EA042281B1 - HYBRID GAS GENERATOR - Google Patents

Description

SUBSTANCE: invention relates to devices for creating gas volumes and can be used in cannon launchers and jet rocket engines. Known and most widely used chemical devices:

1) solid propellant gas generators - used in propelling barreled rifle, artillery systems and in the first stages of light gas guns (patent RU 2668481 C2), as well as in solid rockets (Vinitsky A.M., Rocket engines on solid fuel, M., 1973). The advantages are: relative simplicity, no problem of possible fuel leaks, the possibility of long-term storage, reliability. The disadvantages of such gas generators are: low specific impulse; expensive fuel and a large amount of aggressive substances in the exhaust. So, for example, during each launch of the Space Shuttle, ~ 1000 tons of solid fuel combustion products containing over 100 tons of gaseous hydrogen chloride were emitted into the atmosphere;

2) liquid gas generators are currently used as a liquid-propellant rocket engine (LRE), using liquids as fuel, including liquefied gases. By the number of components used, one- and two-component liquid-propellant rocket engines are distinguished (Design and design of liquid rocket engines. Chambers. D.I. Zavistovsky, V.V. Spesivtsev. Textbook. Kharkov: National Aerospace University Kharkov Aviation Institute, 2006. 122 p. ). Advantages - LRE has the highest specific impulse in the class of chemical rocket engines. More than 4500 m/s for a pair of oxygen + hydrogen and 3500 m/s for a pair of kerosene + oxygen. Eco-friendly and cheap fuels. Disadvantages - LRE: they are much more complex and more expensive than equivalent solid fuel, despite the fact that 1 kg of liquid fuel is several times cheaper than solid fuel.

The use of liquid fuel components in receiver systems has not yet left the experimental stage (CHRIS JENKINS. MONERGOLS AND DIERGOLS - THE WAY FORWARD FOR PROJECTILES. MILITARY TECHNOLOGY, 1988, No 7).

It is promising to use three fuel components simultaneously, for example, hydrogen - beryllium - oxygen and hydrogen - lithium - fluorine. Beryllium and lithium burn, and hydrogen is mostly used as a working fluid. This makes it possible to achieve specific impulse values in the region of 550–560 s. However, this is technically very difficult, and has never been used in practice (Wikipedia).

Another type of gas generators is known - with a phase transition. Here, the volumes of the working fluid increase without chemical transformations. Patent KZ 33305 - cryo-evaporative gas generator in an autonomous air gun and a device for throwing a projectile - patent KZ 31797. Their advantage is in environmental friendliness, simple design, availability and reliability. The disadvantage for the stated purpose is a small specific impulse.

Closest to the claimed invention is a device according to RF patent No. 2511986. A hybrid rocket engine using fuel components in different states of aggregation. The presence of a solid component makes it possible to significantly simplify the design. The first flight of a rocket equipped with a hybrid engine, designed under the direction of S.P. Queen, took place on May 23, 1934.

Advantages in comparison with LRE: simplicity of design, simpler refueling infrastructure; it is possible to add a powder of reactive metals to the fuel to increase both the specific impulse and density. Advantages in comparison with solid propellant engines: higher specific impulse, environmental friendliness, lower explosiveness - does not explode from cracks in the fuel block; the fuel is not sensitive to parasitic electric charge and is not prone to self-ignition due to heating; the rocket can be transported, installed without an oxidizer and refueled on the spot. Disadvantages of hybrid rocket engines: the fuel is equipped with channels, and therefore its density is not so high; regenerative cooling of the nozzle and fuel curtain is impossible (as in solid rockets); specific impulse is less than in LRE.

The use of hybrid fuel in barreled propellant systems is currently not encountered.

The objective of this invention is the development of a gas generator:

1) simple and reliable like solid fuel, and with a specific impulse like a rocket engine;

2) with the possibility of using several fuel components and applying the effect of the phase transition of hydrogen to achieve an even greater specific impulse;

3) using inexpensive and environmentally friendly fuel;

4) applicable in barreled throwing systems, including powerful light-gas cannons with high throwing speed.

The technical result is expressed:

(1) in increasing the environmental friendliness, reliability of the device and its performance;

(2) in reducing the cost of plant design and fuel cost.

The technical result of the invention is achieved by the fact that the hybrid gas generator contains a combustion chamber, fuel components in different states of aggregation and a device for releasing the generated gas. In this case, all components are placed in the combustion chamber. Fuel components in the solid aggregate state can be both solid volumes suitable for long-term combustion and granules with a large outer surface, if a high reaction rate is required.

Components can be segmented in whole or in part using wrappers. Devices can be installed on the walls of the shells to start the reaction. In this case, the components will react in a certain order to be able to control the speed and power of the reaction.

To reduce fuel heating outside the combustion zone, devices are applicable to reduce heat transfer by radiation and turbulent transfer of heated masses from the combustion zone.

Part of liquid hydrogen can be used not as a fuel, but as a fuel with a phase change. The speed of sound in hydrogen is greater than in other substances. Therefore, hydrogen can accelerate itself and partially disperse dust particles faster than any other gas. Increasing the speed of the jet stream increases the specific impulse.

The low density of hydrogen increases the size of the device. To increase the fuel density using hydrogen, denser hydrogen-containing components can be used. These can be chemical compounds - methane, borazan, etc. or hydrogen sorbents. When hydrogen is produced from methane, which decomposes at 1500°C, carbon is simultaneously released in the form of soot or graphite. In order for dust particles to reduce the speed of gases less, the gas generator can be equipped with a device for reducing the proportion of the condensed phase in the outgoing gas stream.

Borohydrides, especially diborane, have the highest hydrogen content. But they are very dangerous, unstable and poisonous. However, in a state of deep freezing, like any substance, they will be neutral. Therefore, a promising fuel, where the components are nitrogen and borane in condensed states. As a result of the reaction of this pair, hydrogen and boron nitride are formed. These substances are non-toxic, so the exhaust will be environmentally friendly.

Blueprints

Fig. 1 - an example of a specific design of the device - a hybrid gas generator as a light gas gun. 1. Combustion chamber with thermal insulation. 2. Liquid hydrogen. 3. Oxygen in the solid state in granules. 4. Igniting charge. 5. Barrel. 6. Starting device.

The device shown in the example works as follows: when the charge (4) ignites, the surface of the oxygen granules (3) closest to the charge and part of the hydrogen (2) heat up and react. Gives off heat and water vapor. Liquid hydrogen (2) evaporates intensively. The pressure increases, and the launch vehicle (6) starts moving along the shaft (5). The total volume of the combustion chamber with the barrel increases. As the temperature rises, more and more oxygen granules take part in combustion.

This provides the progressive combustion required to maintain pressure as the volume increases multiple times behind the accelerating projectile. The burning rate of pellets depends on their size;

fig. 2 - an example of a specific implementation of the device - a hybrid gas generator as a rocket jet engine. 1. Combustion chamber with thermal insulation. 2. Liquid hydrogen. 3. Oxygen in the solid state. 4. Fuel component from magnesium powder (as options: from lithium, aluminum, or others) in shells, for example, from plastic. 5. Triggering device, such as a filament. 6. An outlet device with the possibility of locking before starting the reaction, for example, an outlet with a bursting disc. 7. Nozzle. 8. Hydrogen filler and drain valve. 9. Oxygen filling port and drain valve. 12. A device for reducing the heating of liquid hydrogen by radiation from the combustion zone and reducing turbulent mixing, for example, reflective, perforated plates. 13. Device for reducing the heating of solid oxygen by radiation from the combustion zone (reflecting plates). 14. Device for reducing the proportion of the condensed phase in the gas jet. For example, an electric vortex dust collector.

The ratio of the volumes of the components is given conditionally. The rate of fuel conversion is determined by the shape, the number of individual volumes with components, their relative position and the outlet section in the outlet device. Accurate calculations of these parameters for the given characteristics of the gas generator can be performed on the basis of experiments;

fig. 3 - the device shown in the example works as follows. First of all, the combustion chamber (1) is filled with liquid hydrogen (2) through the fitting (8). Next, liquid oxygen (3) is poured through the fitting (9). Oxygen, surrounded by colder hydrogen, turns into a solid state. After preparing the fuel components, the filament (5) of the starting device burns through the shell material, ignites the magnesium (4) and oxygen. An intense release of heat begins. Between the combustion zone and the outlet device (6), liquid hydrogen (2) passes into gas and partially reacts with the released gaseous oxygen. There is a combustion zone (11), which expands until the complete combustion of oxygen, metal powder, shells and part of hydrogen. The pressure in the combustion chamber (1) increases. The rupture disc of the release device (6) is destroyed. And the gases (15) rush into the nozzle (7), where they are additionally accelerated and create jet thrust. Part of the heated hydrogen gases (10) escape as fuel with a phase transition. In this case, they serve as a thermal curtain for the walls of the nozzle.

Claims (1)

A hybrid gas generator containing a combustion chamber and a device for discharging the generated gas, characterized in that all fuel components are located in the combustion chamber, while in the combustion chamber the state of aggregation of one of the fuel components differs from the state of aggregation of the other fuel component.