A variable structure combustion chamber for a rocket-based combined power cycle engine

Abstract

The present invention discloses a variable structure combustion chamber for a rocket-based combined power cycle engine, comprising: an isolation section, a first combustion chamber, and a second combustion chamber, which are sequentially connected from front to back; the lower walls of the first combustion chamber and the second combustion chamber are in the same plane; the present invention can control an adjustment plate to slide on the upper wall of the second combustion chamber through a servo motor, thereby changing the expansion ratio of the second combustion chamber and achieving geometric congestion, thereby meeting the requirements for the variable structure RBCC engine to operate efficiently within the Ma3-6 range.

Description

Technical Field

[0001] The present invention belongs to the field of rocket-based combined power cycle combustion chambers, and in particular relates to a variable structure combustion chamber for a rocket-based combined power cycle engine. Background Art

[0002] The Rocket-Based Combined Cycle (RBCC) engine is a combined propulsion system that organically integrates a high thrust-to-weight ratio, low specific impulse rocket engine with a low thrust-to-weight ratio, high specific impulse ramjet engine. RBCC engines integrate ejection, subsonic, scramjet, and pure rocket modes. This enables self-starting, a wide flight envelope, and strong mission adaptability, making them one of the most promising new propulsion systems for the future. The combustion chamber / nozzle is a critical component of an air-breathing engine. For air-breathing engines, the combustion chamber must enable the fuel to be injected, atomized, vaporized, mixed, and burned within a limited space and time within the high-speed airflow, maximizing the conversion of chemical energy into heat. This heat is then converted to kinetic energy through the nozzle, generating thrust. In the scramjet mode, to meet the requirements of supersonic combustion, the combustor flow path must maintain an expanding structure. In the jet and subjet modes, however, the combustor flow path can adopt a convergent-divergent structure to ensure efficient combustion. Furthermore, as the flight Mach number increases, the heating ratio in the combustor gradually decreases, and the expansion ratio must be reduced accordingly to achieve high performance at different flight Mach numbers. Given that multiple modes share a single flow path, variable engine structure technology is one of the effective ways to ensure optimal performance throughout the entire engine lifecycle.

[0003] Currently, engines using variable-structure combustion chambers include dual-mode ramjets, such as the French WRR (wide-range ramjet) engine, which utilizes a wide range of variable combustion chamber profiles to achieve high performance across the entire Mach number range (AIAA Paper 2000-3340, 2000). The PIAF engine utilizes horizontal movement of the outer shroud to alter the combustion chamber geometry, achieving wide-range operation (AIAA Paper 2003-7031, 2003). For RBCC engines, variable-structure solutions are limited to the intake and exhaust components. For these components, maintaining wide-range inlet performance through adjustable inlets is a widely accepted and widely adopted approach. For example, Aerojet has proposed a simple variable-structure RBCC engine with an inlet and tail nozzle for single-stage-to-orbit (SSTO) missions (NASA Technical Memorandum 107422), ensuring efficient and coordinated multi-mode operation. Due to the harsh operating conditions and complex mechanisms, RBCC combustion chambers are generally still fixed structures. To improve the performance of RBCC engines, the use of variable structure combustion chambers is a feasible solution. The RBCC team of Northwestern Polytechnical University in China proposed a variable structure RBCC combustion chamber solution, which improved the performance of RBCC. The RBCC team of Northwestern Polytechnical University also proposed a variable structure rocket-based combined power cycle engine and a rocket-based combined power cycle engine (RBCC) variable structure combustion chamber. The former uses an adjustable top plate of the combustion chamber to slide back and forth along the direction of the fixed top plate of the combustion chamber to change the combustion chamber area (CN106907272B), while the latter uses a variable surface section on the combustion chamber upper wall to change the combustion chamber area ratio (CN105240160B). Summary of the Invention

[0004] The purpose of the present invention is to provide a variable structure combustion chamber for a rocket-based combined power cycle engine, which can operate efficiently in the Ma3-6 range and improve the performance of the RBCC engine.

[0005] The present invention adopts the following technical solution: a variable structure combustion chamber for a rocket-based combined power cycle engine, comprising: an isolation section, a first combustion chamber, and a second combustion chamber connected in sequence from front to back;

[0006] The first combustion chamber is provided with a support plate rocket and a fuel support plate from front to back.

[0007] A strip-shaped insertion hole is formed along the upper wall of the second combustion chamber. A servo motor is fixedly connected to the upper side of the outer cavity of the second combustion chamber. A drive rod of the servo motor extends through the insertion hole into the inner cavity of the second combustion chamber. An adjustment plate is fixedly connected to the lower end of the drive rod. The adjustment plate is "V"-shaped and has an upward opening. The upper ends of the adjustment plates are both against the inner side of the upper wall of the second combustion chamber. The adjustment plates are used to move back and forth under the drive of the servo motor, thereby meeting the expansion ratio requirements of the second combustion chamber under different incoming flow Mach numbers.

[0008] The lower wall surfaces of the first combustion chamber and the second combustion chamber are in the same plane.

[0009] Furthermore, the angle between the plane where the upper wall of the first combustion chamber is located and the upper wall of the second combustion chamber is 5 to 10 degrees.

[0010] Furthermore, the adjustment plate is composed of a front throat plate and a rear throat plate fixedly connected, the lower end of the front throat plate is fixedly connected to the lower end of the rear throat plate, and the angle between the front throat plate and the rear throat plate is 122°.

[0011] Furthermore, the angle between the front throat plate and the upper wall of the second combustion chamber is 13°, and the angle between the plane where the front throat plate is located and the lower wall of the second combustion chamber is 3°.

[0012] Furthermore, the angle between the rear throat plate and the upper wall of the second combustion chamber is 45°, and the angle between the plane where the rear throat plate is located and the lower wall of the second combustion chamber is 55°.

[0013] Furthermore, the angle between the plane where the upper wall surface of the second combustion chamber is located and the plane where the lower wall surface is located is 10°.

[0014] Furthermore, the ratio of the mapped length of the front throat plate on the lower wall of the second combustion chamber to the length of the second combustion chamber is 0.34:1.

[0015] Furthermore, the length ratio of the first combustion chamber to the second combustion chamber is 1:2 to 2.5.

[0016] The beneficial effects of the present invention are:

[0017] The present invention can control the adjustment plate to slide on the upper wall of the second combustion chamber through a servo motor, thereby changing the expansion ratio of the second combustion chamber and achieving geometric congestion, thereby meeting the requirements of the variable structure RBCC engine to operate efficiently within the range of Ma3-6.

[0018] The combustion chamber of the present invention comprises a first combustion chamber and a second combustion chamber with two different expansion ratios. The angle between the upper wall of the first combustion chamber and the lower wall of the first combustion chamber is 5°. The first combustion chamber can meet the low expansion ratio operation of Mach 4-6, while reducing the total pressure loss of the combustion chamber at high inflow Mach numbers, which is beneficial to improving engine performance.

[0019] The angle between the upper wall surface of the second combustion chamber and the lower wall surface of the second combustion chamber of the present invention is 10°. The second combustion chamber can meet the large expansion ratio of Ma3-4, while reducing the total pressure loss of the combustion chamber under the incoming flow Mach number, which is beneficial to improving the engine performance; if the angle is too large, the expansion ratio of the regulating plate to the second combustion chamber will be greatly weakened. If the angle is too small, it cannot meet the demand for a large expansion ratio under low Mach numbers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention;

[0021] Figure 2 is a cross-sectional view of the present invention;

[0022] Figure 3 This is the combustion chamber structure at Ma3 of this embodiment;

[0023] Figure 4 This is the combustion chamber structure at Ma4 of this embodiment;

[0024] Figure 5 This is the combustion chamber structure at Ma6 of this embodiment.

[0025] Among them: 10. Isolation section; 11. First combustion chamber; 12. Second combustion chamber; 13. Support plate rocket; 14. Fuel support plate; 15. Servo motor; 16. Adjustment plate; 17. Drive rod; 18. Front throat plate; 19. Rear throat plate; 20. Closing plate. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. The "direction" in the present invention is based on the direction of the present invention. Figure 1 Description of the direction of the state.

[0028] The present invention discloses a variable structure combustion chamber for a rocket-based combined power cycle engine, such as Figure 1 and Figure 2 As shown, it includes: an isolation section 10, a first combustion chamber 11, and a second combustion chamber 12 which are connected in sequence from front to back.

[0029] A support plate rocket 13 and a fuel support plate 14 are installed in the first combustion chamber 11 from front to back; a strip-shaped insertion hole is opened along the upper wall of the second combustion chamber 12, and a servo motor 15 is fixedly connected to the upper side of the outer cavity of the second combustion chamber 12. The driving rod 17 of the servo motor 15 passes through the insertion hole and extends into the inner cavity of the second combustion chamber 12. The lower end of the driving rod 17 is fixedly connected to an adjustment plate 16. The adjustment plate 16 is "V"-shaped and opens upward. The upper ends of the adjustment plates 16 are all against the inner side of the upper wall of the second combustion chamber 12. The adjustment plates 16 are used to move back and forth under the drive of the servo motor 15, thereby meeting the expansion ratio requirements of the second combustion chamber 12 under different incoming flow Mach numbers; the lower walls of the first combustion chamber 11 and the second combustion chamber 12 are in the same plane.

[0030] The angle between the plane containing the upper wall of the first combustion chamber 11 and the upper wall of the second combustion chamber 12 is 5-10 degrees. The adjustment plate 16 is composed of a front throat plate 18 and a rear throat plate 19, which are fixedly connected. The lower end of the front throat plate 18 is fixedly connected to the lower end of the rear throat plate 19, and the angle between the front throat plate 18 and the rear throat plate 19 is 122 degrees. The angle between the front throat plate 18 and the upper wall of the second combustion chamber 12 is 13 degrees, and the angle between the plane containing the front throat plate 18 and the lower wall of the second combustion chamber 12 is 3 degrees. The angle between the rear throat plate 19 and the upper wall of the second combustion chamber 12 is 45 degrees, and the angle between the plane containing the rear throat plate 19 and the lower wall of the second combustion chamber 12 is 55 degrees. The angle between the plane containing the upper wall of the second combustion chamber 12 and the plane containing the lower wall is 10 degrees. The ratio of the projected length of the front throat plate 18 on the lower wall of the second combustion chamber 12 to the length of the second combustion chamber 12 is 0.34:1. The length ratio of the first combustion chamber 11 to the second combustion chamber 12 is 1:2 to 2.5.

[0031] like Figure 3-5As shown, the regulating plate 16 is controlled by the servo motor 15 to move forward as the incoming Mach number increases, thereby adjusting the expansion ratio of the second combustion chamber 12. Within the Mach range of 3-4, the regulating plate 16 is located at the rearmost side of the second combustion chamber 12, near the nozzle. When the incoming Mach number increases to the range of 4-6, the regulating plate 16 moves forward rapidly to the middle of the second combustion chamber 12. After the incoming Mach number increases to 6, the regulating plate 16 continues to move forward rapidly to the frontmost side of the second combustion chamber 12, near the first combustion chamber 11. The movement of the regulating plate 16 is not linearly related to the change in the incoming Mach number. Instead, it maintains a common position within a Mach number range. In other words, three adjustments are sufficient to achieve efficient engine operation when the incoming Mach number is 3-6.

[0032] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A variable structure combustion chamber for a rocket-based combined power cycle engine, characterized in that: include: An isolation section (10), a first combustion chamber (11), and a second combustion chamber (12) are sequentially connected from front to back; A support plate rocket (13) and a fuel support plate (14) are sequentially installed in the first combustion chamber (11) from front to back; The upper wall of the second combustion chamber (12) is provided with a strip-shaped insertion hole along its direction, a servo motor (15) is fixedly connected to the upper side of the outer cavity of the second combustion chamber (12), a driving rod (17) of the servo motor (15) passes through the insertion hole and extends into the inner cavity of the second combustion chamber (12), the lower end of the driving rod (17) is fixedly connected to an adjustment plate (16), the adjustment plate (16) is "V"-shaped and has an upward opening, the upper end of the adjustment plate (16) is against the inner side of the upper wall of the second combustion chamber (12), the adjustment plate (16) is used to move back and forth under the drive of the servo motor (15), thereby meeting the expansion ratio requirements of the second combustion chamber (12) under different incoming flow Mach numbers; The lower walls of the first combustion chamber (11) and the second combustion chamber (12) are in the same plane.

2. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 1, characterized in that: The angle between the plane where the upper wall of the first combustion chamber (11) is located and the upper wall of the second combustion chamber (12) is 5 to 10 degrees.

3. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 1, characterized in that: The regulating plate (16) is composed of a front throat plate (18) and a rear throat plate (19) fixedly connected, the lower end of the front throat plate (18) is fixedly connected to the lower end of the rear throat plate (19), and the angle between the front throat plate (18) and the rear throat plate (19) is 122 degrees.

4. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 3, characterized in that: The angle between the front throat plate (18) and the upper wall of the second combustion chamber (12) is 13°, and the angle between the plane where the front throat plate (18) is located and the lower wall of the second combustion chamber (12) is 3°.

5. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 4, characterized in that: The included angle between the rear throat plate (19) and the upper wall of the second combustion chamber (12) is 45°, and the included angle between the plane where the rear throat plate (19) is located and the lower wall of the second combustion chamber (12) is 55°.

6. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 1, characterized in that: The angle between the plane where the upper wall surface of the second combustion chamber (12) is located and the plane where the lower wall surface is located is 10°.

7. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 4, characterized in that: The ratio of the mapped length of the front throat plate (18) on the lower wall of the second combustion chamber (12) to the length of the second combustion chamber (12) is 0.34:

1.

8. The variable structure combustion chamber for a rocket-based combined power cycle engine according to claim 1, characterized in that: The length ratio of the first combustion chamber (11) to the second combustion chamber (12) is 1:2-2.5.

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