Water pressure detection device for solid rocket engine

Abstract

The invention discloses a water pressure detection device for a solid rocket engine. The device consists of a combustion chamber shell, a spray pipe shell, a top cover, a rear blanking cap, a cushion block, a sealing ring, a bolt and a locking nut, the top cover is connected with the front connector through a bolt, and a first sealing ring is arranged on the front connector of the combustion chamber shell. The spray pipe shell is connected with a combustion chamber shell rear connector through a bolt, and a second sealing ring is arranged on the combustion chamber shell rear connector. A step is arranged on the largest outer cylindrical surface of the rear blanking cap and forms an end face sealing groove with the tail step of the spray pipe shell, and a third sealing ring is installed; the small end of the rear blanking cap is provided with an external thread, penetrates through the step at the tail part of the spray pipe shell and the cushion block, and is tensioned by the locking nut; the middle of the rear blanking cap is provided with a through hole as a water inlet channel, and the small end is provided with internal threads for connecting a water inlet pipe. The pressure bearing capacity of the combustion chamber shell, the spray pipe shell and the top cover is examined through one-time hydraulic test, the sealing performance of the sealing ring and the strength performance of the connecting structure are examined, and efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of solid rocket motor testing technology, and more specifically to a solid rocket motor water pressure testing device. Background Technology

[0002] A solid rocket motor is a jet propulsion device that directly generates reaction force. The high-temperature, high-pressure gas produced by the combustion of solid propellant is discharged at high speed through a nozzle, generating reaction thrust. It typically consists of a propellant grain, a combustion chamber shell, a nozzle, an ignition device, and a top cover. Because the engine generates significant internal pressure during operation, the combustion chamber shell, nozzle shell, and top cover need to be subjected to hydrostatic testing. Existing technologies often perform hydrostatic tests on the combustion chamber shell, nozzle shell, and top cover separately, requiring the design of multiple sets of tooling. Furthermore, the aforementioned tooling patents restrict the free deformation of the shell under internal hydrostatic pressure, which does not match the actual internal pressure conditions.

[0003] Chinese patent CN220583962U discloses a hydraulic pressure testing fixture. This device includes a combustion chamber shell and a nozzle shell connected by an annular pressure block, a radial seal with an O-ring, and a water inlet core rod tightened by a tension screw and an end face cap to seal the front opening of the combustion chamber shell and the end face of the nozzle shell. This testing fixture restricts the axial deformation of the combustion chamber shell and the nozzle shell, which is inconsistent with the actual working conditions of a solid rocket motor. During actual operation of a solid rocket motor, the combustion chamber shell and the nozzle shell will undergo axial deformation under internal pressure.

[0004] Chinese patent CN116625663A discloses a hydraulic inspection and water pressure burst test fixture for a small long-tail nozzle housing. This fixture includes a nozzle housing connected to a front sealing disc assembly and a rear sealing disc, achieving radial sealing via sealing rings 1 and 2, and secured by a threaded tie rod, spring washer, and nut. Under internal water pressure, the axial deformation of the nozzle housing is restricted by this test fixture.

[0005] Chinese patent CN106979097A discloses a hydrostatic testing device for a solid rocket engine combustor shell, suitable for large-diameter combustor shells. The combustor shell is placed on two support frames within a load-bearing vertical platform. The front and rear joints of the combustor shell are connected and sealed using front and rear plugs, respectively. One end of the thrust frame contacts the load-bearing vertical platform, and the other end connects to the front skirt of the combustor shell. An axial through hole is formed in the center of the rear plug, through which an unloading piston is inserted into the combustor shell. The unloading piston and the rear plug are sealed by a sealing ring. The cross-sectional area of ​​the unloading piston in this testing device is equal to the area of ​​the nozzle throat of the solid rocket engine. Under the action of water pressure inside the combustor shell, the unloading piston moves backward under axial pressure, transferring the force to the load-bearing support. The magnitude of this axial force is approximately equal to the pressure load on the nozzle throat area, simulating the unloading effect of the nozzle on the internal pressure of the combustor shell, which is more consistent with the actual pressure situation of the combustor shell. However, the front skirt of the combustion chamber shell is connected to the thrust frame and presses against the load-bearing vertical platform, which limits the axial deformation of the front skirt.

[0006] In the aforementioned patent, a single hydrostatic test only assessed the pressure-bearing capacity of the combustion chamber shell, nozzle shell, or the combustion chamber shell and nozzle shell, without assessing the pressure-bearing capacity of the solid rocket engine top cover and connecting structure, or the sealing performance of the sealing ring. This resulted in low efficiency and an incomplete assessment. Summary of the Invention

[0007] Based on the above-mentioned technical problems, this invention proposes a solid rocket engine water pressure testing device to solve the problems of existing water pressure tests failing to assess the pressure-bearing capacity of the solid rocket engine top cover and connecting structure, the sealing performance of the sealing ring, and low efficiency.

[0008] To solve the above-mentioned technical problems, one of the objectives of this invention is to provide a solid rocket engine water pressure testing device, which consists of a combustion chamber shell 1, a nozzle shell 2, a top cover 3, a rear plug 4, a pad 5, a first sealing ring 6, a bolt 7, a lock nut 8, a second sealing ring 10, a third sealing ring 11, and a bracket 9. The water pressure testing device is placed horizontally and supported by only two brackets 9, without any other constraints that restrict the free deformation of the shell; The combustion chamber housing 1 has a sealing groove on the front connector, and a matching sealing ring 6 is installed; the top cover 3 is connected to the front connector by bolts 7. The combustion chamber housing 1 has a sealing groove on the rear connector, and a matching sealing ring 10 is installed; the nozzle housing 2 is connected to the rear connector by bolts 7. A step is provided on the maximum outer cylindrical surface of the rear plug 4 to form an end face sealing groove with the tail step of the nozzle housing 2, and a sealing ring 311 is installed for sealing. The rear plug 4 has an external thread at its small end, which passes through the tail step and pad 5 of the nozzle housing 2 and is tightened by the locking nut 8. The rear plug 4 has a through hole in the middle as a water inlet channel, and an internal thread at the small end for connecting the water inlet pipe.

[0009] Furthermore, the assembly of the front and rear joints of the combustion chamber shell 1 with the top cover 3 and the nozzle shell 2 is carried out according to the formal assembly process of solid rocket engines, by tightening the bolts at the designated points and applying the specified torque.

[0010] Furthermore, the outer diameter of the pad 5 is equivalent to the outer diameter of the straight section of the nozzle housing 2, and it is placed at the tail of the nozzle housing to limit the deformation of the tail end step of the nozzle housing and to limit the locking nut.

[0011] Furthermore, the large end of the water inlet channel of the rear plug 4 is provided with a 60° chamfer to change the force direction of the rear plug and alleviate the stress deformation of the shell.

[0012] Furthermore, the maximum outer cylindrical surface of the rear plug 4 is tightly fitted with the inner hole of the straight section of the nozzle housing 2, serving as a positioning feature for the rear plug.

[0013] Furthermore, the sealing ring one, sealing ring two, and sealing ring three are O-rings.

[0014] The above-described one or more technical solutions of the present invention have at least one or more of the following technical effects: A single hydrostatic test simultaneously assesses the pressure-bearing capacity of the combustion chamber shell, nozzle shell, and top cover, as well as the sealing performance of the sealing ring and the strength of the connection structure, thus improving efficiency. The water pressure testing device does not apply constraints to the outside of the combustion chamber shell or nozzle shell, simulating the real working condition of a solid rocket engine under internal pressure, and the test results are more realistic and accurate. The water pressure testing device was assembled using the formal assembly process of a solid rocket engine, simulating the actual assembly process of a solid rocket engine and providing more thorough verification. Attached Figure Description

[0015] Figure 1 Schematic diagram of the water pressure testing device; Figure 2 : Schematic diagram of the connection between the top cover and the combustion chamber shell; Figure 3 Schematic diagram of the connection between the nozzle housing and the combustion chamber housing; Figure 4 : Schematic diagram of the connection between the rear plug and the nozzle housing; Figure 5 : Schematic diagram of the rear end cap structure; Wherein: 1-combustion chamber shell, 2-nozzle shell, 3-top cover, 4-rear plug, 5-pad, 6-sealing ring one, 7-bolt, 8-locking nut, 9-bracket, 10-sealing ring two, 11-sealing ring three. Detailed Implementation

[0016] This invention assembles the combustion chamber shell, nozzle shell, and top cover using standard components such as sealing rings, top cover, and other parts supplied with a solid rocket motor, without any external constraints on the shell. Water is injected through an opening at the tail of the nozzle shell, and a pressurization device is used to increase the water pressure to the design pressure. This invention more closely approximates the actual pressure conditions of the shell, simultaneously assessing the pressure-bearing capacity of the combustion chamber shell, nozzle shell, and top cover through a single hydrostatic test, as well as the sealing performance of the sealing ring and the strength of the connection structure. This multi-faceted approach provides a more comprehensive and efficient assessment.

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments obtained. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0018] A solid rocket motor hydraulic pressure testing device comprises a combustion chamber shell 1, a nozzle shell 2, a top cover 3, a rear plug 4, a pad 5, a first sealing ring 6, bolts 7, a lock nut 8, a second sealing ring 10, a third sealing ring 11, and a bracket 9. The device is placed horizontally and supported only by two brackets 9, without any other constraints limiting the free deformation of the shell. A sealing groove is provided on the front connector of the combustion chamber shell 1, where the matching first sealing ring 6 is installed. The top cover 3 is connected to the front connector via bolts 7. The combustion chamber housing 1 has a sealing groove on the rear connector, and a matching sealing ring 10 is installed. The nozzle housing 2 is connected to the rear connector by bolts 7. The rear plug 4 has a step on its largest outer cylindrical surface, which forms an end face sealing groove with the tail step of the nozzle housing 2, and a sealing ring 11 is installed for sealing. The small end of the rear plug 4 has an external thread that passes through the tail step and pad 5 of the nozzle housing 2 and is tightened by a locking nut 8. The rear plug 4 has a through hole in the middle as a water inlet channel, and an internal thread at the small end for connecting the water inlet pipe.

[0019] The main components of the solid rocket motor, including the combustion chamber shell, nozzle shell, top cover, sealing ring, and bolts, are assembled without any external constraints. Then, the rear cap is installed. The rear cap is sealed using the stepped end of the nozzle shell and serves as a water inlet. Water is introduced from the pressurization system and pressurized to the specified pressure and maintained. A single water pressure test simultaneously assesses the pressure-bearing capacity of the main components of the solid rocket motor, including the combustion chamber shell, nozzle shell, top cover, sealing ring, and bolts.

[0020] This invention assembles the combustion chamber shell, nozzle shell, and top cover, and uses a solid rocket motor with pre-matched sealing rings, top cover, standard parts, etc. A schematic diagram of the water pressure testing device is shown below. Figure 1 No external constraints are applied to the casing; water is injected through the opening at the tail of the nozzle casing, and a pressurizing device is used to increase the water pressure to the design pressure.

[0021] The water pressure testing device consists of a combustion chamber shell, a nozzle shell, a top cover, bolts, a sealing ring, a rear plug, a gasket, and a lock nut; it can simultaneously test the pressure-bearing performance of the formal supporting components of a solid rocket engine: the combustion chamber shell, the nozzle shell, the top cover, bolts, and the sealing ring.

[0022] The combustion chamber shell front connector has a sealing groove for installing the standard matching sealing ring; the top cover is connected to the front connector by bolts. Following the standard assembly procedure for solid rocket motors, the bolts are tightened at the specified points and to the specified torque. A schematic diagram of the connection between the top cover and the combustion chamber shell front connector is shown below. Figure 2 As shown.

[0023] The combustion chamber shell rear connector has a sealing groove for installing the standard matching sealing ring 2; the nozzle shell is connected to the rear connector by bolts. Following the standard assembly procedure for solid rocket motors, the bolts are tightened at the specified points and to the specified torque. (Diagram showing the connection between the nozzle shell and the combustion chamber shell rear connector) Figure 3 As shown.

[0024] The largest outer cylindrical surface of the rear plug fits tightly with the inner hole of the straight section of the nozzle housing, serving as a positioning feature. A step on the largest outer cylindrical surface of the rear plug forms an end-face sealing groove with the tail step of the nozzle housing, achieving a triple seal using sealing rings. The small end of the rear plug has an external thread that passes through the tail step and pad of the nozzle housing, and is then tightened using a lock nut. A schematic diagram of the connection between the rear plug and the nozzle housing is shown below. Figure 4 As shown.

[0025] The rear plug has a through hole in the middle as a water inlet channel, and an internal thread at the small end for connecting the water inlet pipe; the large end of the water inlet channel of the rear plug has a 60° chamfer to change the direction of force on the rear plug and alleviate stress deformation of the shell. (See diagram of the rear plug structure.) Figure 5 As shown.

[0026] The outer diameter of the pad is adapted to the outer diameter of the straight section of the nozzle housing. It is placed at the tail of the nozzle housing to limit the deformation of the tail end step of the nozzle housing and to limit the locking nut.

[0027] The assembly process of this water pressure testing device adopts the formal assembly process of solid rocket motors, thus verifying the solid rocket motor assembly process in advance.

[0028] The work process is as follows: (1) The top cover 3 is connected to the combustion chamber shell 1 by bolts 7. An end face sealing groove is provided on the end face of the combustion chamber shell 1, and a sealing ring 6 is placed in the groove to keep it sealed. The bolts 7 are evenly arranged in the circumferential direction, tightened at the points, and tightened with the specified torque.

[0029] (2) such as Figure 4 The rear plug 4 is inserted into the long straight section of the nozzle housing 2. The first step of the largest outer cylindrical surface and the tail step of the nozzle housing 2 form a sealing groove, and the sealing ring 311 is installed for sealing. The pad 5 and the lock nut 8 are installed on the protruding external thread part of the plug 4 to tighten it.

[0030] (3) The nozzle housing 2 and the combustion chamber housing 1 are connected by bolts 7. An end face sealing groove is provided on the end face of the combustion chamber housing 1, and a sealing ring 10 is placed in the groove to keep it sealed. The bolts 7 are evenly arranged in the circumferential direction, tightened at the points, and tightened with the specified torque.

[0031] (4) The combustion chamber shell 1 is placed horizontally on the bracket 9 without any axial or circumferential constraints.

[0032] (5) The water inlet pipe is connected by the internal thread of the rear plug 4. Water enters the combustion chamber housing 1 and the nozzle housing 2 through the middle through hole of the rear plug 4. After being filled with water, it is pressurized to the specified pressure by the pressurization system and maintained.

[0033] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

[0034] This invention has undergone more than 1,000 experiments, shortening the water pressure testing cycle. The tested solid rocket engine combustion chamber shell, nozzle shell, top cover, and connecting structure showed no abnormalities in subsequent work, proving the feasibility of this invention.

Claims

1. A water pressure detection device for a solid rocket engine, characterized by: The water pressure detection device is composed of a combustion chamber shell (1), a nozzle shell (2), a top cover (3), a rear plug cover (4), a cushion block (5), a sealing ring one (6), a bolt (7), a locking nut (8), a sealing ring two (10), a sealing ring three (11) and a bracket (9). The water pressure detection device is horizontally placed and only supported by two brackets (9) without other constraints for restricting the free deformation of the shell. The combustion chamber shell (1) is provided with a sealing groove on the front joint, and the sealing ring one (6) is installed. The combustion chamber shell (1) is provided with a sealing groove on the rear joint, and the sealing ring two (10) is installed. The rear plug cover (4) is provided with a step on the maximum outer cylindrical surface to form an end face sealing groove with the tail step of the nozzle shell (2), and the sealing ring three (11) is installed. The rear plug cover (4) is provided with an external thread at the small end, which passes through the tail step of the nozzle shell (2) and the cushion block (5), and is pulled tight by the locking nut (8). The rear plug cover (4) is provided with a through hole in the middle as a water inlet channel, and an internal thread at the small end for connecting a water inlet pipe.

2. The solid rocket engine water pressurization detection apparatus according to claim 1, characterized by: The front and rear joints of the combustion chamber shell (1) are assembled with the top cover (3) and the nozzle shell (2) respectively, and the bolts are tightened according to the solid rocket engine assembly process.

3. The solid rocket engine water pressurization detection apparatus of claim 1, wherein: The outer diameter of the cushion block (5) is adapted to the outer diameter of the straight cylinder segment of the nozzle shell (2), which is placed at the tail of the nozzle shell to limit the deformation of the tail closing step of the nozzle shell and the locking nut.

4. The solid rocket engine water pressurization detection apparatus of claim 1, wherein: The large end of the water inlet channel of the rear plug cover (4) is provided with a 60° chamfer to change the stress direction of the rear plug cover and relieve the stress deformation of the shell.

5. The solid rocket engine water pressurization detection apparatus of claim 1, wherein: The maximum outer cylindrical surface of the rear plug cover (4) is tightly matched with the inner hole of the straight cylinder segment of the nozzle shell (2) for positioning the rear plug cover.

6. The solid rocket engine water pressurization detection apparatus of claim 1, wherein: The sealing ring one, the sealing ring two and the sealing ring three are O-rings.

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