RU191519U1 - ONE-COMPONENT LIQUID ROCKET LIQUID ROCKET ENGINE - Google Patents

Abstract

The utility model relates to space technology and can be used to create single-component liquid propellant rocket engines that are part of the satellite thrust propulsion systems for solving orbital maneuvering tasks. One-component liquid propellant small thrust rocket engine contains a fuel supply pipe 1, injector 2 in the bottom of decomposition chamber 3 , nozzle 4. In the fuel decomposition chamber 3 there is a catalytic package consisting of a granular catalyst 5, and an elastic briquette 6 of a porous refractory meta material placed in a pressed state between the catalyst 5 and the entrance to the nozzle 4. The briquette 6 is formed of pre-twisted into a spiral and spatially formed into a cylinder of annealed catalyst wire with a ratio of wire diameter to the inner diameter of the spiral at a level of (0.25-0 , 3) and porosity of the order of (65-85)%. A grid 7 is installed at the inlet of the decomposition chamber, distributing fuel throughout the entire volume of the granular catalyst and eliminating the ingress of catalyst granules 5 into the inlet of the injector 2. A useful model provides an increase in the efficiency of the decomposition of fuel and, as a result, an increase in the flow rate of the decomposition chamber and the engine life as a whole.

Description

The utility model relates to space technology and can be used to create single-component liquid rocket engines that are part of the low-thrust propulsion systems of satellites for solving problems of orbital maneuvering.

One of the problems inherent in single-component liquid thrust engines that use a granular catalyst is the formation of voids between the catalyst granules resulting from the destruction and erosion of the granules in the process of their friction between themselves under mechanical stresses, as well as during the functioning of the engine (especially when inclusions at low temperatures of the decomposition chamber). The formation of voids between the granules in the catalytic stack leads to the development of increased pressure fluctuations in the decomposition chamber, which, in turn, leads to even greater destruction of the catalyst and a decrease in the overall engine life. In the presence of mobility of the granules and subsequent mechanical impacts, their further destruction also occurs due to mutual displacement and friction between them. This problem in known engines is solved by constantly preloading the bag with the catalyst with a coil spring.

Known is a one-component liquid rocket engine containing an injector, a fuel decomposition chamber with a granular catalyst pack and a coil spring placed inside it, and a nozzle whose axis is perpendicular to the axis of the engine. The catalyst package on both sides is limited by grids, and the grid installed at the outlet of the catalytic package has elastic properties and is peripherally mounted on the wall of the decomposition chamber. A cylindrical spring in a preload state is inserted in the axial region of the decomposition chamber between the outlet mesh and the end surface of the decomposition chamber. During the development of the catalyst, a coil spring presses the net at the outlet in the direction of entry (Japan Patent JPH 1182171, IPC F02K 9/68, 1999).

The known engine has the following disadvantages:

- during axial fuel supply, the main destruction of the catalyst occurs in the axial region of the catalytic package, respectively, particles of the destroyed granules to a greater extent in the central axial region clog the space between the granules, increasing the pressure drop across the catalytic package. Local application of force by a coil spring from the opposite side creates uneven pressure on the outlet surface of the catalytic package and, thereby, exacerbates the blockage of the central axial region of the catalytic package, reducing engine performance and its service life;

- the spring force is applied to the grid at the outlet locally, and therefore non-uniformly and maximally in the central axial region of the catalytic package and minimally in the peripheral (wall) region and, thus, even before the firing, the central axial region of the catalytic package is subjected to increased loads, which can lead to to increased destructibility of the catalyst in the axial region of the catalytic package. The application of external mechanical influences along the axis of the chamber, for example, when a spacecraft is put into orbit, can enhance the process of destruction of the catalyst in the axial region of the catalytic package before the firing of the engine;

- a layout solution of the engine with a lateral location of the nozzle relative to the decomposition chamber and with a cylindrical spring located in the axial region of the decomposition chamber, when one of its ends abuts against the outlet end surface of the chamber, as a rule, has limited application and can generally affect the engine characteristics.

A known one-component liquid rocket engine, adopted for the prototype, containing an injector, a fuel decomposition chamber with a granular catalyst pack placed inside it, limited on both sides by platinum grids, and a coil spring made of rhodium-plated tungsten wire, and a nozzle. The grid at the outlet of the stream from the catalytic bag is attached to a support ring that can move in the axial direction. The coil spring is located in a compressed state between the outlet grid and the nozzle (Japanese Patent Application JP 2010174649, IPC F02K 9/68, 2010).

The known engine has the following disadvantages:

- local application of force by a coil spring in the peripheral zone of the catalytic package to the support of the bearing support ring with the output mesh attached to it, with not absolute stiffness of this mesh itself, creates uneven pressure on the output surface of the catalyst package - increased in the peripheral zone and lowered in the axial one. Thus, the risks of increased destruction of the catalyst granules in the peripheral zone of the catalytic package, a corresponding increase in the pressure drop in this zone due to clogging of the space between the granules and, consequently, a decrease in the functioning efficiency of this zone, which entails a decrease in the service life of the engine as a whole, increase;

- the range of changes in the diameter of the spring provided in accordance with the equation in the description of the engine design allows its diameter to be reduced to 50% of the diameter of the outlet mesh, which, provided the spring is supported by the support ring, entails an increase in the width of the support ring. Thus, the gas output from the decomposition of fuel in the peripheral zone of the catalytic package can be substantially shielded, which will reduce the efficiency of the catalytic package and the engine as a whole.

Both analog and prototype have the following disadvantages:

- due to the fact that the coil spring is in the temperature and direction of the flow of high-temperature gas, there may be a distortion of the flow parameters, for example, due to a change in the properties of the spring itself or when it is moved in the chamber under mechanical stresses on the engine. That is, the stability of the gas flow at the inlet to the nozzle and the parameters of the engine as a whole may be affected;

- increased chamber volume due to the need to place a coil spring of relatively large length, which affects the dynamic characteristics of the engine.

When creating the invention, the problem was solved of increasing the efficiency of the decomposition of fuel and the associated increase in the flow rate of the decomposition chamber and the serviceability of the engine as a whole.

The problem is solved due to the fact that in the well-known single-component liquid propellant small thrust rocket engine containing a fuel decomposition chamber with an injector located in it along the axis, a catalytic stack with a granular catalyst limited by an inlet grid and an elastic element located between the catalytic stack and the nozzle and providing constant preloading of the catalytic package, and the nozzle, according to the utility model, the elastic element is made of refractory not annealed wire with catalytic properties twigs, previously twisted into a spiral and spatially formed into a cylindrical briquette with a porosity of (65-85)%.

The execution of the elastic element from a refractory not annealed wire with catalytic properties, previously twisted into a spiral and spatially formed into a cylindrical briquette with a porosity of (65-85)%, allows you to:

- to ensure uniform and constant preloading of all granules along the entire output surface and the catalytic package as a whole and, accordingly, to increase the efficiency of the decomposition of fuel and the related engine life;

- due to the catalytic properties of the material of the briquette to further increase the efficiency of decomposition of fuel and, accordingly, to increase the flow rate of the decomposition chamber and the life of the engine as a whole;

- effectively perform the role of the output grid to hold the granules of the catalytic package;

- significantly reduce the length of the output part of the decomposition chamber after the catalytic package due to the use of a briquette with a relatively low height in comparison with, for example, the length of the coil spring, which improves the overall mass characteristics of the engine as a whole.

The invention is illustrated in the drawing, where in FIG. 1 shows a general view of a single-component liquid propulsion thruster; in FIG. 2 - photograph of the briquette (top view); in FIG. 3 - photograph of the briquette (side view).

A one-component liquid propellant small thrust rocket engine contains a fuel supply pipe 1, an injector 2 in the bottom of the decomposition chamber 3, a nozzle 4. In the fuel decomposition chamber 3 there is a catalytic package consisting of granular catalyst 5, and an elastic briquette 6 of a porous refractory metal material installed in prepressed state between the catalyst 5 and the entrance to the nozzle 4. The briquette 6 is formed from pre-twisted into a spiral and spatially formed into a cylinder of annealed catalyst wire, for example, and molybdenum-rhenium alloy, secured to the wire diameter ratio of the inner diameter of the helix at the level of (0.25-0.3) and porosity of the order of (65-85)%. The relatively high porosity provides the briquette 6 with elastic properties and, accordingly, the catalyst granules 5 are in constant and equally uniform compression in the direction of the grid 7 in the input part of the decomposition chamber. The grid 7 provides the distribution of fuel throughout the volume of the granular catalyst and eliminates the ingress of granules of the catalyst 5 into the inlet of the injector 2.

A single-component liquid thruster rocket engine operates as follows:

Previously, if necessary, the decomposition chamber 3 is heated by an electric heater (not shown in the drawing) installed on its housing to the temperature of reliable engine start. At the time of starting, after the fuel is fed through the injector 2, the liquid fuel enters the catalyst package 5, where, upon contact with the surface of the granular catalyst, the fuel begins to decompose. Next, in the briquette 6 there is an additional decomposition of the fuel and decomposition products, expiring through the nozzle 4, create engine thrust. Both in the manufacture and in the operation of the engine, due to the action of the elastic briquette 6, the catalyst granules 5 are constantly and uniformly pressed over the entire output surface of the catalytic package and, accordingly, over the entire volume of the package as a whole, thereby eliminating the formation of voids between the granules in it catalyst 5, which arise as a result of their destruction and erosion.

The claimed utility model of a liquid propellant small thrust engine has successfully passed a cycle of ground tests and confirmed its increased engine life and increased flow rate of the decomposition chamber.

Claims (2)

1. A one-component liquid propellant small thrust rocket engine comprising a fuel decomposition chamber with an injector disposed therein, a catalytic bag with a granular catalyst limited by an inlet grid, and an elastic element located between the catalytic bag and the nozzle and providing constant compression of the catalytic bag, and nozzle, characterized in that the elastic element is made of a refractory not annealed wire with catalytic properties, previously twisted into a spiral and spatially with normed with a cylindrical preform porosity,%: 65-85. 2. A one-component liquid propulsion thruster according to claim 1, characterized in that the ratio of the diameter of the wire to the inner diameter of the spiral is 0.25-0.3.

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