CN114165356B

CN114165356B - Miniature ramjet engine

Info

Publication number: CN114165356B
Application number: CN202111415807.8A
Authority: CN
Inventors: 蔡文哲; 王文正; 郭依尘
Original assignee: Beijing Power Machinery Institute
Current assignee: Beijing Power Machinery Institute
Priority date: 2021-11-25
Filing date: 2021-11-25
Publication date: 2023-01-10
Anticipated expiration: 2041-11-25
Also published as: CN114165356A

Abstract

The invention relates to a miniature ramjet engine, and belongs to the technical field of engines. The micro ramjet has a simple structure, realizes micro thrust by adopting a jet method, and realizes efficient combustion of fuel by an advanced swirl combustion organization mode in a small space; the miniature ramjet has the advantages of low cost, compact and reliable structure and convenience for installation on an aircraft body, and the length-diameter ratio range of a combustion chamber can reach 0.2-1.0; the device has the characteristic of modularization, can be used as auxiliary power to be installed at different parts of the aircraft and is used for directly controlling the attitude of the aircraft.

Description

Miniature ramjet engine

Technical Field

The invention belongs to the technical field of engines, and particularly relates to a miniature ramjet engine.

Background

The working process of the traditional ramjet is as follows: the air enters the direct-current combustion chamber after being subjected to deceleration and pressurization in the air inlet channel, the fuel is sprayed into the direct-current combustion chamber to be combusted, heated and heated, and then the air is expanded and accelerated to be depressurized through the spray pipe, so that part of heat energy is converted into kinetic energy and is discharged into the atmosphere, the thermodynamic cycle of the ramjet engine as a heat engine is formed, and meanwhile, the surplus impulse of the exhaust gas of the ramjet engine and the surplus impulse increment of the intake air of the air inlet channel are generated, so that the thrust is generated.

The traditional ramjet engine comprises an air inlet channel, a combustion chamber spray pipe and engine accessories, wherein the engine accessories comprise an ignition system, an oil supply adjusting system, an engine adjustable part actuating servo system and a control system.

The traditional ramjet engine cannot be started to work at zero flying speed and can work only when flying is accelerated to a certain Mach number; when the traditional ramjet engine works, working media and oxygen come from the atmosphere, and air intake is directly related to the flight speed of an aircraft and is limited; the traditional ramjet combustion chamber generally needs a specific geometric wall surface or a flame stabilizer to ensure the combustion stability and completeness; the thrust range of the traditional ramjet engine is generally over 1000N, and the traditional ramjet engine is difficult to be miniaturized to reach the thrust range of 10-100N.

Disclosure of Invention

Technical problem to be solved

The technical problem to be solved by the invention is as follows: 1) The micro thrust is realized through a simple structure; 2) The high-efficiency combustion of fuel is realized; 3) The low cost, the reliable structure and the convenient installation are realized; 4) The modularized characteristic is realized, and the auxiliary power device can be used as auxiliary power to be installed at different parts of the aircraft and is used for directly controlling the attitude of the aircraft.

(II) technical scheme

In order to solve the technical problem, the invention provides a miniature ramjet engine which comprises an air inlet pipeline 1, a swirler 2, a combustion chamber 3, a shell 4, an igniter 5, a laval nozzle 6, a positioning support plate 7, a fixed seat 8 and a swirl nozzle 9; the air inlet pipeline 1 is connected with the shell 4 through a flange and positioned, and an inlet of the air inlet pipeline 1 is a gradually expanding section; the combustion chamber 3 and the shell 4 are both in an axisymmetric thin-wall structure; the combustion chamber 3 and the shell 4 are fixed through 4 positioning support plates 7; the igniter 5 is arranged on the shell 4 and the wall surface of the combustion chamber 3, and the igniter 5 is fixed at the position of a fixed seat 8 on the shell 4; the axial installation position of the igniter 5 is within a range of 1D-3D from the outlet of the swirler 2 in the axial direction, wherein D is the diameter of the swirler 2; the swirler 2 is connected with the combustion chamber 3, and the nozzle 9 is fixedly arranged in the swirler 2; the Laval nozzle 6 is fixed on the shell 4; the swirler 2 and the laval nozzle 6 are located at both ends of the combustion chamber 3.

Preferably, the wall thickness of the combustion chamber 3 and the housing 4 is distributed between 0.5mm and 2 mm.

Preferably, the swirler 2 is a single-stage or double-stage axial swirler.

Preferably, the head of the combustion chamber 3 is designed to be rich in oil.

Preferably, the positioning support plate 7 is in a streamlined body shape.

Preferably, the igniter 5 is screwed to a fixed seat 8 on the housing 4.

Preferably, the swirler 2 and the combustion chamber 3 are connected by a welded structure.

Preferably, the nozzle 9 is fixedly mounted inside the cyclone 2 by means of a screw thread.

Preferably, the laval nozzle 6 and the housing 4 are secured by screws.

The invention also provides a working method of the miniature ramjet, which comprises the following steps: the incoming air is rectified by an air inlet pipeline 1 and then divided into two parts, wherein one part enters a combustion chamber 3 through a swirler 2; the other end of the air flow enters an annular cavity channel between the combustion chamber 3 and the shell 4 and then enters the combustion chamber 3 through holes distributed on the wall surface of the combustion chamber 3 according to a certain rule; fuel oil is sprayed into the combustion chamber 3 through a swirl nozzle 9 arranged in the swirler 2, and then the fuel oil and air entering the combustion chamber 3 are mixed and combusted to form high-temperature fuel gas; after the high-temperature fuel gas is fully mixed in the combustion chamber 3, an outlet temperature field with a specific rule is formed, and the high-temperature fuel gas is accelerated through the Laval nozzle 6 to form supersonic speed airflow to be sprayed out to form certain thrust.

(III) advantageous effects

The invention adopts the straight connecting pipe for air inlet, and the inlet is a gradual expansion section, thereby reducing the loss of the diffusion section; the temperature field of the outlet of the combustion chamber is low outside and high in the middle, and a cooling air film is formed on the exhaust section (the air inlet section of the spray pipe) of the combustion chamber; the high-temperature-resistant Laval nozzle is adopted, so that the structure is simple and reliable; the swirler adopts a single-stage or double-stage axial swirler, axial double-vortex flow is combusted, the number of the vortex flow is distributed between 0.5 and 1.0, and a sufficient backflow area can be formed, so that the combustion stability and completeness are ensured; the flow of the swirler head accounts for 30% -50% of the total air flow, the combustion chamber head adopts rich oil design, the equivalence ratio is larger than 1, and the ignition of an engine is facilitated; the thrust range of the engine is generally 0-200N, the radial dimension of the engine can be fully ensured to be in the range of 0-180mm, the installation of the engine in the overall aircraft is convenient, and the accompanying vector thrust is convenient to form by matching with a main engine. The micro ramjet has a simple structure, realizes micro thrust by adopting a jet method, and realizes efficient combustion of fuel by an advanced swirl combustion organization mode in a small space; the miniature ramjet has the advantages of low cost, compact and reliable structure and convenience for installation on an aircraft body, and the length-diameter ratio range of a combustion chamber can reach 0.2-1.0; the device has the characteristic of modularization, can be used as auxiliary power to be installed at different parts of the aircraft and is used for directly controlling the attitude of the aircraft.

Drawings

FIG. 1 is a schematic view of a micro ramjet according to the present invention;

FIG. 2 is a schematic view of the combustion-tissue vortex structure of the present invention;

fig. 3 is an outlet flow field of the combustor of the present invention.

Detailed Description

In order to make the objects, contents, and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be made in conjunction with the accompanying drawings and examples.

As shown in fig. 1, the present invention provides a micro ram engine including: the device comprises an air inlet pipeline 1, a swirler 2, a combustion chamber 3, a shell 4, an igniter 5, a Laval nozzle 6, a positioning support plate 7, a fixed seat 8 and a swirl nozzle 9;

the air inlet pipeline 1 is connected and positioned with the shell 4 through flanges, the flanges are fixed through bolts, and an inlet of the air inlet pipeline 1 is a gradually expanding section; the combustion chamber 3 and the shell 4 are in axisymmetric thin-wall structures, and the wall thickness is distributed between 0.5mm and 2 mm; the combustion chamber 3 and the shell 4 are fixed through 4 positioning support plates 7, and in order to reduce disturbance of airflow in an annular cavity channel formed between the combustion chamber 3 and the shell 4, the positioning support plates 7 are in a streamlined structure; the igniter 5 is arranged on the shell 4 and the wall surface of the combustion chamber 3 to form certain penetrating power, and is fixed on a fixed seat 8 on the shell 4 through threads; the axial installation position of the igniter 5 is within the range of 1D-3D from the outlet of the swirler 2 in the axial direction, wherein D is the diameter of the swirler 2; the swirler 2 is connected with the combustion chamber 3 through a welding structure, and the nozzle 9 is fixedly arranged in the swirler 2 through threads; the Laval nozzle 6 and the shell 4 are fixed through screws; the swirler 2 and the laval nozzle 6 are located at both ends of the combustion chamber 3. The swirler 2 adopts a single-stage or double-stage axial swirler; the head of the combustion chamber 3 adopts a rich oil design.

The working process of the miniature ramjet is as follows:

the incoming air is rectified by an air inlet pipeline 1 and then divided into two parts, and one part enters a combustion chamber 3 through a swirler 2; the other end of the air flow enters an annular cavity channel between the combustion chamber 3 and the shell 4 and then enters the combustion chamber 3 through holes distributed on the wall surface of the combustion chamber 3 according to a specific rule; fuel oil is sprayed into the combustion chamber 3 through a swirl nozzle 9 arranged in the swirler 2, and then the fuel oil and air entering the combustion chamber 3 are mixed and combusted to form high-temperature fuel gas, referring to fig. 2; after the high-temperature fuel gas is fully mixed in the combustion chamber 3, an outlet temperature field with a specific rule is formed (the rule is that the temperature of a small-radius area is high, the temperature of a large-radius area is low, see the figure 3), and then the high-temperature fuel gas is accelerated through the Laval nozzle 6 to form supersonic speed airflow to be sprayed out, so that the effect of forming a certain thrust force by the miniature ramjet engine is achieved.

It can be seen that the miniature ramjet of the invention has the advantages of wide working range, wide thrust magnitude and the like. According to the invention, by adjusting and matching the working state of the main engine, the main engine and the miniature ramjet of the invention can work in the optimal matching state, and the mounting number and direction of the miniature ramjet are matched according to the requirement, so that the vector maneuvering performance of the engine can be greatly improved, and an effective scheme is provided for realizing that the aircraft has direct force attitude control in different directions. Therefore, the invention realizes the miniature jet ramjet engine capable of realizing large thrust-weight ratio in a compact and small radial space range, the engine is convenient to install at a proper position of a medium-small aircraft due to small envelope size, and the engine and a main engine of the aircraft share an air path, an oil path and a control system, so that the thrust direction of the engine is not constrained, direct vector thrust can be brought to the aircraft, and a main-auxiliary adjoint vector engine system is formed. It should be noted that the size of the miniature ramjet engine can be enlarged or reduced according to the present invention, so as to obtain miniature ramjets with different thrust levels.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.

Claims

1. A micro ramjet is characterized by comprising an air inlet pipeline (1), a swirler (2), a combustion chamber (3), a shell (4), an igniter (5), a Laval nozzle (6), a positioning support plate (7), a fixed seat (8) and a swirl nozzle (9); the air inlet pipeline (1) is connected and positioned with the shell (4) through a flange, and an inlet of the air inlet pipeline (1) is a gradually expanding section; the combustion chamber (3) and the shell (4) are both in axisymmetric thin-wall structures; the combustion chamber (3) and the shell (4) are fixed through 4 positioning support plates (7); the igniter (5) is arranged on the shell (4) and the wall surface of the combustion chamber (3), and the igniter (5) is fixed at the position of a fixed seat (8) on the shell (4); the axial installation position of the igniter (5) is within the range of 1D-3D from the outlet of the swirler (2), wherein D is the diameter of the swirler (2); the swirler (2) is connected with the combustion chamber (3), and the nozzle (9) is fixedly arranged inside the swirler (2); the Laval nozzle (6) is fixed on the shell (4); the swirler (2) and the Laval nozzle (6) are positioned at two ends of the combustion chamber (3);

incoming air is rectified by an air inlet pipeline (1) and then divided into two parts, wherein one part enters a combustion chamber (3) through a swirler (2); the other end of the air flow enters an annular cavity channel between the combustion chamber (3) and the shell (4) and then enters the combustion chamber (3) through holes distributed on the wall surface of the combustion chamber (3) according to a certain rule; fuel oil is sprayed into the combustion chamber (3) through a swirl nozzle (9) arranged in the swirler (2), and then the fuel oil and air entering the combustion chamber (3) are mixed and combusted to form high-temperature fuel gas; after the high-temperature fuel gas is fully mixed in the combustion chamber (3), an outlet temperature field with a specific rule is formed, and the high-temperature fuel gas is accelerated through the Laval nozzle (6) to form supersonic airflow to be sprayed out to form a certain thrust.

2. A miniature ramjet according to claim 1, characterized in that the wall thickness of the combustion chamber (3) and the housing (4) is distributed between 0.5mm-2 mm.

3. The miniature ramjet engine according to claim 1, characterized in that said swirler (2) is a single-stage or double-stage axial swirler.

4. The micro-ramjet according to claim 1, characterized in that the head of the combustion chamber (3) is of oil-rich design.

5. The miniature ramjet according to claim 1, characterized in that said positioning plate (7) has a streamlined body.

6. The miniature ramjet according to claim 1, wherein said igniter (5) is screwed to a fixed seat (8) on the housing (4).

7. The miniature ramjet engine according to claim 1, characterized in that said swirler (2) and said combustion chamber (3) are connected by means of a welded structure.

8. A miniature ramjet according to claim 1, wherein said nozzle (9) is fixedly mounted inside the swirler (2) by means of a screw thread.

9. The miniature ramjet according to claim 1, characterized in that said laval nozzle (6) and said housing (4) are fixed by screws.