Boron-based powder fuel bimodal ramjet engine
By designing an intake assembly, combustion chamber, and pneumatic plug-type powder fuel supply assembly, a boron-based powder fuel dual-mode ramjet engine was developed, solving the problems of transporting and mixing boron-based powder fuel in a dual-mode scramjet engine, and achieving smooth mode switching and improved combustion efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHWESTERN POLYTECHNICAL UNIV
- Filing Date
- 2026-02-05
- Publication Date
- 2026-05-12
AI Technical Summary
In existing dual-mode scramjet engines, the intermodal switching of boron-based powder fuel is difficult. The powder is difficult to deliver stably and controllably under a wide range of back pressure conditions, and the mixing efficiency with the incoming flow is low, resulting in unstable combustion and low efficiency.
A boron-based powder fuel dual-mode ramjet engine was designed, comprising an intake assembly, a combustion chamber, an annular fuel gas generator, and a pneumatic plug-type powder fuel supply assembly. The incoming flow is divided into driving gas and fluidizing gas through an annular guide channel component to achieve stable delivery of boron-based powder fuel. A two-stage concave cavity structure is designed in the combustion chamber to extend the mixing time between the powder fuel and the incoming flow.
It achieves a smooth transition between subsonic and supersonic modes, improves the blending and combustion efficiency of powder fuels, and ensures the stability and efficiency of combustion, especially under low-speed and high-speed flight conditions.
Smart Images
Figure CN122014457A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ramjet engine technology, and in particular to a boron-based powder fuel dual-mode ramjet engine. Background Technology
[0002] As a crucial component of air-breathing propulsion systems, ramjet engines are considered ideal power plants for achieving hypersonic flight due to their simple structure, high specific impulse, and ability to operate over a wide Mach number range. In particular, the dual-mode scramjet (DMSJ) engine, which achieves both subsonic and supersonic combustion within the same engine, combines the advantages of both. It achieves subsonic combustion in the combustion chamber when the engine's flight Mach number is 3-6, and supersonic combustion when the flight Mach number is greater than 6. Therefore, the dual-mode ramjet engine, capable of autonomously switching between subsonic and scramjet modes based on incoming flow conditions, has become a current research hotspot.
[0003] Existing dual-mode scramjet engines mostly use liquid hydrocarbon fuels or hydrogen fuels. Liquid fuels suffer from drawbacks such as low fuel density and system complexity. Furthermore, they exhibit problems like the dissociation of combustion products at high Mach numbers, poor combustion stability, and limited engine specific impulse. While hydrogen possesses excellent reactivity and a wide flammability limit, its low density, inconvenient storage and transportation, and safety hazards limit its application.
[0004] To improve the performance of dual-mode scramjet engines across a wide Mach number range, boron-based powder fuels with higher calorific value are being applied to this field. Boron-based powder fuel dual-mode scramjet engines utilize high-calorific-value, storage-stable, and safe boron-based powder fuels, which significantly improve the specific impulse performance of the scramjet engine. At high Mach numbers, the higher total incoming flow temperature makes the combustion products of the powder fuel less prone to dissociation, allowing for the full release of the fuel's chemical energy.
[0005] However, when using boron-based powdered fuels in a dual-mode scramjet engine, the transition between modes is challenging, and stable, controllable, continuous delivery of the powder is difficult under a wide range of varying back pressure. Furthermore, the high inertia of powdered fuels results in low mixing efficiency with high-speed incoming flow, and their extremely short residence time in supersonic gas streams leads to problems such as ignition difficulties, unstable combustion, and low efficiency. This is especially true at low speeds, where the overall temperature of the incoming flow is low, making mixing and combustion even more difficult. Summary of the Invention
[0006] Based on this, it is necessary to provide a boron-based powder fuel dual-mode ramjet engine that can achieve smooth switching between sub-combustion and supercombustion modes, stable and controllable delivery of powder fuel, and high efficiency in mixing and combustion with the incoming flow, in order to address the aforementioned technical problems.
[0007] This invention provides a boron-based powder fuel dual-mode ramjet engine, including an intake assembly, a combustion chamber, an annular fuel gas generator, and a pneumatic plug-type powder fuel supply assembly; The intake assembly is used to introduce and compress incoming air; The combustion chamber is provided with an integrally connected straight section, injection section and expansion section. The straight section is axially fixed to the rear end of the intake assembly. The injection section has a first cavity and a second cavity arranged in sequence along the direction away from the intake assembly. The injection section has a plurality of first powder through hole arrays located in front of the first cavity and a plurality of gas through hole arrays located between the first cavity and the second cavity. The plurality of first powder through hole arrays and the plurality of gas through hole arrays are all evenly distributed along the circumference of the injection section. The annular fuel gas generator is used to deliver fuel-rich gas to the injection section through the gas through-hole array. It is sleeved on the outside of the injection section, with its front end located behind the first powder through-hole array and fixedly connected to the outer wall of the injection section, and its rear end located at the end of the injection section. The pneumatic plug-type powder fuel supply assembly includes an annular flow guide channel component and a powder supply component; The annular flow guide channel component is fitted into the combustion chamber to introduce the incoming flow and divide the incoming flow into fluidizing gas and driving gas, which are then delivered to the powder supply assembly. The powder supply assembly is fitted onto the annular guide channel component and is used to drive the internal boron-based powder fuel output with the aid of driving gas and input it into the combustion chamber through the first powder through-hole array. During the output of the boron-based powder fuel, the boron-based powder fuel is atomized by fluidized gas.
[0008] In one embodiment, the annular fuel gas generator includes a first annular cylindrical hollow shell, a second annular cylindrical hollow shell, an annular guide plate, a first annular solid fuel propellant grain, and a second annular solid fuel propellant grain; The first and second annular hollow shells are both fitted onto the injection section; The first and second annular hollow shells are open on opposite sides and sealed on opposite sides. The two end walls of the annular drainage concave plate are axially fixedly connected to the outer walls of the first and second annular hollow shells, respectively. The first annular solid fuel propellant grain is filled inside the first annular hollow shell, and the second annular solid fuel propellant grain is filled inside the second annular hollow shell. The gap between the inner walls of the first annular hollow shell and the second annular hollow shell forms a fuel-rich gas passage, and the gap distance is greater than or equal to the width of the gas passage array along the engine axis. Igniters are fixedly mounted on the inner side of the outer wall at the opening of both the first and second annular hollow shells.
[0009] In one embodiment, the annular guide channel component is provided with a hollow annular shell, an annular fixed disk, and a first annular support disk. The first annular support disk is integrally connected to the front end of the hollow annular shell, and the annular fixed disk is integrally connected to the rear end face of the hollow annular shell. The inner wall of the first annular support disk is fixedly connected to the portion of the straight section located at the front end of the first powder through-hole array. The inner diameters of the annular fixed disk and the first annular support disk are both smaller than the inner diameter of the inner wall of the hollow annular shell and are equal to the outer diameter of the injection section. The outer wall of the hollow annular shell is provided with at least two rings of evenly distributed fluidizing gas passages and at least two rings of evenly distributed driving gas passages along the circumferential direction, and at least one air inlet is provided at the front end of the outer wall; the fluidizing gas passages are provided at the front end of the first cavity, and the driving gas passages are provided at the rear end of the hollow annular shell. The hollow annular shell is provided with a second powder through hole array in the part in front of the fluidizing gas through hole, penetrating the inner and outer walls; the second powder through hole array in the inner wall of the hollow annular shell and the second powder through hole array in the outer wall are sealed and connected by an arc-shaped connecting plate, and the projection of each through hole of the second powder through hole array on the outer side wall of the combustion chamber along the radial direction of the hollow annular shell coincides with each through hole of the second powder through hole array. Inside the hollow annular shell, there are first and second annular baffles of the same size and with inner diameters equal to those of the straight section. The first and second annular baffles are located on both sides of the first powder through-hole array along the axial direction of the straight section.
[0010] In one embodiment, the powder supply assembly includes a hollow annular powder storage tank, a fluidizing cone, a fluidizing disc, an annular piston, and an annular regulating sleeve. The front end of the hollow annular powder storage box is open and the rear end is sealed. The front end of the hollow annular powder storage box is located on the rear side of the fluidizing gas passage along the combustion chamber axis, and the rear end is fixedly assembled with the annular fixed plate. The larger opening sides of both the fluidizing cone and the fluidizing disk face the hollow annular powder storage tank. An annular adjusting sleeve is located on the axial front side of the second powder through-hole array along the combustion chamber and is fixedly sleeved onto the hollow annular shell. The front end of the fluidizing disc is located between the second powder through-hole array and the fluidizing gas through-hole, and is sleeved on the hollow annular shell. The rear end of the fluidizing disc is axially fixedly connected to the front end face of the hollow annular powder storage tank. The front end of the fluidizing cone is fixedly sleeved to the annular adjusting sleeve, and the rear end is axially fixedly connected to the front end face of the hollow annular powder storage tank. The annular piston is located inside the hollow annular powder storage box. Its outer side wall abuts against the inner side of the outer side wall of the hollow annular powder storage box, and its inner side wall abuts against the inner side of the inner side wall of the hollow annular powder storage box. It can slide along the axial direction of the fluidizing disk of the hollow annular powder storage box under the action of the driving gas.
[0011] In one embodiment, the annular regulating sleeve includes a second annular support plate and an annular sealing plate. The second annular support plate is fixedly sleeved on the hollow annular shell, and the front end of the annular sealing plate is integrally sleeved on the second annular support plate. The cavity formed between the annular sealing plate and the hollow annular shell is a powder flow regulating cavity. A third annular support plate is vertically fixed to the inner side of the inner wall of the hollow annular powder storage box. The third annular support plate is located on the rear side of the drive air passage along the combustion chamber axis. The cavity formed between the inner wall of the hollow annular powder storage box and the hollow annular shell is an annular flow guiding and regulating cavity. The powder flow regulating chamber is equipped with a first annular regulating plate that can slide along the axial direction of the hollow annular shell. The first annular regulating plate is sleeved on the hollow annular shell and is used to adjust the overall opening of the second powder through hole array. The annular flow guiding and regulating cavity is provided with a second annular regulating plate and a third annular regulating plate that can slide along the axial direction of the hollow annular shell. Both the second annular regulating plate and the third annular regulating plate are sleeved on the hollow annular shell, and the second annular regulating plate is located close to the fluidizing plate. The second annular adjusting plate is used to adjust the number of opening turns of the fluidizing air passage, and the third annular adjusting plate is used to adjust the number of opening turns of the driving air passage.
[0012] In one embodiment, the intake assembly includes an intake pipe and a guide cone, with the rear end of the intake pipe fixedly connected to the front end of the straight section. The front end of the guide cone extends from the intake pipe, the middle part is fixedly connected to the inner wall of the front end of the intake pipe through ribs circumferentially assembled on its outer wall, and the end is located at the tail of the intake pipe. The gap between the intake pipe and the guide cone forms an intake channel.
[0013] The beneficial effects of this invention are: (1) When the power device of the present invention operates at low Mach, i.e. 3-6 Ma, the annular fuel gas generator can generate fuel-rich gas after ignition. This gas mixes and burns with the incoming flow downstream to form a high-temperature zone. The powdered fuel burns fully in the high-temperature zone, and a subsonic region appears in the combustion chamber. The back pressure is transmitted back to the isolation section, where a shock wave train is generated by pressure. The combustion chamber mode is the subsonic mode. When operating at high Mach, i.e. above 6 Ma, since the total temperature of the incoming flow is already high enough, the annular powdered fuel supply device operates alone. The powdered fuel mixes and burns fully with the incoming flow in the low-speed backflow region formed by the two-stage concave cavities. At this time, there is no subsonic region in the combustion chamber, and its mode is the supersonic mode. The device of the present invention can control the smooth transition between the two modes in the combustion chamber by controlling the ignition timing of the annular fuel gas generator and adjusting the powder injection flow rate.
[0014] (2) The present invention divides the incoming flow into driving gas and fluidizing gas through an annular guide channel component to drive and fluidize the boron-based powder fuel in the powder supply component, and inputs it into the combustion chamber through the first powder through hole array. By using the incoming flow to transport boron-based powder fuel and fluidize it at the same time, the stable transport of boron-based powder fuel can be achieved.
[0015] (3) In this invention, boron-based powdered fuel can be initially mixed and burned in the first concave cavity with the incoming flow, and the fuel-rich gas generated by the annular fuel gas generator can be mixed and burned with the incoming flow in the second concave cavity to form a downstream high-temperature region. The low-speed recirculation region generated by the two-stage concave cavity structure design prolongs the residence time of powdered fuel in the engine and improves the mixing and combustion efficiency of powdered fuel with the incoming flow. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the overall structure of the wide-speed-range flight boron-based powder fuel power device provided in an embodiment of the present invention; Figure 2 yes Figure 1 A schematic cross-sectional view along the combustion chamber axis; Figure 3 This is a schematic diagram of the air intake assembly provided in an embodiment of the present invention; Figure 4 yes Figure 3 A cross-sectional view along the axis; Figure 5 This is a schematic diagram of the overall structure of the combustion chamber provided in an embodiment of the present invention; Figure 6 yes Figure 5 A cross-sectional view along the axis; Figure 7 This is a schematic diagram of the overall structure of the annular fuel gas generator provided in an embodiment of the present invention; Figure 8 yes Figure 7A cross-sectional view along the axis; Figure 9 This is a schematic diagram of the structure of the pneumatic plug-type powder fuel supply assembly provided in an embodiment of the present invention; Figure 10 yes Figure 9 A cross-sectional view along the axis; Figure 11 This is a schematic diagram of the structure of the annular flow guiding channel component provided in an embodiment of the present invention; Figure 12 yes Figure 11 A cross-sectional view along the axis; Figure 13 yes Figure 11 A cross-sectional view along the centerline of the arc-shaped connecting plate parallel to the combustion chamber axis.
[0017] Explanation of reference numerals in the attached drawings: 10. Intake assembly; 11. Intake pipe; 12. Draft cone; 13. Rib; 20. Combustion chamber; 21. Straight section; 22. Injection section; 23. Expansion section; 24. First concave cavity; 25. Second concave cavity; 26. First powder through-hole array; 27. Gas through-hole array; 30. Annular fuel gas generator; 31. First annular hollow shell; 32. Second annular hollow shell; 33. Annular guide plate; 34. First annular solid fuel propellant grain; 35. Second annular solid fuel propellant grain; 36. Fuel-rich gas through-hole; 37. Ignition device; 40. Pneumatic plug-type powder fuel supply assembly; 41. Annular flow channel component; 411. Hollow annular shell; 412. Annular fixed disk; 413. First annular support disk; 414. Fluidizing gas passage; 415. Driving gas passage; 416. Air inlet; 417. Second powder through-hole array; 418. First annular baffle; 419. Second annular baffle; 420. Arc-shaped connecting plate; 42. Powder supply assembly; 421. Hollow annular powder storage tank; 422. Fluidizing cone; 423. Fluidizing disc; 424. Annular piston; 425. Annular adjusting sleeve; 4251. Second annular support disc; 4252. Annular sealing plate; 4253. Powder flow regulating chamber; 4254. Third annular support disc; 4255. Annular flow guiding regulating chamber; 4256. First annular adjusting plate; 4257. Second annular adjusting plate; 4258. Third annular adjusting plate. Detailed Implementation
[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0019] It should be noted that in the description of this invention, "upper," "lower," "top," "bottom," and orientation or positional relationship are based on the appendix. Figure 1 The orientations or positional relationships shown are for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention.
[0020] In one embodiment, such as Figure 1 and Figure 2 As shown, the boron-based powder fuel dual-mode ramjet engine of this embodiment includes an intake assembly 10, a combustion chamber 20, an annular fuel gas generator 30, and a pneumatic plug-type powder fuel supply assembly 40.
[0021] The intake assembly 10 is used to introduce and compress incoming air, and to deliver compressed air into the combustion chamber 20. Specifically, as... Figure 3 and Figure 4 As shown, the intake assembly 10 includes an intake pipe 11 and a guide cone 12. The rear end of the intake pipe 11 is fixedly connected to the front end of the straight section 21. The front end of the guide cone 12 extends from the intake pipe 11, and its middle part is fixedly connected to the inner wall of the front end of the intake pipe 11 through a rib 13 circumferentially mounted on its outer wall. The end is located at the tail end of the intake pipe 11, and the gap between the intake pipe 11 and the guide cone 12 forms an intake channel.
[0022] The combustion chamber 20 is provided with an integrally connected straight section 21, injection section 22, and expansion section 23. For example... Figure 5 and Figure 6 As shown, the straight section 21 is axially fixedly connected to the rear end of the air intake assembly 10. The injection section 22 has a first cavity 24 and a second cavity 25 arranged sequentially in the direction away from the air intake assembly 10. The injection section 22 has a plurality of first powder through hole arrays 26 located in front of the first cavity 24 and a plurality of gas through hole arrays 27 located between the first cavity 24 and the second cavity 25. The plurality of first powder through hole arrays 26 and the plurality of gas through hole arrays 27 are evenly distributed along the circumference of the injection section 22.
[0023] In this embodiment, the axes of each hole in the powder through-hole array and the gas through-hole array 27 are perpendicular to the axis of the combustion chamber 20, and the injection direction is radially injected into the combustion chamber 20. Each powder through-hole array and gas through-hole array 27 includes multiple arrayed through-holes. Specifically, in this embodiment, each of the two arrays includes 3×3 through-holes. The powder injection flow rate and gas injection flow rate can be adjusted by adjusting the number of openings in the powder through-hole array and the gas through-hole array 27. The device in this embodiment forms airflow channels and powder channels through structural opening design, avoiding a large number of external pipes and effectively reducing the redundant mass of the overall device. The straight section 21 is fixedly connected to the rear end of the intake assembly 10 through a flange. The expansion section 23 has an expansion angle of 1-2°. The high-temperature, high-pressure, supersonic gas generated by fuel combustion is accelerated and ejected through the expansion section 23, generating thrust.
[0024] The annular fuel gas generator 30 is used to supply fuel-rich gas to the injection section 22 through the gas through hole array 27. It is sleeved on the outside of the injection section 22, with its front end located behind the first powder through hole array 26 and fixedly connected to the outer wall of the injection section 22, and its rear end located at the end of the injection section 22.
[0025] Powdered fuel is injected into the combustion chamber 20 from the front of the first concave cavity 24, where it is initially mixed and burned with the high-temperature incoming flow in the primary concave cavity. The gas generated by the annular fuel gas generator 30 is injected into the combustion chamber 20 between the first concave cavity 24 and the second concave cavity 25, forming a high-temperature recirculation zone in the second concave cavity 25, where it is fully mixed and burned with the powdered fuel. The combustion chamber 20 is designed with two stages of concave cavities; this design enhances the degree of fuel mixing, stabilizes combustion, and improves combustion efficiency.
[0026] like Figure 7 and Figure 8 As shown, the pneumatic plug-type powder fuel supply assembly 40 includes an annular guide channel component 41 and a powder supply assembly 42. The annular guide channel component 41 is sleeved on the combustion chamber 20 and is used to introduce the incoming flow and divide the incoming flow into fluidizing gas and driving gas, which are then transported to the powder supply assembly 42. By using the incoming flow to transport and simultaneously fluidize the powder fuel, stable delivery of boron-based powder fuel can be achieved.
[0027] The powder supply assembly 42 is sleeved on the annular guide channel component 41 and is used to drive the internal boron-based powder fuel to be output by means of driving gas and input into the combustion chamber 20 through the first powder through hole array 26. During the output of boron-based powder fuel, the boron-based powder fuel is atomized by means of fluidized gas.
[0028] In this embodiment, boron-based powdered fuel with high volumetric energy density is used to replace traditional liquid fuels such as liquid hydrogen and kerosene, fundamentally solving the contradiction of low density of liquid hydrogen and limited specific impulse of kerosene. This allows the power unit of this embodiment to store more energy in the same volume, or to have a more compact structure and lighter weight for the same energy demand, thereby significantly improving the payload coefficient and thrust-to-weight ratio of the aircraft equipped with the power unit of this embodiment.
[0029] In one embodiment, such as Figure 9 and Figure 10 As shown, the annular fuel gas generator 30 includes a first annular cylindrical hollow shell 31, a second annular cylindrical hollow shell 32, an annular guide plate 33, a first annular solid fuel propellant grain 34, and a second annular solid fuel propellant grain 35.
[0030] The first annular hollow shell 31 and the second annular hollow shell 32 are both sleeved on the injection section 22; the opposite sides of the first annular hollow shell 31 and the second annular hollow shell 32 are open, and the opposite sides are sealed. The two end walls of the annular drainage concave plate 33 are axially fixedly connected to the outer side walls of the first annular hollow shell 31 and the second annular hollow shell 32, respectively.
[0031] In this embodiment, the first annular hollow shell 31 and the second annular hollow shell 32 are the same size and are symmetrically arranged relative to the annular guide plate 33. The annular guide plate 33 is concave inward, and its function is to guide the ignited gas into the combustion chamber 20.
[0032] Specifically, a first annular solid fuel propellant grain 34 is filled inside the first annular hollow shell 31, and a second annular solid fuel propellant grain 35 is filled inside the second annular hollow shell 32. A gap between the inner walls of the first and second annular hollow shells 31 and 32 forms a fuel-rich gas passage 36, and the gap distance is greater than or equal to the width of the gas passage array 27 along the engine axial direction. Igniters 37 are fixedly mounted on the inner side of the outer wall of the openings of both the first and second annular hollow shells 31 and 32. Igniters 37 can be controlled by the ramjet engine's control system to ignite the fuel.
[0033] In this embodiment, the annular solid fuel propellant grain can be, but is not limited to, a combination of hydroxyl-terminated polybutadiene, ammonium perchlorate, and aluminum powder, which produces fuel-rich combustion gas upon combustion. After ignition, the fuel-rich combustion gas generated by the annular solid fuel propellant grain transitions through the fuel-rich gas through-hole 36 into the gas through-hole array 27 via a sealed transition, and is then injected into the space between the first concave cavity 24 and the second concave cavity 25. There, it mixes and combusts with the incoming flow within the second concave cavity 25, forming a downstream high-temperature region, which can improve the powder combustion efficiency.
[0034] Furthermore, the ramjet engine in this embodiment integrates the powder fuel supply device into the outer layer of the combustion chamber 20 wall, and the efficient structural arrangement makes full use of space. In addition, this design fully utilizes the internal space of each structure, introducing gas and transporting fuel through internal channels, avoiding the design of numerous external pipes and reducing redundant mass.
[0035] In one embodiment, such as Figure 11 and Figure 12 As shown, the annular guide channel component 41 is provided with a hollow annular shell 411, an annular fixing disk 412, and a first annular support disk 413. The first annular support disk 413 is integrally connected to the front end of the hollow annular shell 411, and the annular fixing disk 412 is integrally connected to the rear end face of the hollow annular shell 411. The inner wall of the first annular support disk 413 is fixedly connected to the portion of the straight section 21 located at the front end of the first powder through-hole array 26. The inner diameters of the annular fixing disk 412 and the first annular support disk 413 are both smaller than the inner diameter of the inner wall of the hollow annular shell 411, and are equal to the outer diameter of the injection section 22.
[0036] The outer wall of the hollow annular shell 411 is provided with at least two rings of evenly distributed fluidizing gas passages 414 and at least two rings of evenly distributed driving gas passages 415 along the circumferential direction, and at least one air inlet 416 is provided at the front end of the outer wall; the fluidizing gas passages 414 are provided at the front end of the first cavity 24, and the driving gas passages 415 are provided at the rear end of the hollow annular shell 411.
[0037] In this embodiment, the annular fixed disk 412 and the first annular support disk 413 form a sealed cavity between the annular flow guide channel component 41 and the wall of the combustion chamber 20 to house the annular fuel gas generator 30. The rear end of the annular fuel gas generator 30 is fixedly connected to the annular fixed disk 412 by bolts.
[0038] Specifically, both the fluidizing gas passage 414 and the driving gas passage 415 have 3 turns, with the through holes in each turn evenly distributed along the outer wall of the hollow annular shell 411.
[0039] The hollow annular shell 411, located in front of the fluidizing gas passage 414, is provided with a second powder passage array 417 that penetrates both the inner and outer walls. For example... Figure 13 As shown, the second powder through hole array 417 on the inner wall of the hollow annular shell 411 and the second powder through hole array 417 on the outer wall are sealed and connected by an arc-shaped connecting plate 420, and the projection of each through hole of the second powder through hole array 417 on the outer wall of the combustion chamber 20 along the radial direction of the hollow annular shell 411 coincides with each through hole of the second powder through hole array 417.
[0040] An arc-shaped connecting plate 420 is integrally connected to the inner and outer walls of the hollow annular shell 411. Multiple holes, equal in number to the number of through holes in the second powder through-hole array 417, are distributed on the plate to connect the inner and outer walls of the hollow annular shell 411. Adjacent arc-shaped connecting plates 420 are spaced apart, allowing the incoming flow to pass between them.
[0041] Inside the hollow annular shell 411, a first annular baffle 418 and a second annular baffle 419 of the same size and with an inner diameter equal to that of the straight section 21 are vertically fixedly connected. The first annular baffle 418 and the second annular baffle 419 are located on both sides of the first powder through-hole array 26 along the axial direction of the straight section 21, respectively. The function of the first annular baffle 418 and the second annular baffle 419 is to form a sealed channel between the second powder through-hole array 417 and the first powder through-hole array 26.
[0042] In one embodiment, the powder supply assembly 42 includes a hollow annular powder storage tank 421, a fluidizing cone 422, a fluidizing disc 423, an annular piston 424, and an annular adjusting sleeve 425.
[0043] The front end of the hollow annular powder storage tank 421 is open and the rear end is sealed. The front end of the hollow annular powder storage tank 421 is located on the rear side of the fluidizing gas through hole 414 along the axial direction of the combustion chamber 20, and the rear end is fixedly assembled with the annular fixed plate 412. The larger side of the fluidizing cone 422 and the fluidizing plate 423 both face the hollow annular powder storage tank 421. The annular adjusting sleeve 425 is located on the front side of the second powder through hole array 417 along the axial direction of the combustion chamber 20 and is fixedly sleeved on the hollow annular shell 411.
[0044] In this embodiment, the rear end face of the hollow annular powder storage box 421 is fixedly connected to the annular fixed plate 412 by bolts.
[0045] The front end of the fluidizing disc 423 is located between the second powder through hole array 417 and the fluidizing gas through hole 414, and is sleeved on the hollow annular shell 411. The rear end of the fluidizing disc 423 is axially fixedly connected to the front end face of the hollow annular powder storage tank 421. The front end of the fluidizing cone 422 is fixedly sleeved onto the annular adjusting sleeve 425, and the rear end is axially fixedly connected to the front end face of the hollow annular powder storage tank 421. Specifically, the rear end of the fluidizing cone 422 is fixedly connected to the front end of the hollow annular powder storage tank 421 via a flange.
[0046] An annular piston 424 is disposed inside a hollow annular powder storage tank 421. Its outer side wall abuts against the inner side of the outer side wall of the hollow annular powder storage tank 421, and its inner side wall abuts against the inner side of the inner side wall of the hollow annular powder storage tank 421. Under the action of a driving gas, it can slide along the axial direction of the hollow annular powder storage tank 421 towards the fluidizing disk 423. When the annular piston 424 slides, it can push the powder inside the hollow annular powder storage tank 421 towards the storage tank outlet. An annular sealing strip is embedded in the outer side wall of the annular piston 424.
[0047] In this embodiment, the area between the fluidizing cone 422 and the fluidizing disk 423 is the powder inlet cavity, the area between the fluidizing disk 423 and the head of the hollow annular powder storage box 421 is the fluidizing cavity, and the area between the piston and the tail of the hollow annular powder storage box 421 is the driving cavity.
[0048] To achieve adjustable piston thrust and fluidization degree, in one embodiment, the annular adjusting sleeve 425 includes a second annular support plate 4251 and an annular sealing plate 4252. The second annular support plate 4251 is fixedly sleeved on the hollow annular shell 411, and the front end of the annular sealing plate 4252 is integrally sleeved on the second annular support plate 4251. The cavity formed between the annular sealing plate 4252 and the hollow annular shell 411 is a powder flow regulating cavity 4253. A third annular support plate 4254 is vertically fixedly connected to the inner side of the inner wall of the hollow annular powder storage tank 421. The third annular support plate 4254 is located on the rear side of the drive air passage 415 along the axial direction of the combustion chamber 20. The cavity formed between the inner wall of the hollow annular powder storage tank 421 and the hollow annular shell 411 is an annular flow guiding regulating cavity 4255.
[0049] The powder flow regulating cavity 4253 is provided with a first annular regulating plate 4256 that can slide along the axial direction of the hollow annular shell 411. The first annular regulating plate 4256 is sleeved on the hollow annular shell 411 and is used to adjust the overall opening of the second powder through hole array 417.
[0050] The annular flow guiding and regulating cavity 4255 is provided with a second annular regulating plate 4257 and a third annular regulating plate 4258 that can slide along the axial direction of the hollow annular shell 411. Both the second annular regulating plate 4257 and the third annular regulating plate 4258 are sleeved on the hollow annular shell 411. The second annular regulating plate 4257 is located close to the fluidizing plate 423. The second annular regulating plate 4257 is used to adjust the number of opening turns of the fluidizing air passage 414, and the third annular regulating plate 4258 is used to adjust the number of opening turns of the driving air passage 415.
[0051] This embodiment does not limit the adjustment and pushing method of each annular adjustment plate. For example, in this embodiment, several drive motors and several adjustment rods can be provided inside both the powder flow adjustment cavity 4253 and the annular guide flow adjustment cavity 4255. The drive motors are electrically connected to an external control system, and the adjustment rods are connected to the annular adjustment plates. The drive motors drive the extension of the adjustment rods to drive the annular adjustment plates to slide axially, thereby realizing the adjustment of the opening degree of the corresponding through holes.
[0052] The ramjet engine in this embodiment can achieve a rapid and smooth transition between subsonic and supersonic modes by independently controlling the injection strategy of powdered fuel and fuel-rich gas, and by adjusting the thermal circulation and pressure distribution within the combustion chamber 20 at different flight stages through an annular regulating plate. At low Mach (3-6 Mach), the annular fuel gas generator 30 and the annular powder supply assembly 42 operate simultaneously. The fuel-rich gas generated by the annular fuel gas generator 30 mixes and combusts with the incoming flow downstream, forming a high-temperature zone. The powdered fuel burns fully within this high-temperature zone, resulting in a subsonic region within the combustion chamber 20. Back pressure is transmitted to the isolation section, where pressure induces a shock wave train. At this time, the engine is in the subsonic mode. At high Mach (above 6 Mach), since the total temperature of the incoming flow is already sufficiently high, the powder supply assembly 42 operates independently. The powdered fuel mixes and combusts fully with the incoming flow in the low-speed recirculation region formed by the two-stage concave cavities. At this time, there is no subsonic region within the combustion chamber 20, and the engine is in the supersonic mode.
[0053] The ramjet engine in this embodiment can achieve a smooth transition between sub-combustion mode and supercombustion mode.
[0054] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.
Claims
1. A boron-based powder fuel dual-mode ramjet engine, characterized in that, It includes an intake assembly (10), a combustion chamber (20), an annular fuel gas generator (30), and a pneumatic plug-type powder fuel supply assembly (40); The air intake assembly (10) is used to introduce and compress incoming air; The combustion chamber (20) is provided with an integrally connected straight section (21), injection section (22) and expansion section (23). The straight section (21) is axially fixedly connected to the rear end of the air intake assembly (10). The injection section (22) has a first cavity (24) and a second cavity (25) arranged sequentially in the direction away from the air intake assembly (10). The injection section (22) has a plurality of first powder through hole arrays (26) located in front of the first cavity (24) and a plurality of gas through hole arrays (27) located between the first cavity (24) and the second cavity (25). The plurality of first powder through hole arrays (26) and the plurality of gas through hole arrays (27) are all evenly distributed along the circumference of the injection section (22). The annular fuel gas generator (30) is used to supply fuel-rich gas to the injection section (22) through the gas through hole array (27), and is sleeved on the outside of the injection section (22). Its front end is located behind the first powder through hole array (26) and is fixedly connected to the outer wall of the injection section (22), and its rear end is located at the end of the injection section (22). The pneumatic plug-type powder fuel supply assembly (40) includes an annular flow channel component (41) and a powder supply assembly (42); The annular flow guide channel component (41) is sleeved on the combustion chamber (20) to introduce the incoming flow and divide the incoming flow into fluidizing gas and driving gas to be delivered to the powder supply assembly (42); The powder supply assembly (42) is sleeved on the annular guide channel component (41) and is used to drive the internal boron-based powder fuel to be output by means of driving gas and input into the combustion chamber (20) through the first powder through hole array (26), and to atomize the boron-based powder fuel by means of fluidized gas during the output of boron-based powder fuel.
2. The boron-based powder fuel dual-mode ramjet engine according to claim 1, characterized in that, The annular fuel gas generator (30) includes a first annular cylindrical hollow shell (31), a second annular cylindrical hollow shell (32), an annular flow guide plate (33), a first annular solid fuel propellant grain (34), and a second annular solid fuel propellant grain (35); The first annular hollow shell (31) and the second annular hollow shell (32) are both fitted onto the injection section (22); The first annular hollow shell (31) and the second annular hollow shell (32) are open on opposite sides and sealed on opposite sides. The two end walls of the annular drainage concave plate (33) are axially fixedly connected to the outer walls of the first annular hollow shell (31) and the second annular hollow shell (32), respectively. The first annular solid fuel propellant grain (34) is filled inside the first annular hollow shell (31), and the second annular solid fuel propellant grain (35) is filled inside the second annular hollow shell (32); The gap between the inner walls of the first annular hollow shell (31) and the second annular hollow shell (32) forms a fuel-rich gas through hole (36), and the gap distance is greater than or equal to the width of the gas through hole array (27) along the engine axis; Igniters (37) are fixedly mounted on the inner side of the outer wall of the opening of the first annular hollow shell (31) and the second annular hollow shell (32).
3. The boron-based powder fuel dual-mode ramjet engine according to claim 2, characterized in that, The annular guide channel component (41) is provided with a hollow annular shell (411), an annular fixing disk (412) and a first annular support disk (413). The first annular support disk (413) is integrally connected to the front end of the hollow annular shell (411), and the annular fixing disk (412) is integrally connected to the rear end face of the hollow annular shell (411). The inner wall of the first annular support disk (413) is fixedly connected to the portion of the straight section (21) located at the front end of the first powder through-hole array (26). The inner diameters of the annular fixing disk (412) and the first annular support disk (413) are both smaller than the inner diameter of the inner wall of the hollow annular shell (411) and are equal to the outer diameter of the injection section (22). The outer wall of the hollow annular shell (411) is provided with at least two rings of evenly distributed fluidizing gas passages (414) and at least two rings of evenly distributed driving gas passages (415) along the circumferential direction, and at least one air inlet (416) is provided at the front end of the outer wall; the fluidizing gas passages (414) are provided at the front end of the first cavity (24), and the driving gas passages (415) are provided at the rear end of the hollow annular shell (411); The hollow annular shell (411) is provided with a second powder through hole array (417) in the part in front of the fluidizing gas through hole (414) that penetrates the inner wall and the outer wall; the second powder through hole array (417) on the inner wall of the hollow annular shell (411) and the second powder through hole array (417) on the outer wall are sealed and connected by an arc-shaped connecting plate (420), and the projection of each through hole of the second powder through hole array (417) on the outer wall of the combustion chamber (20) along the radial direction of the hollow annular shell (411) coincides with each through hole of the second powder through hole array (417); The hollow annular shell (411) has a first annular baffle (418) and a second annular baffle (419) of the same size and with an inner diameter equal to that of the straight section (21) vertically fixed inside. The first annular baffle (418) and the second annular baffle (419) are respectively located on both sides of the first powder through hole array (26) along the axial direction of the straight section (21).
4. The boron-based powder fuel dual-mode ramjet engine according to claim 3, characterized in that, The powder supply assembly (42) includes a hollow annular powder storage tank (421), a fluidizing cone (422), a fluidizing disc (423), an annular piston (424), and an annular regulating sleeve (425); The front end face of the hollow annular powder storage box (421) is open and the rear end face is sealed. The front end face of the hollow annular powder storage box (421) is located on the rear side of the fluidizing gas passage (414) along the axial direction of the combustion chamber (20), and the rear end face is fixedly assembled with the annular fixed plate (412). The larger opening sides of both the fluidizing cone (422) and the fluidizing disk (423) face the hollow annular powder storage tank (421); The annular adjusting sleeve (425) is disposed on the front side of the second powder through hole array (417) along the axial direction of the combustion chamber (20) and is fixedly sleeved on the hollow annular shell (411); The front end of the fluidizing disk (423) is located between the second powder through hole array (417) and the fluidizing gas through hole (414), and is sleeved on the hollow annular shell (411). The rear end of the fluidizing disk (423) is axially fixedly connected to the front end face of the hollow annular powder storage tank (421). The front end of the fluidizing cone (422) is fixedly sleeved on the annular adjusting sleeve (425), and the rear end is axially fixedly connected to the front end face of the hollow annular powder storage tank (421). The annular piston (424) is disposed inside the hollow annular powder storage box (421). Its outer side wall abuts against the inner side of the outer side wall of the hollow annular powder storage box (421), and its inner side wall abuts against the inner side of the inner side wall of the hollow annular powder storage box (421). It can slide along the axial direction of the hollow annular powder storage box (421) toward the fluidizing plate (423) under the action of the driving gas.
5. The boron-based powder fuel dual-mode ramjet engine according to claim 4, characterized in that, The annular regulating sleeve (425) includes a second annular support plate (4251) and an annular sealing plate (4252). The second annular support plate (4251) is fixedly sleeved on the hollow annular shell (411). The front end of the annular sealing plate (4252) is integrally sleeved on the second annular support plate (4251). The cavity formed between the annular sealing plate (4252) and the hollow annular shell (411) is a powder flow regulating cavity (4253). The inner wall of the hollow annular powder storage tank (421) is vertically fixed with a third annular support plate (4254). The third annular support plate (4254) is located on the rear side of the drive air passage (415) along the axial direction of the combustion chamber (20). The cavity formed between the inner wall of the hollow annular powder storage tank (421) and the hollow annular shell (411) is an annular flow guiding and regulating cavity (4255). The powder flow regulating cavity (4253) is provided with a first annular regulating plate (4256) that can slide along the axial direction of the hollow annular shell (411). The first annular regulating plate (4256) is sleeved on the hollow annular shell (411) and is used to adjust the overall opening of the second powder through hole array (417). The annular flow guiding and regulating cavity (4255) is provided with a second annular regulating plate (4257) and a third annular regulating plate (4258) that can slide along the axial direction of the hollow annular shell (411). The second annular regulating plate (4257) and the third annular regulating plate (4258) are both sleeved on the hollow annular shell (411). The second annular regulating plate (4257) is located close to the fluidizing plate (423). The second annular adjusting plate (4257) is used to adjust the number of opening turns of the fluidizing air passage (414), and the third annular adjusting plate (4258) is used to adjust the number of opening turns of the driving air passage (415).
6. The boron-based powder fuel dual-mode ramjet engine according to claim 5, characterized in that, The intake assembly (10) includes an intake pipe (11) and a guide cone (12), and the rear end of the intake pipe (11) is fixedly connected to the front end of the straight section (21); The front end of the guide cone (12) extends from the air intake pipe (11), and the middle part is fixedly connected to the inner wall of the front end of the air intake pipe (11) through the rib (13) circumferentially assembled on its outer wall. The end is located at the tail of the air intake pipe (11), and the gap between the air intake pipe (11) and the guide cone (12) forms an air intake channel.