Variable-expansion-ratio spray pipe of single-chamber double-thrust solid rocket engine

Abstract

The utility model belongs to the field of solid rocket engine design, and provides a variable-expansion-ratio spray pipe of a single-chamber double-thrust solid rocket engine, which comprises an engine rear seal head, a spray pipe expansion section front section and a spray pipe expansion section rear section. The nozzle expansion section front section and the nozzle expansion section rear section are assembled in a cylindrical sleeving mode and fixed through screws, a cutting rope is arranged on the inner side of the nozzle expansion section rear section, a weakening groove is formed in the outer surface of the nozzle expansion section rear section, the detonating device is installed near the annular cutting rope, and the detonating device detonates and ignites the cutting rope. The rear section of the nozzle expansion section is cut off from the weakening groove, and the rear section of the nozzle expansion section is separated from the front section of the nozzle expansion section under the action of internal pressure of a combustion chamber, so that the expansion ratio of the nozzle is variable, two optimal working states of a boosting working section and an endurance working section of a single-chamber double-thrust solid rocket engine can be met, and the working efficiency of the nozzle is improved.

Description

Technical Field

[0001] The utility model belongs to the field of solid rocket engine design, in particular to a single-chamber dual-thrust solid rocket engine with a variable expansion ratio nozzle. Background Art

[0002] Solid rocket engine nozzle efficiency enhancement technology is a key technology for solid rocket engines. Its primary function is to address the operating characteristics of single-chamber, dual-thrust engines. The first stage, with its high thrust, operates in the boost phase. To provide initial acceleration, it corresponds to a higher operating pressure and requires a larger nozzle expansion ratio to improve nozzle efficiency. The second stage, with its low thrust, operates in the endurance phase, ensuring thrust-drag balance during flight. It corresponds to a lower operating pressure and requires a relatively smaller nozzle expansion ratio to improve nozzle efficiency. To adapt to these operating conditions, a two-stage nozzle expansion section design is employed. After the first stage's thrust is complete, the rear nozzle expansion section is severed at the weakening groove using a cutting cable. Under the action of the combustion chamber's internal pressure, the rear nozzle expansion section is separated from the front nozzle expansion section and ejected from the projectile, thereby improving engine performance during the endurance phase.

[0003] At present, single-chamber dual-thrust solid rocket engines mostly use a fixed expansion ratio nozzle. Although certain achievements have been made in the field of solid rocket engine nozzle efficiency improvement technology and engine performance has been improved, there are still many shortcomings, which are as follows: First, under the two working pressure states, the conventional fixed expansion ratio nozzle cannot take into account the two design states, which will cause one or both thrusts (working pressures) to be in a non-design state. If the high thrust (high pressure) working state is taken into account, the nozzle is in an over-expanded working state when working at low thrust (low pressure), resulting in a certain energy loss, which reduces the nozzle working efficiency. At the same time, the excess part of the nozzle expansion section will still produce a certain negative mass; if the low pressure working state is taken into account, the nozzle is in an under-expanded working state when working at high pressure, resulting in a certain energy loss, which reduces the nozzle working efficiency; second, the conventional fixed expansion ratio nozzle can only improve the nozzle working efficiency by optimizing the inner profile of the nozzle expansion section. It is a fixed inner profile and has a bottleneck. Summary of the Invention

[0004] In order to solve the above problems, the utility model provides a single-chamber dual-thrust solid rocket engine with a variable expansion ratio nozzle, which can take into account both the boost working section and the endurance working section of the single-chamber dual-thrust solid rocket engine, thereby improving the working efficiency of the nozzle.

[0005] The technical solutions of the present invention are as follows:

[0006] The utility model provides a single-chamber, dual-thrust solid rocket engine variable expansion ratio nozzle, comprising an engine rear end cap, a nozzle expansion front section, and a nozzle expansion rear section. The engine rear end cap and the nozzle expansion front section are connected by threads, and the nozzle expansion front section and the nozzle expansion rear section are assembled using a cylindrical sleeve connection and secured by screws. A cutting rope is arranged on the inner side of the nozzle expansion rear section with epoxy resin adhesive, and a protective cover is installed on the outer side of the cutting rope, which is also adhered to the inner side of the nozzle expansion rear section with epoxy resin adhesive. A weakening groove is provided on the outer surface of the nozzle expansion rear section, and an initiator is installed near the annular cutting rope.

[0007] Furthermore, the number and width of the weakening grooves are determined based on the thickness and diameter of the expansion section of the separation nozzle, and the number of grooves can be selected to be 1 to 10, and the groove width can be selected to be 1 mm to 20 mm.

[0008] Furthermore, the weakening position of the weakening groove is determined according to the nozzle expansion ratio required for the low-thrust working state of the engine, and can be selected to be 10mm to 400mm away from the straight section of the nozzle.

[0009] Furthermore, the weakening groove is provided with two U-shaped grooves arranged 180 degrees in a circumferential direction, and the cutting rope is installed through the U-shaped grooves during assembly.

[0010] Furthermore, the weakened groove is equipped with a detonating device for cutting the rope.

[0011] Furthermore, the detonating devices are arranged symmetrically in a 180° circle, and the number is 2.

[0012] Furthermore, the number and diameter of the screws are determined according to the connection strength between the rear section of the nozzle expansion section housing and the front section of the nozzle expansion section housing. A specification of (4-48)×(M2-M9) can be selected.

[0013] The beneficial effects of the present invention are as follows:

[0014] The utility model installs a cutting rope on the nozzle of a single-chamber dual-thrust solid rocket engine and ignites the cutting rope through an initiator, thereby achieving a variable nozzle expansion ratio. It can take into account both the boosting working section and the endurance working section of the single-chamber dual-thrust solid rocket engine, so that the engine nozzle working efficiency reaches the optimal level in both working states, breaking through the technical bottleneck of conventional nozzles that can only improve the nozzle working efficiency by optimizing the inner surface of the nozzle expansion section. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Attachment Figure 1 Schematic diagram of the variable expansion ratio nozzle structure

[0016] Attachment Figure 2 Schematic diagram of a cross-section of a variable expansion ratio nozzle

[0017] Attachment Figure 3Schematic diagram of the cut cord detonation part

[0018] Attachment Figure 4 Schematic diagram of a single-chamber dual-thrust solid rocket engine in high-thrust working state

[0019] Attachment Figure 5 Schematic diagram of a single-chamber dual-thrust solid rocket engine in low-thrust working state

[0020] Among them, 1 is the engine rear head, 2 is the screw, 3 is the front section of the nozzle expansion section, 4 is the rear section of the nozzle expansion section, 5 is the weakening groove, 6 is the cutting rope, 7 is the protective cover, 8 is the U-shaped groove, and 9 is the detonator. DETAILED DESCRIPTION

[0021] This section is an embodiment of the present invention, which is used to explain and illustrate the technical solution of the present invention. In the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0022] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0023] like Figures 1 to 3 As shown, the utility model is a single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle, including an engine rear head 1, a nozzle expansion section front section 3, and a nozzle expansion section rear section 4. The engine rear head 1 and the nozzle expansion section front section 3 are connected by threads, and the nozzle expansion section front section 3 and the nozzle expansion section rear section 4 are assembled in a cylindrical sleeve manner and fixed by screws 2. A cutting rope 6 is arranged on the inner side of the nozzle expansion section rear section 4 by epoxy resin glue, and a protective cover 7 is installed on the outside of the cutting rope 6. The protective cover 7 is glued to the inner side of the nozzle expansion section rear section 4 by epoxy resin glue. A weakening groove 5 is provided on the outer surface of the nozzle expansion section rear section 4, and an initiator 9 is installed near the annular cutting rope 6.

[0024] The number and width of the weakening grooves 5 are determined based on the thickness and diameter of the expansion section of the separation nozzle. The number of the weakening grooves 5 can be 1 to 10, and the width can be 1 mm to 20 mm.

[0025] The weakening position of the weakening groove 5 is determined according to the nozzle expansion ratio required for the low-thrust working state of the engine, and can be selected to be 10mm to 400mm away from the straight section of the nozzle.

[0026] The weakening groove 5 is provided with two U-shaped grooves 8 arranged at 180 degrees in a circumferential direction. During assembly, the cutting rope (6) is inserted into the U-shaped grooves (8).

[0027] The weakened groove 5 is provided with a detonating device 9 for cutting the rope 6 .

[0028] The detonating devices 9 are arranged symmetrically in a 180° circle.

[0029] The screw 2 can be selected with specifications of (4-48)×(M2-M9).

[0030] The number and diameter of the screws 2 are determined according to the connection strength between the rear section 4 of the nozzle expansion section housing and the front section 3 of the nozzle expansion section housing.

[0031] In order to adapt to the two different working states of the single-chamber dual-thrust solid rocket engine, improve the nozzle working efficiency and improve the engine performance, a variable nozzle expansion ratio design method is provided. At the end of the engine boost working phase, Figure 4 As shown, a detonation command and a power supply current are sent to the detonator 9, the detonator 9 detonates, ignites the cutting rope 6, ensures that the weakening groove 5 is reliably broken when the cutting rope 6 works, and effectively separates the rear section 4 of the nozzle expansion section from the projectile under the action of the internal pressure of the combustion chamber, waiting for the single-chamber dual-thrust solid rocket engine to enter the endurance working section, as shown in FIG. Figure 5 As shown, a portion of the passive mass is reduced at the same time. Conventional fixed expansion ratio nozzles cannot take into account both design states and have a certain amount of energy loss. This embodiment can effectively solve this technical problem.

[0032] Although preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they become aware of the basic inventive concepts. Therefore, the scope of protection of this application is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of this application. Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of protection of this application and its equivalents, then this application is also intended to include these modifications and variations.

Claims

1. A single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle, characterized in that: The invention comprises an engine rear head (1), a nozzle expansion section front section (3), and a nozzle expansion section rear section (4); the engine rear head (1) and the nozzle expansion section front section (3) are connected by threads; the nozzle expansion section front section (3) and the nozzle expansion section rear section (4) are assembled in a cylindrical sleeve manner and fixed by screws (2); a cutting rope (6) is bonded to the inner side of the nozzle expansion section rear section (4); a protective outer cover (7) is installed on the outside of the cutting rope (6); the protective outer cover (7) is bonded to the inner side of the nozzle expansion section rear section (4); a weakening groove (5) is provided on the outer surface of the nozzle expansion section rear section (4); and a detonating device (9) is installed near the annular cutting rope (6).

2. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The number and width of the weakening grooves (5) are determined based on the thickness and diameter of the expansion section of the separation nozzle, and the number of grooves can be selected to be 1 to 10, and the width can be 1 mm to 20 mm.

3. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The weakening position of the weakening groove (5) is determined according to the nozzle expansion ratio required for the low-thrust working state of the engine, and can be selected to be 10mm to 400mm away from the straight section of the nozzle.

4. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that Two U-shaped grooves (8) are arranged at an angle of 180 degrees in the weakening groove (5), and the cutting rope (6) is inserted into the U-shaped grooves (8) during assembly.

5. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The weakened groove (5) is provided with a detonating device (9) for cutting the rope (6).

6. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The detonating devices (9) are arranged symmetrically in a 180° circumferential direction.

7. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The screw (2) can be selected with specifications of (4-48)×(M2-M9).

8. The single-chamber dual-thrust solid rocket engine variable expansion ratio nozzle according to claim 1, characterized in that The number and diameter of the screws (2) are determined according to the connection strength between the front section (3) of the nozzle expansion section and the rear section (4) of the nozzle expansion section.

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