RU2241846C1 - Rocket engine telescopic solid-propellant charge - Google Patents

Abstract

FIELD: rocketry.

SUBSTANCE: proposed telescopic solid-propellant charge for rocket engine consists of outer and inner cylindrical grains with equal thickness of burning dome. Outer and inner grains are made as freely fitted in, channel, all-round-burning charges. Longitudinal projections are made on outer surface of outer and inner grains and/or on surface of outer grain channel. Height of projections on outer surface of outer grain is 0.9 … 1.0 of thickness of radial clearance between outer grain and combustion chamber. Height of projections on outer surface of inner grain and on surface of channel of outer grain is 0.9-1.0 of thickness of clearance between inner and outer grains.

EFFECT: increased tightness of filling of combustion chamber with propellant, thrust-to-weight ratio, inflammability and reliability of functioning of rocket engine.

5 cl, 4 dwg

Description

The invention relates to the field of rocket technology, namely to the development, design and manufacture of solid propellant charges for rocket engines.

One of the urgent problems in the development of a solid propellant rocket engine (RDTT) is to ensure a high level of their thrust-weight ratio when used in multiple launch rocket systems (MLRS), as well as for launch stages of missiles for various purposes. As a rule, solid propellant charges in the form of all-round burning checkers are used for these systems (see, for example, N.M. Shapiro, G.Yu. Masing, N.E. Prudnikov "Theory of solid propellant rocket engines", M., 1966 , p. 44, Fig. 2.5, 2.6; RF patent No. 2178092). Closest to the patented charge is the design of the telescopic charge, shown in Fig.2.7 in East. N.M.Shapiro, G.Yu. Masing, N.E. Prudnikov "Theory of solid propellant rocket engines", M., 1966, p. 44, adopted by the authors as a prototype (Figure 1).

The design of the prototype is implemented in the form of a central (inner) rod unarmored checker located in the channel of the outer checker, armored on the outer surface, ensuring equal thicknesses of the burning roof for the inner and outer checkers. The advantage of the prototype is the ability to implement close to the neutral curve "pressure - time" at an acceptable level of thrust for solid propellant rocket systems. The disadvantages of the prototype are the limited level of thrust-weight ratio, reduced manufacturability of the charge associated with the need to book an external checker, reduced weight and size characteristics of the charge and the level of operational reliability in the rocket engine in connection with the use of armor plating for the external checker. In addition, due to significant axial pressure differences along the length of the rocket engine’s combustion chamber inherent in charges of this class, to prevent the loss of axial stability by the charge, the core structure of the central prototype charge is rigidly mounted in the engine chamber.

An object of the invention is to create a plug-in charge of solid fuel with a high charge density, reliable in operation and effective in terms of creating a high level of thrust of a rocket engine (high thrust-weight ratio).

The technical result is achieved by developing a telescopic charge in the form of two external and internal cylindrical channel blocks of all-round combustion with equal thickness of the burning vault, which are freely enclosed in each other, while the external block is made in dimensions close to the diameter of the combustion chamber of the engine, and the internal is placed in the channel of the external checkers. The design of the patentable charge and prototype shown in figure 1, 2, 3, 4, 5:

Figure 1 - design of the prototype: 1 - external checker; 2 - inner checker; 3 - reservation.

Figure 2 and Figure 3 - the design of the patented charge (in the setting, thin lines show the contours of the solid propellant combustion chamber): 1 - external checker; 2 - inner checker; 3 - reservation; 4 - longitudinal protrusions (ridges); h ₁ - the height of the protrusions on the outer surface of the outer checkers; h ₂ - the height of the protrusions on the outer surface of the inner checkers or on the surface of the channel of the outer checkers; δ ₁ is the thickness of the gap between the external checker and the solid propellant chamber; δ ₂ - the thickness of the gap between the inner and outer checkers; D _k is the diameter of the combustion chamber of a rocket engine; D ₁ is the outer diameter of the outer checker; d ₁ - the diameter of the channel of the outer checkers; D ₂ - the outer diameter of the inner checkers; 2e - the thickness of the burning arch; B is the width of the zig (ledges) along the chord.

Figure 4 - cross section of the patented charge (option): 1 - external checker; 2 - inner checker; 4 - longitudinal protrusions (ridges).

Figure 5 - cross section of the patented charge (option): 1 - external checker; 2 - inner checker.

To ensure the rigidity of the structure, the development of the combustion surface in the initial period, to ensure the reliability of the ignition of the charge (Figure 2, Figure 3), longitudinal ridges (protrusions) are performed on the surfaces of both the internal and external checkers, centering the external checker relative to the combustion chamber of the engine, and internal - in the channel of the external checkers. The height of the protrusions is selected from the condition

h ₁ ≤ δ ₁ = (D _k -D ₁ ) / 2; h ₂ ≤ δ ₂ = (d ₁ -D ₂ ) / 2,

where h ₁ - the height of the protrusions on the outer surface of the outer checkers;

h ₂ - the height of the protrusions on the outer surface of the inner checkers or on the surface of the channel of the outer checkers;

δ ₁ - the thickness of the gap between the external checker and the engine chamber;

δ ₂ - the thickness of the gap between the inner and outer checkers;

D _k is the internal diameter of the combustion chamber of the engine;

D ₁ is the outer diameter of the outer checker;

d ₁ - the diameter of the channel of the outer checkers;

d ₂ - the outer diameter of the inner checkers.

Experience in technological and bench testing of a patentable charge with a view to ensuring maximum loading density allows us to recommend

h ₁ = (0.9 ... 1.0) δ ₁ ; h ₂ = (0.9 ... 1.0) δ ₂ .

The width of the protrusions (B), taking into account the provision of minimum degressive residues, is assigned from the condition

B≤2e

where e is the thickness of the burning arch of the checkers.

To increase the stability of the flight of the rocket on the trajectory due to the restriction of the movement of the blocks relative to each other in the initial section of the flight, longitudinal protrusions can also be performed on the channel surface of the outer checker between the protrusions on the outer surface of the inner checker (Figure 4). In this case, the protrusions on the outer surface of the inner checker are oriented into depressions on the channel profile of the outer checker, and the profile of the depressions on the channel of the outer checker is made equidistant to the profile of the protrusions on its outer surface. In relation to a specific rocket engine, the profiles of the internal and external checkers can be made star-shaped (Figure 5). When stabilizing the flight of a rocket by rotation (usually the most common method of stabilizing tactical missiles), the protrusions of the internal and external checkers, in contact with each other, help to limit the rotation of the checkers relative to each other, which results in a more stable flight of the rocket (additional disturbances are excluded). At the same time, the presence of protrusions at the same time contributes to the development of the combustion surface of the internal and external checkers and, consequently, to a better and more reliable ignition of the charge.

To ensure a pressure diagram close to neutral or neutral, part or all of the ends of the pieces are made armored.

The positive effect of the invention is to increase the efficiency of the charge of solid rocket fuel: thrust-weight ratio, filling density of the combustion chamber with fuel, flammability, and overall reliability.

The design of the patented charge consists (Fig. 2, Fig. 3) of external (1) and internal (2) blocks, centered relative to each other and the combustion chamber of the engine with longitudinal protrusions (zigs) (4).

The design is practically implemented in the form of a charge with an overall length of 500 ... 700 mm with the dimensions of the blocks on the outer diameter: external - ⌀ 195 ... 200 mm; inner - ⌀ 95 ... 100 mm. The height of the longitudinal protrusions is 4 ... 8 mm.

Checkers are made of ballistic solid rocket fuel and are manufactured using standard technology.

The charge works as follows: when the head or nozzle igniter is activated, the outer and channel surfaces of the pieces, including the surfaces of the protrusions (zigs), ignite. The expiration of the products of charge combustion through the nozzle block of the rocket engine allows you to realize the necessary dependence "thrust - time".

Claims (5)

1. Telescopic solid propellant charge for a rocket engine, consisting of external and internal cylindrical checkers with an equal thickness of the burning arch, characterized in that the external and internal checkers are made freely enclosed, channel, all-round burning, and on the outer surface of the outer and inner checkers and / or longitudinal protrusions are made on the surface of the channel of the outer checker, while the height of the protrusions on the outer surface of the outer checker is 0.9 ... 1.0 of the thickness of the radial clearance between the outer checker and the camera with burning out, and the height of the projections on the outer surface of the inner channel checkers and checkers outer surface is 0.9 ... 1.0 the thickness of the gap between the inner and outer checkers. 2. The telescopic solid propellant charge according to claim 1, characterized in that the protrusions on the inner and / or outer checkers are made in the form of a star-shaped profile. 3. The telescopic solid propellant charge according to any one of claims 1 and 2, characterized in that the protrusions on the outer surface of the inner checker are oriented into depressions on the channel profile of the outer checker. 4. The telescopic solid propellant charge according to claim 3, characterized in that the profile of the depressions on the channel of the external checker is made equidistant to the profile of the protrusions on its outer surface. 5. The telescopic charge according to any one of claims 1 to 4, characterized in that some or all of the ends of the internal and external checkers are armored.

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