RU2298110C2 - Solid-propellant rocket engine - Google Patents

Abstract

FIELD: rocketry.

SUBSTANCE: proposed solid-propellant rocket engine has body, front and nozzle bottoms and solid-propellant charge with slots from side of front bottom of engine. Solid-propellant charge is attached to body by protection and holding layer. Dome of charge increases in direction of nozzle bottom of engine owing to changing of cylindrical channel from side of front bottom into cone narrowing towards nozzle bottom. Slots are arranged in symmetrical pairs at ratio of angles between slots of one pair and between adjacent slots of adjacent pairs being 0.1-0.4. height of slots "a" is 0.3-0.7 of value of complete burning dome "c" of charge. Length of slots is 0.05 - 0.25 of total length of engine body.

EFFECT: increased filling of combustion chamber, possibility of use of charge for thermal protection of nozzle part of engine at provision of neutral performance curve of engine.

3 dwg

Description

The invention relates to the field of rocket technology, namely to rocket engines of solid fuel, and can find application in the development of new samples of rocket engines of large elongations and with a neutral character of the thrust diagram.

The problem of providing neutral engine thrust during the entire operating time for mid-flight engines of various rocket systems is relevant in terms of minimizing deviations of ballistic parameters and improving the performance of rocket systems in general.

Known rocket engine according to patent RU No. 215175, 6 F02K 9/28, adopted by the authors for an analogue containing a head half charge with a star-shaped channel and a tail half charge with a conical axial channel expanding to the nozzle.

However, the detailed design provides for a two-section version of the engine. What is not optimal from the point of view of the weight excellence of rocket engines. The closest in technical essence and the achieved technical result to the claimed invention is a rocket engine according to patent RU No. 2152529, 7 F02K 9/08. It contains a housing, a solid fuel charge, the channel of which is made sequentially star-shaped, cylindrical and conical at the rear end of the charge. The objective of this invention was to reduce the mass of degressive residues, increase the total thrust impulse, ensure maximum bulk density of the housing filling with fuel and increase the average pressure level in the engine due to the organization of erosive combustion on a large part of the channel surface.

However, an engine of this design has disadvantages, since it does not exclude the presence of degrading fuel residues, the effect of erosive combustion is not fully used, additional thermal protection of the engine housing from the nozzle end is required.

The objective of the invention is to increase the volumetric filling of the combustion chamber and the use of charge fuel for thermal protection of the nozzle part of the engine housing while providing a neutral diagram of the engine thrust.

The problem is achieved in that the slots in the charge as a compensator for combustion progressivity are radial slots located in the front of the engine in symmetrical pairs with an angle ratio between slots of one pair and between adjacent slots of adjacent pairs of 0.1-0.4, while the height of the slots is 0.3-0.7 of the magnitude of the charge vault at the location of the slots, and the length of the gaps is 0.05-0.25 of the total length of the engine casing, the magnitude of the vault of charge increases toward the nozzle bottom of the engine.

The proposed design of a solid fuel rocket engine will allow:

- increase the speed of the gas flow in the charge channel, thereby increasing the rate of erosive combustion of fuel in the rest of the charge;

- reduce the initial surface of the slots in 1.5-2 times compared with the cracks of the nozzle location and thereby increase the degree of filling of the engine with fuel;

- increase the heat resistance of the housing in the front part, since the slots are made in the amount of 0.3-0.7 from the full burning arch of the charge;

- to ensure that the charge is burning according to a law close to neutral, when the gaps are made to such a depth and the symmetrical arrangement of the gaps in a circle;

- to provide the required combustion degradation of the slit part due to the location of the slots in pairs with the proposed ratio of the angles between the slots of one pair and between adjacent slots of adjacent pairs;

- eliminate degradingly burning residues and increase the coefficient of volumetric filling of the engine with fuel by performing a charge channel cylindrical in the front part, where erosive combustion is insignificant, and conical in the nozzle part with a minimum channel diameter at the charge end facing the nozzle;

- eliminate the need for additional thermal protection of the nozzle of the housing due to the taper of the channel, tapering to the nozzle, as it provides complete burnout of fuel simultaneously along the entire length of the housing;

- to provide a sharp cut-off thrust due to the absence of degressively dying residues and providing a neutral traction diagram;

- reduce the complexity of the technological process of filling the engine casing with fuel by simplifying the formative equipment (one-piece needle of the channel of the fuel block).

The essence of the invention is illustrated by a diagram of a longitudinal section of the engine, shown in figure 1, and diagrams of cross-sections of the engine, presented in figure 2 and 3.

The proposed engine consists of a housing 1, with front 2 and nozzle 3 bottoms, a protective-fixing layer 4 and a charge 5 of solid fuel. The charge 5 is bonded to the housing 1 by a protective-fixing layer 4. At the front bottom there are slots 6 of height a, comprising 0.3-0.7 of the full burning charge gadget c at the location of the slots. The slots are arranged in symmetrical pairs. The angle ratio between the slots of one pair and between adjacent slots of adjacent pairs α / β lies in the range of 0.1-0.4. The length of the slots is 0.05-0.25 of the total length of the motor housing. The charge vault 5 increases towards the nozzle bottom of the engine due to the transition of the cylindrical channel from the front of the bottom to the tapering towards the nozzle bottom. The taper is determined from the condition of ensuring simultaneous burning of the arch of charge along the entire length of the engine.

The operation of the engine, made in accordance with the invention, is as follows. At the moment the engine is turned on, the gas inlet from the slot compensator increases the gas flow rate in the charge channel, contributing to an increase in the fuel burning rate due to the erosion effect. Since the slots are not made to the full depth of the charge vault and the slots are evenly spaced around the circumference, the slot section burns according to a law close to neutral until the peak reaches the slit of the engine wall. The location of the slots in symmetrical pairs leads to a quick burnout of fuel between the slots of each pair. The presence of a cylindrical channel in the front of the charge and conical in the nozzle with a minimum channel diameter at the end facing the nozzle eliminates degressively dying residues. The taper of the channel provides simultaneous burnout of the arch along the entire length of the charge.

The height and length of the slots, the ratio of the angles between the slots of one pair and between adjacent slots of adjacent pairs and the taper of the channel are determined by calculation in each case, depending on the requirements of the engine, and can be refined in the process of experimental testing.

The performance of the engine, made in accordance with the invention, is confirmed by fire bench tests.

The source of information

1. Patent RU No. 2152529, 7 F02K 9/08 - prototype.

Claims (1)

A solid fuel rocket engine comprising a housing, a front and nozzle bottoms, as well as a solid fuel charge having slots on the front of the engine bottom, characterized in that the solid fuel charge is bonded to the housing with a protective-fixing layer, the charge vault increases towards the nozzle bottom engine due to the transition of the cylindrical channel from the front of the bottom into a tapering towards the nozzle bottom, and the slots are arranged in symmetrical pairs with the ratio of the angles between the slots of one pair and between adjacent slots the neighboring pairs are 0.1-0.4, while the height of the slots a is 0.3-0.7 of the value of the full burning arch of the charge c, and the length of the slots is 0.05-0.25 of the total length of the engine casing.

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