CN115628464B - Three-way scramjet engine combustion chamber - Google Patents

Abstract

The invention discloses a three-way scramjet engine combustion chamber, and particularly relates to the field of scramjet engines. The combustion chamber consists of an isolation section, an expansion section and an equal straight section, wherein adjacent parts of the isolation section, the expansion section and the equal straight section are connected through flanges, two partition boards are distributed in the combustion chamber, and first fuel injection holes respectively positioned in the isolation section, the expansion section and the equal straight section are formed in two sides of each partition board; the combustion chamber is internally provided with three stable combustion support plates, the three stable combustion support plates are respectively arranged between the two partition plates and the combustion chamber and between the two partition plates, the stable combustion support plates are provided with second fuel injection holes and oxygen supplementing holes, the second fuel injection holes are arranged on the front surface of the stable combustion support plates, the oxygen supplementing holes are arranged on the side surfaces, the side surfaces of the stable combustion support plates are also provided with grooves positioned outside the oxygen supplementing holes, and plasma igniters are arranged in the grooves. By adopting the technical scheme of the invention, the problem of thrust lifting of the combustion chamber is solved, and the overall thrust of the combustion chamber can be improved.

Description

A three-channel scramjet engine combustion chamber

Technical Field

The invention relates to the field of scramjet engines, and in particular to a three-channel scramjet engine combustion chamber.

Background Art

Scramjet engines have attracted extensive discussion among scholars at home and abroad due to their high specific impulse, high speed and safety far superior to rockets. As one of the important components of scramjet engines, the essential function of the supersonic combustion chamber is to provide stable and high effective thrust for the aircraft.

In order to achieve this goal, the combustion chamber with strict structure and mass restrictions inevitably has a need for flame stabilizers. The current combustion stabilization methods are mainly support plate stabilization and cavity stabilization. In the extensive research process, the support plate stabilization gradually derived the support plate/wall stabilization mode, which greatly enhanced the multi-stage heat release capacity of the combustion chamber and extended its stable working time, but it has reached a bottleneck stage in the long-term development process. Under the limitation of the energy equation, if you want to further improve the thrust of the combustion chamber, you need a higher intensity heat release rate inside the combustion chamber. Some scholars have proposed to increase the intake flow rate, increase the fuel consumption in the same time, break the barrier of heat loss to obtain higher thrust, but in the field of gas dynamics, due to the congestion effect of the pipeline, the inlet flow of the combustion chamber can only approach the limit value and cannot exceed it. Therefore, it is necessary to change the geometric structure of the combustion chamber, but due to the limitation of the scale effect, geometric similarity through simple area expansion cannot meet the relevant dynamic similarity conditions at the same time. For example, the additional losses such as the thickening of the combustion chamber boundary layer will reduce its effective thrust, making the combustion chamber performance improvement flat.

Summary of the invention

The present invention aims to provide a three-channel scramjet engine combustion chamber, which solves the problem of increasing the thrust of the combustion chamber.

In order to achieve the above-mentioned object, the technical scheme of the present invention is as follows: a three-channel scramjet engine combustion chamber, the combustion chamber is composed of an isolation section, an expansion section and an equal straight section, the isolation section, the expansion section and the equal straight section are adjacently connected by flanges, an annular fuel injector is arranged between the two flanges on the expansion section and the equal straight section, a plurality of third fuel injection holes are equidistantly opened on the four side walls in the annular fuel injector, two partitions are equidistantly distributed in the combustion chamber, each of the partitions extends from the isolation section to the equal straight section, the partitions Both sides of the plate are provided with first fuel injection holes which are respectively located in the isolation section, the expansion section and the straight section; three combustion stabilizing support plates are arranged in the combustion chamber, and the three combustion stabilizing support plates are respectively arranged between the two partitions and the inner wall of the combustion chamber and between the two partitions; second fuel injection holes and oxygen supply holes are arranged on the combustion stabilizing support plates; the second fuel injection holes are arranged on the front side of the combustion stabilizing support plates, and the oxygen supply holes are arranged on the side; the side of the combustion stabilizing support plates is also provided with a groove located outside the oxygen supply hole, and a plasma igniter is installed in the groove.

Furthermore, the partition is composed of multiple first short plates, second short plates and third short plates, the first short plate is arranged in the isolation section, the two ends of the second short plate extend into the isolation section and the straight section respectively, the third short plate is arranged in the straight section, and the joints between the first short plate and the second short plate, and the second short plate and the third short plate are provided with grooves that are interlocked with each other.

Through the above arrangement, the use of grooves for snap connection can increase the replaceability and experimental variability while ensuring the stable operation of the combustion chamber.

Compared with the prior art, this solution has the following beneficial effects:

This scheme is based on the stable combustion strategy of support plate/wall injection. In order to further enhance the pressure rise performance of the supersonic combustion chamber and improve the effective thrust of the scramjet engine, a three-channel scramjet engine combustion chamber is proposed. The large-scale combustion chamber is divided into three parallel and independently working channels by a partition. On the one hand, it is equivalent to three combustion chambers working in parallel, each of which exerts the ability of stable combustion through the stable combustion support plate; on the other hand, while increasing the intake flow rate, it reduces the potential problems caused by the scale effect, and uses the wall injection holes of the partition to achieve multi-stage heat release in each channel to further improve the effective thrust of the combustion chamber; at the same time, it provides a large intake flow rate and avoids the scale effect caused by geometric similarity. Starting from two aspects, the fuel consumption and heat release of the supersonic combustion chamber are increased to produce a high pressure rise, thereby further improving the overall thrust of the scramjet engine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a top view of a three-channel scramjet combustion chamber of the present invention;

FIG2 is a front view of a three-channel scramjet combustion chamber;

Fig. 3 is a cross-sectional view taken along line A-A in Fig. 2;

Fig. 4 is a cross-sectional view taken along line B-B in Fig. 3;

FIG5 is a top view of the combustion stabilizing support plate in this embodiment;

FIG. 6 is a rear view of the combustion stabilizing support plate in this embodiment.

DETAILED DESCRIPTION

The present invention is further described in detail below through specific embodiments:

The figure marks in the drawings of the specification include: isolation section 1, expansion section 2, equal straight section 3, partition 4, first fuel injection hole 5, combustion stabilization support plate 6, second fuel injection hole 7, oxygen supply hole 8, groove 9, annular fuel injector 10, and third fuel injection hole 11.

Example

As shown in Figures 1-6, a three-channel scramjet engine combustion chamber is composed of an isolation section 1, an expansion section 2 and an equal straight section 3. The isolation section 1, the expansion section 2 and the equal straight section 3 are adjacently connected by flanges. An annular fuel injector 10 is abutted between the two flanges of the expansion section 2 and the equal straight section 3. The annular fuel injector 10 is composed of a rectangular frame structure and a plurality of third fuel spray holes 11 equidistantly distributed on the four side walls of the frame structure. The third fuel spray holes 11 are respectively located in each channel. The isolation section 1 is used to resist the non-starting phenomenon induced by the back pressure generated by the combustion in the combustion chamber to ensure the stable operation of the front air intake; the expansion section 2 is used to provide high-pressure and low-distortion air for the internal flow field and increase the heat release space of the combustion chamber to improve performance; the equal straight section 3 will generate a thermal throat in the subsonic mode to accelerate the subsonic airflow to a supersonic state.

There are two partitions 4 spaced evenly in the combustion chamber, each partition 4 extends from the isolation section 1 to the straight section 3, and the partition 4 is embedded in the isolation section 1, the expansion section 2 and the straight section 3. The partition 4 is composed of a plurality of first short plates, second short plates and third short plates. The first short plate is arranged in the isolation section 1, and the two ends of the second short plate extend into the isolation section 1 and the straight section 3 respectively. The third short plate is arranged in the straight section 3. The joints of the first short plate and the second short plate, and the second short plate and the third short plate are provided with grooves 9 for interlocking. The use of the grooves 9 for interlocking can increase the replaceability and the variability of the experiment under the premise of ensuring the stable operation of the combustion chamber. Both sides of the partition 4 are provided with first fuel injection holes 5 located in the isolation section 1, the expansion section 2 and the straight section 3 respectively. The diameter of the first fuel injection holes 5 is 0.5 mm, the number is 6 and they are evenly distributed on the partition 4 in the longitudinal direction, thereby realizing multi-stage injection of fuel.

Gas inlet and outlet channels are formed between the two partitions 4 and the inner wall of the combustion chamber and between the two partitions 4. Each channel is provided with a 6mm thick combustion stabilizing support plate 6. A through hole is opened on the expansion section 2 for sliding and sealing connection with the combustion stabilizing support plate 6. Each combustion stabilizing support plate 6 is installed in the center of the channel, and the tail of the combustion stabilizing support plate 6 is in the same plane as the cross-sectional expansion of the expansion section 2. The combustion stabilizing support plate 6 is provided with a second fuel injection hole 7 symmetrically distributed on the combustion stabilizing support plate 6 and two rows of oxygen supply holes 8 arranged at intervals. The second fuel injection hole 7 is arranged on the front of the combustion stabilizing support plate 6 and is perpendicular to the incoming flow. The two rows of oxygen supply holes 8 are arranged on the side and are parallel to the incoming flow. The side of the combustion stabilizing support plate 6 is also provided with a groove 9 located in front of the two rows of oxygen supply holes 8, and a plasma igniter is installed in the groove 9. The fuel injection hole realizes momentum exchange with the high-speed airflow during the flow of the fuel along the side wall of the support plate through countercurrent injection, thereby improving the mixing efficiency; the oxygen supply hole 8 forms a low-speed recirculation zone and a free shear layer at the trailing edge of the support plate while replenishing oxygen, further enhancing the mixing; a plasma igniter is installed at the position of the groove 9, and the gas-liquid two-phase fuel gathered here is ignited by the high energy injected by the igniter to form an initial flame.

The working process of this program:

The supersonic airflow is diverted by the partition 4 at the inlet of the combustion chamber into three independently working isolation sections 1, and the stable combustion support plate 6 at the outlet section injects fuel into the combustion chamber, and an initial stable flame is established under the operation of the igniter. In this scheme, the oxygen injected by the oxygen supply hole 8 is used to establish a low-speed recirculation zone at the tail of the stable combustion support plate 6, and the fuel injected by the second fuel injection hole 7 located upstream is ignited by the plasma igniter in the shear layer to form a stable flame. The injection holes evenly arranged on the partition 4 cooperate with the wall injection ring processed in an integrated manner to realize the multi-stage injection and combustion organization of the fuel. Since its design purpose is to conduct experiments as the leading factor, in order to achieve the design requirements of multiple experiments to facilitate replacement and multiple repeated experiments, the partition 4 adopts a docking mechanical fastening, and at the same time has the functions of separating channels and wall injection, which improves the replaceability and subsequent experimental variability under the premise of meeting stability. In the three-channel combustion chamber, the supersonic airflow enters different channels at the inlet of the combustion chamber through diversion to establish stable combustion, which can effectively avoid the potential problems caused by the scale effect of the combustion chamber and output stable and large thrust to the outside.

The above are only embodiments of the present invention, and common knowledge such as the known specific structures and/or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims (2)

1. A three-channel scramjet engine combustion chamber, characterized in that: the combustion chamber consists of an isolation section (1), an expansion section (2) and an equal straight section (3), wherein the isolation section (1), the expansion section (2) and the equal straight section (3) are connected adjacently through flanges, an annular fuel injector (10) is arranged between two flanges on the expansion section (2) and the equal straight section (3), a plurality of third fuel spray holes (11) are formed in four side walls in the annular fuel injector (10) at equal intervals, two partition plates (4) are distributed in the combustion chamber at equal intervals, each partition plate (4) extends from the isolation section (1) to the equal straight section (3), and first fuel spray holes (5) respectively formed in the isolation section (1), the expansion section (2) and the equal straight section (3) are formed in two sides of each partition plate (4); three stable combustion support plates (6) are arranged in the combustion chamber, the three stable combustion support plates (6) are respectively arranged between the two partition plates (4) and the inner wall of the combustion chamber and between the two partition plates (4), second fuel injection holes (7) and oxygen supply holes (8) are formed in the stable combustion support plates (6), the second fuel injection holes (7) are formed in the front face of the stable combustion support plates (6), the oxygen supply holes (8) are formed in the side face, grooves (9) located outside the oxygen supply holes (8) are formed in the side face of the stable combustion support plates (6), and plasma igniters are mounted in the grooves (9).

2. A three-way scramjet engine combustion chamber as set forth in claim 1, wherein: the baffle (4) comprises polylith first short board, second short board and third short board, first short board sets up in isolation section (1), the both ends of second short board stretch into isolation section (1) and waiting straight section (3) respectively, the third short board sets up in waiting straight section (3), all open the recess (9) of mutual lock joint in the department of meeting of first short board and second short board, second short board and third short board.