High-pressure embedded blanking cap assembly for solid rocket engine jet pipe

Abstract

The invention provides a high-pressure embedded blanking cap assembly for a solid rocket engine jet pipe, which is characterized in that a throat part of the solid rocket engine jet pipe and the front area of an expansion section at the downstream of the throat part are thinned from the inner wall to the outer side to form a mounting concave part of the blanking cap assembly; the blanking cap assembly comprises a blanking cap, a pressing ring and a throat liner which are sequentially installed in the gas ignition direction, the throat liner is installed on the throat portion of the spray pipe, the blanking cap is a thin-wall metal piece and adheres to the throat liner into a whole, the blanking cap is used by nesting of the metal pressing ring, and the blanking cap and the metal pressing ring are jointly adheres to the front area of the expansion section on the downstream portion of the throat portion to plug an outlet of the throat portion. The inner hole of the compression ring serves as a composition section of the inner molded surface of the spray pipe and is consistent with the inner molded surface of the front area of the expansion section on the downstream of the throat. The blanking cap structure has the advantages of being good in opening pressure intensity stability, high in reliability and high in consistency under the short-time ignition high-pressure opening requirement.

Description

Technical Field

[0001] This invention belongs to the technical field of plugs for solid rocket engine nozzles, and specifically relates to a high-pressure embedded plug assembly for solid rocket engine nozzles. Background Technology

[0002] The nozzle plug is a key component of the engine nozzle, fixed to it by adhesive or connection to provide a seal and prevent moisture damage. During engine ignition, it facilitates the rapid establishment of high-pressure combustion gases. Plate-type nozzle plugs are often used in small-diameter engines and applications where nozzle size is limited; they can be machined or stamped. Some solid rocket engines require a short time to reach high pressure to ensure consistent thrust across multiple booster systems. However, the opening pressure of adhesive-bonded nozzle plugs is sometimes insufficient or unstable, failing to meet the requirement for consistent high-pressure opening in solid rocket engines during short periods. Summary of the Invention

[0003] In order to overcome the shortcomings of the existing technology, the inventors have conducted intensive research and provided a high-pressure embedded plug assembly for solid rocket engine nozzles, which solves the problem of needing to establish an indoor high pressure (≥8MPa) in a short time (≤1s) to ignite the solid rocket engine combustion gas.

[0004] The technical solutions provided by the present invention are as follows:

[0005] A high-pressure embedded plug assembly for a solid rocket motor nozzle, wherein the throat and the front region of the downstream expansion section of the solid rocket motor nozzle are thinned from the inner wall to the outer wall to form an installation recess for the plug assembly.

[0006] The plug assembly includes a plug, a pressure ring, and a throat liner installed sequentially along the gas ignition direction. The throat liner is installed at the nozzle throat. The plug is a thin-walled metal part and is bonded to the throat liner as a whole. The plug is nested with a metal pressure ring and is bonded together to the front region of the expansion section downstream of the throat to seal the throat outlet. The inner hole of the pressure ring is a component section of the nozzle inner profile and is consistent with the profile of the front region of the expansion section downstream of the throat.

[0007] The high-pressure embedded plug assembly for solid rocket motor nozzles provided by the present invention has the following beneficial effects:

[0008] (1) The present invention provides a high-pressure embedded plug assembly for solid rocket engine nozzles, comprising a plug, a pressure ring and a throat liner installed sequentially along the combustion direction of the gas. The plug is nested by a metal pressure ring, which solves the problem that when the thick plug is directly bonded to the throat liner, the plug is deformed due to the strong pressure of the gas in the middle of the plug, and the reverse force of the outer edge of the plug on the throat liner causes damage to the adhesion between the plug and the throat liner, and between the throat liner and the inner surface of the nozzle. The high-temperature gas penetrates into the damaged adhesion surface, further reducing the adhesion strength between the throat liner and the inner surface of the nozzle, and causing the throat liner to fall off.

[0009] (2) The present invention provides a high-pressure embedded plug assembly for a solid rocket engine nozzle. The material strength of the pressure ring in the plug assembly is greater than that of the plug, and the working wall thickness of the pressure ring is greater than that of the plug. This buffers the thrust of the outer edge of the plug on the throat liner, prevents the throat liner from moving after being squeezed, and ensures that the plug is opened by high-pressure gas under a set pressure breaking through the plug, thus ensuring the consistency of the opening form and the stability of the opening pressure.

[0010] (3) The present invention provides a high-pressure embedded plug assembly for solid rocket engine nozzles, the structural design of which can meet the requirements of solid rocket engines to establish indoor high pressure (≥8MPa) in a short time (≤1s). Attached Figure Description

[0011] Figure 1 This is a schematic diagram showing the installation position of the plug assembly on the nozzle.

[0012] Figure 2 This is an enlarged schematic diagram of the plug assembly installed on the nozzle.

[0013] Figure 3 This is a schematic diagram of the plug structure;

[0014] Figure 4 This is a schematic diagram of the plug-pressure ring assembly. Detailed Implementation

[0015] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0016] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0017] See Figure 1 and Figure 2This invention provides a high-pressure embedded plug assembly for a solid rocket motor nozzle. The throat and the front region of the downstream expansion section of the solid rocket motor nozzle are thinned from the inner wall to the outer wall to form an installation recess for the plug assembly. The plug assembly includes a plug, a pressure ring, and a throat liner installed sequentially along the combustion direction. The throat liner is installed at the nozzle throat. The plug is a thin-walled metal part and is bonded to the throat liner. The plug is nested within the metal pressure ring and is bonded together to the front region of the downstream expansion section of the throat to seal the throat outlet. The inner hole of the pressure ring is a component of the nozzle's inner profile and is consistent with the profile of the front region of the downstream expansion section of the throat, without disrupting the aerodynamic profile.

[0018] The outer surfaces of the plug, pressure ring, and throat liner are bonded to the inner surface of the mounting recess. The plug and pressure ring are bonded together. The throat liner aligns with the converging ring bonded to the inner surface of the nozzle housing upstream of the throat, thus limiting the position of the plug assembly upstream of the throat. Before bonding, the nozzle, pressure ring, plug, and throat liner are cleaned, such as by lightly grinding the bonding surfaces of the pressure ring and plug. After grinding, they are washed again with water and degreased with acetone.

[0019] See Figure 3 and Figure 4 The plug has multiple protrusions or at least one annular protrusion on one side of its plate. The protrusions are embedded in the groove of the pressure ring and are filled and bonded with adhesive. The depth of the pressure ring groove is slightly greater than the height of the plug protrusion to ensure that the adhesive completely penetrates into the end face groove and enhances the airtightness of the nozzle.

[0020] Solid rocket motors require a short time (≤1s) to establish a high pressure chamber (≥8MPa), necessitating a thick cap that cannot be too thin, otherwise it will rupture before reaching the high-pressure chamber. However, without a pressure ring, a thick cap cannot be used; otherwise, even if it doesn't rupture, the central part of the cap will deform under the high pressure of the combustion gases. The reverse force of the cap's outer edge on the throat liner will damage the adhesion between the cap and the throat liner, and between the throat liner and the nozzle's inner surface. High-temperature combustion gases penetrating the damaged adhesion surface further reduces the adhesion strength between the throat liner and the nozzle's inner surface, easily leading to the risk of throat liner detachment. Therefore, installing a pressure ring between the cap and the throat liner is a necessary means to ensure stable throat liner installation.

[0021] In the plug assembly, the material strength of the pressure ring is greater than that of the plug, and the working wall thickness of the pressure ring is greater than that of the plug. This buffers the counter-thrust force of the outer edge of the plug on the throat liner, prevents the throat liner from moving after being squeezed, and ensures that the plug is opened by high-pressure gas under a set pressure breaking through the plug.

[0022] The maximum pressure that the plug can withstand is controlled by adjusting the plug thickness and the pressure-bearing diameter. The relationship between the plug thickness and the maximum withstand pressure is as follows:

[0023]

[0024] In the formula, P is the maximum bearing pressure, τ is the allowable shear stress of the material, δ is the thickness of the plug, and D is the maximum bearing pressure. c The diameter of the pressure-bearing cap.

[0025] The pressure-bearing diameter of the plug is the inner diameter of the plug's adhesive surface at the mounting recess. The expression for the pressure-bearing diameter of the plug is:

[0026] D c =d + Δx·tanα

[0027] In the formula D c d is the pressure-bearing diameter of the plug; d is the throat diameter; Δx is the distance from the plug bonding surface of the mounting recess to the throat outlet; α is the expansion half angle.

[0028] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0029] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A high-pressure embedded plug assembly for a solid rocket motor nozzle, characterized in that, The throat and the front region of the downstream expansion section of the solid rocket motor nozzle are thinned from the inner wall to the outer wall to form the mounting recess of the plug assembly. The plug assembly includes a plug, a pressure ring, and a throat liner installed sequentially along the gas ignition direction. The throat liner is installed at the nozzle throat. The plug is a thin-walled metal part and is bonded to the throat liner as a whole. The plug is nested with a metal pressure ring and is bonded together to the front region of the expansion section downstream of the throat to seal the throat outlet. The inner hole of the pressure ring is a component section of the nozzle inner profile and is consistent with the profile of the front region of the expansion section downstream of the throat.

2. The high-pressure embedded plug assembly for solid rocket motor nozzles according to claim 1, characterized in that, The outer surfaces of the plug, pressure ring, and throat liner are bonded to the inner surface of the mounting recess. The plug and pressure ring are bonded together. The throat liner is connected to the converging ring bonded to the inner surface of the nozzle housing upstream of the throat, thus limiting the position of the plug assembly upstream of the throat.

3. The high-pressure embedded plug assembly for solid rocket motor nozzles according to claim 1, characterized in that, The plug has multiple protrusions or at least one annular protrusion on one side of its plate. The protrusions are embedded in the groove of the pressure ring and are filled and bonded with adhesive. The depth of the pressure ring groove is slightly greater than the height of the plug protrusion, and the adhesive can completely penetrate into the end face groove.

4. The high-pressure embedded plug assembly for solid rocket motor nozzles according to claim 1, characterized in that, The material strength of the pressure ring is greater than that of the plug, and the working wall thickness of the pressure ring is greater than that of the plug.

5. The high-pressure embedded plug assembly for solid rocket motor nozzles according to claim 1, characterized in that, The maximum pressure that the plug can withstand is controlled by adjusting the plug thickness and the pressure-bearing diameter. The relationship between the plug thickness and the maximum withstand pressure is as follows: In the formula, P is the maximum bearing pressure, τ is the allowable shear stress of the material, δ is the thickness of the plug, and D is the maximum bearing pressure. c The diameter of the pressure-bearing cap.

6. The high-pressure embedded plug assembly for solid rocket motor nozzles according to claim 5, characterized in that, The pressure-bearing diameter of the plug is the inner diameter of the plug's adhesive surface at the mounting recess. The expression for the pressure-bearing diameter of the plug is: D c =d+Δx·tanα In the formula D c d is the pressure-bearing diameter of the plug; d is the throat diameter; Δx is the distance from the plug bonding surface of the mounting recess to the throat outlet; α is the expansion half angle.

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