Solid rocket engine nozzle shell strength hydraulic test tool

Abstract

The present application relates to a kind of solid rocket engine nozzle shell strength hydraulic test tool, belong to the field of solid rocket engine;Hydraulic end is the shell structure of axial horizontal placement;Nozzle shell and hydraulic end coaxial butt joint;Snap ring is arranged at the butt joint of nozzle shell and hydraulic end, relative fixation limiting of nozzle shell and hydraulic end is realized;Nozzle shell axial middle inner wall is stepped structure;Hydraulic nipple is coaxially clamped in the step of nozzle shell inner cavity;Convergent ring is attached to the inner wall of nozzle shell axial end directed to hydraulic end;Hydraulic connecting rod is coaxially arranged at the axis of nozzle shell;The center of hydraulic nipple is provided with through hole;The axial one end of hydraulic connecting rod is fixed with hydraulic end, and the axial other end of hydraulic connecting rod is inserted into the through hole of hydraulic nipple;The present application solves the problem that nozzle shell is easily deformed after hydraulic test under the premise of overall examination of nozzle shell structure performance.

Description

Technical Field

[0001] This invention belongs to the field of solid rocket engines and relates to a hydraulic testing fixture for the strength of a solid rocket engine nozzle casing. Background Technology

[0002] Solid rocket engines, as the power plant and key component of solid-propellant missiles or spacecraft, are extremely important for safety. Damage to the engine's structural integrity is a major cause of catastrophic failures. The nozzle, as a crucial component of a solid rocket engine, is a vital part of energy conversion. The nozzle is the outlet for the high-temperature, high-pressure combustion gases within the combustion chamber, and it needs to maintain a certain combustion chamber pressure during operation. Therefore, the structural integrity of the nozzle directly affects the engine's performance.

[0003] The nozzle shell, as the supporting structure of the nozzle, primarily functions to connect the various parts into a unified whole. The hydraulic strength test of the nozzle shell is a mandatory test item for solid rocket motors during development and before delivery. The purpose of the hydraulic strength test is mainly to assess the connection performance between the nozzle and the combustion chamber shell, as well as the pressure-bearing capacity of the convergence section. Conventional hydraulic cold testing of the nozzle shell only assesses the nozzle shell separately, and the testing conditions are quite stringent. Typically, the nozzle shell is tested in a fully enclosed manner, with the maximum design pressure of the combustion chamber as the test target. Even when the design margin meets the usage requirements, the nozzle shell often deforms after the cold test, thus failing the test. To avoid this problem, the design process often selects steel with superior mechanical properties or increases the shell wall thickness to increase the shell's strength and rigidity, ensuring that the nozzle shell does not deform after the cold test. However, this also leads to a structural design that is too heavy and less economical.

[0004] During actual engine operation, the internal pressure load generated by the high-temperature and high-pressure combustion gas inside the combustion chamber is borne jointly by the nozzle housing and the thermal protection layer. Furthermore, the nozzle throat, as the jet outlet, does not generate an internal pressure load on the nozzle housing. Therefore, it is inaccurate to conduct a fully enclosed cold test to assess the strength of the nozzle housing alone. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a hydraulic testing fixture for the strength of a solid rocket engine nozzle shell. Under the premise of comprehensively evaluating the structural performance of the nozzle shell, this invention solves the problem of easy deformation of the nozzle shell after hydraulic testing.

[0006] The solution of the present invention is:

[0007] A hydraulic testing fixture for the strength of a solid rocket motor nozzle shell, characterized in that it includes a hydraulic end cap, a hydraulic plug, a hydraulic connecting rod, a convergent ring, a nozzle shell, and a retaining ring;

[0008] The hydraulic end cap is a shell structure placed horizontally in the axial direction; the nozzle shell and the hydraulic end cap are coaxially connected; a retaining ring is set at the connection between the nozzle shell and the hydraulic end cap to achieve relative fixation and limitation of the nozzle shell and the hydraulic end cap; the inner wall of the nozzle shell in the middle of the axial direction has a stepped structure; the hydraulic end cap is coaxially locked in the inner cavity of the nozzle shell at this step; a convergent ring is attached to the inner wall of the nozzle shell at the end pointing axially towards the hydraulic end cap; the hydraulic connecting rod is coaxially set at the axis of the nozzle shell; a through hole is set in the center of the hydraulic end cap; one axial end of the hydraulic connecting rod is fixedly connected to the hydraulic end cap, and the other axial end of the hydraulic connecting rod extends into the through hole of the hydraulic end cap.

[0009] The aforementioned hydraulic testing fixture for the strength of a solid rocket engine nozzle casing further includes a first sealing structure, a second sealing structure, and a third sealing structure. The first sealing structure is located at the junction of the outer wall of the nozzle casing and the inner wall of the hydraulic head, achieving a seal between the nozzle casing and the hydraulic head. The second sealing structure is located at the junction of the outer wall of the hydraulic end cap and the inner wall of the nozzle casing, achieving a seal between the hydraulic end cap and the nozzle casing. The third sealing structure is located at the junction of the outer wall of the hydraulic connecting rod and the inner wall of the hydraulic end cap, achieving a seal between the hydraulic connecting rod and the hydraulic end cap.

[0010] In the aforementioned hydraulic strength testing fixture for a solid rocket engine nozzle casing, a water injection port is provided on the hydraulic end cap. Water is filled into the inner cavity of the nozzle casing through the water injection port to perform a hydraulic strength test on the nozzle casing.

[0011] In the aforementioned hydraulic testing fixture for the strength of a solid rocket engine nozzle casing, the actual nozzle is formed by attaching a non-metallic material to the inner wall of the nozzle casing to create a throat; the diameter of the central through hole of the hydraulic plug is the same as the throat diameter of the actual nozzle.

[0012] In the aforementioned hydraulic strength testing fixture for a solid rocket motor nozzle casing, during the hydraulic strength test of the nozzle casing, the nozzle casing and the converging ring jointly bear the internal pressure load.

[0013] In the aforementioned hydraulic testing fixture for the strength of a solid rocket engine nozzle casing, since the hydraulic connecting rod is connected to the hydraulic end cap, the axial pressure load at the central through hole of the hydraulic end cap is borne by the hydraulic end cap, simulating the situation where the air passage at the throat of the nozzle does not generate an axial force on the nozzle casing during actual operation.

[0014] The assembly process of the hydraulic testing fixture for the strength of a solid rocket engine nozzle casing, as described above, is as follows:

[0015] The second sealing structure is placed in the sealing groove of the hydraulic end cap and coaxially installed in the middle of the inner cavity of the nozzle housing; the convergent ring is installed on the nozzle housing, and the first sealing structure is placed in the sealing groove of the nozzle housing; the threaded interface end of the hydraulic connecting rod is installed in the threaded hole on the hydraulic end cap, and the third sealing structure is placed in the sealing groove at the other end of the hydraulic connecting rod; the hydraulic connecting rod on the hydraulic end cap passes through the central through hole of the hydraulic end cap to complete the sealing between the nozzle housing and the hydraulic end cap and the hydraulic end cap; the retaining ring is installed through the retaining ring groove window on the hydraulic end cap to complete the fixed connection between the hydraulic end cap and the nozzle housing; water is injected from the water inlet on the hydraulic end cap to complete the hydraulic strength test of the nozzle housing.

[0016] In the aforementioned hydraulic testing fixture for the strength of a solid rocket motor nozzle casing, a convergent ring is installed on the inner wall of the nozzle casing to simulate the inner wall of the actual nozzle inlet end after non-metallic materials are attached.

[0017] In the aforementioned hydraulic testing fixture for the strength of a solid rocket engine nozzle casing, the hydraulic end cap is made of steel with a safety factor greater than or equal to 2; the hydraulic plug is also made of steel with a safety factor greater than or equal to 2.

[0018] In the aforementioned hydraulic testing fixture for the strength of a solid rocket engine nozzle casing, the hydraulic connecting rod is made of steel, and one axial end of the hydraulic connecting rod is threaded, connecting to the hydraulic end cap via the thread; the converging ring is a carbon fiber molded product.

[0019] The beneficial effects of this invention compared to the prior art are:

[0020] (1) When the nozzle housing of the present invention is subjected to a strength hydraulic test, the joint bearing effect of the non-metallic section of the converging section and the nozzle housing is considered.

[0021] (2) When the nozzle housing of the present invention is subjected to a strength hydraulic test, the actual bearing surface size of the nozzle is considered (i.e. the nozzle throat is not under load).

[0022] (3) The present invention can simulate the actual pressure bearing performance of the nozzle under static conditions, avoid over-testing, and improve the accuracy of the design. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the hydraulic testing fixture for the nozzle housing strength of the present invention. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments.

[0025] This invention provides a hydraulic pressure test fixture for the strength of a solid rocket engine nozzle casing. The test method uses the nozzle casing and thermal protection layer to jointly bear the load and simulates the nozzle throat being unloaded under the actual working conditions of the engine. This more accurately simulates the actual pressure conditions of the nozzle casing during engine operation, thereby solving the problem of easy deformation of the nozzle casing after hydraulic testing while comprehensively evaluating the structural performance of the nozzle casing.

[0026] Hydraulic testing fixture for the strength of solid rocket motor nozzle casing, such as Figure 1 As shown, it specifically includes a hydraulic end cap 1, a hydraulic plug 2, a hydraulic connecting rod 3, a convergent ring 4, a nozzle housing 5, and a retaining ring 6.

[0027] The hydraulic end cap 1 is a shell structure placed horizontally in the axial direction; the nozzle shell 5 is coaxially connected to the hydraulic end cap 1; the retaining ring 6 is set at the connection between the nozzle shell 5 and the hydraulic end cap 1 to achieve relative fixation and limitation of the nozzle shell 5 and the hydraulic end cap 1; the inner wall of the nozzle shell 5 in the axial middle section has a stepped structure; the hydraulic end cap 2 is coaxially locked at the stepped section in the inner cavity of the nozzle shell 5; the converging ring 4 is attached to the inner wall of the nozzle shell 5 at the end pointing axially towards the hydraulic end cap 1; the hydraulic connecting rod 3 is coaxially set at the axis of the nozzle shell 5; the hydraulic end cap 2 has a through hole in its center; one axial end of the hydraulic connecting rod 3 is fixedly connected to the hydraulic end cap 1, and the other axial end of the hydraulic connecting rod 3 extends into the through hole of the hydraulic end cap 2.

[0028] Hydraulic end cap 1 is made of steel with a safety factor greater than or equal to 2; hydraulic end cap 2 is made of steel with a safety factor greater than or equal to 2. Hydraulic connecting rod 3 is made of steel, and one axial end of hydraulic connecting rod 3 is threaded, connecting to hydraulic end cap 1 via the thread; the converging ring 4 is a carbon fiber molded product.

[0029] The hydraulic testing fixture also includes a first sealing structure 7, a second sealing structure 8, and a third sealing structure 9. The first sealing structure 7 is located at the junction of the outer wall of the nozzle housing 5 and the inner wall of the hydraulic head 1, thereby achieving a seal between the nozzle housing 5 and the hydraulic head 1. The second sealing structure 8 is located at the junction of the outer wall of the hydraulic plug 2 and the inner wall of the nozzle housing 5, thereby achieving a seal between the hydraulic plug 2 and the nozzle housing 5. The third sealing structure 9 is located at the junction of the outer wall of the hydraulic connecting rod 3 and the inner wall of the hydraulic plug 2, thereby achieving a seal between the hydraulic connecting rod 3 and the hydraulic plug 2.

[0030] The hydraulic end cap 1 is equipped with a water inlet 10, through which water is filled into the inner cavity of the nozzle housing 5 to perform a strength hydraulic test on the nozzle housing 5. The actual nozzle is formed by attaching a non-metallic material to the inner wall of the nozzle housing 5, creating a throat; the diameter of the central through-hole of the hydraulic end cap 2 is the same as the throat diameter of the actual nozzle. During the strength hydraulic test, the nozzle housing 5 and the converging ring 4 share the internal pressure load.

[0031] Since the hydraulic connecting rod 3 is connected to the hydraulic end cap 1, the axial pressure load at the central through hole of the hydraulic end cap 2 is borne by the hydraulic end cap 1, simulating the situation where the throat ventilation does not generate axial force on the nozzle housing 5 during actual operation.

[0032] The assembly process of the hydraulic testing fixture is as follows:

[0033] The second sealing structure 8 is placed in the sealing groove of the hydraulic plug 2 and coaxially installed in the middle of the inner cavity of the nozzle housing 5; the convergent ring 4 is installed on the nozzle housing 5, and the first sealing structure 7 is placed in the sealing groove of the nozzle housing 5; the threaded interface end of the hydraulic connecting rod 3 is installed in the threaded hole on the hydraulic head 1, and the third sealing structure 9 is placed in the sealing groove at the other end of the hydraulic connecting rod 3; the hydraulic connecting rod 3 on the hydraulic head 1 is passed through the central through hole of the hydraulic plug 2 to complete the sealing between the nozzle housing 5 and the hydraulic head 1 and the hydraulic plug 2; the retaining ring 6 is installed through the retaining ring groove window on the hydraulic head 1 to complete the fixed connection between the hydraulic head 1 and the nozzle housing 5; water is injected from the water inlet 10 on the hydraulic head 1 to complete the strength hydraulic test of the nozzle housing 5.

[0034] The convergence ring 4 is installed on the inner wall of the nozzle housing 5 to simulate the inner wall of the actual nozzle inlet after non-metallic materials are attached.

[0035] This invention relates to a hydraulic pressure testing fixture structure for the strength of a solid rocket motor nozzle casing. During the hydraulic strength test of the nozzle casing, the nozzle casing and the converging ring jointly bear the inner pressure core. The diameter of the central hole of the hydraulic end cap is the same as the actual throat diameter of the nozzle. Since the hydraulic connecting rod is connected to the hydraulic end cap, the axial pressure core at this central hole is borne by the hydraulic end cap, simulating the situation where airflow through the throat of the nozzle does not generate axial force on the nozzle casing during actual operation. Its assembly sequence is as follows:

[0036] S1. Place the sealing ring in the sealing groove of the hydraulic plug and install it together into the cylindrical section of the nozzle housing;

[0037] S2. Install the convergent ring on the nozzle housing and place the sealing ring in the sealing groove of the nozzle housing;

[0038] S3. Install the threaded end of the hydraulic connecting rod into the threaded hole of the hydraulic head, and place the sealing ring in the sealing groove at the other end of the hydraulic connecting rod.

[0039] S4. Pass the hydraulic connecting rod on the hydraulic end cap through the center hole of the hydraulic end cap to complete the sealing between the nozzle housing and the hydraulic end cap and the hydraulic end cap;

[0040] S5. Insert the circumferential retaining ring through the retaining ring groove window on the hydraulic head to complete the fixed connection between the hydraulic head and the nozzle housing.

[0041] S6. Inject water through the water inlet on the hydraulic head to complete the hydraulic strength test of the nozzle shell.

[0042] During the hydraulic strength test of the nozzle housing, the nozzle housing and the converging ring jointly bear the inner pressure core. The diameter of the central hole of the hydraulic end cap is the same as the actual throat diameter of the nozzle. Since the hydraulic connecting rod is connected to the hydraulic end cap, the axial pressure core at the central hole is borne by the hydraulic end cap, simulating the situation where the air passage at the throat does not generate axial force on the nozzle housing during actual operation.

[0043] The structure described in this invention has been applied in a certain model of product. The product's manufacturability and feasibility have been verified. The structure is reliable, the function is stable, and it meets the usage requirements.

[0044] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A solid rocket motor nozzle case strength hydraulic test fixture, characterized by: The hydraulic test tool comprises a hydraulic head (1), a hydraulic plug (2), a hydraulic connecting rod (3), a converging ring (4), a nozzle shell (5) and a snap ring (6). The hydraulic head (1) is an axially horizontally placed shell structure; the nozzle shell (5) is coaxially connected with the hydraulic head (1); the snap ring (6) is arranged at the joint of the nozzle shell (5) and the hydraulic head (1) to fix and limit the relative positions of the nozzle shell (5) and the hydraulic head (1); the inner wall of the middle part of the nozzle shell (5) in the axial direction is a stepped structure; the hydraulic plug (2) is coaxially clamped in the inner cavity of the nozzle shell (5) at the step; the converging ring (4) is attached to the inner wall of the end of the nozzle shell (5) in the axial direction pointing to the hydraulic head (1); the hydraulic connecting rod (3) is coaxially arranged at the axis of the nozzle shell (5); the center of the hydraulic plug (2) is provided with a through hole; one end of the hydraulic connecting rod (3) in the axial direction is fixedly connected with the hydraulic head (1), and the other end of the hydraulic connecting rod (3) in the axial direction extends into the through hole of the hydraulic plug (2).

2. The solid rocket engine nozzle case strength hydraulic test fixture of claim 1, wherein: The hydraulic test tool further comprises a first sealing structure (7), a second sealing structure (8) and a third sealing structure (9); the first sealing structure (7) is arranged at the joint of the outer wall of the nozzle shell (5) and the inner wall of the hydraulic head (1) to seal the space between the nozzle shell (5) and the hydraulic head (1); the second sealing structure (8) is arranged at the joint of the outer wall of the hydraulic plug (2) and the inner wall of the nozzle shell (5) to seal the space between the hydraulic plug (2) and the nozzle shell (5); and the third sealing structure (9) is arranged at the joint of the outer wall of the hydraulic connecting rod (3) and the inner wall of the hydraulic plug (2) to seal the space between the hydraulic connecting rod (3) and the hydraulic plug (2).

3. The solid rocket motor case strength hydrostatic test fixture of claim 2, wherein: The hydraulic head (1) is provided with a water injection port (10) for filling water into the inner cavity of the nozzle shell (5) to perform a strength hydraulic test on the nozzle shell (5).

4. The solid rocket motor case strength hydrostatic test fixture of claim 2, wherein: The actual nozzle is formed by attaching a non-metallic material to the inner wall of the nozzle shell (5) to form a throat; the diameter of the through hole in the center of the hydraulic plug (2) is the same as the throat diameter of the actual nozzle.

5. The solid rocket motor case strength hydrostatic test fixture of claim 3, wherein: When the nozzle shell (5) is subjected to a strength hydraulic test, the nozzle shell (5) and the converging ring (4) jointly bear the internal pressure load.

6. The solid rocket motor case strength hydrostatic test fixture of claim 5, wherein: Since the hydraulic connecting rod (3) is connected with the hydraulic head (1), the axial pressure load at the through hole in the center of the hydraulic plug (2) is borne by the hydraulic head (1), thereby simulating the situation that the throat venting of the nozzle does not generate an axial force on the nozzle shell (5) in the actual working process of the nozzle.

7. The solid rocket motor case strength hydrostatic test fixture of claim 6, wherein: The assembly process of the hydraulic test tool is as follows: The second sealing structure (8) is placed in the sealing groove of the hydraulic head (2) and is coaxially arranged in the middle part of the inner cavity of the nozzle shell (5); the converging ring (4) is arranged on the nozzle shell (5), and the first sealing structure (7) is placed in the sealing groove of the nozzle shell (5); the threaded interface end of the hydraulic connecting rod (3) is arranged in the threaded hole of the hydraulic head (1), and the third sealing structure (9) is placed in the sealing groove at the other end of the hydraulic connecting rod (3); the hydraulic connecting rod (3) on the hydraulic head (1) passes through the central through hole of the hydraulic head (2) to complete the sealing of the nozzle shell (5), the hydraulic head (1) and the hydraulic head (2); the clasp ring (6) is arranged in the clasp ring slot window of the hydraulic head (1) to complete the fixed connection of the hydraulic head (1) and the nozzle shell (5); water is injected from the water injection port (10) of the hydraulic head (1) to complete the strength hydraulic test of the nozzle shell (5).

8. The solid rocket motor case strength hydrostatic test fixture of claim 7, wherein: The converging ring (4) is arranged on the inner wall of the nozzle shell (5) to realize the simulation of the actual inner wall of the inlet end of the nozzle attached to the non-metallic material.

9. The liquid pressure test tooling for solid rocket motor case strength of claim 1, wherein: The hydraulic head (1) is made of steel material, and the safety factor is greater than or equal to 2; the hydraulic head (2) is made of steel material, and the safety factor is greater than or equal to 2.

10. The liquid pressure test tooling for solid rocket motor case strength of claim 1, wherein: The hydraulic connecting rod (3) is made of steel material, and the axial end of the hydraulic connecting rod (3) is provided with a thread, which is connected with the hydraulic head (1) through the thread; the converging ring (4) is a carbon fiber molded product.

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