RU2312999C1 - Solid-propellant rocket engine - Google Patents

Abstract

FIELD: rocketry; construction of solid-propellant rocket engines with fastened composite propellant charge, for example in cruising engines of winged missiles of short radius of action.

SUBSTANCE: proposed solid-propellant rocket engine has body with unrestricted end faces; engine is secured to heat-resistant central tube. Heat-resistant central tube is mounted along axis of charge and is fastened with charge channel and is secured to grids located near rear and front heads of body resting on it. Heat-resistant central tube is made from rigid material, from metal for example, covered with heat protective coat or from composite material. Split collar fitted in between outer surface of charge and body is provided with continuous strip in its center part.

EFFECT: enhanced reliability of rocket engine due to reduction of stresses in charge and avoidance of propellant separation into plies; increased total pulse of jet force due to increased mass of propellant.

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Description

The invention relates to rocket technology and can be used in the construction of solid propellant rocket engines (solid propellant rocket engines) with a solidly bonded mixed solid fuel charge, for example, in marching engines of short-range cruise missiles.

A known design of the cruise solid propellant solid-propellant cruise missile with a long operating time (150-300 s), consisting of a cylindrical body, in the middle part of which there are several nozzles whose axes are located at an angle of 15 ... 20 ° to the longitudinal axis of the engine. A solid fuel charge consists of two half-charges reserved on all surfaces except one end. The burning surfaces of the half charges are facing each other, which ensures the constancy of the center of mass of the engine during its operation [see I.Kh. Fakhrutdinov, A.V. Kotelnikov. Design and engineering of solid propellant rocket engines. M., Mechanical Engineering, 1987, p. 28].

A disadvantage of the known device is the low value of the total impulse of reactive force. The reason for this is the use of an end-to-end combustion charge, in which a sufficiently large volume of the combustion chamber occupies heat-protective and armor coatings, as well as a guaranteed gap between these coatings (stagnant zone). In addition, the presence of inclined nozzles increases the loss of engine thrust.

The known design of the solid propellant rocket motor, consisting of a shell, front and rear bottoms, on the last of which a nozzle is installed, the axis of which coincides with the longitudinal axis of the engine. The charge is made firmly bonded in outer diameter to the motor housing. Along the longitudinal axis of the charge, a heat-resistant elastic pipe is installed, firmly bonded to the charge channel, which serves as the gas duct and the armor coating of the charge channel. The charge burns from both ends, which ensures the constancy of the center of mass of the engine [see US patent No. 3765177, priority of October 16, 1973, CL. F02K 9/04]. This device is adopted as a prototype.

The features of the prototype, which are common with the claimed invention, are a housing with a coaxial nozzle, a charge with unarmored ends, bonded to a heat-resistant central tube mounted along the charge axis and firmly bonded to the charge channel.

A disadvantage of the known device adopted for the prototype is the high stress-strain state of the charge, due to the fact that the charge is firmly bonded in outer diameter to the motor housing and when the temperature decreases, it begins to compress and tends to break away from the housing in its maximum diametric size. This leads to high stresses on the charge-housing contact and significant deformations of the fuel in the channel area and, consequently, to a decrease in engine reliability. In addition, the disadvantage is the low reliability of the armor coating, which will be in the high-temperature flow of combustion products, and under loading by external pressure due to the pressure difference between the combustion zone and the charge channel.

The objective of the invention is to increase the reliability and full impulse of solid propellant solid propellant rocket motor for a long time.

The problem is solved due to the fact that in the well-known solid-fuel rocket engine containing a housing with a coaxial nozzle located, a charge with unarmoured ends bonded to a heat-resistant central tube mounted along the charge axis and firmly bonded to the charge channel, the heat-resistant central tube is made of rigid material, for example, from metal with a heat-insulating coating or from composite material, and is fixed to gratings located at the rear and front bottom of the housing and supported and a housing between the outer surface of the charge and the casing installed split sleeve, having in the middle a continuous crosspiece.

The features of the proposed device, distinctive from the prototype, are the construction of a heat-resistant central pipe made of hard material, for example, metal with a heat-insulating coating or composite material, and fixed to the grilles that are located at the rear and front bottom of the body and rest on the body; the presence of a split cuff installed between the outer surface of the charge and the housing and having a solid jumper in the middle part.

Due to the fact that the charge is bonded to the engine housing on the surface of the charge channel, the contact between the mount and the fuel occurs at the minimum diameter, which reduces the stress-strain state of the charge. As the temperature decreases, the charge begins to compress and fits the rigid central tube. The maximum stresses are reduced by 3 ... 5 times. In addition, the detachment of fuel from the housing is completely eliminated. All this leads to an increase in engine reliability. Reducing the stress-strain state makes it possible to increase the ratio between the outer and inner diameters of the charge. This will increase the coefficient of lateral filling of the combustion chamber with fuel, increase the total momentum of the reactive power of the engine and the range of the rocket. The heat-resistant central tube performs the function of not only thermal protection, but also the power element on which the charge is attached, so it must have the necessary strength and rigidity. It can be made of composite material or of metal with a heat-protective coating. The central pipe is attached to the grilles installed in the front and rear bottoms of the engine housing and transferring the load to the housing. To protect the outer surface of the charge from burning, a split cuff is installed on it, one surface fastened to the inner surface of the housing, and the other to the outer surface of the charge. In order to prevent the flow of combustion products along the mantle cavity, the incision is not made in its middle part.

Figure 1 shows a General view of the solid-state solid-propellant rocket engine for a long time.

Figure 2 shows fragment A in figure 1.

Figure 3 shows a fragment of B in figure 1.

The design of the solid-state solid-propellant solid-propellant rocket engine for a long time includes a housing 1 with a coaxial nozzle 2, a solid fuel charge 3 bonded to a heat-resistant central pipe 4. The central pipe 4 is attached to the grilles 5, which are located at the rear and front bottom of the housing 1 and rest on the housing 1. Between the outer surface of the charge 3 and the inner surface of the housing 1 is installed a split cuff 6, having in the middle part a solid jumper.

The proposed device operates as follows. During operation, the engine is affected by fluctuations in ambient temperature, temperature stresses occur in the charge 3, which are absorbed by the central tube 4. The stresses in this place will be compressive, therefore, fuel detachments from the central tube 4 are excluded. There are no stresses at the charge-casing of the engine due to the presence of the split cuff 6. There is no cut in the middle part of the cuff 6, therefore rather high stresses arise in this part, but they are not perceived by fuel, but by rubber, the physicomechanical characteristics of which are much higher, than fuel. When the engine starts, the ends of the charge 3 are ignited, the products of combustion from the front end of the charge 3 pass through the hole of the central pipe 4, mix with the products of combustion from the rear end of the charge 3 and expire through the nozzle 2, the axis of which is parallel to the axis of the housing. Combustion products also fill the cavity. The flow of combustion products in the gap between the outer surface of the charge 3 and the housing 1 of the engine is excluded by the presence of an uncut part of the cuff in its middle part.

The proposed device allows to increase the reliability of the engine by reducing the voltage in the charge by 3 ... 5 times and eliminating delamination of the fuel while increasing the total impulse of the reactive power of the engine by 4 ... 6% due to the increase in fuel mass.

Claims (1)

A solid fuel rocket engine comprising a housing with a coaxial nozzle, a charge with unarmoured ends, bonded to a heat-resistant central tube mounted along the charge axis and firmly bonded to the charge channel, characterized in that the heat-resistant central tube is made of hard material, for example, metal coated with a heat-shielding coating or made of composite material, and fixed to gratings located at the rear and front bottom of the housing and resting on the housing, between the outer surface th charge and the body is installed a split cuff, having in the middle part a solid jumper.

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