JP3135702B2 - Scrumjet engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scramjet engine, and more particularly to a technique for eliminating a choke phenomenon or the like during operation.

[0002]

2. Description of the Related Art In recent years, as a propulsion engine for a hypersonic aircraft, Japanese Patent Application Laid-Open Nos. 2-115559 and 2-291 have been disclosed.
As described in Japanese Patent No. 431 and the like, the development of a scramjet (supersonic combustion ramjet) engine is in progress. The scramjet engine allows air taken in from the air intake (air intake) to pass at supersonic speed even inside the engine, and can fly at a hypersonic speed of 5 Mach or more that can not be reached with a normal ramjet engine. Even if it is performed, it has such features that the rise in air temperature due to adiabatic compression is small and the combustor does not melt.

[0003]

In an aircraft equipped with a conventional scramjet engine (hereinafter abbreviated as engine), the combustion pressure rapidly increases or the amount of air flowing from the air intake due to a change in the attitude of the aircraft is sharply increased. , The pressure (static pressure) of the throat portion rises abnormally. In this case, a choke phenomenon occurs in which the air flow flowing into the air intake is often blocked by the throat portion, and the flow velocity in the engine becomes subsonic, resulting in an unstart (non-start) state. Then, a vertical shock wave is pushed forward of the air intake due to an increase in static pressure of the throat portion, and the air intake efficiency of the air intake decreases. As a result, the resistance increases and moments such as pitching and yawing change, which greatly affects the stability of the aircraft.

In order to solve such a problem and restart the engine, it is necessary to eliminate the choke phenomenon. However, in the unstarted state, since the engine is not started, it is expected that the combustion pressure will decrease due to the control of the fuel injection amount and the throat pressure will decrease due to the decrease in the amount of inflow air due to changes in the aircraft attitude. It was difficult to restart the engine. Even if the engine does not start unintentionally, when the vehicle is about to be choked, it is only possible to reduce the combustion pressure by controlling the amount of fuel injected or to reduce the pressure in the throat due to the decrease in the amount of air flowing in due to changes in the attitude of the aircraft. Control of the engine was extremely difficult.

Accordingly, the present invention solves the above-mentioned problems of the prior art, and changes the amount of air overflowing from the front of the cowl and the amount of air flowing into the throat portion according to the pressure in the compression portion, thereby changing the choke state. It is an object of the present invention to provide a scramjet engine that eliminates such problems.

[0006]

In order to achieve the above object, a scramjet engine according to the present invention is provided in an aircraft aircraft.
A plurality of wedge-shaped side walls erected on the body surface and these side walls
The air intake is controlled by the cowl mounted between the tips.
Compression in which the cross-sectional area of the air passage decreases rearward
Section, and the compression section is partitioned from a rear combustion section.
Scramjet with throat section with minimum cross-sectional area
In the engine, the cowl moves back and forth on the side wall.
Air that is freely mounted and overflows from the air intake
The cowl can be controlled and the cowl can be moved back and forth.
Cowl driving device to measure the static pressure of air in the compression section.
A pressure sensor to be set based on the detection result of the pressure sensor.
A control device for controlling the operation of the cowl driving device,
Wherein the control device is static pressure in the compression section to increase
Then the cowl is retracted and overflows from the air intake.
As the amount of air flowing out increases, the static
When the pressure is reduced, the cowl is advanced and the air
The cowl to reduce the amount of air overflowing the
Controlling the operation of the drive unit.

[0007]

According to the present invention, when the choke phenomenon occurs or occurs in the engine, the static pressure in the compression section of the air flow path increases, and the value is detected by the pressure sensor. The control device controls the cowl driving device based on the detection result of the pressure sensor, and moves the cowl backward along the air flow direction. Then, since the amount of air overflowing from the air intake increases, the amount of air flowing into the throat portion decreases, and the static pressure of the throat portion decreases, thereby eliminating the choke phenomenon. Conversely, when the static pressure in the throat portion decreases and supersonic combustion cannot be maintained, the cowl is moved forward along the air flow direction. Then, since the amount of air overflowing from the air intake decreases, the amount of air flowing into the throat increases, the static pressure of the throat increases, and supersonic combustion is restarted.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the scramjet engine according to the present invention will be described below with reference to the accompanying drawings.

[0009] In the aircraft shown in FIG.
Is equipped with an engine 3. As shown in FIG. 2 (enlarged view of the portion A in FIG. 1), the engine 3 is provided between the left and right side walls 4 and 5 having a receding angle and the center side wall 6 for fuel injection having the same shape as the side wall 6. The struts 7, 8 are arranged, and a cowl 9 is attached to the side walls 4, 5, 6 and the lower surface of the struts 7, 8 so as to cover the rear half thereof.

As shown in FIG. 3, the inner surfaces of the side walls 4, 5, 6 and the struts 7, 8 are formed in a wedge shape in which the cross-sectional area decreases along the flow direction of the air and forward and backward. . Therefore, the cross-sectional area of the air flow path 10 defined by the side walls 4, 5, 6 and the struts 7, 8 is gradually reduced in the compression section 11 which is the first half of the stroke, and the throat section 12 having the smallest cross-sectional area is reduced. At the boundary, it is gradually expanded in the combustion part 13 in the latter half of the stroke.
Four pressure sensors 14 are attached to the side surfaces of the side walls 4, 5, and 6 on the side of the compression section 11, respectively. In the figure,
Reference numeral 15 denotes an oblique shock wave generated at the side walls 4, 5, 6 and the tips of the struts 7, 8.

As shown in FIG. 4, the cowl 9 has side walls 4,
It moves forward and backward while being guided by rails 16 arranged on the lower surfaces of the fifth and the sixth. As shown in FIG. 5 (a cross-sectional view taken along the line BB in FIG. 3), the body 1 has a servomotor 17, a ball screw shaft 19 connected to a rotation shaft 18 of the servomotor 17, and a screw shaft 19. A combined nut 20 is provided. The nut 20 is connected to the cowl 9 via a drive plate 22 that penetrates a guide groove 21 formed in the struts 7 and 8, and these constitute a cowl driving device. The servomotor 17 is connected to the control device 23 and receives power supply from the control device 23. In the state shown in FIGS. 4 and 5, the cowl 9 is in a so-called nominal position in which the front edge thereof coincides with the top a of the throat portion 12 (shown by a broken line in the drawings).

On the other hand, as shown in FIG. 5, a linear encoder 24 is provided behind the ball screw shaft 19, detects the front and rear positions of the nut 20, and sends the information as an electric signal to the controller 23. input. Further, the above-described pressure sensor 14 constantly detects the static pressure of the compression unit 8 and inputs the information to the control device 23 as an electric signal.

The operation of this embodiment will be described below.

In the engine 3, supersonic air taken into the air passage 10 from the air intake 25 at the front end thereof is subjected to dynamic pressure compression in the compression section 11, and thereafter, a fuel injection device (not shown) in the combustion section 13. And continuously burn by injecting fuel. Then, a high-temperature gas having a large energy is generated. The high-temperature gas is expanded to the atmospheric pressure to have a hypersonic speed, and is ejected from the nozzle 26 at the rear end of the engine 3.

When the combustion pressure suddenly increases during the operation of the engine 3 or the amount of air flowing from the air intake rapidly increases due to a change in the attitude of the body, as described above, the static pressure of the throat portion increases. Rises abnormally. As a result, as shown in FIGS. 6 and 7, a choke phenomenon occurs in which the air flow taken in the air flow path 10 is blocked by the throat portion 12 . At this time, the overflowing air was cowl 9
From the front, and at the same time, the static pressure in the compression part 11 also rises.

Then, in this embodiment, the static pressure in the compression section 11 of each air flow path 10 is detected by the pressure sensor 14, and the information is input to the control device 23. The pressure sensor 1
4 are provided for each one of the compression units 11, the average value of the input information is obtained in the control device 23, and the influence of partial pressure abnormality, erroneous detection of the pressure sensor 14, and the like is determined. Exclude. Next, in the control device 23, calculation of the required movement amount of the cowl 9 or search from the control map is performed according to the input static pressure value.

When the required moving amount of the cowl 9 is obtained, the control device 23 drives the servomotor 17 to move the cowl 9 backward as shown in FIG. Then cowl 9
The amount of air overflowing from the front of the vehicle increases, and as a result, the choke phenomenon is eliminated. At this time, the control device 2
In step 3, the servo motor 17 is feedback-controlled based on the information input from the linear encoder 24 so that the actual movement amount of the cowl 9 matches the required movement amount.

When the choke phenomenon is eliminated and the air again passes through the air flow path 10 at a supersonic speed, the compression unit 1
The static pressure in 1 naturally drops. When the control device 23 detects this from the information from the pressure sensor 14, it then drives the servomotor 17 in the opposite direction to the foremost position to return the cowl 9 to the original position, and restarts the engine 3. In the present embodiment, since the cowl 9 is moved by the servomotor 17, the change in the amount of air flowing into the throat section 12 is continuously changed, and the choke state can be eliminated while the internal flow of the engine is maintained in a stable state. it can.

On the other hand, when the static pressure of the throat section 12 decreases and supersonic combustion cannot be maintained, the control device 23 moves the cowl 9 in the air flow direction according to the value of the static pressure input from the pressure sensor 14. Move forward along. Then, the amount of air overflowing from the front of the cowl 9 decreases, and the throat portion 1
2, the supersonic combustion is restarted.

The inventors conducted a high-speed wind tunnel test at a speed of 4 Mach using the models shown in FIGS. 9 and 10, and determined the wall surface CP (static pressure coefficient) of the engine side wall. In these figures, 27 and 28 are side walls, and 29 is a strut for air injection. Reference numeral 30 denotes an upper plate corresponding to the lower surface of the fuselage, and reference numeral 31 denotes a cowl that moves back and forth. Air corresponding to the fuel of the actual machine is injected from the strut 29, and a simulation can be performed when the combustion pressure increases. The cowl 31 can be moved forward and backward by 20 mm from the nominal position.

As a result of the test, it was confirmed that when air was not injected from the strut 29, the engine was started without falling into a choke state even at the nominal position, as shown in FIG. In addition, when air is injected from the strut 29, as shown in FIG.
It was confirmed that the chalk state was eliminated by retreating. The distance in the flow direction in FIGS. 11 and 12 is expressed assuming that the distance from the tip of the side wall 27, 28 to the top a of the throat is 100%.

Now, the description of the specific embodiments has been completed.
Embodiments of the present invention are not limited to this embodiment. For example, the cowl driving device may be a single hydraulic cylinder, or may be configured by a combination of an electric motor and a link mechanism. Further, a simple device mainly including an amplifier may be employed as the control device, or the number of pressure sensors for one compression unit may be other than four.

[0023]

As is apparent from the above description, according to the present invention, the cowl, which is a component of the scramjet engine, can be moved back and forth, and the cowl can be moved according to the static pressure in the compression section of the air flow path. Since the engine is moved in the front-rear direction, if a choke phenomenon occurs in the engine during operation and the engine starts to run out, the cowl is retracted to increase the amount of air overflowing from the compression section. Then, the amount of air flowing into the throat portion is reduced, the static pressure in the throat portion is reduced, the choke phenomenon is eliminated, and the engine can be restarted. On the other hand, when the static pressure in the throat section decreases and supersonic combustion cannot be maintained, the cowl is advanced to reduce the amount of air overflowing from the compression section. Then, the amount of air flowing into the throat portion increases, and the static pressure in the throat portion increases, so that supersonic combustion can be restarted.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a hypersonic aircraft.

FIG. 2 is an enlarged view of a portion A in FIG.

FIG. 3 is a cross-sectional view showing one embodiment of a scramjet engine according to the present invention.

FIG. 4 is a side view of the same.

FIG. 5 is a sectional view taken along line BB in FIG. 3;

FIG. 6 is a cross-sectional view showing a choke state in the embodiment.

FIG. 7 is a side view of the same.

FIG. 8 is a side view showing an operating state of the cowl in the embodiment.

FIG. 9 is a cross-sectional view showing a model subjected to a high-speed wind tunnel test.

FIG. 10 is a side view of the same.

FIG. 11 is a graph showing the results of a high-speed wind tunnel test.

FIG. 12 is a graph showing the results of a high-speed wind tunnel test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Airframe 3 Scramjet engine 4,5,6 Side wall 7,8 Strut 9 Cowl 10 Air flow path 11 Compression part 12 Throat part 13 Combustion part 14 Pressure sensor 17 Servo motor 19 Ball screw shaft 20 Nut 23 Control device 24 Linear encoder 25 Air intake

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02K 7/14 F02C 7/04 B64D 33/02

Claims (1)

(57) [Claims] 1. A plurality of wedge-shaped erects on the surface of an aircraft body.
Side walls and the cowl mounted between the tips of these side walls
Therefore, the cross-sectional area of the air intake and the air flow path is
The compression section, which is thus reduced, and the combustion behind the compression section
A throat section with the smallest cross-sectional area defined from the section is formed
The cowl is mounted on the side wall so as to be able to move back and forth,
It is possible to control the amount of air that overflows from the air intake
Together, and the cowl driving device for longitudinal movement of the cowl, a pressure sensor for measuring the static pressure of the air in the compression section, the cowl driving instrumentation based on the detection result of said pressure sensor
A control device for controlling the operation of the device, the control device, when the static pressure in the compression unit rises,
The sky that overflows from the air intake by retracting the cowl
As the air volume increases, the static pressure in the compression section decreases
Then, move the cowl forward and from the air intake
The cowl driving device is arranged to reduce the amount of air that overflows.
Control the operation of the device.
Engine.