PL241329B1 - Hydrogen peroxide rocket engine - Google Patents

Abstract

The subject of the application is a rocket engine using the phenomenon of thermal decomposition of hydrogen peroxide, having: a body (1) inside which there is a hydrogen peroxide decomposition chamber, a system for the injection (5) of hydrogen peroxide into the decomposition chamber, an outlet nozzle (6) located on the other on the side of the distribution chamber in relation to the injection system (5), the heating coil (3) inside the body (1) in the distribution chamber and between the injection system (5) and the outlet nozzle (6), an insulating insert (4) placed between the heating coil ( 3) and the wall of the body (1), characterized by the fact that it additionally has: a filling (2) placed in the decomposition chamber in the body (1) in a space limited by a heating spiral (3), which is made of a material permeable to liquids and gases with having an open pore foam structure or a longitudinal, open and straight channel structure, or a powder structure or any combination thereof.

Description

PL 241 329 B1

Description of the invention

The present invention relates to a rocket engine fueled with hydrogen peroxide, operating on the thermal decomposition of a single-component propellant.

Various types of rocket motors are known in the art, which are usually powered by a one-component or two-component propellant. Among monocomponent propellants / fuels is hydrogen peroxide (H2O2), which generates large amounts of hot gas during decomposition - sufficient to power rocket motors, e.g. satellite correction motors. Particularly useful is the use of concentrated hydrogen peroxide (called HTP - High Test Peroxide), which is not highly toxic compared to another popular propellant, N2H4 - hydrazine.

In the state of the art, various types of structures are known, in which the decomposition of hydrogen peroxide in a rocket engine is carried out at a relatively low temperature in the presence of a catalyst within the so-called catalytic decomposition. An exemplary solution of this type is presented in the Korean patent application KR20100066613, according to which hydrogen peroxide is directed to a zone filled with spheres, which spheres are covered on the surface with a layer of material acting as a catalyst for the decomposition of H2O2. The same document also describes advantageous modifications of such a solution, which is the use of open-pore balls, thanks to which the surface of such a catalytic bed is significantly increased and, as a result, the decomposition reaction takes place much faster, enabling the development of a rocket engine with relatively high power while maintaining a small size. Unfortunately, such rocket engines have a big disadvantage - the catalytic material degrades quickly and with a particularly long operating time - can completely lose its ability to initiate the H2O2 decomposition reaction at relatively low temperatures. Accordingly, it would be desirable to provide an H2O2 engine with a design that maintains its properties and does not degrade over time.

One of the known solutions in the art is the use of a hydrogen peroxide engine in which the decomposition reaction would be initiated thermally by heating H2O2 to the decomposition temperature. This was proposed at the 7 ^th EUROPEAN CONFERENCE FOR AERONAUTICS AND SPACE SCIENCES (EUCASS) conference in an article entitled "Possibility of Using Thermal Decomposition of Hydrogen Peroxide For Low Thrust Propulsion System Application" (DOI: 10.13009 / EUCASS2017-626). According to the proposed solution, instead of using a catalyst, a heating coil and a system spraying hydrogen peroxide are placed in the rocket engine. Upon contact with the heated spiral, H2O2 decomposes and a large amount of hot gases is produced which, escaping through the nozzle, can generate the desired draft. While such a solution is promising from the point of view of the long service life of such an engine, it presents many technical challenges due to the difficulties in designing an engine of this type. Despite more and more perfect programs for performing numerical analyzes of various phenomena, the results of calculations concerning digital models of such engines differ significantly from the results of prototype tests. Moreover, it is a very difficult task to design a well-coordinated H2O2 spraying system, a heating coil and a chamber in which the decomposition reaction is to take place, and with a poorly designed engine of this type - it is possible to lose propellant that has not broken down inside the engine. Due to the low usefulness of digital models - designers are in fact forced to a tedious research process based on prototypes for each design modification.

Accordingly, it would be desirable to develop a rocket engine that runs on clean fuel, is easy to design, and has a long service life - an engine having such characteristics is the subject of the present invention.

A rocket engine using the phenomenon of thermal decomposition of hydrogen peroxide, having: - a body inside which there is a hydrogen peroxide decomposition chamber, - a system for the injection of hydrogen peroxide into the decomposition chamber, in which there is a swirler, - an outlet nozzle on the other side of the decomposition chamber with respect to injection system, - a heating coil located inside the body in the distribution chamber and between the injection system and the outlet nozzle,

- an insulating insert, placed between the heating coil and the body wall, additionally having:

- a filling placed in the decomposition chamber in the body in a space limited by a heating spiral, which is made of a liquid and gas-permeable material with an extended surface area, having an open-pored foam structure,

The interior of the motor housing is substantially axially symmetrical, the heating coil is of the electric heater type, the filling has a porosity in the range of 75% -95%, the filling is in the form of an open-pored foam made of ceramic, possibly with the addition of an open-pored foam made of metal or metal alloy.

Preferably, the filling is made of several foams with different porosities and different pore sizes.

Preferably, the heating coil is spaced apart from the insulating insert, the filling being arranged in the space between the heating coil and the insulating insert.

Preferably, the motor has a double heating coil formed by an inner and outer helix and where the filling is disposed at a distance between the inner and outer helix.

Preferably, the ceramic material of the filler is selected from the group consisting of: ZrO2, Al2O3, SiO2, SiC, SiC / Al2O3 / SiO2, Al2O3 / SiO2, Al2O2 / SiO2 / graphite.

Preferably, the metal or metal alloy in the filler is selected from the group consisting of: Nickel, NiFeCrAI, Inconel, NiCrAI, Monel, FeCrAI.

The invention will now be illustrated in more detail in a preferred embodiment with reference to the attached drawings, in which:

Fig. 1 shows a diagram of a rocket engine according to the first embodiment,

Fig. 2 is a schematic diagram of a rocket motor according to the second embodiment, and Fig

Fig. 3 shows a comparison of the temperature distribution in a prior art engine (above) with an engine according to one embodiment of the invention (below).

A preferred embodiment of the invention

List of numerical designations:

- rocket engine body with a hydrogen peroxide decomposition chamber

- filling / material with a foam structure with open pores (short - foam material)

- electric heater / heating coil

- thermal insulation / insulating insert

- injection system

- nozzle

The rocket engine according to the invention has three main components:

- body 1, in which there is a decomposition chamber - the reaction of decomposition of hydrogen peroxide takes place in it, where the body preferably has an axisymmetric structure,

- a nozzle 6 through which hot gases from the decomposition of H2O2 are directed outside the rocket engine, and

injection system 5, for injecting hydrogen peroxide into the decomposition chamber in the body 1.

Another element is an electric heater 3 which is placed in the body 1 inside the decomposition chamber and whose role is to obtain and maintain a sufficiently high temperature for the thermal decomposition of hydrogen peroxide to take place. The electric heater 3 is preferably in the form of a spiral with a geometry similar to that of a pipe / ring section (cf. Fig. 1).

In order to protect the walls of the body 1 against overheating, in particular during the pre-heating of the heating coil 3, an insulating insert 4, e.g. made of ceramic material, is placed inside the decomposition chamber in the area between the electric heater 3 and the wall of the body 1.

A key element of the engine according to the invention is an additional packing 2, e.g. with an open-pored foam structure, placed substantially inside the electric heater 3. The foam material 2 can be made of porous metal or ceramic materials that have an open-pored foam structure allowing free passage. fluid (especially gas) through such foam material 2. Preferably, the porosity of the foam material 2 is in the order of 75% -95%. The use of foam material 2 is particularly advantageous in view of the invention as it allows the temperature to be uniformly distributed inside the decomposition chamber in the body 1.

Moreover, by using a filling 2 with high porosity and open pores, which may additionally be heated by a heating electric heater, it is ensured that the hydrogen peroxide injected (through the injection system 5) comes into contact with the surface hot enough to initiate thermal decomposition of H2O2. This has a tremendous benefit in terms of achievement

Due to the fact that the design of such engines is easier to design, the problem of uneven decomposition reactions inside the decomposition chamber in the engine body 1 disappears. the heating coil 3 and the foam material 2 fill practically all the free space inside the decomposition chamber over a certain distance, the thermal decomposition reaction can take place evenly and all hydrogen peroxide will decompose even before it leaves the nozzle 6 (such a risk of wasting propellant could occur with poorly designed engines on H2O2, in which the thermal decomposition reaction would be caused only by a heating spiral, without any foam material). The difference in the temperature distribution in the decomposition chamber in the body 1, between the motor equipped only with a heating coil 3 and the motor equipped with a heating coil 3 and foam material 2 is illustrated in Fig. 3, where at the top you can see the annular outline of the hot heating coil 3, with a much cooler the area in the middle and at the bottom shows the circular outline of the foam material 2 surrounded by the heating coil 3, which are quite evenly heated (on the right-hand side of Fig. 3 you can see the 'color' marking of the temperature scale in ° C).

The condition for the selection of a specific type of material from which the foam material 2 should be made is appropriate mechanical and thermal strength, as well as sufficiently high thermal conductivity, guaranteeing a short pre-heating time. In some embodiments, a suitable group of materials for the foam material 2 is porous ceramics, while in other embodiments, a suitable group of materials is porous metal materials. In still other embodiments, it is preferable to use a foam material 2 made of several different materials, e.g. different ceramics, different metals, or a set of ceramic and metal materials.

In embodiments of the invention where the packing 2 is used partially or completely from one or more metal / metal alloys, the metal / metal alloy (s) are preferably selected from the group consisting of: nickel, NiFeCrAI, Inconel, NiCrAI, Monel, FeCrAI.

In embodiments of the invention where a packing 2 made partially or entirely of one or more ceramic material (s) is used, preferably the ceramic material (s) is selected from the group consisting of: ZrO2, Al2O3 , SO2, SiC, SiC / Al2O3 / SiO2, Al2O3 / SiO2, Al2O2 / SiO2 / graphite.

According to the second preferred embodiment of the invention, schematically illustrated in Fig. 2, it is advantageous to use a double heating coil 3, i.e. a pipe geometry heating spiral arranged in the second pipe with a spacing therebetween (in other words, there is an inner and an outer helix). In this embodiment, the foam material 2 is present in two zones - between the inner and outer helix and in the space in the center of the inner helix.

In still other exemplary embodiments, it is advantageous to distance the heating coil 3 from the thermal insulation 2 and to fill the space between them with foam material 2.

While it has been indicated in the above embodiments that it is particularly advantageous to use an open pore foam material, this should not be considered restrictive, as in some embodiments it is preferable to use materials with a different type of structure which also have an extensive surface area. Examples of materials with an extensive surface area are:

- materials with straight longitudinal channels, e.g. circular or hexagonal, - materials with a spongy structure, with open pores - with an alternating distribution of pores and structural elements,

- powders (it is obvious that when using powders it may be necessary to use additional elements that would prevent the loss of such powder from the engine, e.g. sieves).

It is particularly advantageous to use a foam-like material with an open porosity of a spongy structure with a regular and alternating pore distribution with a constant, defined diameter. The used porous elements can be one foam with a defined porosity, or several foams with different porosities can be used. This structure forces the hydrogen peroxide to contact the hot wall and distributes the heat provided by the heater well. The proposed solution is therefore not only a heat exchanger but also a surface expansion for the surface reaction of thermal decomposition of hydrogen peroxide.

Claims (6)

PL 241 329 B1 During operation of the engine according to the invention, the hydrogen peroxide is supplied to the chamber via an injection system 5 (preferably - including an injector) which preferably has an orifice adapted to the planned / anticipated possible mass flow rate and a swirler. As a result of contact of hydrogen peroxide with the hot surface of the heating coil 3 and with the heated foam material 2, thermal decomposition of H2O2 is initiated. In the proposed solution, the foam material 2 is the carrier of the heat flux from the heating element and is an ideal precursor to initiate the thermal decomposition of hydrogen peroxide. The initiated process of decomposition of hydrogen peroxide is sustained by a constant flow of heat from the heater. The hydrogen peroxide, which has decomposed and transformed into a mixture of hot gases, then escapes from the body of the engine 1 through the nozzle 6, generating a thrust, used, for example, to correct the position of the satellite in orbit. The practical use of the phenomenon of thermal decomposition of hydrogen peroxide enables the use of lighter and cheaper rocket engine designs, especially correction engines, as there would be no need to install a catalytic bed in the system, which is highly susceptible to poisoning, and in the case of silver (and hydrogen peroxide of the highest concentration class) , fusing. Moreover, due to the lack of a catalyst sensitive to degradation, it is possible to use such a solution in a long period of operation. Patent claims 1. Rocket engine using the thermal decomposition of hydrogen peroxide, having: - body (1), inside which there is a hydrogen peroxide decomposition chamber, - hydrogen peroxide injection system (5) into the decomposition chamber, in which there is a swirler, - an outlet nozzle (6), located on the other side of the decomposition chamber in relation to the injection system (5), - a heating coil (3) located inside the body (1) in the distribution chamber and between the injection system (5) and the outlet nozzle (6), - an insulating insert (4), placed between the heating coil (3) and the body wall (1), additionally having: - filling (2) placed in the decomposition chamber in the body (1) in the space limited by the heating coil (3), which is made of a liquid and gas-permeable material with an extended surface area, having an open-pored foam structure, the interior of the body ( 1) of the engine is essentially axisymmetric, the heating coil (3) being of the electric heater type, the filling (2) having a porosity in the range of 75% -95%, characterized in that the filling (2) is an open-pored foam made of of ceramic material, possibly with the addition of an open-pored foam made of metal or metal alloy. 2. A rocket engine as claimed in claim 1; 3. A method as claimed in claim 1, characterized in that the filling (2) is made of several foams with different porosities and different pore sizes. 3. A rocket engine as claimed in claim 1; A method as claimed in claim 1 or 2, characterized in that the heating coil (3) is spaced apart from the insulating insert (4), the filling (2) being arranged in the space between the heating coil (3) and the insulating insert (4). 4. A rocket engine as claimed in claim 1; A heating element as claimed in any one of claims 1, 2 or 3, characterized in that it has a double heating coil (3) formed by an inner and an outer helix and wherein the filling (2) is placed at a distance between the inner and outer helix. 5. A rocket engine as claimed in claim 1; 1, 2, 3 or 4, characterized in that the ceramic material included in the filling (2) is selected from the group consisting of: ZrO2, Al2O3, SO2, SiC, SiC / Al2O3 / SiO2, Al2O3 / SiO2, Al2O2 / SiO2 / graphite . A rocket engine as claimed in claim 1; The method of claim 5, characterized in that the metal or metal alloy constituting the filling (2) is selected from the group consisting of: nickel, NiFeCrAI, Inconel, NiCrAI, Monel, FeCrAI.