Blanking cover structure of underwater solid rocket engine jet pipe

Abstract

A composite blanking cap structure of an underwater solid rocket engine jet pipe comprises a jet pipe shell, a jet pipe lining, a blanking cap, a blanking cap pressing plate, a fireproof plate and a sealing ring, the jet pipe shell and the jet pipe lining are bonded through an adhesive, the blanking cap, the blanking cap pressing plate and the fireproof plate are sequentially assembled on the jet pipe shell, axial sealing is achieved between the blanking cap and the jet pipe shell through the sealing ring, and the sealing ring is arranged between the blanking cap and the jet pipe shell. An annular square groove is formed in the side, making contact with the spray pipe shell, of the plug cover, the diameter of the center of the annular square groove is the same as the diameter of an inner hole of the plug cover pressing plate and the diameter of an inner hole of the fireproof plate, and the spray pipe shell, the plug cover and the plug cover pressing plate are radially positioned through hole-shaft fit. By means of the structural design, the underwater solid rocket engine nozzle blanking cap has the functional characteristics of being good in sealing performance, weak in internal pressure bearing capacity and high in external pressure bearing capacity, meanwhile, it can be guaranteed that the coaxiality among the nozzle shell, the blanking cap body and the blanking cap pressing plate is good, high thermal protection capacity is achieved, and the reliability of the overall structure of the nozzle can be guaranteed.

Description

Technical Field

[0001] This invention relates to the field of solid rocket engines, and more specifically to a composite plug structure for an underwater solid rocket engine nozzle. Background Technology

[0002] The nozzle cap is one of the most important components of a solid rocket motor nozzle. Its main functions are to ensure the internal space is sealed during engine storage, to assist in establishing ignition pressure during initial engine operation, and to open once the critical ignition pressure is reached. Therefore, it must possess excellent sealing performance and a certain internal pressure resistance. For underwater solid rocket motors, the nozzle cap must also withstand the high external pressure caused by the water depth before engine ignition. Therefore, in addition to sealing performance and internal pressure resistance, the underwater solid rocket motor nozzle cap must also possess strong external pressure resistance.

[0003] The existing underwater solid rocket motor nozzle sealing structure has the following problems: 1. During assembly, radial misalignment easily occurs between the nozzle flange, plug, and pressure ring, making precise assembly impossible. Furthermore, the shear groove is triangular, which easily leads to misalignment of parts, causing the tip of the shear groove to misalign with the inner hole of the pressure ring, thus preventing the plug from being easily sheared open; 2. There is no heat protection structure on the outside of the pressure ring. When the engine is running, some of the exhaust flame backflow will cause the temperature of the metal parts on the nozzle to rise, thereby reducing the mechanical properties of the metal materials and ultimately reducing the reliability of the nozzle structure. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a composite plug structure for underwater solid rocket motor nozzles, which solves the issues of difficulty in accurately cutting and opening the plugs and poor thermal protection.

[0005] The technical solution adopted in this invention is: a composite plug structure for an underwater solid rocket motor nozzle, comprising a nozzle shell, a nozzle liner, a plug, a plug pressure plate, a fire baffle, and a sealing ring. The nozzle liner is provided inside the nozzle shell, and the plug, plug pressure plate, and fire baffle are sequentially installed at the small end port of the nozzle shell. The plug and the nozzle shell are axially sealed by the sealing ring.

[0006] Furthermore, the nozzle housing and the nozzle liner are bonded together with adhesive.

[0007] Furthermore, the plug is made of 1035O aluminum alloy.

[0008] Furthermore, the material of the plug plate is 30CrMnSiA high-strength steel.

[0009] Furthermore, the plug has an annular groove on the side that contacts the nozzle housing. The cross-section of the annular groove is square, and the diameter at the center of the annular groove is the same as the diameter of the center hole of the plug pressure plate and the diameter of the center hole of the fire baffle plate.

[0010] Furthermore, the diameter D1 at the center of the plug annular groove is greater than the sum of the nozzle liner outlet inner diameter D2 and the plug annular groove width d.

[0011] Furthermore, axial steps are provided at the connection point A between the nozzle housing and the plug and the connection point B between the plug and the plug pressure plate, and the fit method is H8 / f7 hole shaft fit.

[0012] Furthermore, the fire baffle is made of high-silica cloth / phenolic molding laminate.

[0013] The advantages of this invention compared to the prior art are:

[0014] (1) The plug and nozzle housing and plug pressure plate of the present invention have radial positioning structures, which have high fitting accuracy. The annular square groove on the plug and the inner hole of the plug pressure plate have good coaxiality, which can avoid the situation where radial misalignment between parts causes the plug to be unable to be properly sheared and opened.

[0015] (2) The annular groove on the plug of the present invention has a rectangular cross section, which can ensure that the edge of the inner hole of the plug pressure plate corresponds to the thin wall position of the plug even when there is a slight misalignment between the plug and the plug pressure plate, so that the plug can be cut open normally, and the square groove has better processability.

[0016] (2) The present invention has a fire baffle plate after the plug plate, which can protect the metal parts when the engine is working, and prevent the flame backflow from burning heat transfer, which would lead to a decrease in the mechanical properties of the material and ultimately reduce the reliability of the nozzle structure. Attached Figure Description

[0017] The technical solution of the present invention will be described below through specific embodiments.

[0018] Figure 1 This is a three-dimensional structural cross-sectional view of the present invention;

[0019] Figure 2 This is a partial cross-sectional view of the opening portion of the plug in this invention;

[0020] Figure 3 This is a partial cross-sectional view of the plug assembly part of the present invention.

[0021] In the diagram: 1. Nozzle housing, 2. Nozzle lining, 3. Plug, 4. Plug pressure plate, 5. Fire baffle, 6. Screw, 7. Sealing ring. Detailed Implementation

[0022] The application of the present invention will be described in detail with reference to the accompanying drawings.

[0023] like Figures 1 to 3 As shown, the present invention provides a composite plug structure for an underwater solid rocket motor nozzle, including a nozzle housing 1, a nozzle liner 2, a plug 3, a plug pressure plate 4, a fire baffle 5, screws 6, and a sealing ring 7. The nozzle housing 1 and the nozzle liner 2 are bonded together with adhesive. The plug 3, the plug pressure plate 4, and the fire baffle 5 are sequentially assembled onto the nozzle housing 1 by screws 6. The plug 3 and the nozzle housing 1 are axially sealed by the sealing ring 7.

[0024] The plug 3 disclosed in this embodiment is made of 1035O aluminum alloy, and the plug pressure plate 4 is made of 30CrMnSiA high-strength steel. The plug 3 has an annular square groove on the side that contacts the nozzle housing 1. The wall thickness δ1 = 1 mm and the groove width d = 2.5 mm at the annular square groove. The wall thickness of the remaining parts of the plug 3 is δ2 = 3.5 mm. The diameter D1 at the center of the annular square groove (D1 refers to the distance from the centerline of twice the cross-section of the annular square groove to the center of the plug 3, D1 = D3 + d, where D3 is the diameter of the inner wall of the annular square groove) is the same as the inner diameter of the plug pressure plate 4 and the inner diameter of the fire baffle 5, both being 60 mm. The outlet inner diameter D2 of the nozzle lining 2 is 50 mm. This allows the plug 3 to maintain structural integrity when subjected to high external underwater pressure, and allows it to be sheared and destroyed from the annular square groove after the critical ignition pressure is reached inside the engine.

[0025] In this embodiment, the diameter D1 at the center of the annular square groove of the plug 3 is greater than the sum of the inner diameter D2 of the nozzle liner 2 outlet and the width d of the annular square groove of the plug 3, i.e., D1 > D2 + d. This ensures that when the plug 3 is subjected to external pressure, the thin-walled structure at the annular square groove can maintain its structural integrity under the support of the nozzle liner 2.

[0026] In this embodiment, an axial step is provided at the assembly connection point A between the nozzle housing 1 and the plug 3, and at the assembly connection point B between the plug 3 and the plug pressure plate 4. The fit is H8 / f7 hole-shaft fit. This can maintain good coaxiality between the nozzle housing 1, the plug 3, and the plug pressure plate 4, thereby avoiding large radial misalignment between the inner hole of the plug pressure plate 4 and the annular square groove of the plug 3, which would prevent the plug 3 from being properly sheared open.

[0027] The annular square groove on the plug 3 disclosed in this embodiment is a square groove with a width d = 2.5 mm. This ensures that the annular square groove of the plug 3 can still be subjected to the shearing action of the inner hole of the plug pressure plate 4 even when there is a slight radial misalignment caused by the fit clearance between the plug 3 and the plug pressure plate 4.

[0028] The fire baffle 5 disclosed in this embodiment is made of high-silica cloth / phenolic molding laminate with a wall thickness of 5mm. This can protect the metal products such as the plug 3 and plug pressure plate 4 when the exhaust flame of the engine flows back, prevent the parts material temperature from being too high and causing performance degradation, and avoid the problem of reduced reliability of the overall nozzle structure.

[0029] The product manufacturability, fabricationability, assembly capability, and connection reliability of the structure described in this invention have all been verified and have passed testing. The structure is reliable, the function is stable, and it meets the usage requirements.

[0030] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary examples described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0031] The parts of this invention not described in detail are well-known to those skilled in the art.

Claims

1. A composite closure structure for a submerged solid rocket engine nozzle, characterized by: It comprises a nozzle shell (1), a nozzle liner (2), a plug cover (3), a plug cover pressing plate (4), a fire baffle (5) and a sealing ring (7), the nozzle liner (2) is arranged in the nozzle shell (1), the plug cover (3), the plug cover pressing plate (4) and the fire baffle (5) are sequentially arranged in the small end port of the nozzle shell (1), and the plug cover (3) and the nozzle shell (1) are axially sealed by the sealing ring (7).

2. The composite closure structure of an underwater solid rocket engine nozzle according to claim 1, characterized in that: The nozzle shell (1) and the nozzle liner (2) are bonded by an adhesive.

3. The composite closure structure of an underwater solid rocket engine nozzle according to claim 1, wherein: The material of the plug cover (3) is 1035 O-state aluminum alloy.

4. The composite closure structure of an underwater solid rocket engine nozzle according to claim 1, wherein: The material of the plug cover pressing plate (4) is 30CrMnSiA high-strength steel.

5. The composite closure structure of an underwater solid rocket engine nozzle according to claim 1, wherein: The plug cover (3) is provided with an annular groove on the side in contact with the nozzle shell (1), the cross section of the annular groove is square, the diameter at the center of the annular square groove is the same as the diameter of the center hole of the plug cover pressing plate (4) and the diameter of the center hole of the fire baffle (5).

6. The composite closure structure of an underwater solid rocket engine nozzle according to claim 5, characterized in that: The diameter D1 at the center of the annular square groove of the plug cover (3) is greater than the sum of the inner diameter D2 of the nozzle liner (2) outlet and the width d of the annular square groove of the plug cover (3).

7. The composite closure structure of an underwater solid rocket engine nozzle according to claim 1, wherein: The assembly connection places A of the nozzle shell (1) and the plug cover (3) and the assembly connection place B of the plug cover (3) and the plug cover pressing plate (4) are respectively provided with axial steps, and the cooperation modes are both H8 / f7 hole shaft cooperation.

8. The composite closure structure of an underwater solid rocket engine nozzle according to claim 7, characterized in that: The fire baffle (5) is made of high-silicon oxide cloth / phenolic molding laminated.

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