RU2247254C1 - Solid-propellant rocket engine - Google Patents

Abstract

FIELD: rocketry.

SUBSTANCE: proposed solid-propellant rocket engine contains housing with fitted-in channel charge and igniter. Igniter is arranged in spade limited by front bottom of engine and end face of charge. Diaphragm is installed between igniter and end face of charge. Said diaphragm is made of combustion material in form of disk with local cutouts over periphery.

EFFECT: reduced initial peak of pressure in solid propellant rocket engine.

2 cl, 6 dwg

Description

The invention relates to the field of rocket technology and can be used in the design, development and manufacture of solid propellant rocket engines and ignition devices for them.

In solid propellant rocket engines (TTRD), various designs of igniters and igniter devices are widely used (US Pat. RU 2170842, RU 2053401, US 3564845).

One of the drawbacks of the existing designs of turbojet engines and devices that ensure their launch is the presence of an initial igniter pressure peak in the engine chamber, which negatively affects the overall weight characteristics of the engine and the rocket as a whole. This drawback is especially acute in a turbojet engine with a small initial free volume. In this case, reducing the ignitor’s weight, in order to reduce the initial peak, leads, as a rule, to ignition delays.

This drawback is to some extent eliminated in the design of US Pat. RU 2053401, adopted by the authors for the prototype. In this case, the peak pressure in the design of the prototype is reduced by decreasing the peak maximum pressure of the igniter itself (figure 1).

The disadvantages of the known turbojet engines and igniters to them, including prototype, are the complexity of the design and a significant proportion of useless, from the point of view of using in turbojet engines, dispersion of the energy of the igniter in the initial period.

The technical task of the patented invention is to create a simple and reliable design TTRD with a reduced initial peak pressure, especially TTRD with a small initial free volume.

The specified problem in the claimed design is solved by sequentially connecting to the combustion process of individual surfaces of the charge itself.

The invention and its differences from the prototype are illustrated by the following graphic materials.

Figure 1. The effectiveness of reducing the pressure peak in the design of the prototype.

1 - pressure – time component p (t), determined by the surface of the charge itself;

2 - component p (t), determined by the igniter proper of a conventional design;

3 - component p (t) of the actual igniter prototype;

4 - the resulting dependence p (t) for an ignitor of a conventional design;

5 - the resulting dependence p (t) for the prototype igniter;

6 - the resulting dependence p (t) at steady state;

7 - decrease in pressure peak when using the prototype igniter.

Figure 2. The effectiveness of reducing the peak pressure in the claimed design.

1 - component p (t), determined by the surface of the charge itself in the absence of a membrane;

2 - component p (t), determined by the surface of the charge itself in the presence of a membrane;

3 - component p (t), which is determined by the surface of the charge itself during combustion of the entire surface (outer, channel, ···);

4 - component p (t) of the igniter itself;

5 - the resulting dependence p (t) for the claimed design (with a membrane);

6 - the resulting dependence p (t) without a membrane;

7 - the resulting dependence p (t) at steady state;

8 is a decrease in pressure peak for the claimed igniter design.

Figure 3. General view of the claimed design.

1 - engine housing; 2 - charge of solid rocket fuel (TRT);

3 - tablets TPT;

4 - hitch igniter composition in the shell;

5 - membrane;

Figure 4. The nature of the distribution of combustion products in the claimed design.

1 - housing;

2 - charge;

3 - membrane.

Figure 5. The nature of the distribution of combustion products in TTRD - prototype.

6. Membrane.

D _M - the outer diameter of the membrane;

Д _ДВ - internal diameter of the combustion chamber of the engine.

The essence of the invention lies in the overlap, at the time of starting the engine, of the charge channel (from the igniter side) by the membrane, which allows you to direct the bulk of the flammable gases along the outer surface of the charge. The ignition of the channel is provided from the nozzle end with a delay in time with respect to the outer surface. This allows:

- firstly, to reduce the initial pressure peak, since the maximum pressure developed by the igniter itself is realized with a substantially smaller burning surface of the charge (Fig. 1) than in the case of simultaneous ignition along the channel and the outer surface;

- secondly, to increase the efficiency and reliability of ignition in engines with a small initial free volume, due to the intensification of heat supply (by forced convection) to the local, in this case only to the outer surface of the charge. In this case, the entire mass of combustion products is purposefully passed over the outer surface of the charge (figure 4), and is not dispersed, as in the designs of analogues and prototype, throughout the volume of the combustion chamber (figure 5);

- taking into account the latter, it seems possible to reduce the total mass of the igniter as a whole.

To reduce the influence of the membrane on the stationary mode of the engine, it can be made of combustible material, such as polyethylene.

The design of the patented turbojet engine is shown in Fig.3. The design includes a weighed igniter composition in the film shell (4) and solid fuel pellets placed in the front cover of the engine in front of the end of the charge and separated by a membrane (5).

The igniter is designed for a turbojet engine with a charge having a through channel and burning along the channel and the outer surface. In this case, the charge is fixed in the engine chamber along the supporting surfaces, and the passage of gases from the igniter to the outer surface of the charge is ensured by the annular gap between the end of the charge and the engine housing, as well as by making additional cutouts along the periphery of the membrane (Fig. 6). This allows you to adjust the initial pressure in the local volume between the cap and the end of the charge and thereby provide the necessary pressure level for effective ignition of the igniter itself.

Distinctive features of the patented invention (from the prototype) are:

- the presence of a membrane overlapping (locking) the charge channel at the time of ignition;

- the implementation of the membrane from combustible material, such as polyethylene;

- the implementation of the membrane in the form of a circular disk with cuts along the periphery and a diameter corresponding to the inner diameter of the engine at the installation site of the membrane.

The patented design has been developed with reference to the ATGM accelerating engine.

An example of a practical implementation of the design:

- igniter device: 1 g sample of DRP-2 gunpowder in 2 film bags;

- polyethylene membrane;

- charge of ballistic TRT with dimensions: length 100 mm, outer diameter 116 mm, channel diameter 50 mm;

- charge mass 1.3 kg.

The positive effect of the invention is the reduction of the initial peak pressure in the combustion chamber of the turbojet engine, especially with a small initial free volume; decrease in weight and size characteristics of the turbojet engine.

Claims (2)

1. A solid propellant rocket engine containing a housing with a plug-in channel charge and an igniter located in it, located in a volume limited by the front bottom of the engine and the end of the charge, wherein the engine is equipped with a membrane installed between the ignitor and the end of the charge, characterized in that the membrane is made of combustible material in the form of a disk with local cutouts on the periphery. 2. The solid rocket engine according to claim 1, characterized in that the membrane is made of polyethylene.

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