JP2000008955A - Turbojet engine and compound engine provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small turbojet engine with a high thrust which can increase the thrust per a unit weight as a rocket engine and a compound engine which can reduce the weight and installation volume of a propulsion system by applying the turbojet engine to the compound engine for a space craft and takeoff and landing at an airfield. SOLUTION: An air compression work is dropped extremely by cooling an inlet air by the cold of an excessive very cold fuel of a theoretical mixing ratio or more and also the entire excessive fuel is suppied to a combustor 3 and the combustion gas flow rate flowing in a turbine 4 is increased and the air compression carried out with a small turbine expansion ratio. Thereby, the pressure of exhaust gas is increased and the thrust is improved. The space between the plural outer walls of the turbo-jet engine is utilized as a ram jet engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a propulsion engine applicable to a spacecraft, a high-speed aircraft, a launch vehicle, and the like, particularly a turbojet engine capable of obtaining a high pressure thrust, and a spacecraft equipped with the turbojet engine. The present invention relates to a composite engine suitable for use in

[0002]

2. Description of the Related Art Conventionally, as a propulsion engine for a high-speed aircraft and a space shuttle, a turbojet engine (including a turbofan engine and the like, hereinafter simply referred to as a turbojet engine) and a ramjet engine (including a scramjet engine and the like) are known. (Hereinafter simply referred to as a ramjet engine), rocket engines and their derivatives, and composite types of these engines.

[0003] Of the conventional propulsion engines, only rocket engines can operate independently into outer space. However, a rocket engine has a drawback that the specific impulse is lower in the atmosphere than that of other types of engines, so that the fuel efficiency is poor and the weight of fuel and oxidizer consumed is excessive. On the other hand, a turbojet engine and a ramjet engine that operate by inhaling air in the atmosphere exhibit higher specific thrust than a rocket engine when flying in the atmosphere, but cannot be used in space. Therefore, in order to increase the average specific thrust of the entire flight area from takeoff and landing to outer space and reduce the weight of fuel and oxidizer consumed, the above-mentioned plurality of types of engines are mounted, and It is effective to operate the engines. However, if each engine is mounted as it is, the weight of the propulsion system becomes excessively large and the volume of the engine storage part increases, so that there is a problem that the mounted weight cannot be increased so much.

[0004] Therefore, a composite engine has been proposed in which a plurality of types of engine components are shared in whole or in part to prevent the propulsion system from becoming excessively heavy and increasing in volume. Conventionally proposed composite engines include, for example, a turbojet ramjet rocket propulsion in which a rocket engine is arranged in a central fuselage, and an annular airflow pipe around the rocket engine is used as a turbojet engine and a ramjet engine. A combined engine (US Pat. No. 5,052,176) or a multi-function scramjet engine in which a rocket engine function is added to a scramjet engine so that the scramjet engine can be used during takeoff and flight outside the atmosphere (Japanese Patent Laid-Open No. 7-4314).
Or a combination of two types of engines, an air liquefied rocket engine (LACE) and a scramjet engine (JP-A-7-34969).

On the other hand, a turbojet engine is known as a high-speed propulsion engine up to about Mach 4 in the atmosphere. A conventional turbojet engine has a higher specific impulse than a rocket engine, but has a higher operating pressure. To get the same thrust as a high-pressure rocket engine because it is low,
It is necessary to increase the size of the engine itself, the weight of the propulsion system becomes excessive, and it is difficult to apply it to a high-speed aircraft requiring high thrust.

[0006]

The composite engine for a spacecraft which has been proposed so far has a function of switching between turbojet propulsion, ramjet propulsion and rocket propulsion in each speed range and altitude range. As a propulsion system in a low speed range up to about Mach 4, either a rocket engine or a turbojet engine is used. However, in the case of a rocket engine, as described above, it operates at a lower specific thrust in the atmosphere than in other types of engines, resulting in poor fuel efficiency, excessive consumption of fuel and oxidizer, and an excessively large loading weight. There is a problem that it cannot be increased. In addition, for rocket engines,
There is a problem that take-off and landing at an airfield is difficult because the distance at which low-speed power flight is possible during take-off and landing is short, which is not desirable when manned flight is considered. On the other hand, a turbojet engine has a low operating pressure, so a large and heavy engine is required to generate thrust equivalent to a high-pressure rocket engine, and the weight and surface area of a combined engine are increased. There is a point.

SUMMARY OF THE INVENTION Accordingly, a first object of the present invention is to obtain a small, high-thrust turbojet engine by increasing the thrust per unit weight of a turbojet engine to the same level as a rocket engine. High thrust turbojet engine applied to space propulsion complex propulsion engines to increase the average specific thrust of the entire flight area, thereby reducing the weight and installation volume of the propulsion system and increasing the installed weight It is a second object of the present invention to obtain a combined engine suitable for a spacecraft capable of taking off and landing at an airfield.

[0008]

According to the present invention, in order to increase the thrust per unit weight of a turbojet engine to the same level as a rocket engine, an excessive amount of cryogenic fuel having a stoichiometric mixture ratio or more is supplied to air. By performing inlet air cooling using the cold heat of the fuel, the air compression work is greatly reduced, and the excess gas is supplied to the combustor to increase the flow rate of the combustion gas flowing into the turbine. By performing the air compression by the above, the pressure of the exhaust gas is improved, and a high-thrust turbojet engine can be obtained.

That is, a turbojet engine according to the present invention which solves the above-mentioned problems has an inlet air cooler for cooling air flowing into a compressor by the cold heat of cryogenic fuel supplied from a fuel tank, and the inlet air cooler. A fuel line for supplying the cryogenic fuel used for the compressor to the combustor, cooling the air flowing into the compressor by the inlet air cooler, and supplying the cryogenic fuel used for the inlet cooler to the combustor. To increase the flow rate of the combustion gas flowing into the turbine and perform air compression at a small turbine expansion ratio, thereby increasing the pressure of the exhaust gas to improve the thrust.

An oxidant injector for injecting oxidant into exhaust gas flowing out of the turbine is provided. An excessive cryogenic fuel having a stoichiometric ratio or more is supplied to the inlet air cooler, and the excess fuel is combusted. A high-pressure thrust similar to that of a rocket engine can be obtained by supplying an oxidizing agent to the exhaust gas with excess fuel at a high pressure obtained by supplying the fuel to the exhaust gas and burning the exhaust gas in an exhaust duct. On the other hand, by supplying a fuel having a stoichiometric mixture ratio or less to the inlet cooler and supplying a lean fuel having a stoichiometric mixture ratio or less to the combustor and burning it, it is possible to operate with a high specific thrust. A shut-off valve for preventing backflow of the combustion gas is provided at the inlet of the combustor, and the shut-off valve shuts off the combustor inlet to supply fuel and oxidant to the exhaust duct portion, so that the exhaust duct portion has a high pressure. It can be operated as a rocket engine for propulsion, and a turbojet engine having a rocket engine function can be obtained.

In order to realize the operation of a plurality of types of engines having a high specific thrust with a minimum increase in weight, the composite engine for a spacecraft of the present invention is provided with a plurality of high thrust turbojet engines which are also used as the rocket engine. By adopting and operating the space between the turbojet engines as a ramjet engine, it is possible to reduce the weight and surface area of the propulsion system per unit thrust and enable powered flight on the runway during takeoff and landing. It was done.

That is, the spacecraft composite engine of the present invention comprises at least an intake switching door, an inlet air cooler,
A plurality of turbojet engines each including a compressor, a shutoff valve, a combustor, a turbine, an oxidizer injector, an exhaust duct, and a nozzle switching door are arranged at intervals, and a ramjet is provided between outer walls of the turbojet engine. A ramjet engine is formed in the space between the outer walls by providing a fuel injector, controls opening and closing of the intake switching door, the nozzle switching door, and the shutoff valve, and the combustor or the ramjet fuel injector By controlling the fuel supply to the oxidizer and the oxidizer to the oxidizer injector to switch to any one of turbojet propulsion, ramjet propulsion, and rocket propulsion. It is.

[0013] The turbojet propulsion mechanism is configured to supply a fuel having a stoichiometric ratio or less to the combustor and burn it to obtain a high specific thrust, and to supply a high pressure excess exhaust gas to the exhaust duct portion at a high pressure. It is possible to switch to a mechanism for supplying high-pressure propulsion by supplying and burning the oxidant by the oxidant injector.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows an embodiment of a turbojet engine of the present invention, and FIG. 2 shows an engine system diagram thereof. In the figure, 1 is an inlet air cooler, 2 is a compressor, 3 is a combustor, 4 is a turbine, 5 is an oxidizer injector, 6 is an exhaust duct, 7 is an intake switching door, 9 is a shutoff valve, and 10 is a nozzle. It is a switching door. The intake switching door 7 can switch the air intake between an open state and a closed state, and can be opened to an open position where the engine performance is optimal according to the flight state. Similarly, the nozzle switching door 10 can also open and close the nozzle of the exhaust gas from the exhaust duct 6 to an open position where the engine performance is optimal according to the flight mode, according to the flight status. I have. The exhaust duct 6 is designed for high pressure so that the exhaust duct part can be operated as a rocket engine.

In the turbojet engine shown in FIG. 1, the exhaust duct portion is made to function as a rocket engine so that it can also be used as a rocket engine. When used only as a jet engine and a high-thrust turbojet engine, the shut-off valve 9 is unnecessary.

In the turbo-jet engine system diagram shown in FIG. 2, solid arrows indicate the direction of air flow or exhaust gas flow.
Dashed arrows indicate the flow of fuel or oxidant. As shown in the engine system diagram of FIG. 2, the turbojet engine supplies an inlet air cooler 1 from a fuel tank 20 filled with a cryogenic fuel (for example, liquid hydrogen) by a fuel pump 21 to the inlet air cooler 1. All of the fuel circulated through the cooler 1 is supplied to the combustor 3 via the line 28. When the turbojet engine is operated at a high thrust or as a rocket engine, the oxidant tank 30 storing the oxidant (for example, liquid oxygen) is supplied from the oxidant tank 30 by the oxidant pump 31 to the inlet side of the exhaust duct 6. The oxidizing agent is supplied to the oxidizing agent injector 5 provided in the above.

The turbojet engine according to the present embodiment is configured as described above. When the turbojet engine is operated as a turbojet engine, the intake switching door 7 and the nozzle switching door 10 are located at positions where the engine performance is optimized in accordance with the flight condition. Keep it open. In the operating state of the turbojet engine, excess cryogenic fuel exceeding the stoichiometric ratio with respect to air is supplied from the fuel tank to the inlet air cooler 1, and the air is cooled by the cold heat of the cryogenic fuel. By cooling the inflowing air, the air compression work in the compressor 2 is greatly reduced, and the density of the air is increased, so that a large weight of air can be supplied to the compressor 2 of the same size. The efficiency and operating performance of the gas turbine can be improved. In addition, the excess cryogenic fuel used for cooling the air is all supplied to the combustor 3 through the pipe 28 to increase the flow rate of the combustion gas flowing into the turbine 4. Then, even with a small turbine expansion ratio, sufficient power can be taken to perform air compression. Thereby, the pressure of the exhaust gas in the exhaust duct 6 increases, and the thrust of the turbojet engine can be improved in addition to the effect of increasing the air flow rate.

At that time, since the exhaust duct 6 is supplied with exhaust gas at a high pressure and excess fuel, the oxidant is supplied from the oxidant tank 30 through the oxidant injector 5 and burned. The same operation as a high-pressure rocket engine can be performed. As a result, the thrust per unit weight of the propulsion system can be significantly improved, and the size of the engine can be reduced. In addition, a turbojet engine that can be adopted as a high-speed aircraft engine up to about Mach 6 is obtained. In the case of low-speed power flight during takeoff and landing, fuel having a stoichiometric ratio or less should be supplied to the inlet air cooler 1.
By supplying the fuel to the combustor 3 and burning it, it is possible to operate with a high specific thrust. At this time, no oxidant is supplied to the exhaust duct.

When the turbojet engine is operated as a rocket engine, the shut-off valve 9 provided at the inlet of the combustor 3 is closed to prevent the combustion gas from flowing back. Fuel is supplied to the combustor 3, passes through the turbine 4, and is supplied to the exhaust duct 6, similarly to the turbojet engine. The oxidant is supplied to the exhaust duct 6 through the oxidant injector 5. At that time, the intake switching door 7 closes to the turbojet engine side, and the nozzle switching door 10 opens to discharge the combustion gas of the rocket engine.

Next, a description will be given of an embodiment of a space shuttle composite engine constituted by employing the turbojet engine constituted as described above with reference to FIG. FIG. 3 is a conceptual diagram of a spacecraft composite engine as a propulsion system of the spacecraft 13. The space shuttle composite engine of the present invention can reduce the size of the turbojet engine combined with the rocket engine as described above, so that the space between the outer walls of a plurality of turbojet engines can be used as a ramjet engine, and By increasing the average specific thrust of the entire flight area, the propulsion system could be made smaller and the surface area reduced. In the example shown in FIG. 3, the turbojet engine 14 based on the same principle shown in the above embodiment is arranged as a set of two vertically arranged engines,
As shown in the figure, five sets are arranged at intervals in the horizontal direction.
The laterally spaced spaces 16 constitute a ramjet engine 15. Note that, in the figure, the same members as those of the turbojet engine shown in FIG.
The same reference numerals are given and the detailed description is omitted.

Next, the main part of the composite engine for spacecraft shown above will be described in detail with reference to FIGS. 4 shows the operating state of the turbojet engine, FIG. 5 shows the operating state of the ramjet engine (the virtual line indicates the operating state of the turbojet engine), and FIG. 6 shows the operating state of the rocket engine. The main part of the composite engine for spacecraft differs from the turbojet engine of FIG. 1 in that it has a fuel injection for ramjet.

FIG. 4 is a schematic diagram showing the fuel and oxidizer system of the above-mentioned combined engine. The fuel and oxidizer system is moved to a predetermined position by a fuel pump 21 from a fuel tank 20 filled with cryogenic fuel (liquid hydrogen). Supply a flow of fuel. In the present embodiment, the first to third 3
The fuel lines are branched into two fuel lines 22 to 24, and valves 24 to 26 are provided respectively, so that the fuel lines can be switched and controlled according to the flight state. The first fuel line 22 is
A pipe is supplied from the pump 21 to the inlet air cooler 1 and supplies all the fuel circulated through the inlet air cooler 1 to the combustor 3. The second fuel line 23 is a line that supplies fuel directly from the pump to the ramjet fuel injector 8. The third fuel line 24 is a line for supplying fuel directly from the pump to the fuel injector of the combustor 3. In addition,
In this embodiment, when operating the rocket propulsion mechanism, only the valve 27 is opened to supply the fuel directly to the combustor through the third fuel line, but without providing the third fuel line, When operating the rocket propulsion mechanism, fuel may be supplied to the combustor through the first fuel line. Although not shown, the pump and each valve are controlled by a fuel control unit, and the fuel flow and the opening / closing control of the valve are performed by the pump according to the respective flight conditions.

The oxidizing agent system includes an oxidizing agent (for example, liquid oxygen).
From the oxidizer tank 30 where the oxidizer pump 30 is stored.
1. The oxidizing agent is supplied to the oxidizing agent injector 5 provided on the exhaust duct inlet side via the oxidizing agent line 33 via the valve 32. The oxidizer is supplied to the oxidizer injector during high thrust flight by the turbojet propulsion mechanism and when the rocket engine mechanism is operating.

The spacecraft composite engine according to the present embodiment is constructed as described above, and is operated by a turbojet engine from the start until it reaches approximately Mach 6, and the scramjet is operated between approximately Mach 6 and 12. When the engine is in operation, it flies with a rocket operating in Mach 12 or higher and in space. When operating as a turbojet engine, the intake switching door 7 and the nozzle switching door 10 are opened at positions where the engine performance is optimal according to the flight conditions. At this time, the ram jet fuel injector 8
Is not used, the shut-off valve 9 is opened to allow the intake air to pass, and turbojet propulsion is performed in the same manner as described above.

As the flight speed increases, the specific impulse of the ramjet engine becomes higher than that of the turbojet engine. Therefore, in the present embodiment, Mach 6 to Mach 12
In the speed range, the ramjet engine is switched to the operating state. At this time, as shown in FIG. 2, the intake switching door 7 and the nozzle switching door 10 are closed on the turbojet engine side, and only the valve 26 is opened. Thereby, fuel is injected from the ramjet fuel injector 8 provided in the space between the outer walls of the plurality of turbojet engines, and the space is used as a ramjet engine.

Further, when flying in space without air, the state is switched to the rocket engine operating state. In the rocket engine operating state, as shown in FIG. 6, the intake switching door 7 is closed to the turbojet engine side, the nozzle switching door 10 is opened to discharge the combustion gas of the rocket engine, and is provided at the inlet of the combustor. The closing valve 9 is closed to prevent the combustion gas from flowing back. In the fuel system, the valves 25 and 26 are closed, the valve 27 is opened to supply fuel to the combustor, and the oxidizer is injected from the oxidizer tank 30 to the exhaust duct by the oxidizer injector to form a high-pressure rocket engine. Operate.

[0027]

As described above, the turbojet engine of the present invention can increase the thrust per unit weight to the same level as a rocket engine, and can reduce the size and obtain high thrust. Therefore, the turbojet engine of the present invention and the combined engine employing the same are:
It can exhibit good specific thrust from the ground to outer space without a large increase in weight. Therefore, by employing the engine of the present invention for a spacecraft, a high-speed aircraft, a launch vehicle, and the like, the mounting weight can be increased as compared with the conventional case.

In addition, when performing low-speed power flight during takeoff and landing, since high specific thrust can be operated, safe manned flight can be realized in a space shuttle vehicle or the like.

[Brief description of the drawings]

FIG. 1 is a conceptual sectional view of a turbojet engine according to an embodiment of the present invention.

FIG. 2 is an engine system diagram.

FIG. 3 is a conceptual perspective view of a composite engine for a spacecraft.

FIG. 4 is a conceptual cross-sectional view of a main part when a turbojet engine is propelled.

FIG. 5 is a conceptual sectional view of a main part when the ramjet engine is propelled.

FIG. 6 is a conceptual cross-sectional view of a main part when the rocket engine is propelled.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Inlet air cooler 2 Compressor 3 Combustor 4 Turbine 5 Oxidizer injector 6 Exhaust duct 7 Intake switching door 8 Fuel injector for ramjet 9 Shutoff valve 10 Nozzle switching door 13 Space shuttle 14 Turbojet engine 15 Ramjet Engine 16 Space 20 Fuel tank 21 Fuel pump 22 to 24, 28, 33 Pipeline 25 to 27, 32 Valve 30 Oxidant tank 31 Oxidant pump

[Procedure amendment]

[Submission date] May 24, 1999 (1999.5.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

2. A turbojet engine comprising at least a plurality of intake switching doors, an inlet air cooler, a compressor, a shutoff valve, a combustor, a turbine, an oxidizer injector, an exhaust duct, and a nozzle switching door. And a ramjet engine is formed in the space between the outer walls by providing a ramjet fuel injector between outer walls of the turbojet engine, and the intake switching door, the nozzle switching door, and the shutoff valve are provided. Propulsion of turbojet propulsion, ramjet propulsion or rocket propulsion by controlling opening / closing and controlling fuel supply to the combustor or ramjet fuel injector and oxidant supply to the oxidant injector A composite engine characterized by being switchable to a mechanism.

3. The turbojet propulsion mechanism supplies a fuel having a stoichiometric ratio or less to the combustor and burns the combustor to obtain a high specific thrust. 6. The combined engine according to claim 5, wherein the combined engine is switchable to a mechanism that obtains high-pressure propulsion by supplying gas and supplying oxidant by the oxidant injector and burning the oxidant.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

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[0008]

According to the present invention, in order to increase the thrust per unit weight of a turbojet engine to the same level as a rocket engine, an excessive amount of cryogenic fuel having a stoichiometric mixture ratio or more is supplied to air. By performing inlet air cooling using the cold heat of the fuel, the air compression work is greatly reduced, and the excess gas is supplied to the combustor to increase the flow rate of the combustion gas flowing into the turbine. By performing the air compression, the pressure of the exhaust gas was improved, and a high-thrust turbojet engine was obtained . That is, the turbo of the present invention
The jet engine converts the air flowing into the compressor into a fuel tank.
Inlet cooled by the cryogenic fuel supplied from
The air cooler cools the cryogenic fuel used for the inlet air cooler.
A fuel line for supplying to the kiln;
Cooling the air flowing into the compressor and
The cryogenic fuel used for the mouth cooler is supplied to the combustor,
Increases the flow of combustion gas into the bin and reduces
By compressing air at the expansion ratio, the pressure of exhaust gas
To increase thrust.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

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The exhaust gas flowing out of the turbine is oxidized.
An oxidant injector for injecting an agent, wherein the inlet air cooler
To the cryogenic fuel in excess of the theoretical mixing ratio.
High pressure obtained by supplying the fuel to the combustor
Supply oxidant to exhaust gas with excess fuel
Combustion inside the rocket makes it as high as a rocket engine.
Pressure thrust can be obtained. Meanwhile, the inlet cooler
To the stoichiometric mixture, and supply
By supplying the lean fuel below to the combustor and burning it,
It can be operated with specific thrust. And the air intake
Can be switched between open and closed states, and
An opening that can be opened to the open position for optimal gin performance
Work door and exhaust gas nozzle from the exhaust duct.
Optimum engine performance depending on opening / closing switching and flight conditions
Nozzle switching door that can be opened to the open position
And a shut-off valve at the inlet of the combustor for preventing backflow of the combustion gas.
And shut off the combustor inlet with the shut-off valve to oxidize fuel and fuel.
By supplying the agent to the exhaust duct, the exhaust duct
To operate as a high-pressure propelled rocket engine
Turbojet with rocket engine function
You can get an engine.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

That is, the present invention solves the above problems.
Bodget engine with at least air intake open
Switchable to closed and engine performance depending on flight status
Switching that can be opened to the optimal open position
Doors, compressors, and air flowing into the compressors
Air cooled by the cryogenic fuel supplied from
Cryogenic cooler, combustor, cryogenic fuel used for the inlet air cooler
Fuel line for supplying fuel to the combustor, the combustion in a closed state
Shut-off valve, turbine, acid to prevent backflow of combustion gas
Agent injector, exhaust duct, exhaust gas from the exhaust duct
Switching the nozzles between open and closed and engine performance according to flight conditions
Nozzle switching door that can be opened to the optimal open position
The intake switching door and the nozzle switching door
A) controlling the oxidizer injector and the shut-off valve;
High thrust turbojet engine or high pressure location
That the engine can be switched
It is a feature.

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

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FIG.

[Procedure amendment 6]

[Document name to be amended] Drawing

[Correction target item name] Fig. 4

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FIG. 4

[Procedure amendment 7]

[Document name to be amended] Drawing

[Correction target item name] Fig. 6

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FIG. 6 ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 16, 1999 (1999.8.1
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

Claims (6)

[Claims] In a turbojet engine, an inlet air cooler for cooling air flowing into a compressor by the cold heat of a cryogenic fuel supplied from a fuel tank, and a cryogenic fuel used for the inlet air cooler is combusted by a combustor. A fuel line is provided for supplying air to the compressor, the inlet air cooler cools the air flowing into the compressor, and the cryogenic fuel used for the inlet cooler is supplied to the combustor and flows into the turbine. A turbojet engine characterized by increasing the flow rate of combustion gas and performing air compression at a small turbine expansion ratio to increase the pressure of exhaust gas to improve thrust. 2. An oxidant injector for injecting oxidant into exhaust gas flowing out of the turbine is provided, and an excessive cryogenic fuel having a stoichiometric ratio or more is supplied to the inlet air cooler. A high thrust similar to that of a rocket engine can be obtained by supplying an oxidizing agent to the exhaust gas that is excessively fueled at a high pressure obtained by supplying it to the combustor and burning it in the exhaust duct. The turbojet engine according to claim 1. 3. A high specific thrust operation by supplying a fuel having a stoichiometric ratio or less to the inlet cooler and supplying and burning a lean fuel having a stoichiometric ratio or less to the combustor. The turbojet engine according to claim 1, wherein: 4. A shut-off valve for preventing backflow of combustion gas is provided at the inlet of the combustor, and the shut-off valve shuts off the combustor inlet to supply fuel and oxidant to an exhaust duct, thereby providing a high pressure Claim 1 which can operate as a rocket engine.
The turbojet engine described. 5. A turbo-jet engine comprising at least a plurality of intake switching doors, an inlet air cooler, a compressor, a shutoff valve, a combustor, a turbine, an oxidizer injector, an exhaust duct, and a nozzle switching door. And a ramjet engine is formed in the space between the outer walls by providing a ramjet fuel injector between outer walls of the turbojet engine, and the intake switching door, the nozzle switching door, and the shutoff valve are provided. Propulsion of turbojet propulsion, ramjet propulsion or rocket propulsion by controlling opening / closing and controlling fuel supply to the combustor or ramjet fuel injector and oxidant supply to the oxidant injector A composite engine characterized by being switchable to a mechanism. 6. The turbojet propulsion mechanism supplies a fuel having a stoichiometric ratio or less to the combustor and burns the fuel to obtain a high specific thrust. 6. The combined engine according to claim 5, wherein the combined engine is switchable to a mechanism that obtains high-pressure propulsion by supplying gas and supplying oxidant by the oxidant injector and burning the oxidant.