JPH1182173A - Ejector rocket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase thrust by inflow air at low speed and low altitude and obtain high propulsion efficiency by a appropriate expansion of combustion gas in a vacuum. SOLUTION: An ejector rocket is composed of an expansion nozzle 14 for expanding combustion gas, a duct 15 connected to the base end part of the expansion nozzle 14, a combustion chamber 16 arranged in ring shape on the lower reaches of the duct 15 so as to surround the duct 15, and an ejector nozzle 17 provided at an outlet of the combustion chamber 16 so as to inject combustion gas in a direction along the wall surface of the expansion nozzle 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine incorporated in a rocket launched from the atmosphere into space.

[0002]

2. Description of the Related Art A liquid rocket launched into the space from the atmosphere incorporates a liquid rocket engine using a liquid propellant, so it is suitable for high-precision guidance control and is capable of continuous combustion for a long time. However, it requires the installation of an oxidizer along with fuel, and is less fuel efficient in the atmosphere than a jet engine. In order to improve fuel economy, several spacecraft equipped with a combined engine combining a jet engine and a rocket engine have been proposed (for example, see Japanese Patent Application Laid-Open No. 7-34969).

[0003] In the spacecraft equipped with the above-described composite engine, flight in a vacuum uses a rocket engine, and flight in the atmosphere uses a jet engine or directly liquefies the atmosphere to extract liquid oxygen. They are trying to improve fuel efficiency by using this as an oxidant for rockets.

Further, in a rocket engine, a reduction in efficiency due to overexpansion under a high atmospheric pressure state or insufficient expansion in a vacuum is inevitable. In order to prevent this reduction in efficiency, an extension nozzle as shown in FIG. 5 is used.

The extension nozzle 6 has an extendable outlet cone 6a. In a low air with high pressure, as shown in FIG. 5 (a), the outlet cone 6a is housed in a compact manner, and a low pressure high altitude is formed. In a vacuum, the outlet cone portion 6a is extended as shown in FIG. 5 (b) to prevent overexpansion or insufficient expansion.

[0006]

However, a combined engine, which is a combination of a jet engine and a rocket engine employed to improve fuel efficiency, has a separate engine for each flight speed or flight altitude, so the mechanism is It is complex and heavy, and has not been put to practical use due to technical difficulties.

[0007] In the extension nozzle, the efficiency can be improved in accordance with the use conditions by changing the length of the skirt depending on the speed. However, there is a problem that the mechanism becomes complicated and the weight increases. is there.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has been developed to improve fuel economy during flight in the atmosphere and to provide a fixed nozzle which does not change the length of the nozzle due to external atmospheric pressure. It is an object of the present invention to provide a rocket engine capable of achieving the same effect as that of a rocket.

[0009]

The ejector rocket according to the present invention is provided with a duct for introducing air upstream of an expansion nozzle for expanding combustion gas, and has a ring shape surrounding the duct near a junction between the expansion nozzle and the duct. A combustion gas ejector nozzle is provided at the outlet of the combustion chamber, and the combustion gas generated in the combustion chamber is injected through the combustion gas ejector nozzle in the direction along the wall surface of the expansion nozzle, thereby reducing the speed and speed. It is possible to increase the thrust and the fuel efficiency by the inflow air at an altitude, and to obtain high propulsion efficiency and the fuel efficiency by appropriate expansion of the combustion gas in a vacuum.

Further, in the ejector rocket of the present invention, by providing the fuel ejection nozzle upstream of the ring-shaped combustion chamber of the duct, fuel is ejected upstream of the primary gas coming out of the ejector nozzle, and this fuel flows in. By burning with oxygen in the atmosphere, this fuel can be burned without an oxidizing agent, and the fuel efficiency can be improved.

In the ejector rocket of the present invention, an opening / closing mechanism is provided at the entrance of the duct, and the duct is closed by the opening / closing mechanism in a vacuum.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a spacecraft according to the present invention.
The spacecraft 10 has a fuselage 11, an engine 12 provided below the rear of the fuselage 11, and a liquid hydrogen storage tank 13 provided inside the fuselage 11.

The engine 12 is, as shown in FIG.
An expansion nozzle 14 for expanding combustion gas, and a duct 15 for introducing air connected to a base end of the expansion nozzle 14
A combustion chamber 16 arranged in a ring shape so as to surround the duct 15 near a joint between the expansion nozzle 14 and the duct 15;
An ejector nozzle 17 is provided at an outlet of the combustion chamber 16 and injects combustion gas generated in the combustion chamber 16 in a direction along a wall surface of the expansion nozzle.

The expansion nozzle 14 has a conical shape or an inner diameter such that the combustion gas does not overexpand on the ground, an air flow path is formed in the center at a low altitude, and the combustion gas does not underexpand in a vacuum. It has a bell shape. The combustion chamber 16 is provided with a fuel supply port 18 connected to a fuel tank (not shown) and an oxidant supply port 19 connected to an oxidant tank (not shown).

On the other hand, a fuel injection nozzle 20 is provided upstream of the combustion chamber 16 of the duct 15 of the engine 12,
An opening and closing mechanism 21 as shown in FIG.
Is provided. When the atmospheric pressure decreases, the opening / closing mechanism 21 moves to the position 20a and closes the duct 15, whereby the opening / closing mechanism 21 can receive the pressure of the nozzle.

Next, the operation will be described. When the rocket is launched at a low speed and a high atmospheric pressure, the combustion gas generated in the combustion chamber 16 is ejected by the ejector nozzle 1 as shown in FIG.
7, the fuel is injected in a direction along the wall surface 14 a of the expansion nozzle 14. The combustion gas to be injected realizes a flow along the wall surface 14a of the expansion nozzle 14 due to the Coanda effect and flows without being separated from the wall surface 14a of the expansion nozzle 14, so that the combustion gas to be injected is excessively expanded in the expansion nozzle 14. Never.

Since the opening / closing mechanism 21 provided at the entrance of the duct 15 opens the entrance of the duct 15, the combustion gas flows from the ejector nozzle 17 to the wall surface 14 a of the expansion nozzle 14.
When the fuel is injected in the direction along the arrow, the air in the duct 15 is drawn to the combustion gas from the ejector nozzle 17 and the drawn air is accelerated, so that the engine thrust increases by the air flow rate.

Further, fuel injected from a fuel injection nozzle 20 provided on the upstream side of the combustion chamber 16 of the duct 15 is
Since the fuel is burned by the oxygen in the air flowing into the duct 15, the fuel can be burned without using the oxidizing agent provided, and the fuel efficiency can be improved.

As the speed of the rocket increases, the ejector effect cannot be obtained. However, as long as the air in the inflowing air can be used, oxidant-free combustion can be performed in the wake, and good fuel efficiency can be obtained. Become.

The combustion gas generated in the combustion chamber 16 is ejected from the ejector nozzle 17 along the wall surface 14a of the expansion nozzle 14 in a vacuum, as shown in FIG. An expansion space is formed in the portion 14b. Since the expansion space is formed in the central portion of the expansion nozzle 14 as described above, the combustion gas does not become insufficiently expanded in the expansion nozzle 14, and a high propulsion efficiency due to appropriate expansion of the combustion gas can be obtained.

When the atmospheric pressure decreases, the expansion nozzle 14
However, even if the outlet area of the expansion nozzle 14 is set so that the ratio of the nozzle area of the ejector nozzle 17 is sufficiently large, the performance on the low speed / low altitude side is not impaired. A decrease in efficiency can be prevented.

The open / close mechanism 21 provided at the entrance of the duct 15 is closed when the atmospheric pressure is reduced, as shown in FIG. The mechanism 21 can receive the pressure of the expansion nozzle, thereby preventing thrust loss.

[0023]

As described above, according to the present invention, since a duct through which air flows is connected to the base end of the expansion nozzle for expanding the combustion gas, an increase in thrust due to inflow air at a low speed and a low altitude and fuel consumption can be achieved. Improvement is obtained, and by ejecting the combustion gas in the direction along the wall surface of the expansion nozzle with the ejector nozzle provided at the outlet of the combustion chamber, it is possible to perform appropriate expansion of the combustion gas in a vacuum, Propulsion efficiency and improved fuel efficiency can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a spacecraft incorporating an ejector rocket according to the present invention.

FIG. 2 is a sectional view of an ejector rocket engine according to the present invention.

FIG. 3 is a view showing the action of combustion gas when launching an ejector rocket according to the present invention.

FIG. 4 is a view showing the action of a combustion gas in a vacuum of an ejector rocket according to the present invention.

FIG. 5 is a view showing the operation of the extension nozzle.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Space shuttle 11 Airframe 12 Engine 14 Expansion nozzle 15 Duct 16 Combustion chamber 17 Ejector nozzle 20 Fuel ejection nozzle 21 Opening / closing mechanism

Claims (4)

[Claims] An expansion nozzle for expanding combustion gas, a duct connected to a base end of the expansion nozzle, a combustion chamber arranged in a ring shape so as to surround the duct downstream of the duct, and An ejector rocket provided with an engine, comprising: an ejector nozzle provided at an outlet of the combustion chamber to inject combustion gas in a direction along a wall surface of the expansion nozzle. 2. The ejector rocket according to claim 1, wherein the expansion nozzle has an inside diameter that does not cause insufficient expansion in a vacuum. 3. The ejector rocket according to claim 1, wherein a fuel ejection nozzle is provided upstream of the ring-shaped combustion chamber of the duct. 4. The ejector rocket according to claim 1, wherein an opening / closing mechanism is provided at an entrance of the duct.