RU2626353C2 - Method for manufacturing solid-fuel rocket engine charging from mixed rocket fuel - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: method of manufacturing a charge from a mixed rocket fuel is carried out by vacuum thermal pressing of the powdered composition directly into the body of a solid-fuel jet engine. For this purpose, a powdered fuel mixture is placed in the engine casing, from the open side of the casing, a process cylinder temporarily placed, containing a carefully fitted piston with a gas outlet through which the air is removed from the fuel mixture. After pumping out the air, the body is heated, starting from the bottom and from the side surface. As the fuel mixture melts, the piston moves to the bottom, compressing the mixture until it completely turns into a melt. After the entire mixture is melted, the charge is cooled and the piston is removed.

EFFECT: method enables to simplify the technology of fuel preparation as much as possible, to significantly shorten the period of equipping the engine and to fill the solid fuel rocket with fuel at the launch site, which eliminates the need to transport a charged engine.

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Description

The invention relates to a method for manufacturing a charge of a solid propellant rocket engine (solid propellant rocket engine).

There are different ways of preparing solid mixed propellant rocket propellant (SRT), with the aim of filling it in solid propellant rocket fuel. One of the first was the method of preparing solid CPT drafts, which were then inserted into the solid-propellant rocket motor case. For several reasons, it is not very convenient for the manufacture of very small and large engines based on mixed fuels. For small model rocket engines (MRJ), for example, it was convenient to press the mixed fuel powder directly into the engine housing (Scott Dixon, Barry Tunick, Edwin Brown. Composite propellant compositions / Patent US 20040094250 A1).

Sometimes the so-called “Casting compounds” when molten fuel is simply poured into the engine block (Igor Afanasyev, Andrey Suvorov. Into space with sugar: “Caramel” fuel. “Popular Mechanics”, 2008, No. 4, p. 80). For the manufacture of large charges directly in the engine casing, injection molding compounds are also often used, which by their nature are usually very viscous and require preliminary rolling to obtain a homogeneous composition. After being placed in the solid propellant rocket engine it is usually necessary to wait a long time (5-10 days) until the fuel-bundle is polymerized (Protsun E.G., Zvonarev Yu.V. MIXTURE SOLID MISSILE FUEL // Patent RU 2258057, 10.28.2003). At the same time, the engine casing with fuel must be heated all the time, strictly observing the temperature regime. In this case, the “survivability” of the fuel composition, in which it maintains the necessary viscous flow state, is 5-10 hours, after which its further processing becomes impossible. The fuel preparation device itself is very complex, and when rolling it is possible to capture air bubbles. (Garanin L.P., Kutsenko G.V. METHOD FOR PREPARING FUEL MASS FOR CHARGE FROM MIXED SOLID ROCKET FUEL // Patent RU 2316524, July 20, 2006). It can be seen that the technology itself is quite complex and has a lot of disadvantages:

1. There is a danger of disrupting the technological regime, since after the survivability period all fuel mass disappears.

2. There is a danger of getting defective checkers of the Republic of Tatarstan in the engine casing if the temperature regime has been violated.

3. The need to use complex homogenizers-rollers, which makes it possible to prepare solid propellant rocket motors only in the factory.

4. The long cooking time of the fuel, which is associated with its polymerization.

5. The ability to capture air bubbles in the fuel mass during rolling. Why do you have to use additional special evacuation.

6. Possible sticking of viscous components in the apparatus of the mixer and homogenizer on the equipment elements, which reduces the accuracy of dosing of both the fuel components and the fuel itself.

7. The complexity of the process of preparing “injection fuels” makes it impossible to prepare solid propellant rocket engines at the launch site, similar to refueling rockets based on liquid propellant engines. Which of course complicates the massive introduction of solid propellant rocket rocket in space.

The problem to which the present invention is directed is to create a simpler technology that would get rid of these disadvantages.

The problem is solved by vacuum thermal pressing of powdered fuel. The powdered fuel mixture should initially include solid fossil fuels in powder form, which melts at a relatively low temperature. Much lower than the ignition temperature of the fuel. It is known that ammonium perchlorate begins to decompose at 150 ° C. For CPT based on ammonium perchlorate, it can be powdered sevilen (“adhesive” with high adhesion for many materials and powders, a copolymer of polyethylene and vinyl acetate), which softens in the temperature range of 60-80 ° C, or powdered bitumen, which melts in the temperature range 50-90 ° C. For fuels based on potassium perchlorate, this can be sorbitol, which melts in the temperature range of 80-120 ° C.

The powdered fuel mixture 1 is placed in the engine casing 2, where at the bottom of the casing 3 there is a technological plug in the form of a partition 4 (Fig. 1). On the other side of the casing, a process cylinder 5 is temporarily placed, which contains a carefully adjusted piston 6. This is necessary in order to accommodate the required amount of fuel, since during pressing the volume of the mixture is greatly reduced. If necessary, the process cylinder may be further a rocket body. The piston contains a gas outlet 7, which allows you to remove air from the fuel mixture. When air is removed, a vacuum is created in the pumped volume. On the one hand, this avoids voids and cavities in the fuel. On the other hand, under the influence of atmospheric pressure, the piston begins to put pressure on the fuel mixture. Thus, a press is obtained.

After evacuation of air, the engine casing starts to warm up, starting from the bottom and from the side surface (Fig. 2). This can be ensured by the fact that the engine case, clad in a removable jacket-glass, is immersed in a vessel containing an aqueous solution of salt, which is heated by an electric heater from the bottom of the vessel. In this method, which was already used in practice, a significant temperature gradient of the saline solution was recorded: the temperature at the bottom can exceed that on the surface by 30-50 degrees, which is necessary for the desired character of heating. Or the heating of the case is carried out by heating elements that are located on its surface, and their heating is controlled by electronics, which provides the above-described nature of heating.

As the fuel mixture is melted, the piston begins to move to the bottom of the engine, compressing the mixture until it completely turns into a melt (Fig. 3). To prevent the mixture from entering the gas outlet, a special filter made of fibrous material is placed in it. Since the fuel mixture is melted from the bottom and walls of the body, it becomes clogged with melt at the very last moment, at the time the process is completed. Or in front of the piston 6 you can put another additional piston 8, in which the gap with the walls of the housing is about the size of the particles of the fuel mixture. In this case, the powder will be locked in the evacuated volume, and air will be removed through the gap. In order for the additional piston not to block the gas outlet opening, its surface facing the gas outlet must have a certain roughness or special notch channels. After the entire mixture is melted, the engine cools, the mixture solidifies and sets, and thus the entire organic component of the fuel turns into a reliable bond-glue. That is, a fusible substance or a thermoplastic polymer after heating during the pressing process becomes a binder component of the fuel. After that, the piston with the gas outlet is removed, and the additional piston after certain procedures can be left as a plug for the engine.

Or a special plug can be glued after removing it. The technological plug at the bottom of the body also retracts, providing access to the fuel mass. The nozzle 9 can be glued after removing the entire bottom, or removing the plug just opens the exit surface of the formed checkers. In this case, the bottom of the engine should be made of combustible material.

This method is most convenient for preparing end-combustion charges. For the mass production of small MAJs, a piston with a gas outlet can create a vacuum in a common chamber where many engines are located. Here, for each engine, a separate additional piston is provided.

For the manufacture of channel combustion charges, the technological plug at the bottom of the body is connected to the profile 10, which forms the channel in the future checker (Fig. 4). In this case, the piston with a gas outlet has holes that exactly match the shape of the profile.

Thus, the proposed method allows to simplify the technology of manufacturing solid propellant rocket charge, reduce the time of its manufacture by an order of magnitude, makes it possible to refuel the engine with fuel mixture directly at the rocket launch site. The fuel mixture can be made in a special blender from the original components. This eliminates the need to transport both the original fuel and the engine equipped with fuel.

Claims (1)

A method of manufacturing a solid rocket engine (RDTT) charge from mixed rocket fuel in a solid rocket motor housing, comprising placing a powdered fuel mixture in an engine housing, temporarily placing a process cylinder on the open side of the housing, which contains a carefully fitted piston with a gas outlet through which air is removed from the fuel mixtures with the creation of a vacuum in the pumped-out volume, after evacuation of air, the body is heated, starting from the bottom and from the side surface, and as fuel mixture, the piston moves to the bottom of the housing, compressing the mixture until it completely turns into a melt, after which the engine is cooled and the piston is removed.

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