DE3304681A1 - Fixing of a solid propellant charge in the engine housing of a rocket engine - Google Patents

Abstract

Fixing of a solid propellant charge in the engine housing of a rocket engine with a suspension casing provided between the propellant charge and the inside of the engine housing, that is in the radial annular expansion gap, which casing is adhesively connected directly to annular, radially outer fixing zones or by way of an insulation layer indirectly to the inside of the engine housing and directly to annular radially inner fixing zones or by way of a combustion- inhibiting layer indirectly to the propellant charge, the annular radially outer fixing zones and the annular radially inner fixing zones alternating with one another when viewed in the longitudinal direction of the propellant charge.

Description

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Attachment of a solid propellant in the combustion chamber housing of a rocket engine

The invention relates to an attachment of a solid propellant charge in the combustion chamber housing of a rocket engine, the propellant charge only with part of its outer circumference with the inside of the combustion chamber housing is firmly connected.

The arrangement of a fixed propellant charge in the combustion chamber housing is special in various respects Problems associated with the previously known and used embodiments are not equally satisfactory be solved. So it is necessary between the mostly made of steel combustion chamber housing and the outer circumference of the propellant made from chemical substances due to the different coefficients of thermal expansion to leave a relatively large annular gap in order to avoid the considerable expansion differences., which occur as a result of the different day and night as well as summer and winter temperatures, without damage for the fuel to be able to take up.

As important as the radial expansion gap is on the one hand for absorbing the different expansions, it is also disadvantageous it affects the ignition process under certain circumstances. As is well known, the propellant ignites on best at its own critical temperature and pressure. Both factors, but in particular the pressure is strongly dependent on the currently available free combustion chamber volume upstream of a Insulation arranged in the nozzle shark cross-section. This fact is particularly serious with a forehead burner,

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in which the free annular gap occupies a non-negligible free volume fraction. Now is this free annular gap very high on extremely cold days, the critical ignition pressure is not reached because the ignition gases are too need to fill the radial expansion gap. In contrast, it is the free annular gap on extremely hot days very small, it can happen that the propellant is damaged by the increased ignition pressure. The consequences would be at least a bad burn.

Another problem with the attachment of a solid propellant charge is that the only a small internal Tensile strength chemical propellant on large parts of its surface over the entire length of the fastening device must be supported in order to be able to absorb the high shear forces.

According to DE-OS 2 258 115 it is known that the solid propellant of a rocket engine only via individual, outer Longitudinal strips, which form part of the burn-off insulation, firmly adhering to the inside of the combustion chamber housing associate. This probably ensures that the shrinkage stresses are reduced at extreme minus temperatures; conversely, however, at maximum temperatures, especially in the area of these strips, disproportionate pressure loads occur which should also be avoided.

Furthermore, US Pat. No. 2,957,309 shows the arrangement of a solid propellant charge in the combustion chamber housing leaving a radial expansion gap formed by a corrugated cardboard elastic suspension device is bridged, the outer corrugations with the inside of the combustion chamber and whose inner corrugations are directly or indirectly connected to the propellant in a firmly adhering manner. Also are after Another embodiment provided elastic spacers in the form of tubes. The disadvantage of this concept

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functions is that on the one hand there are ignition difficulties on cold days because of the relatively large radial gap and that on the other hand, when it is very cold, the existing linear vertex connections between the outer corrugations and the combustion chamber and between the inner corrugations and the propellant are overstressed, so that under certain circumstances cracks at these connecting seams occur at the start high acceleration forces can no longer be absorbed.

It is an object of the invention to provide a propellant mount that meets all of the above-mentioned requirements fulfilled and problems mastered.

This object is achieved according to the invention by a between the propellant and the inside of the combustion chamber housing, d. H. provided in the radial expansion gap, the suspension shell with annular, radially outer fastening zones directly or indirectly via an insulation layer with the inside of the combustion chamber housing and with annular, radially inner fastening zones directly or indirectly via an erosion inhibitor layer is firmly adhered to the propellant charge, the annular radially outer fastening zones and the annular radially inner fastening zones - viewed in the longitudinal direction of the propellant charge - alternately follow one another .

In an embodiment of the invention, the suspension jacket consists of a fabric-reinforced, in particular fiber-reinforced plastic film with the fibers running essentially in the direction of pull, ie _? i.e. in the longitudinal direction of the propellant charge.

The invention not only ensures a sufficient radial expansion gap between the combustion chamber housing

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And the outer circumference of the propellant, but also cares for the fact that the ignition volume or the space that is filled with the ignition gases during the ignition process is independent from the respective temperature state, practically constant remains, since the rearmost, radially inner annular fastening zone forms an absolutely gas-tight partition. In addition, the inventive arrangement of the propellant charge is always a relatively large-area suspension given over several, axially one behind the other annular surfaces even at extremely low temperatures.

An advantageous and operationally simple method for producing the fastening according to the invention is characterized characterized in that the suspension jacket and the burn-up inhibitor layer provided for the propellant are outside the Combustion chamber housing over the annular radially inner Fastening zones are connected with one another and then introduced together into the combustion chamber housing and that there the suspension jacket with its annular, radially outer fastening zones which are provided with an adhesive layer are e.g. B. with the help of an inflatable rubber bag radially from the inside directly to the inside of the Combustion chamber housing or if there is an insulation layer is pressed and glued to this and that the propellant is then poured into the combustion chamber housing will.

The drawing shows an embodiment of the invention on the basis of a longitudinal section through a solid rocket engine, FIG. 1 showing the state at extremely low temperatures and FIG. 2 showing the state at extremely high temperatures demonstrated.

330A681

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In a combustion chamber housing 1 with an attached thrust nozzle 2, a solid propellant 3 is installed, the is provided with an erosion inhibitor layer 4 radially on the outside. Likewise, on the inside of the combustion chamber housing 1 a heat insulation layer 5 attached. As can be seen in FIG. 1, at low temperatures (about at - 50 ° C) between the erosion inhibitor layer 4 and the insulation layer 5 due to the different expansion coefficients between the combustion chamber housing 1 and the propellant 3, a radial expansion ring gap 6, the is bridged by a hanger shell 7. This shows Viewed in the longitudinal direction of the propellant charge 3, annular, radially outer fastening zones 7a, which are connected to the insulation layer 5 and are thus firmly adhered to the combustion chamber housing 1, and also annular radially inner fastening zones 7i, which are firmly bonded to the erosion inhibitor layer 4 and thus to the propellant charge 3 are. The fastening zones 7a and 7i follow one another alternately as seen in the longitudinal direction.

Due to the greater expansion of the propellant charge 3 compared to the combustion chamber housing 1, the Annular gap 6 practically back to zero, as FIG. 2 shows.

The installation of the propellant charge 3 in the combustion chamber housing 1 can be carried out in an advantageous manner so that the suspension shell 7 and the combustion inhibitor layer 4 provided for the propellant charge 3 outside the combustion chamber housing 1 via the annular radially inner fastening zones 7i connected to one another and then together in the combustion chamber housing 1 are introduced. There the suspension shell 7 with its annular, radially outer fastening zones 7a, which are provided with an adhesive layer, e.g. B. with the help of an inflatable rubber bag radially from the inside to the Insulation layer 5 pressed and glued. Then the

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Propellant 3 poured into the combustion chamber housing 1, wherein the propellant 3 and the combustion inhibitor layer connect with each other.

The suspension jacket 7 can consist of a fabric-reinforced, in particular fiber-reinforced plastic film, with a course of the fibers essentially in the direction of pull, d. H. in the longitudinal direction of the propellant charge 3, whereby the acceleration forces can be absorbed without any problems.

Claims (3)

• ψ m »m ■ · ■ r - Jf - BTO1 Hn / we Attachment of a solid propellant in the combustion chamber housing of a rocket engine Claims (1 J Attachment of a solid propellant charge in the combustion chamber housing of a rocket engine, the propellant charge being firmly adhered only with part of its outer circumference to the inside of the combustion chamber housing, characterized by a between the propellant charge (3) and the inside of the combustion chamber housing (1), i.e. in the radial direction Expansion ring gap (6) provided suspension jacket (7), with annular, radially outer fastening zones (7a) directly or indirectly via an insulation layer (5) with the inside of the combustion chamber housing (1) and with annular, radially inner fastening zones (7i) directly or via an anti-burnout layer (4) is indirectly connected firmly to the propellant charge (3), the annular, radially outer fastening zones (7a) and the annular, radially inner fastening zones (7i) - viewed in the longitudinal direction of the propellant charge (3) - alternating one after the other. 2. Fastening according to claim 1, characterized in that the suspension jacket (7) consists of consists of a tissue-reinforced, in particular fiber-reinforced plastic film, with a course of the fibers essentially in the direction of pull, d. H. in the longitudinal direction of the propellant charge (3). 3. A method for producing the fastening according to claim 1, characterized in that the Suspension jacket (7) and the one provided for the propellant (3) Burnout inhibitor layer (5) outside of the combustion chamber housing (1) over the annular, radially inner Fastening zones (7i) connected to one another and then introduced together into the combustion chamber housing (1) be and that there the suspension shell (7) with its annular radially outer fastening zones (7a), the are provided with an adhesive layer, e.g. B. with the help of an inflatable rubber bag radially from the inside directly to the inside of the combustion chamber housing (1) or if there is an insulation layer (5) is pressed and glued to this and that the propellant charge (3) is then poured into the combustion chamber housing (1) will.