A RBCC engine combustor structure with two-stage annular rockets
By designing a combustion chamber structure for an RBCC engine with a two-stage ring rocket, the problems of low ejection efficiency and complex structure of existing RBCC engines have been solved, achieving high thrust performance and stable mode transitions, and demonstrating good engineering application potential.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- INST OF AEROSPACE TECH CHINA AERODYNAMIC RES & DEV CENT
- Filing Date
- 2026-06-26
- Publication Date
- 2026-07-24
AI Technical Summary
Existing RBCC engines have low ejection efficiency in ejection mode, limited rocket functionality, and insufficient hybridization in traditional center rocket layouts, resulting in complex structures and large thrust fluctuations during mode transitions.
Design an RBCC engine combustion chamber structure with a two-stage ring rocket. The first-stage ring rocket is installed in the air intake throat, and the second-stage ring rocket is embedded at the outlet of the central combustion chamber. The ejection efficiency and thrust performance are improved by adjusting the working mode at different Mach numbers.
It improves ejection efficiency, reduces thrust fluctuations during mode transitions, achieves stability in thrust performance and compactness in structure, and has good engineering application value.
Smart Images
Figure CN122447723A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of jet propulsion technology, and more specifically, this invention relates to a combustion chamber structure of an RBCC engine with a two-stage annular rocket. Background Technology
[0002] Rocket-based combined cycle (RBCC) engines combine a high thrust-to-weight ratio, low specific impulse rocket engine with a high specific impulse, low thrust-to-weight ratio ramjet engine within the same flow channel. This creates a novel thermodynamic cycle using the rocket jet and ramjet flow channel, employing different operating modes across various flight speed ranges. This covers the entire speed range from ground takeoff to hypersonic flight, and holds promise as an ideal propulsion system for future hypersonic flight. In RBCC engines, the rocket's layout directly influences ejection and suction capabilities, combustion organization, and mode transition characteristics.
[0003] However, when RBCC engines operate in ejector mode or ejector / subsonic ramjet mode, they suffer from low ejection efficiency and limited rocket functionality. Existing RBCC engines typically employ a central support rocket or a discrete rocket design, but these designs have the following drawbacks: the central rocket easily forms a high-speed jet core region, making it difficult for the surrounding air to penetrate, resulting in insufficient mixing, and the small contact area with air limits the mixing region; while discrete rockets with multiple rockets arranged circumferentially can improve mixing, their structure and control system are relatively complex. Summary of the Invention
[0004] One object of the present invention is to solve at least the above-mentioned problems and / or defects, and to provide at least the advantages described below.
[0005] To achieve these and other advantages of the present invention, an RBCC engine combustion chamber structure with a two-stage annular rocket is provided, wherein a first-stage annular rocket is disposed in the air intake throat of the RBCC engine combustion chamber structure, and a second-stage annular rocket is embedded at the outlet of the central combustion chamber of the RBCC engine combustion chamber structure.
[0006] Preferably, the RBCC engine combustion chamber structure further includes: The air intake throat, which connects to the air intake duct; The isolating section is abruptly expanded at the rear end of the intake throat; An expansion combustion chamber section is abruptly located at the rear end of the constant-straight isolation section, and the central combustion chamber is located within the constant-straight isolation section; the expansion combustion chamber section is connected to the tail nozzle.
[0007] Preferably, the diameter of the air intake throat is D1 and the length is 2D1; The diameter of the straight isolation section is 1.2D1, and the length is 5.3D1; The inlet diameter of the expansion-type combustion chamber section is 1.26D1, the expansion half-angle is 2°, and the length is 6.1D1.
[0008] Preferably, the central combustion chamber has a central cone at its front end, and multiple support plates are connected to the outer side of the central cone. The central cone is fixed to the inlet of the expansion combustion chamber section by the multiple support plates. The interior of the central cone is configured as a compression ramp, and the outlet of the support plates is provided with circumferentially uniformly arranged fuel injection holes.
[0009] Preferably, the outer diameter of the central vertebra is 0.46D1 and the length is 0.9D1; the compression ramp has a contraction half angle of 5° and a length of 0.4D1.
[0010] Preferably, an arc-shaped concave cavity section is provided downstream of the compression ramp.
[0011] Preferably, the diameter of the highest point of the arc-shaped concave cavity section is 0.29D1, and the outlet diameter is 0.19D1.
[0012] Preferably, the central combustion chamber is a subsonic combustion chamber.
[0013] Preferably, it has the following operating modes: Ejection mode from ground takeoff to Mach 2.5: Both the first-stage and second-stage ring rockets are fully engaged. The first-stage ring rocket ejects at the air intake throat, increasing the contact area with air through the ring plume, thereby improving ejection efficiency. The second-stage ring rocket heats the core airflow at the entrance of the central combustion chamber, further increasing the thrust of the RBCC engine. Subsonic combustion mode at Mach numbers 2.5 to 5.0: As the Mach number increases, the flow rate of the first-stage ring rocket is gradually reduced until it is shut down, and subsonic combustion is organized inside the central combustion chamber; the second-stage ring rocket continues to operate, while the flow rate is gradually reduced, and its high-temperature jet acts as a support plate flame, further igniting the fuel injected to support the support plate; In the scramjet mode with Mach numbers of 5.0 to 7.0: the first-stage and second-stage ring rockets remain closed, and the central combustion chamber plays a role in flame stabilization; Mach number 7.0 and above and pure rocket mode outside the atmosphere: the air intake throat is closed, the first-stage ring rocket and the second-stage ring rocket are fully activated, and the RBCC engine operates in pure rocket mode.
[0014] This invention offers at least the following advantages: It provides a combustor structure for an RBCC engine with a two-stage annular rocket. In ejection mode, compared to the traditional central rocket layout, it significantly improves ejection efficiency. During mode transitions, thrust fluctuations are reduced and smooth transitions are achieved through flow regulation of the two-stage rocket. The central combustor highly integrates functions such as flame stabilization, fuel injection, and rocket thrust enhancement. The combustor designed in this invention possesses advantages such as excellent thrust performance, flexible adjustment, and compact structure, demonstrating significant engineering application value.
[0015] Other advantages, objectives and features of the present invention will become apparent in part from the following description, and in part from those skilled in the art through study and practice of the invention. Attached Figure Description
[0016] Figure 1 This is a cross-sectional schematic diagram of the combustion chamber structure of an RBCC engine with a two-stage ring rocket.
[0017] The corresponding labels for each structure in the diagram are as follows: 1. Inlet throat, 2. Straight isolation section, 3. Expansion combustion chamber section, 4. Central combustion chamber, 5. First stage ring rocket, 6. Second stage ring rocket, 7. Support plate, 9. Compression ramp, 10. Arc-shaped concave cavity section, 12. Central cone. Detailed Implementation
[0018] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.
[0019] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof. Example 1 like Figure 1 As shown, an RBCC engine combustion chamber structure with a two-stage annular rocket includes: The air intake throat 1 houses a first-stage annular rocket 5. The first-stage annular rocket 5 and the air intake throat 1 are either integrated or bolted together and then welded. The first-stage annular rocket 5 is in close contact with the outer shell of the RBCC engine combustion chamber. The first-stage annular rocket 5 and the air intake throat 1 together form an annular rocket nozzle. The axis of the first-stage annular rocket 5 is on the same straight line as the axis of the central combustion chamber of the RBCC engine. The air intake throat 1 is connected to the air intake duct. The diameter of the air intake throat 1 is D1, and the length is 2D1. The isolating section 2 is abruptly extended at the rear end of the intake throat 1; the diameter of the isolating section 2 is 1.2D1 and the length is 5.3D1. The expanding combustion chamber section 3 is abruptly expanded at the rear end of the constant-straight isolation section 2. The central combustion chamber 4 is located within the constant-straight isolation section 3. A second-stage ring rocket 6 is embedded at the outlet of the central combustion chamber 4 of the RBCC engine combustion chamber structure. The second-stage ring rocket 6 and the central combustion chamber are integrated or bolted and then welded. The second-stage ring rocket 6 mainly provides a support flame and increases thrust. The expanding combustion chamber section 3 is connected to the tail nozzle. The central combustion chamber 4 is a subsonic combustion chamber, mainly playing a role in flame stabilization in subsonic and scram modes. The inlet diameter of the expansion-type combustion chamber section 3 is 1.26D1, the expansion half-angle is 2°, and the length is 6.1D1.
[0020] A central cone 12 is provided at the front end of the central combustion chamber 4. Multiple support plates 7 are connected to the outer side of the central cone 12. The central cone 12 is fixed to the inlet of the expansion-type combustion chamber section 3 by the support plates 7. The central cone 12 has an outer diameter of 0.46D1 and a length of 0.9D1. The interior of the central cone 12 is configured as a compression ramp 9. Fuel injection holes are circumferentially evenly arranged at the outlet of the support plates 7, through which fuel is injected into the main flow. The compression ramp 9 has a contraction angle of 5° and a length of 0.4D1. Downstream of the compression ramp 9, there is an arc-shaped concave cavity section 10. The diameter of the highest point of the arc-shaped concave cavity section 10 is 0.29D1, and the outlet diameter is 0.19D1. The arc-shaped concave cavity section 10 mainly plays a role in stabilizing the flame in the internal flow field.
[0021] Figure 1 The middle arrow indicates the incoming flow into intake throat 1.
[0022] Example 2 In Example 1, the RBCC engine combustion chamber structure with a two-stage ring rocket is in the ejection mode from ground takeoff to Mach 2.5: the first-stage ring rocket 5 and the second-stage ring rocket 6 are both activated. The first-stage ring rocket is ejected at the air intake throat 1, and the ring plume increases the contact area with the air, thereby improving the ejection efficiency. The second-stage ring rocket 6 heats the core airflow at the entrance of the central combustion chamber, further improving the thrust of the RBCC engine.
[0023] Example 3 In Example 1, the combustion chamber structure of the RBCC engine with a two-stage ring rocket operates in the subsonic combustion mode at Mach numbers of 2.5 to 5.0: as the Mach number increases, the flow rate of the first-stage ring rocket 5 is gradually reduced until it is shut down, and subsonic combustion is organized inside the central combustion chamber 4; the second-stage ring rocket 6 continues to operate, while its flow rate is gradually reduced, and its high-temperature jet acts as a support plate flame, further igniting the fuel injected to support the support plate.
[0024] Example 4 In Example 1, the combustion chamber structure of the RBCC engine with two-stage ring rockets operates in the scramjet mode at Mach numbers 5.0 to 7.0: the first-stage ring rocket 5 and the second-stage ring rocket 6 remain closed, and the central combustion chamber 4 plays a role in flame stabilization.
[0025] Example 5 In Example 1, the combustion chamber structure of the RBCC engine with a two-stage ring rocket operates in pure rocket mode at Mach 7.0 and above and outside the atmosphere: the air intake throat is closed, the first-stage ring rocket 5 and the second-stage ring rocket 6 are both activated, and the RBCC engine operates in pure rocket mode.
[0026] The number of devices and processing scale described herein are for the purpose of simplifying the description of the invention. Applications, modifications, and variations of the invention will be readily apparent to those skilled in the art.
[0027] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.
Claims
1. A combustion chamber structure for an RBCC engine with a two-stage annular rocket, characterized in that, The RBCC engine combustion chamber structure has a first-stage ring rocket installed in the air intake throat, and a second-stage ring rocket is embedded at the outlet of the central combustion chamber.
2. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 1, characterized in that, The structure of the RBCC engine combustion chamber also includes: The air intake throat, which connects to the air intake duct; The isolating section is abruptly expanded at the rear end of the intake throat; An expansion combustion chamber section is abruptly located at the rear end of the constant-straight isolation section, and the central combustion chamber is located within the constant-straight isolation section; the expansion combustion chamber section is connected to the tail nozzle.
3. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 2, characterized in that, The diameter of the air intake throat is D1, and the length is 2D1; The diameter of the straight isolation section is 1.2D1, and the length is 5.3D1; The inlet diameter of the expansion-type combustion chamber section is 1.26D1, the expansion half-angle is 2°, and the length is 6.1D1.
4. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 1, characterized in that, The central combustion chamber has a central cone at its front end, and multiple support plates are connected to the outer side of the central cone. The central cone is fixed to the inlet of the expansion combustion chamber section by the multiple support plates. The interior of the central cone is configured as a compression ramp, and the outlet of the support plates is provided with circumferentially uniformly arranged fuel injection holes.
5. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 4, characterized in that, The central vertebra has an outer diameter of 0.46D1 and a length of 0.9D1; the compression ramp has a contraction half angle of 5° and a length of 0.4D1.
6. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 4, characterized in that, A concave arc section is provided downstream of the compression ramp.
7. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 6, characterized in that, The diameter of the highest point of the arc-shaped concave cavity section is 0.29D1, and the outlet diameter is 0.19D1.
8. The RBCC engine combustion chamber structure with a two-stage annular rocket as described in claim 1, characterized in that, The central combustion chamber is a subsonic combustion chamber.
9. The combustion chamber structure of an RBCC engine with a two-stage annular rocket as described in any one of claims 1-8, characterized in that, It has the following working modes: Ejection mode from ground takeoff to Mach 2.5: Both the first-stage and second-stage ring rockets are fully engaged. The first-stage ring rocket ejects at the air intake throat, increasing the contact area with air through the ring plume, thereby improving ejection efficiency. The second-stage ring rocket heats the core airflow at the entrance of the central combustion chamber, further increasing the thrust of the RBCC engine. Subsonic combustion mode at Mach numbers 2.5 to 5.0: As the Mach number increases, the flow rate of the first-stage ring rocket is gradually reduced until it is shut down, and subsonic combustion is organized inside the central combustion chamber; the second-stage ring rocket continues to operate, while the flow rate is gradually reduced, and its high-temperature jet acts as a support plate flame, further igniting the fuel injected to support the support plate; In the scramjet mode with Mach numbers of 5.0 to 7.0: the first-stage and second-stage ring rockets remain closed, and the central combustion chamber plays a role in flame stabilization; Mach number 7.0 and above and pure rocket mode outside the atmosphere: the air intake throat is closed, the first-stage ring rocket and the second-stage ring rocket are fully activated, and the RBCC engine operates in pure rocket mode.