JP2654577B2 - Supersonic precooler for aircraft engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to supersonic disposed in front of the aircraft air-breathing engines that flies supersonic precooler aircraft engines have been made air intake Re so that .

[0002]

2. Description of the Related Art In this type of aircraft air breathing engine, the intake air can be compressed to as high a pressure as possible to improve the launch capability of the aircraft, the size can be reduced, and the intake air can be reduced. It is required to lower the temperature of the air there below the heat resistant temperature of the blade material of the axial compressor to be compressed.

[0003] As an air intake for an air breathing engine that meets such a demand, a structure disclosed in Japanese Patent Application Laid-Open No. 61-70158 is conventionally known. The air breathing engine disclosed in this publication has an air intake upstream of an axial compressor,
A plate-tube or fin-tube type air precooler using liquid hydrogen or a liquid heat source of liquid hydrogen and liquid oxygen is attached, and the air cooled to near the liquefaction temperature by this air precooler flows axially. While the pressure is increased by the compressor and introduced into the combustor, liquid hydrogen or the like heated by heat exchange in the air precooler is supplied to the preburner and burned, and downstream of the air precooler. Further, an air liquefier is provided, and a portion of the air liquefied by the air liquefier is supplied to the preburner and burned.

[0004] The conventional air breathing device having the above configuration
According to the engine, the intake air from the air intake is pre-cooled by an air precooler, or a part of the air is liquefied to lower the temperature of the air flowing into the axial compressor, thereby reducing the specific volume of air. , The required power of the compressor can be reduced, and the compression ratio can be increased to increase the thrust. In other words, the conventional air pre-cooling described above
Or air with air precooler and air liquefier
ー In the breathing engine,
Preliminary cooling of the incoming air reduces its specific volume.
The power required for the axial compressor can be reduced.
Decrease and increase the compression ratio to reduce
The thrust can be increased, and the temperature of the axial compressor can be increased.
Can be suppressed.
You.

[0005]

However, the above structure
According to Suzuki, since a plate-tube type or a fin-tube type is used as a precooler, it is not only insufficient in terms of heat exchange performance, that is, cooling performance of intake air, but also inadequate. However, when flying in a supersonic field of Mach 1 or more, it is necessary to separately arrange a supersonic diffuser that reduces the supersonic flow below the sonic speed, upstream of the supersonic diffuser. There was much room for improvement for the air breathing engine used below. In particular,
If the front opening edge of the intake body is lower than the upper front edge
Inside the air breathing engine over the front edge
Located in a plane perpendicular to the axis passing through the heart
From above the front edge of the intake body during supersonic flight
A so-called BOW shock wave is generated just before the flow,
Flow in the air flow path of the air conditioner is "unstarted"
Deceleration as a supersonic flow is possible, and the BOW shock wave
Downstream, just before the intake body or air cooler
At subsonic speeds, and
Sudden pressure drop of 1/20 and pressure of 1/20 and temperature
Degree rise occurs. The decrease in thrust and temperature due to this pressure drop
From the problem of heat resistance of the material of the air cooler due to temperature rise,
Engines with OW shock waves are usually not practical
It becomes a thing. In order to improve this,
For example, the part that reduces the supersonic air flow to the subsonic flow
Structural separation from the part that cools the subsonic airflow
It is important to compare these with simultaneous deceleration and cooling.
The engine as a whole becomes larger and heavier
Instead of cooling air with subsonic flow
Recovery is not expected and the power required for the air compressor is reduced.
Initially increasing the thrust per unit air volume by reducing
There are issues that cannot achieve the objectives of the above. These things
Are disclosed in JP-A-1-273860 and JP-A-2-115.
No. 559, discloses a supersonic air flow.
Almost the same issues exist for the cut engine air intake system.
is there.

The present invention has been made in view of the above circumstances, and when used in a supersonic field, the supersonic intake and the precooler are integrated to enable a significant reduction in the size of the equipment, and the cooling performance of the intake air. Air breathing
It is an object of the present invention to provide a supersonic precooler for an aircraft engine capable of expanding an operation range of the engine.

[0007]

In order to achieve the above object, a supersonic precooler for an aircraft engine according to the present invention is arranged in front of an air breathing engine having an axial compressor and a turbine. the intake, the intake air to a supersonic precooler for air breathing engine was made to direct to the axial compressor, and the intake body to have a supersonic diffuser inside, supersonic internal this intake body and a precooler which is incorporated integrally with the diffuser, the intake
The main body is the center of the above air breathing engine
It consists of a rectangular wind tunnel inclined with respect to the passing axis, and
The front opening edge is inclined backward from the upper front edge to the lower front edge.
And a supersonic diffuser inside.
And a subsonic diffuser, the precooler is composed of a plurality of panel-like bodies having a refrigerant flow path closely formed, and is formed by vertically forming a ventilation path between vertically adjacent panel-like bodies and vertically stacking. Characterized by being composed
It shall be the.

[0008]

According to the above construction, the air taken into the supersonic diffuser formed by the intake body flows into the ventilation passages between the vertically adjacent panel-like bodies in the precooler, and is introduced into the rear axial compressor. Is done. Here, the air taken into each ventilation path is a supersonic flow,
The shock wave generated by this supersonic flow collides with the opposing surface.
Cooling the air taken in by the pre-cooler by repeating reflection stabilizes the boundary layer, making it less likely to separate from the surface of the panel-like body, and improving the heat transfer coefficient by increasing the flow speed to increase the required heat transfer area. Can be reduced, so that the heat exchanger can be downsized. Special
According to the above configuration, the front opening edge of the intake body is
Slant backward and downward from upper front edge to lower front edge
Pressure just before the opening edge of the front end of the intake body.
BOW shock wave with extremely large loss and temperature rise is generated
To generate those small oblique shockwaves
In the uniform deceleration flow behind the oblique shock wave.
Arrange the front edge of the precooler and set the front edge of this precooler
Reduces the strength of the shock wave generated at the edge, resulting in a stronger shock than necessary
Waves collide with the panel and reflect between them
The large energy losses that accumulate when traveling
It can be effectively prevented.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of a supersonic precooler for an aircraft engine according to the present invention, and FIG.
In the figure, 1 is an air breathing engine, the air-breathing engine 1 is an axial compressor, since the tip turbine, is well known consisting comprises a combustion chamber and a nozzle, wherein, the details A detailed configuration is omitted.

Reference numeral 2 denotes an intake body which is disposed in front of the air breathing engine 1 to take in air, and guides the taken air to an axial compressor of the air breathing engine 1, which is viewed from the front. As shown in FIG. 2, four side plates 2A, 2B, 2C, 2
D are arranged in a rectangular shape and their side plates 2
The inner surfaces of A, 2B, 2C and 2D are inclined with respect to an axis a passing through the center of the air breathing engine 1;
And the front end opening edge 2E extends from the front end edge of the upper plate 2A to the lower plate 2A.
B is inclined so as to be positioned obliquely rearward and downward toward the front edge of B, and forms a supersonic diffuser 3A and a subsonic diffuser 3B therein.

4 is a supersonic precooler integrally incorporated in the supersonic diffuser 3A inside the intake main body 2,
5 is a subsonic diffuser 3 inside the intake main body 2
This is a subsonic precooler integrated into B. As shown in FIGS. 3 and 4, the supersonic precooler 4 uses LH2, which is fuel in the air breathing engine 1, as a refrigerant, and moves the LH2 refrigerant flow path 6 in a direction orthogonal to the axis a. A plurality of panel-like bodies 7 formed in a zigzag shape at a high density are arranged between the panel-like bodies 7, 7 whose front edges coincide with the front-end opening edges 2E of the intake body 2, and which are vertically adjacent to each other. Vent 8
A, 8B,... 8N are vertically stacked so as to be formed. The end and the start of the LH2 refrigerant flow path 6 of the plurality of panel-like bodies 7 constituting the supersonic precooler 4 are sequentially connected via a communication pipe 9 bent substantially in a U-shape.

The subsonic precooler 5 includes a plurality of LH2 refrigerant pipes 10 which are disposed in the subsonic diffuser 3B at appropriate intervals in the vertical and horizontal directions, respectively, and communicate with each other. For example, as shown in FIG. 6, the cross section has a low aerodynamic pressure loss with respect to the flow direction of the intake air.

Next, the operation of the supersonic precooler for an aircraft engine having the above configuration will be described. With the supersonic flight of the aircraft, air taken into the supersonic diffuser 3A inside the intake main body 2 flows into the upper and lower multi-stage air passages 8A, 8B,... 8N in the supersonic precooler 4, respectively. 8A, 8B,... 8N flows backward. Here, the shock wave SW generated at the front edge of the panel-shaped body 7 due to the supersonic flow of the intake air is transmitted to each of the ventilation paths 8.
When the light propagates backward in A, 8B,..., 8N, as shown in FIG. 5, it collides with and reflects on the opposing surfaces of the vertically adjacent panel bodies 7, 7, and propagates backward. Therefore, the air passing between the panel-shaped bodies 7 is absorbed by the LH2 refrigerant and cooled, and the specific volume is reduced. At the same time, shock wave SW
Is attenuated.

Next, in a state where the temperature is lowered and the air that has reached the subsonic range is further cooled down by heat exchange with the LH2 refrigerant flowing in the refrigerant pipe 10 of the subsonic precooler 5, and the specific volume is reduced. It will be introduced into the axial compressor of the air breathing engine 1.

As described above, the required power of the axial compressor can be reduced by reducing the specific volume due to the cooling of the intake air and the pressure loss due to the cooling, and the axial flow can be reduced by lowering the air temperature. It is possible to reduce the cost of the material without imposing excessive demands on the heat-resistant housing such as the blade material of the compressor. Also, the panel-like bodies 7A, 7B at the uppermost stream
The air flow entering the air flow path 8A between
One shock wave SWa generated at the front edge 7a of the
And the flow is reduced by the shock wave SWa.
Although the degree of the speed is small, the flow path length of the air flow path 8A is small.
Due to its long length, the reflection of the shock wave SWA in the air flow path 8A
Can be sufficiently decelerated. On the other hand, the most downstream panel
The air flow entering the air flow path 8N between 7N and 7N + 1 is
In front of all panel-like bodies 7A to 7N upstream of
N oblique shock waves SWa-S generated at edges 7a-7n
Wn, so that the air stream 8N
By the time each of the above shock waves SWa to SWn
Lowermost panel required to reach subsonic speed
Flow path length of air flow path 8N between shaped bodies 7N, 7N + 1
Can also be short as shown. Therefore, these conclusions
As a result, the exit of the supersonic precooler 4, ie, the subsonic precooler
The flow velocity at the inlet of the roller 5 is a substantially uniform subsonic flow.
Of the flow in the subsonic precooler 5
Pressure loss can be kept low.

In the above embodiment, the intake main body 2
Although the supersonic precooler 4 and the subsonic precooler 5 having different configurations are incorporated therein, the configuration of the subsonic precooler 5 is the same as that of the supersonic precooler 4.
The laminated structure of the panel-like body 7 may be used. Further, as the panel-shaped body of the present invention, in the above embodiment, the LH2 refrigerant flow path 6 is shown as being formed in a densely spaced zigzag shape in the panel-shaped body 7 made of a plate, but only the LH2 refrigerant flow path 6 is provided. May be simply formed in a zigzag shape by closely contacting each other.

[0017]

As described above, according to the present invention, a pre-cooler having a laminated structure of a panel-like body is integrally incorporated into a supersonic diffuser in an intake main body.
Since the heat transfer area can be increased by increasing the heat exchange area per unit volume and increasing the flow rate, the heat transfer coefficient can be increased. By increasing the heat transfer coefficient between the intake air and the refrigerant flowing in the refrigerant flow path formed in the panel-like body by the shock wave, the cooling performance of the intake air is improved, and the reduction rate of the specific volume of the intake air is increased. The static pressure of the flow can be significantly increased. In addition, cooling allows pressure recovery. Therefore, the required power of the compressor is reduced, and when a compressor with the same capacity as the conventional one is used, a decrease in the compressor inlet temperature and an increase in the turbine outlet temperature can be achieved at the same time. And the operating area of the air breathing engine can be expanded. Further, since the inlet temperature of the compressor can be lowered by cooling, there is an effect that the cost of the compressor blade material can be reduced. Special
According to this invention, the front opening edge of the intake body is
Slant backward and downward from upper front edge to lower front edge
Pressure loss immediately before the front edge of the intake body.
And a BOW shock wave with a very large temperature rise
To generate those small oblique shock waves.
Preforms in the uniform deceleration flow behind the oblique shock wave.
Arrange the front edge of the cooler and attach it to the front edge of this precooler.
Weaken the strength of the generated shock wave, and a stronger shock wave than necessary
Backward between panel-like bodies while colliding with and reflecting on panel-like bodies
Effectively accumulates large energy losses as it travels
Can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a supersonic precooler for an aircraft engine according to the present invention.

FIG. 2 is a front view of FIG.

FIG. 3 is a partially cutaway perspective view of an air intake with a supersonic precooler.

FIG. 4 is a vertical sectional side view of FIG. 3;

FIG. 5 is a diagram for explaining a cooling operation of a supersonic precooler.

FIG. 6 is a sectional view of a refrigerant pipe of the subsonic precooler.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Near breathing engine 2 Intake body 3A Supersonic diffuser 4 Supersonic precooler 6 LH2 refrigerant channel 7 Panel-shaped body 8A, 8B, ... 8N Vent SW SW Shock wave

Continued on the front page (72) Inventor Akira Fujimoto 1 Kawasaki-cho, Kakamigahara-shi, Gifu Prefecture Inside the Gifu Plant of Kawasaki Heavy Industries, Ltd. (72) Inventor Jun Inai 1-1, Kawasaki-cho, Akashi-shi, Hyogo Prefecture Akashi Kawasaki Heavy Industries, Ltd. Inside the plant (72) Inventor Takashi Kawashima 1-1, Kawasaki-cho, Akashi City, Hyogo Prefecture Inside the Akashi Plant of Kawasaki Heavy Industries, Ltd. (56) References JP-A-61-70158 (JP, A) JP, A) JP-A-2-115559 (JP, A)

Claims (1)

(57) [Claims] 1. A supersonic precooler for an aircraft engine arranged in front of an air breathing engine having an axial compressor and a turbine for taking air therein and directing the intake air to the axial compressor. a is, with the intake body which have a supersonic diffuser therein and a precooler which is incorporated integrally with the intake body of the supersonic diffuser, the intake body,
Axis passing through the center of the above air breathing engine
Consisting of a rectangular wind tunnel inclined with respect to the front end opening
Edge diagonally downward and backward from upper front edge to lower front edge
It is formed with an incline and has a supersonic diffuser and sub-
Constituting a sonic diffuser, the precooler is composed of a plurality of panel-like bodies having a refrigerant channel closely formed, and
Respectively form a vent path between the panel-like body adjacent to the upper and lower
Supersonic precooler for aircraft engines, characterized in that it is configured stacked vertically Te.