsonic ramjet engine being easily extinguished by the high-speed incoming flow. Finally, the auxiliary high-speed airflow on both sides, diverted through the intake cooling channel, has a low degree of compression and effectively cools the wall temperature as it passes over the main combustion chamber of the subsonic ramjet engine, thus extending the combustion chamber life.

[0006] 2. Technical Solution To solve the above problems, the present invention adopts the following technical solution.

[0007] A subsonic ramjet engine based on counter-rotating detonation stabilization ignition includes an external integral casing and an internal subsonic ramjet engine main casing. This intake cooling channel uses a portion of the high Mach number airflow as cooling gas for the main combustion chamber wall temperature, and finally discharges it from the engine tail end, thereby achieving the function of rapidly cooling the main combustion chamber wall temperature.

[0008] A further technical solution involves diverting a portion of the high-speed airflow to both sides into the deceleration cavity to act as an oxidant in the reaction, thus eliminating the need for an oxidant supply system for rotary detonation. A portion of the fuel is drawn from the middle section of the lower fuel tank to serve as an oxidant in the main combustion chamber of the sub-gas ramjet engine, while a portion of the fuel is drawn from the bottom into the deceleration cavity at the top of the rotary detonation generator to serve as fuel for the rotary detonation generator. This eliminates the need for a separate fuel supply system for rotary detonation, thereby achieving a lightweight design for the entire sub-gas ramjet engine.

[0009] A further technical solution involves installing a DC atomizing nozzle at the tail end of the first oil pipeline to atomize the liquid fuel from the upper fuel tank into fine fuel droplets, thereby achieving full and uniform mixing of fuel and oxidant.

[0010] A further technical solution involves adding symmetrical rotating detonation generators to the upper and lower sides of the main combustion chamber of the ramjet engine. The outlet end of the rotating detonation generator is connected to the main combustion chamber of the ramjet engine. The outlet axis of the rotating detonation generator forms an angle of 30° to 60° with the normal direction of the outer wall surface of the main combustion chamber section of the ramjet engine main body casing. The two high-temperature and high-pressure detonation jets generated by the symmetrical rotating detonation generators collide at the central axis of the main combustion chamber of the ramjet engine. At the point where the jets converge, near the fuel injection ring of the main combustion chamber, a low-speed recirculation zone is formed, thereby achieving the flame stabilization effect of the combustion in the main combustion chamber of the ramjet engine.

[0011] A further technical solution involves the instantaneous conversion of kinetic energy into internal energy when the two high-temperature and high-pressure detonation jets generated by the symmetrical rotating detonation generator collide, creating a local high-temperature zone near the point of convergence, thereby achieving forced ignition in the main combustion chamber.

[0012] 3. Beneficial effects Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention provides a sub-gas ramjet engine based on counter-rotating detonation flame stabilization ignition. The high Mach number incoming airflow is divided into multiple high-speed airflows through the intake cooling channel. Part of the airflow flows into the deceleration cavity, eliminating the need for the oxidizer supply system of the rotating detonation generator, thus achieving the lightweighting of the entire sub-gas ramjet engine. The remaining high-speed airflow sweeps over the outer wall of the main combustion chamber, which cools the wall temperature and thus extends the life of the combustion chamber.

[0013] (2) In a sub-fuel ramjet engine based on counter-rotating detonation flame stabilization ignition, fuel is transported from the first oil supply pipe to the deceleration cavity at the top of the rotating detonation generator, and then atomized into fine fuel droplets through the DC atomizing nozzle at the tail end of the first oil supply pipe, thereby realizing the efficient and rapid mixing of fuel and oxidant in the rotating detonation generator.

[0014] (3) The present invention provides a sub-fuel ramjet engine based on counter-rotating detonation flame stabilization ignition. The two high-temperature and high-pressure detonation jets generated by the symmetrical rotating detonation generators installed on the upper and lower sides of the main combustion chamber of the sub-fuel ramjet engine collide on the central axis of the main combustion chamber of the sub-fuel ramjet engine. A low-speed recirculation zone is formed near the fuel injection ring area of ​​the main combustion chamber at the intersection point, thereby achieving the flame stabilization effect of the main combustion chamber of the sub-fuel ramjet engine.

[0015] (4) In the sub-gas ramjet engine based on counter-rotating detonation flame stabilization ignition of the present invention, a high-temperature area is formed at the intersection of the two high-temperature and high-pressure detonation jets generated by the two rotating detonation generating devices, thereby achieving a continuous forced ignition effect and reducing the probability of the flame in the main combustion chamber of the sub-gas ramjet engine being blown out. Attached Figure Description

[0016] Figure 1 This is a front view of the structure of the present invention; Figure 2 This is a half-sectional view of the structure of the present invention; Figure 3 This is a partial cross-sectional view of the deceleration cavity; Figure 4 This is a partial cross-sectional view of the fuel injection ring.

[0017] In the diagram: 1. Rectifier cone; 2. External integral casing; 3. Upper fuel tank; 4. First fuel supply pipe; 5. Deceleration cavity; 6. Rotary knock generator; 7. Internal submersible ramjet engine main casing; 8. Isolation section; 9. Lower fuel tank; 10. Middle fuel supply pipe; 11. Injection ring; 12. Third fuel supply pipe; 13. Submersible ramjet engine main combustion chamber; 14. Contraction-expansion nozzle; 15. Upper air passage; 16. Lower air passage; 17. Middle main air passage; 18. Deceleration cavity DC atomizing nozzle; 19. Injection ring DC atomizing nozzle. Detailed Implementation

[0018] The present invention will now be further described with reference to specific embodiments and accompanying drawings.

[0019] Example 1 This example describes a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition, such as... Figure 1 , 2 As shown, the system includes an external integral casing 2, an internal sub-fuel ramjet engine main casing 7, a sub-fuel ramjet engine main combustion chamber 13, an upper air passage 15, a lower air passage 16, and a middle main air passage 17. The incoming high-Mach number airflow passes through the intake cooling channel, with part entering the upper air passage 15, part entering the lower air passage 16, and the remaining high-speed airflow entering the middle main air passage 17. The high-speed airflow flowing into the upper and lower auxiliary air passages is compressed by the external integral casing 2, resulting in a decrease in speed and an increase in temperature. When it flows through the outer wall of the sub-fuel ramjet engine main combustion chamber 13, it can carry away the high temperature of the main combustion chamber, thus playing a role in the continuous cooling of the outer wall of the main combustion chamber.

[0020] Example 2 This embodiment describes a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition. Its basic structure is the same as in Embodiment 1, with the following differences or improvements: Figure 1 , 3As shown, a portion of the high-speed airflow entering the upper and lower air passages flows into the deceleration cavity 5 at the top of the rotary detonation generator 6. A deceleration cavity DC atomizing nozzle 18, with a diameter of 0.2mm~0.3mm, is installed at the fuel inlet end to atomize the fuel in the fuel delivery pipe into fine fuel droplets, thereby achieving thorough mixing with the oxidizer. The cavity structure within the deceleration cavity slows down the incoming high-speed airflow, thus achieving efficient mixing of fuel and oxidizer within the rotary detonation generator.

[0021] Example 3 This embodiment of a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition has the same basic structure as Embodiment 2, with the following differences or improvements: Figure 1 , 3 As shown, the high-speed airflow from the upper air passage 15 enters the deceleration cavity at the top of the rotating knock generator 6, eliminating the need for an oxidizer supply system for the rotating knock generator 6; a portion of fuel is drawn from the bottom of the upper fuel tank 3 and flows into the deceleration cavity 5 at the top of the rotating knock generator 6 as fuel for the rotating knock generator 6, eliminating the need for a separate fuel supply system for the rotating knock, thus achieving a lightweight effect for the entire submersible ramjet engine.

[0022] Example 4 This embodiment of a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition has the same basic structure as Embodiment 3, with the following differences or improvements: Figure 1 , 2 As shown in Figure 4, the high-speed airflow, which is diverted to the central main air passage 17 through the intake cooling channel, is compressed by the rectifier cone 1 and the internal subsonic ramjet engine main casing 7, reducing its speed to subsonic speed and increasing its temperature. It then enters the main combustion chamber 13 of the subsonic ramjet engine through the isolation section 8. A fuel injection ring 11 is provided at the inlet of the main combustion chamber. The fuel injection ring 11 is circumferentially provided with a fuel injection ring DC atomizing nozzle 19, and the axis of the fuel injection ring DC atomizing nozzle 19 is perpendicular to the plane of the fuel injection ring 11. The diameter of the fuel injection ring DC atomizing nozzle 19 is set to 0.2mm~0.3mm. The subsonic airflow flowing into the main combustion chamber mixes with the fuel atomized by the fuel injection ring DC atomizing nozzle 19 and is ignited to organize combustion. The high-temperature gas generated is accelerated and discharged through the contraction-expansion nozzle 14, thereby generating thrust.

[0023] Example 5 This embodiment of a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition has the same basic structure as Embodiment 4, with the following differences or improvements: Figure 1As shown, symmetrical rotating detonation generators 6 are installed on the upper and lower sides of the main combustion chamber 13 of the sub-fuel ramjet engine. Their outlet ends are connected to the main combustion chamber 13 of the sub-fuel ramjet engine. The outlet axis of the rotating detonation generator 6 forms an angle of 30° to 60° with the normal direction of the outer wall surface of the main combustion chamber section of the main casing 7 of the sub-fuel ramjet engine. The two high-temperature and high-pressure detonation jets generated by the symmetrical rotating detonation generator 6 collide at the central axis of the main combustion chamber 13 of the sub-fuel ramjet engine. At the point where the jets converge, a low-speed backflow zone is formed in the area near the fuel injection ring 11 of the main combustion chamber, thereby achieving the flame stabilization effect of the combustion in the main combustion chamber of the sub-fuel ramjet engine.

[0024] Example 6 This embodiment of a subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition has the same basic structure as Embodiment 5, with the following differences or improvements: Figure 1 The two high-temperature and high-pressure detonation jets generated by the rotating detonation generator 6 shown will collide at the central axis of the main combustion chamber 13 of the sub-gas ramjet engine. A high-temperature area will be formed at the impact point, which can serve as a forced ignition source for the combustion in the main combustion chamber 13 of the sub-gas ramjet engine, thus preventing the flame from being blown out due to the high inlet velocity of the combustion chamber flame.

[0025] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A subsonic ramjet engine based on counter-rotating detonation flame stabilization ignition, comprising an intake cooling channel, an integrated fuel supply device, and a symmetrical rotating detonation flame stabilization device.

2. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 1, characterized in that: The air intake cooling channel includes an outer integral housing (2) and an inner sub-fuel ramjet engine main housing (7).

3. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 1, characterized in that: The integrated fuel supply device includes an upper fuel tank (3), a lower fuel tank (9), a first oil supply pipe (4), a second oil supply pipe (10), and a third oil supply pipe (12). The left inlet end of the first oil supply pipe (4) is connected to the bottom right side of the fuel tank (3). The second oil supply pipe (10) is connected to the circumferential side wall in the middle of the lower fuel tank (9). The outlet end of the second oil supply pipe (10) is connected to the central axis of the injection ring (11).

4. A subsonic ramjet engine based on counter-rotating rotary detonation flame stabilization ignition according to claim 1, characterized in that: The symmetrical rotating detonation flame stabilization device includes a deceleration cavity (5) and a rotating detonation generator (6). The deceleration cavity (5) is installed at the top of the rotating detonation generator and is used to premix fuel with air.

5. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 4, characterized in that: The inlet end of the deceleration cavity (5) is provided with a cavity for decelerating the incoming airflow at high Mach numbers.

6. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 5, characterized in that: The rotating detonation generator (6) is installed on the outer shell (14) of the main combustion chamber of the ramjet engine, and its outlet end is connected to the main combustion chamber (13) of the ramjet engine.

7. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 6, characterized in that: The outlet axis of the rotating detonation generating device (6) forms an angle of 30° to 60° with the normal direction of the outer wall surface of the main combustion chamber section of the internal sub-smooth ramjet engine housing (7).

8. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 7, characterized in that: The oil injection ring (11) is circumferentially provided with a DC atomizing nozzle, and the axis of the DC atomizing nozzle is perpendicular to the plane of the oil injection ring (11).

9. A subsonic ramjet engine based on counter-rotating rotary detonation stabilization ignition according to claim 8, characterized in that: The diameter of the DC atomizing nozzle is 0.2mm~0.3mm.

Images