Rocket-ramjet combined engine with parallel compressor flow channels

Abstract

The present invention relates to a rocket-based combined cycle (RBCC) engine with a parallel compressor flow path, which includes a compressor flow path and an RBCC engine flow path. The compressor flow path and the RBCC engine flow path are arranged in parallel, and the two flow paths share an inlet duct. After the inlet duct flow path, a rocket thrust chamber, a primary combustion chamber, a secondary combustion chamber and a nozzle are provided; the airflow in the compressor flow path converges into the secondary combustion chamber and burns in the secondary combustion chamber.

Description

Technical Field

[0001] The present invention belongs to the technical field of hypersonic combined power, and mainly relates to an RBCC engine with a parallel compressor flow path, specifically a rocket-based combined cycle engine with a wide operating range, which can operate normally within the operating range of Ma0 to 8+ and utilize a dual-flow path within the range of Ma0 to 3.0 to maximize the captured air flow, improve the engine thrust and performance, and significantly improve the performance of the RBCC engine in the low-speed section. Background Art

[0002] Since the RBCC engine emerged in the last century, after decades of development, a large number of numerical and experimental studies have been carried out in the ejector mode. After introducing the rocket thrust chamber, the RBCC engine has working modes such as the ejector mode, subsonic combustion ramjet mode, supersonic combustion ramjet mode, rocket-based combined cycle mode, and rocket mode. By adopting corresponding working modes in different working speed sections, it can achieve an extremely wide operating range of Ma0-8+ and even achieve orbit injection by using the maximum operating Mach number of the rocket mode.

[0003] The working principles of the ramjet mode and the supersonic combustion ramjet engine are the same. In recent years, with the rapid development of hypersonic technology, supersonic combustion ramjet engines, TBCC engines, RBCC engines, and other combined engines have also made great technological progress, completed a large number of key technology research and development and ground test verification, and carried out corresponding flight tests. Relatively speaking, the technical maturity of the high Mach number section is better than that of the low Mach number section, and it basically has the technical ability for engineering applications.

[0004] However, the horizontal takeoff and landing of hypersonic aircraft have always been the pursuit of people. Although the RBCC engine theoretically has the ability to start from zero speed on the ground, its performance is low and it is difficult to support the long-time acceleration process of the aircraft. Its thrust is mainly generated by the rocket thrust chamber, and the specific impulse performance of the engine is slightly higher than that of the rocket thrust chamber, with limited gain improvement. This is the key obstacle restricting the horizontal takeoff and landing of the RBCC engine and urgently needs to be solved. Summary of the Invention

[0005] The technical problem solved by the present invention is that in the low Mach number section, the wide-range RBCC engine operates in the ejector mode. Due to the wide operating range, the intake air flow and thrust are small in the low Mach number section. At the same time, relying solely on rocket ejection, the pressurization ability is insufficient and the specific impulse performance is low, only slightly higher than that of the rocket engine. These two points greatly limit the engineering application ability of the engine. The present invention overcomes the above deficiencies and provides a rocket-based combined cycle engine with a parallel compressor flow path.

[0006] The technical solution of the present invention is as follows: A rocket-based combined cycle (RBCC) engine with a parallel compressor flow path, which includes a compressor flow path and an RBCC engine flow path. The compressor flow path and the RBCC engine flow path are arranged in parallel, and the two flow paths share an air intake. After the air intake flow path, there are a rocket thrust chamber, a primary combustion chamber, a secondary combustion chamber, and a nozzle; the airflow in the compressor flow path converges into the secondary combustion chamber and burns in the secondary combustion chamber.

[0007] Preferably, there are at least 3 rocket thrust chambers, and they adopt a ramp layout, that is, the axis of each thrust chamber has the same included angle with the RBCC engine flow path.

[0008] Preferably, the included angle is less than 15°.

[0009] Preferably, the rocket thrust chambers are symmetrically arranged on both sides of the RBCC engine flow path, and the compressor flow path is placed below the RBCD engine flow path.

[0010] Preferably, the outlet of the rocket thrust chamber extends deep into the RBCC engine flow path, that is, the outlet of the rocket thrust chamber is completely placed inside the RBCC engine flow path.

[0011] Preferably, area compensation is carried out on the flow path of the part of the RBCC engine where the rocket thrust chamber is set to ensure that the area change is a slight expansion, that is, the expansion ratio is 1.0 - 1.05.

[0012] Preferably, the outlet shape of the rocket thrust chamber adapts to the design of the RBCC engine flow path, and is not limited to a circular outlet to adapt to different working requirements.

[0013] Preferably, a compressor and a gas turbine are arranged in the compressor flow path. The compressor compresses the incoming air, and then mixes with the gas driving the turbine and enters the secondary combustion chamber together. The driving gas of the turbine is driven by the gas of the generator; the gas turbine is driven by the catalytic decomposition of H2O2 or the gas from the combustion of H2O2 and kerosene.

[0014] Preferably, an adjusting plate is set in the air intake to adjust the air flow ratio of the two flow paths by rotating the adjusting plate; an adjusting plate is set at the outlet of the compressor flow path, which can be closed when the compressor flow path does not work; an adjusting plate is set on the nozzle, and throttling is achieved by adjusting the nozzle adjusting plate to form a geometric throat; when the geometric throat is not required, the adjusting plate is adjusted to the maximum cross-section position and is flush with the nozzle profile to form a three-dimensional expanding surface.

[0015] Preferably, in the range of Ma0 - 3, both flow paths of the engine work simultaneously, or the compressor flow path works at the maximum flow rate, and the nozzle adjustment realizes the geometric throat to match the high-performance operation of the engine;

[0016] In the range of Ma 3 - 5, the engine compressor flow path is closed, and the engine operates in a single-flow path, working in the subsonic combustion ramjet mode. The nozzle regulating plate forms a geometric throat to achieve high specific impulse and long-duration cruise.

[0017] In the range of Ma 5 - 8, the engine compressor flow path is closed, and the engine operates in a single-flow path, working in the supersonic combustion ramjet mode. The nozzle regulating plate is placed at the maximum opening and does not form a geometric throat.

[0018] After exiting the atmosphere above Ma 8, the engine operates in the rocket mode, with the compressor flow path closed, achieving cross-domain flight.

[0019] The beneficial effects of the present invention compared with the prior art are as follows:

[0020] Aiming at the problem of low overall performance of the engine in the low Mach number range, a combined rocket and ramjet engine with a wide operating range (Ma 0 - 8+) and a parallel compressor flow path is studied in this paper. After the parallel compressor flow path, on the one hand, the flow capture ability of the inlet can be improved, thereby increasing the total thrust of the engine. On the other hand, after pressurization by the compressor, the engine thermodynamic cycle can be improved, and the specific impulse performance of the engine can be enhanced, thus effectively alleviating the problem of low performance at low Mach numbers, improving the comprehensive performance of the engine, and promoting engineering applications.

[0021] After the parallel compressor flow path, the throat area of the inlet can be effectively increased, thereby improving the flow capture ability of the inlet. Analysis shows that the flow coefficient of the inlet at Ma 2 can be increased from 0.2 to above 0.4. When the engine flow rate doubles, the thrust can double, thus significantly improving the thrust performance and acceleration ability of the engine in the range of Ma 0 - 3.

[0022] After introducing the compressor flow path, the air flow is pressurized by the compressor, which can greatly increase the temperature rise ratio or pressure ratio of the thermodynamic cycle, thereby improving the thermal cycle efficiency of the engine and ultimately enhancing the thrust and specific impulse performance of the engine. Compared with general RBCC engines, the overall performance is significantly improved.

[0023] The rocket thrust chamber adopts a ramp layout and variable operating conditions. On the one hand, it can be used as an ejector rocket, and on the other hand, it can be used as an igniter. Only one needs to work at the lowest operating condition. The thrust chambers are arranged on both sides and the lower side, and no rocket thrust chamber is arranged on the upper side, which can effectively reduce the frontal area of the engine, facilitate the integrated design with the aircraft shape, and improve the aerodynamic performance of the aircraft.

[0024] Only a compressor and a turbine are arranged in the parallel flow path, and no combustion chamber is set. The engine structure is compact, which is beneficial to reducing the frontal area and the drag of the engine. In addition, the dead weight of the engine is small when operating at high Mach numbers, which is beneficial to improving the thrust-to-weight ratio. Brief Description of the Drawings

[0025] Figure 1 Schematic diagram of the principle of a rocket-based combined cycle (RBCC) engine with a parallel compressor flow path according to the present invention;

[0026] Figure 2 Layout diagram of three ramp rockets. Specific implementation manners

[0027] The present invention will be further described below in conjunction with embodiments.

[0028] Based on a single-flow-path RBCC engine, a compressor flow path is introduced to form a rocket-based combined cycle engine with a parallel compressor flow path, as shown in Figure 1 . The engine is composed of an inlet duct, a rocket thrust chamber, a two-stage combustion chamber, a nozzle, a nozzle adjustment plate, an inlet duct adjustment plate, a compressor and a gas turbine, and an adjustment plate at the outlet of the compressor flow path. The compressor flow path is arranged in parallel with the RBCC engine flow path, and the two flow paths share the inlet duct. The airflow in the compressor flow path converges into the secondary combustion chamber and burns in the secondary combustion chamber. Adjustment plates are provided for both the inlet duct and the nozzle to achieve the functions of flow rate distribution and geometric throat.

[0029] The implementation of the present invention further lies in that: the rocket thrust chamber adopts a ramp layout scheme and is located near the inlet of the primary combustion chamber. Three rocket thrust chambers are located on both sides and the lower side, as shown in Figure 1 . At this time, the compressor flow path is located below the RBCC engine flow path. There is a certain angle between the axis of the thrust chamber and the flow path (the direction in which the outlet of the rocket thrust chamber enters the flow path), generally less than 15°. The outlet of the thrust chamber extends deep into the engine flow path (as shown in Figure 2 , the outlet of the thrust chamber is completely inside the engine flow path). To maintain the flow area, area compensation is performed on the RBCC engine flow path to ensure that the area change is a slight expansion (expansion ratio about 1.05). The rocket thrust chamber adopts a variable operating condition design to achieve at least a 1:3 operating condition adjustment. The outlet shape adapts to the design of the engine flow path and is not limited to a circular outlet to meet different working requirements.

[0030] The implementation of the present invention further lies in that: the compressor in the parallel flow paths compresses air, then mixes it with the gas for driving the turbine, and they jointly enter the secondary combustion chamber. After adding fuel, combustion occurs. The driving gas for the turbine is high-temperature gas generated by the catalytic decomposition of H2O2, or gas from other generators for driving.

[0031] The implementation of the present invention further lies in that: an adjustment plate is provided for the inlet duct. By rotating the adjustment plate, the air flow rate ratio of the two flow paths can be adjusted, and the compressor flow path can also be closed. An adjustment plate is provided for the nozzle. When the engine operates in the low Mach number range, according to the matching requirements of the combustion chamber flow, the nozzle adjustment plate can be adjusted to achieve throttling and form a geometric throat. When a geometric throat is not required, the adjustment plate is adjusted to the maximum cross-section position and is flush with the nozzle profile to form a three-dimensional expansion and expansion surface.

[0032] The realization of the present invention also lies in that: the engine can open the inlet duct regulating plate in the low Mach number range (Ma0 - 3.0) to enable the two flow channels to work simultaneously. At this time, the ejector rocket and the compressor work simultaneously to achieve the maximum air capture and maximum air utilization rate of the inlet duct, so as to increase the engine thrust. The inlet duct regulating plate can also be adjusted to maximize the flow rate of the compressor flow channel. The compressor works, compresses the air flow, and then burns in the secondary combustion chamber to generate thrust. At this time, the ejector rocket does not work or works in the igniter mode (small operating conditions).

[0033] Embodiment 1

[0034] In view of the technical requirements of an engine with a wide operating range, this paper proposes a rocket ramjet combined engine with a parallel compressor flow channel, as shown in Figure 1 , which is composed of an inlet duct 1, a rocket thrust chamber 2, a primary combustion chamber 3, a secondary combustion chamber 4, a nozzle 5, a nozzle regulating plate 6, an inlet duct regulating plate 7, a compressor 8, a gas turbine 9, and a compressor flow channel outlet regulating plate. In the Ma0 - 3 range, by adjusting the inlet duct regulating plate, the air flow is reasonably distributed into the two flow channels, and the ejector rocket and the compressor work simultaneously, or the ejector rocket works in the igniter mode while the compressor works normally. The gas driving the turbine in the compressor flow channel is mixed with the air and then mixed and burned with the air in the ejector flow channel in the secondary combustion chamber. Adjusting the nozzle regulating plate realizes the geometric throat to match the efficient operation of the combustion chamber.

[0035] Engine working principle:

[0036] 1) In the Ma0 - 3 range, the two flow channels of the engine work simultaneously, or the compressor flow channel works at the maximum flow rate, and the nozzle regulation realizes the geometric throat to match the high-performance operation of the engine;

[0037] 2) In the Ma3 - 5 range, the compressor flow channel of the engine is closed, and the engine works in a single flow channel in the subsonic combustion ramjet mode. The nozzle regulating plate forms a geometric throat, which can achieve high specific impulse long-duration cruise;

[0038] 3) In the Ma5 - 8 range, the compressor flow channel of the engine is closed, and the engine works in a single flow channel in the supersonic combustion ramjet mode, which can achieve hypersonic cruise. The nozzle regulating plate is placed at the maximum opening and does not form a geometric throat;

[0039] 4) After exiting the atmosphere above Ma8, the engine works in the rocket mode, and the compressor flow channel is closed to achieve cross-domain flight.

[0040] Although the present invention has been disclosed above in the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the methods and technical content disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and decorations made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0041] The parts not detailed in the present invention belong to the common general knowledge of those skilled in the art.

Claims

1. A rocket-ramjet combined engine with a parallel compressor flow path, characterized in that: It includes a compressor flow path and an RBCC engine flow path. The compressor flow path and the RBCC engine flow path are arranged in parallel, and the two flow paths share an intake duct. After the intake duct, the RBCC engine flow path is successively provided with a primary combustion chamber, a secondary combustion chamber, and a nozzle; a rocket thrust chamber is arranged after the intake duct, and the rocket thrust chamber is arranged on the RBCC engine flow path. At least 3 rocket thrust chambers are provided and are arranged in a ramp layout. The axis of each rocket thrust chamber has the same included angle with the RBCC engine flow path; the rocket thrust chambers are symmetrically arranged on both sides of the RBCC engine flow path, and the air flow of the compressor flow path converges into the secondary combustion chamber and burns in the secondary combustion chamber.

2. The engine according to claim 1, characterized in that: The included angle is less than 15°.

3. The engine according to claim 1, characterized in that: The outlet of the rocket thrust chamber is completely placed inside the RBCC engine flow path.

4. The engine according to claim 3, characterized in that: Area compensation is carried out on the flow path of the part where the rocket thrust chamber is arranged in the RBCC engine flow path to ensure that the area change is a micro-expansion, and the expansion ratio is 1.0 - 1.

05.

5. The engine according to claim 1, characterized in that: A compressor and a gas turbine are arranged in the compressor flow path. The compressor compresses the incoming air, and then mixes it with the gas driving the gas turbine and enters the secondary combustion chamber together; the gas turbine is driven by the gas of the generator; the gas is the gas generated by the catalytic decomposition of H2O2 or the gas generated by the combustion of H2O2 and kerosene.

6. The engine according to claim 1, wherein: The intake duct is provided with an adjusting plate, and the air flow ratio of the compressor flow path and the RBCC engine flow path is adjusted by rotating the adjusting plate of the intake duct; the outlet of the compressor flow path is provided with an adjusting plate, and the adjusting plate at the outlet of the compressor flow path is closed when the compressor flow path does not work; the nozzle is provided with an adjusting plate, and throttling is achieved by adjusting the adjusting plate of the nozzle to form a geometric throat; when the geometric throat is not required, the adjusting plate of the nozzle is adjusted to the maximum cross-section position and is flush with the nozzle profile to form a three-dimensional expanding expansion surface.

7. The engine according to claim ....... In the Ma0 - 3 range, the compressor flow path and the RBCC engine flow path work simultaneously; In the Ma3 - 5 range, the compressor flow path is closed, and the engine works with a single flow path and operates in a subsonic combustion ramjet mode. The adjusting plate of the nozzle is adjusted to form a geometric throat to achieve high specific impulse long-duration cruise; In the Ma5 - 8 range, the compressor flow path is closed, and the engine works with a single flow path and operates in a supersonic combustion ramjet mode. The adjusting plate of the nozzle is placed at the maximum opening degree and does not form a geometric throat; After exiting the atmosphere above Ma8, the engine operates in a rocket mode, and the compressor flow path is closed to achieve cross-domain flight.

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