RU2351790C1 - Mechanism of fastening uncooled insert in liquid propellant rocket nozzle - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention relates to rocket engines and can be used in optimising weight-and-thrust characteristics of liquid-propellant rocket engines (LPRE), particularly, in developing and producing LPRE chambers with uncooled detachable nozzle insert. The proposed mechanism comprises a shaped insert with a load-bearing surface, regeneratively cooled nozzle with mating bearing sections intended for fastening mechanisms of removing the insert from nozzle, mechanisms of fastening the inserts in the nozzle and removing it therefrom interacting with the insert bearing surface and the mating bearing sections of the nozzle. The mechanism of fastening the inserts in the nozzle and removing it therefrom represents cylinders with pistons fitted on con rods. Note here that one end of the cylinder with con rod is attached to the insert bearing surface, while the other end is fastened to the mating bearing section of the nozzle. Note also that the cylinder has unions to feed working medium in both the above-piston space and below-piston space. Mind that the insert accommodates the pickups to define its position in the nozzle that are linked up with actuator that control working fluid feed into cylinder spaces. Nozzle seats intended for attachment of mechanisms of removing the insert represents split brackets interconnected by pyrotechnical bolts and arranged on the nozzle manifold.

EFFECT: higher reliability, simpler design.

2 cl, 3 dwg

Description

The invention relates to the field of power plants, namely to rocket engines, and can be used to optimize the mass-energy characteristics of liquid rocket engines (LRE), namely when developing and creating LRE chambers with an uncooled removable nozzle insert.

The LPRE nozzle is optimized for certain conditions and cannot equally efficiently operate in a wide range of heights and pressures - from launch to orbit.

High-altitude rocket engines operating along the entire flight path, in the first section, in dense atmospheric layers, operate in an off-design mode, since the pressure of the expiring combustion products is lower than the pressure of the surrounding atmosphere, which leads to losses in the average trajectory specific impulse of thrust.

To reduce the losses of the average trajectory specific impulse of thrust, an uncooled removable insert, which is a profiled shell, the length, output diameter and expansion of which is lower than the expansion degree of the main nozzle, is installed and held for a predetermined time in the nozzle of the rocket engine. After a certain flight time and gaining a given height, the insert is removed using special mechanisms. In this case, the nozzle provides two modes of operation with different parameters at the nozzle exit. In the first section of the flight, the expansion of the combustion products occurs in the insert with a lower degree of expansion and a pressure at the section of the insert close to the ambient pressure. In the second section of the flight, after removing the insert, the expansion of the combustion products occurs in the nozzle with a design pressure at the nozzle exit close to the ambient pressure.

One of the main trends in modern engine building is the replacement of metal parts and assemblies with parts and assemblies made of composite materials (KM), in particular carbon-carbon and carbon-ceramic composite materials (UKKM and UKKM, respectively).

UKKM and UKKM possess a number of unique properties. They retain high physical and mechanical characteristics to very high temperatures (more than 2000 K), have good erosion resistance, and have a density of 1300 ... 2000 kg / m ³ .

One of the main areas of application of these materials in LRE is uncooled nozzle removable inserts. Experimental studies conducted in Russia show that inserts from CCCM can be installed starting from a wall temperature of 1400 ... 1500 K, and NSN from CCCM - from a wall temperature of 1600 ... 1800 K.

However, the widespread use of LRE chambers with a removable insert from a KM is still limited by the complexity of creating a mechanism for attaching and removing an uncooled insert from a regeneratively cooled nozzle of a LRE, since it is necessary to ensure reliable operation of the insert and its retention in the high-speed flow of combustion products for a given period of time, as well as to take into account the significant difference in the coefficients of thermal expansion of metal and non-metallic elements of the joint.

A known mechanism for attaching an uncooled insert in a nozzle of a liquid propellant rocket engine, comprising a profiled insert with a supporting surface, a regeneratively cooled nozzle with reciprocal support points for attaching mechanisms to remove the insert from the nozzle, mechanisms for attaching the insert to the nozzle and removing it from the nozzle, interacting with the supporting surface of the insert and with reciprocal supporting places on the nozzle (Sinyarev GB, Dobrovolsky MV Liquid rocket engines. Theory and design, M., State publishing house rev nnoj industry, in 1955, 498 to page 122, Fig.54 -. prototype).

The main disadvantages of this mechanism are the significant dimensions and weight, the difficulty of holding the insert in the nozzle and removing the insert from the nozzle.

The objective of the invention is to simplify the design and increase the reliability of the mechanism for mounting the uncooled insert in the nozzle of a liquid propellant rocket engine.

The solution to this problem is achieved by the fact that in the proposed mechanism for mounting an uncooled insert in a nozzle of a liquid propellant rocket engine containing a profiled insert with a supporting surface, a regeneratively cooled nozzle with reciprocal supporting places for fixing mechanisms for removing the insert from the nozzle, mechanisms for fixing the insert in the nozzle and removing it from nozzles interacting with the supporting surface of the insert and with the mating bearing places on the nozzle, according to the invention, the mechanism for fixing and removing the insert is made in the form of cylinders with pistons mounted on rods, one end of the cylinder with a rod mounted on the supporting surface of the insert, the other on the reciprocal supporting location of the nozzle, the cylinder has fittings for supplying the working fluid both in the cavity above the piston and in the cavity under the piston and sensors are installed on the insert, which determine its location in the nozzle and are associated with the actuator controlling the supply of the working fluid to the cylinder cavity.

To improve the mass-dimensional characteristics of the LRE chamber with an uncooled nozzle insert, the supporting place on the nozzle for attaching the insert removal mechanisms is made in the form of detachable brackets interconnected by pyro-bolts and mounted on the nozzle manifold.

A comparative analysis of the claimed invention with the prototype and other known solutions in the art showed that the set of features described is unknown from the existing level of technology, on the basis of which we can conclude that the technical solution meets the criteria of the invention of "novelty".

When analyzing other well-known technical solutions in the art, the features that distinguish the claimed invention from the prototype were not identified, and the set of features set out should not be explicitly for a specialist from the existing level of technology, which allows us to conclude that the claimed technical solution meets the criteria of the invention level".

The compliance of the proposed technical solution with the criterion of the invention "industrial applicability" follows from the following example of a specific embodiment of the mechanism for attaching an uncooled insert in a nozzle of a liquid propellant rocket engine.

The invention is illustrated by drawings, in which Fig. 1 shows an axial section of a nozzle of a rocket engine chamber with a removable nozzle insert installed inside it, Fig. 2 is a view of a nozzle with an insert from the cut side, and Fig. 3 are brackets of a hydraulic cylinder attachment assembly on the nozzle manifold.

The main elements of the proposed mounting unit uncooled insert in the nozzle of the rocket engine are:

1 - regeneratively cooled nozzle LRE;

2 - uncooled insert;

3 - supporting surface of the insert;

4 - cylinder;

5 - the piston;

6 - stock;

7 - detachable bracket;

8 - pyrobolt;

9 - nozzle manifold;

10 - cavity;

11 - fitting;

12 - cavity;

13 - fitting.

In the regeneratively cooled nozzle 1 LRE installed uncooled insert 2 made of composite materials. In the output part of the insert 2, a supporting surface 3 is made. The insert is fixed in the nozzle 1 during engine operation and is removed by means of a mounting mechanism made in the form of several cylinders 4, inside of which pistons 5 with rods 6 are installed. At one end, each cylinder is fixed with using detachable brackets 7 with pyro-bolts 8 on the manifold 9 of the nozzle 1, and on the supporting surface 3 of the insert 2. For connecting / discharging the working fluid into the cavity 10 of the cylinder 4, a fitting 11 is installed for supplying / discharging the working fluid into the cavity 12 of the cylinder 4 the core 13 is installed fitting.

The proposed device operates as follows.

Before starting the rocket engine insert 2 is installed in the nozzle 1 inlet. In the cavity 10 of the cylinder 4 through the nozzle 11 is fed a working fluid under pressure. In this case, the piston 5 is shifted towards the critical section of the nozzle and through the rod 6, mounted on the supporting surface of the insert 2, presses the input part of the insert 2 to the inner surface of the nozzle 1.

During the launch of the LRE, a high-speed flow of combustion products acts on the input edge of the insert, which tends to push the insert out of the nozzle. To avoid this, a working fluid is supplied into the cylinder cavity 10, which acts on the piston 5 and presses the insert through the stem 6 to the inner surface of the nozzle.

During engine operation, due to vibration and uneven outflow of combustion products, lateral forces act on the insert, which tend to move the insert from its working position with its next arbitrary removal from the nozzle by an incident flow of combustion products.

In this case, at the command of the position sensors, the change in the angular and radial position of the insert in the nozzle is detected. Depending on its position, a command is given to feed (tap) the working fluid from the cavity 10 while simultaneously feed (tap) the working fluid into the cavity 11. Thus, by alternately feeding (tap) the working fluid into the cavity (from the cavities) of the cylinders 4, to the actuator command, insert 2 is held in nozzle 1 for the entire duration of the rocket engine.

When removing the insert, the working fluid is fed into the cavity of the 11 cylinders 4. The piston 5 of each cylinder moves towards the cut side of the nozzle 1 and moves the insert towards the cut side. This ensures alignment of the movement of the insert in the nozzle in order to exclude the possibility of impact of the insert on the nozzle when it is removed.

At the same time, or with some time delay, a command is issued to trigger the pyro-bolts 8. The pyro-bolts are triggered, the brackets 7 are disconnected and the fastening mechanism, together with insert 2, is completely removed from the nozzle by the oncoming combustion products.

After removing the insert, an abrupt change in the degree of expansion of the nozzle occurs, and the high-altitude nozzle begins to operate in the calculated mode.

Using the proposed technical solution will allow you to create a dual-mode nozzle rocket engine with improved mass-dimensional characteristics.

Claims (2)

1. The mechanism for mounting an uncooled insert in a nozzle of a liquid propellant rocket engine, comprising a profiled insert with a supporting surface, a regeneratively cooled nozzle with reciprocal support points for attaching mechanisms to remove the insert from the nozzle, mechanisms for attaching the insert to the nozzle and removing it from the nozzle, interacting with the supporting surface of the insert and with reciprocal supporting places on the nozzle, characterized in that the mechanism for fixing and removing the insert is made in the form of cylinders with pistons mounted on the rods, while the dyne end of the cylinder with the rod is fixed on the supporting surface of the insert, the other on the reciprocal supporting place of the nozzle, the cylinder has a fitting for supplying the working fluid both in the cavity above the piston and in the cavity under the piston, and sensors are installed on the insert to determine its location in the nozzle and associated with the actuator controlling the supply of the working fluid in the cavity of the cylinders. 2. The fastening mechanism of the uncooled insert according to claim 1, characterized in that the supporting place on the nozzle for attaching the insert removal mechanisms is made in the form of detachable brackets interconnected by pyro-bolts and mounted on the nozzle manifold.

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