JPH05256195A - Ram jet engine - Google Patents

Abstract

PURPOSE:To stabilize an intake efficiency on an orbit in a ram jet engine launched especially into the upper atmosphere. CONSTITUTION:A pointed center body 3 is provided at the head part inner side of an outer cylinder 2 forming a combustion chamber 1, and an air intake 4 is formed between the outer cylinder 2 and the center body 3. The head part of this center body is covered with ablating material 9, and the ablating material 9 is fused and evaporated by aerodynamic heating so as to gradually enlarge the opening area of the air intake 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a ramjet engine, and more particularly to a ramjet engine which is launched and used in the upper atmosphere.

[0002]

2. Description of the Related Art A ramjet engine, as shown in FIG. 3, accommodates a central body 102 inside the head portion of an outer cylinder 101, and an air intake port 1 is provided between the outer cylinder 101 and the central body 102.
03 and diffuser 104 to form the central body 1
A combustion chamber 105 is provided behind the tail of 02, and the outer cylinder 1
A jet nozzle 106 is provided at the tail of 01.

Such a ramjet engine is described, for example, on pages 608 and 609 of "Aerospace Engineering Handbook / Supplementary Edition" issued by Maruzen in April 1983.

[0004]

By the way, in recent years,
It is considered to apply a ramjet engine to a projectile launched into the upper atmosphere. In this case, the ramjet engine is accelerated by a booster such as a solid rocket and starts operating.

However, in the above-described ramjet engine, the outer cylinder 101, the central body 102, and the air intake 103 formed by them have the same shape and size, and are optimal at a predetermined altitude and speed. It is designed to obtain air intake efficiency.

For this reason, assuming that the above ramjet is launched into the upper atmosphere, the air density in the orbit is drastically reduced along with the abrupt increase in altitude, and the air intake efficiency is reduced. Therefore, it was necessary to improve such aspects.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and is intended especially for a ramjet engine launched into the upper atmosphere, and is capable of always maintaining an optimum air intake efficiency. The purpose is to provide a ramjet engine that can.

[0008]

According to a first aspect of the present invention, there is provided a ramjet engine in which a pointed central body is provided inside a head of an outer cylinder forming a combustion chamber. The air intake is formed between the head and the body, and the head of the central body is covered with an ablation material in a cusp shape. Further, according to claim 2, inside the head of the outer cylinder forming the combustion chamber. With a pointed central body, an air intake is formed between the outer cylinder and the central body, and a drive mechanism for moving the head of the central body forward and backward in the machine axis direction is provided. The structure is used as a means for solving the problem.

[0009]

In the ramjet engine according to the present invention, the ablation material covering the head of the central body is sublimated by aerodynamic heating on the orbit after the launch, whereby the outer cylinder and the pointed center are formed. The opening area of the air intake formed with the body will be gradually expanded, or the opening area of the air intake will be gradually expanded by retracting the head of the central body by the drive mechanism. Maintain good air intake efficiency while rising in the upper atmosphere.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining an embodiment according to claim 1 of the present invention.

The ramjet engine R1 is provided with a sharpened central body 3 inside the outer cylinder 2 forming the combustion chamber 1, and between the outer cylinder 2 and the central body 3. It has a structure in which the air intake port 4 and the diffuser 5 are formed. Further, a jet nozzle 6 is provided at the tail of the outer cylinder 2.

The central body 3 is provided with a fuel tank, a fuel injection device (not shown) and the like, as well as a payload mounting portion 7, and a conical portion 8 forming a pointed head thereof. Are abruptly covered with the ablation material 9.

The central body 3 in this embodiment has a conical portion 8
The outer wall of the payload mounting portion 7 and the like are formed of, for example, carbon fiber reinforced plastic. The ablation material 9 is formed of an inner layer 10 made of silica and an outer layer 11 made of alumina, which has a high erosion rate. In this case, the inner layer 10 is the outer layer 11
The erosion rate is higher than that.

A ramjet engine R having the above structure
1 starts and accelerates with a solid propellant loaded in the combustion chamber 1 or a rocket motor or the like connected to the tail of the outer cylinder 2 as a booster, and starts operating when a predetermined speed is reached.

That is, the above ramjet engine R1
Is decelerated and compressed by the diffuser 5 the air taken in from the air intake 4 and introduced into the combustion chamber 1, fuel is injected into the air and continuously burned, and combustion gas is ejected from the jet nozzle 6. Continue to fly by.

Here, when the ramjet engine R1 is launched into the upper atmosphere, the ambient air density is significantly reduced as the altitude is rapidly increased.

Therefore, in the ramjet engine R1, the ablation material 9 covering the head portion (conical portion 8) of the central body 3 is gradually sublimated by aerodynamic heating on the orbit, so that the outer cylinder 2 and The opening area of the air intake port 4 formed between the pointed central body 3 and the apex-shaped central body 3 is gradually enlarged.
Has a higher erosion rate than the outer layer 11, the degree of expansion of the opening area is further increased when the outer layer 11 is completely sublimated, and a good air intake rate with respect to a significant decrease in air density due to the rise. Will be maintained.

Further, the ramjet engine R1 is
With the sublimation of the ablation material 9, the angle of the head of the central body 3 decreases, and the angle of the shock wave generated from the tip of the head can be changed corresponding to the acceleration.

FIG. 2 is a diagram for explaining an embodiment according to claim 2 of the present invention. The same components as those in the previous embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The central body 23 of the ramjet engine R2 is divided into a main body portion 21 for accommodating a fuel tank and the like, and a conical portion 28 forming a pointed head portion and having a payload mounting portion 27 inside. There is.

The conical portion 28 is slidably connected to the head portion of the main body portion 21 in the machine axis direction, and forms a storage space 22 between itself and the main body portion 21. A hydraulic cylinder 31, a hydraulic drive source 32, and the like that connect the main body portion 21 and the conical portion 28 are stored in the storage space 22,
These constitute a drive mechanism 29 for moving the head portion (conical portion 28) of the central body 23 back and forth in the machine axis direction.

A ramjet engine R having the above structure
2 is launched by a booster as in the previous embodiment, and on its orbit, the conical portion 28 is gradually retracted by contracting the hydraulic cylinder 31 of the drive mechanism 29, and the opening of the air intake 3 is opened. The area will be gradually increased to maintain good air intake efficiency.

The drive mechanism 29 uses data of an altimeter and a speedometer mounted on the ramjet engine R2,
And based on pre-programmed data,
It is also possible to advance the conical portion 28 to control the opening area described above.

[0024]

As described above, according to the ramjet engine of the present invention, particularly when it is used for a projectile launched into the upper atmosphere, in response to a remarkable decrease in the ambient air density on the orbit, It can maintain optimum air intake efficiency at all times and maintain stable combustion.For example, compared to a ramjet engine with a fixed center body, stable operation is performed even at high altitude, The effect that the payload weight can be increased is brought about.

[Brief description of drawings]

FIG. 1 is a sectional view with an enlarged head view for explaining an embodiment of a ramjet engine according to claim 1 of the present invention.

FIG. 2 is a sectional view with an enlarged head view for explaining an embodiment of a ramjet engine according to claim 2 of the present invention.

FIG. 3 is a sectional view illustrating a conventional ramjet engine.

[Explanation of symbols]

 R1, R2 Ramjet engine 1 Combustion chamber 2 Outer cylinder 3 23 Central body 4 Air intake 19 Ablation material 29 Drive mechanism

Claims (2)

[Claims] 1. A head part of the central body, which comprises a pointed central body inside the head part of the outer cylinder forming the combustion chamber and forms an air intake between the outer cylinder and the central body. A ramjet engine in which the ablation material is coated in a pointed shape. 2. The head of the central body is provided with a pointed central body inside the head of the outer cylinder that forms the combustion chamber, and forms an air intake port between the outer cylinder and the central body. A ramjet engine, which is provided with a drive mechanism for advancing and retracting the vehicle in the axial direction.