RU2352445C2 - Method of producing liquid-propellant rocket engine chamber nozzle critical section assembly - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: method of producing liquid-propellant rocket engine chamber nozzle critical section assembly comprises producing inner and outer casings. Inner casing represents a cylinder at the nozzle subcritical part and a truncated cone at the nozzle supercritical part. Outer casing represents two mating truncated cones. Inner casing outer surface is furnished with ribbed surfaces and circular grooves arranged on its end cylindrical section. The first of circular grooves houses a solder fitted into the depth smaller than that of the groove and representing band sections tightly fitting to each other. The solder representing galvanic layers is applied onto the mating surfaces of both casings. The structure thus assembled is fitted onto the mandrel to flare the inner casing cylindrical part. The cooling passage is vacuumised. The soldering is made in the furnace at the protective gas pressure.

EFFECT: higher quality of soldered nozzle critical section assembly thanks to increased density of soldered seam in nozzle subcritical part face area.

7 cl, 2 ex, 3 dwg

Description

Technical field

The invention relates to the field of power engineering, in particular to the manufacture of a critical section block of a nozzle of a chamber of a liquid propellant rocket engine.

State of the art

A known method of manufacturing a block of the critical section of the nozzle of the chamber of a liquid propellant rocket engine, according to which a power and thin-walled shell is made, the inner shell is made with regenerative cooling channels separated by fins. In this design, solder (copper-silver) is galvanically applied to the tops of the ribs, and a thin layer of copper is applied to the inner surface of the power shell in the same way.

Next, these shells are assembled and brazed in a furnace according to known technology (see RF patent No. 2158666, MKI B23K 1/02, 2000). This technical solution is an analogue of the claimed invention.

Unfortunately, the description of this invention does not describe the mechanism for forcing the thin-walled shell to the force shell.

A known method of manufacturing a soldered block of the critical section of the nozzle of the chamber of a liquid propellant rocket engine containing the outer and inner shells ("Design and construction of liquid rocket engines" edited by prof. G.G. Gakhun, Moscow, "Engineering", 1989, pp. 101, 108 -112). The method includes manufacturing an outer shell in the form of two conjugated truncated cones and an inner shell in the form of a cylinder in the subcritical part of the nozzle and in the form of a truncated cone in its supercritical part. The inner shell is made of a heat-conducting plastic alloy based on copper. On its outer surface, longitudinal grooves are designed to supply a cooler to them. Solder in the form of galvanic layers of a given thickness is applied to the brazed surfaces of both shells. The shells are assembled to form a cooling path between them, and then a part of the inner shell having the shape of a cylinder is flared until the ribs come in contact with the inner surface of the outer shell. Next, the cooling duct is evacuated and the assembled nozzle structure is soldered in a furnace under the pressure of a protective gas. This technical decision is taken as a prototype of the invention.

The disadvantage of this method of manufacturing this design is that during flaring there is an increase in the area of part of the inner shell by 30-40%, which entails a decrease in the amount of solder on its finned surface, especially in the end zone. The lack of solder in this zone contributes to the formation of jaws between the shells during the soldering process, which can lead to their depressurization after soldering.

Disclosure of invention

The objective of the invention is the search for such a technology of soldering the end section of the conical part of the thin-walled shell of a subcritical section of the nozzle with the inner surface of the power shell of the critical section section of the nozzle of the chamber of a liquid rocket engine, which would provide an increase in the density of the soldered seam in its end zone by introducing an additional amount of solder into this zone .

This problem is solved due to the fact that in the method of manufacturing a block of the critical section of the nozzle of the chamber of a liquid propellant rocket engine, the apparatus comprising the manufacture of an outer shell in the form of two conjugated truncated cones and an inner shell in the form of a cylinder in the subcritical part of the nozzle and in the form of a truncated cone in its supercritical part ; cutting longitudinal grooves on the outer surface of the inner shell with the formation of a finned surface, applying solder in the form of galvanic layers of a given thickness to the soldered surfaces of both shells; assembling the shells with the formation of the cooling path between them, installing the assembled structure on the frame and expanding the cylindrical part of the inner shell to contact the inner surface of the outer shell; evacuation of the cooling path of the assembled structure and its soldering in the furnace under protective gas pressure, while before assembling the shells on the outer surface of the end section of the inner cylindrical shell, solder in the form of pieces of tape is tightly connected to each other to a depth less than the depth of the groove; each piece of solder tape is fixed in the groove mainly by punching the solder.

Other differences of the invention are:

- the outer shell is made of high alloy steel;

- the inner shell is made of an alloy based on copper;

- solder in the form of a layer of galvanic copper is applied to the inner surface of the outer shell;

- solder in the form of galvanic copper-silver layers is applied to the fin surface of the inner shell;

- pieces of solder tape are fixed in cylindrical grooves on both sides of the tape at several points.

The technical result is an increase in the quality of the soldered block of the critical section of the nozzle of the chamber of a liquid rocket engine by increasing the density of the soldered seam in the end zone of the subcritical part of the nozzle.

Brief Description of the Drawings

Figure 1 shows a section of a critical section block of a nozzle of a chamber of a liquid propellant rocket engine, figure 2 shows a fragment 1 of a section of a soldered section of Fig. 1, figure 3 shows a section of a section of a critical section of a nozzle of a chamber of a liquid propellant rocket before expansion.

An example implementation of the invention

The critical section section of the nozzle of the chamber of the liquid-propellant rocket engine 1 (Fig. 1) includes a power shell 2 made in the form of truncated cones 3 and 4 conjugated to each other, and an internal thin-walled shell 5. The power shell 2 is made of high-strength steel, and the inner 5 is made of copper alloy. The outer surface of the shell 5 is made with longitudinal channels 6 formed by ribs, while the conical section 7 of the shell 5 (Fig. 2) is made not ribbed, and annular grooves are made on its external surface. Fig. 2 shows that one of these grooves placed solder 9. The connection of the inner shell 5 and the power shell 2 is carried out by soldering. Before soldering, solder is applied to the tops of the ribs in a galvanic manner, which is also applied to the inner surface of the power shell.

Construction manufacturing example

The power shell 2 was made of high-alloy steel of the VNS-16 grade in the form of two truncated cones 3 and 4 conjugated to each other. As a material of the inner shell 5, a copper alloy of the grade BrX08 was used. Moreover, at the beginning, the inner shell 5 was made in the form of a billet having a cylindrical shape with a diameter equal to the critical diameter of the nozzle and the shape of a truncated cone in its supercritical part. Next, this preform was inserted inside the power shell, as shown in Fig.3. The outer surface of this workpiece is made with longitudinal channels 6, separated by ribs, and the end portion of the outer cylindrical part of the workpiece is made not ribbed, and ring grooves are made on its outer surface (FIG. 2). On the tops of the ribs and the cylindrical surface of the end portion of the inner shell, a solder was applied in a galvanic manner — a copper layer 20–25 μm thick and a silver layer 5–8 μm thick. PSr5, 5 copper-silver solder in the form of pieces of tape 50-70 mm long, 1.2 mm wide and 0.5 mm thick to a depth less than the depth of the groove was laid tightly to one another in one of the grooves with the formation of a protrusion of the inner shell above the surface of the solder . Each piece of solder tape was fixed by punching the solder. The sections of the solder tape were fixed from its two sides at several points of the groove edge, for example, when the length of the segment was 50 mm, fastening was carried out at two points. Solder was deposited on the inner surface of the outer shell in the form of a galvanic copper layer 12-14 microns thick.

Next, the assembled structure was mounted on the frame, and after that the cylindrical section of the inner shell was flared until the ribs contacted with the inner surface of the outer shell. After that, the shells were technologically welded according to the allowances at the ends of the block, and then air was displaced from the longitudinal channels with gaseous argon, after which the cavities of the longitudinal channels were evacuated. The vacuum unit was placed in a furnace where gaseous argon was supplied under a pressure of up to 5 MPa. Soldering was carried out at a temperature of 970 ± 10 ° C. After soldering and cutting sections with technological welding at the ends, strength checks and preparation of the connection with other parts of the chamber of a liquid rocket engine were performed.

The implementation of the annular grooves on the outer surface of the end portion of the cylindrical billet filled with solder made it possible to achieve a high tightness of the soldered joint of two shells after soldering.

Industrial application

The design of the critical section section of the nozzle of the chamber, made according to the proposed technology, is recommended for use in chambers of liquid-propellant engines.

Claims (7)

1. A method of manufacturing a block of a critical section of a nozzle of a chamber of a liquid propellant rocket engine containing an inner and outer shell, comprising manufacturing an outer shell in the form of two conjugated truncated cones and an inner shell with a cylindrical part in the subcritical part of the nozzle and a truncated cone in the supercritical part of the nozzle, cutting longitudinal grooves on the outer surface of the inner shell with the formation of a finned surface and a non-ribbed end portion of the cylindrical part, applied on top the springs of both solder shells in the form of galvanic layers of a given thickness, assembling the shells with the formation of a cooling path between them, installing the assembled structure on the frame and expanding the cylindrical part of the inner shell to contact the inner surface of the outer shell, evacuating the cooling path of the assembled structure and soldering it in a furnace under shielding gas pressure, characterized in that before assembling the shells on the outer surface of the non-finned end portion of the cylindrical part of the inner operate span of annular grooves in the first of which a depth less than the depth of the groove, the solder is laid in a tightly contiguous tape sections. 2. The method according to claim 1, characterized in that the pieces of solder tape are fixed in the annular groove mainly by punching the solder. 3. The method according to claim 1, characterized in that the outer shell is made of high alloy steel VIS-16. 4. The method according to claim 1, characterized in that the inner shell is made of an alloy based on copper grade BrX08. 5. The method according to claim 1, characterized in that the solder in the form of a layer of galvanic copper is applied to the inner surface of the outer shell. 6. The method according to claim 1, characterized in that the solder in the form of galvanic copper-silver layers is applied to the fin surface of the inner shell. 7. The method according to claim 1, characterized in that they use pieces of tape made of silver-silver solder PSr5.5, which are fixed at both ends at several points of the edge of the annular groove.

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