Solid rocket engine combustion chamber shell thermal protection sleeve, external protection structure and forming method of solid rocket engine combustion chamber shell thermal protection sleeve

Abstract

The invention discloses a solid rocket engine combustion chamber shell thermal protection sleeve, an external protection structure and a forming method of the solid rocket engine combustion chamber shell thermal protection sleeve and the external protection structure, and belongs to the technical field of thermal protection structures. The structural layer adopts an integral weaving structure in a 2.5 D weaving, three-direction orthogonal weaving or three-dimensional four-direction weaving mode; the heat insulation layer is a prefabricated body formed by combining a quartz glass net tire or a high-silica glass net tire with a needling mode; normal fibers are introduced between the structural layer and the heat insulation layer through interlayer fibers in a sewing or needling mode, and the sewing depth only reaches the surface layer of the heat insulation layer. Integrated forming of the engine shell is achieved through integral weaving of the prefabricated body and the forming process, the production period is greatly shortened, the repair rate is reduced, manpower and energy losses are reduced, meanwhile, the assembling efficiency is improved, the thermal protection performance is enhanced, and the environment friendliness and the high temperature resistance are good.

Description

Technical Field

[0001] This invention belongs to the field of heat protection structure technology, specifically relating to a heat protection sleeve for the combustion chamber shell of a solid rocket engine, an external protection structure, and its molding method. Background Technology

[0002] For solid rocket motor casings subjected to the harsh conditions of aerodynamic heating of 800-1000°C at high Mach numbers (Ma=6~7), current ablation thermal protection technologies rely on epoxy and rubber-based external thermal protection coatings. However, both have inherent drawbacks: epoxy coatings (high strength, low ductility) are prone to cracking / detachment during storage, making long-term reliability uncertain; while rubber coatings (high ductility, low strength) are susceptible to mechanical damage during assembly. Furthermore, traditional sequential spraying processes limit production efficiency and restrict the feasibility of large-scale equipment application. This invention aims to overcome existing technological bottlenecks through material system optimization and process route innovation, achieving a low-cost, high-reliability upgrade of the thermal protection structure. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a thermal protection sleeve, outer protective structure and molding method for the combustion chamber shell of a solid rocket engine. The engine shell is integrally molded by the integral woven prefabrication and molding process, which greatly shortens the production cycle, reduces the rework rate, reduces manpower and energy consumption, improves assembly efficiency, enhances thermal protection performance, and has good environmental protection and strong high temperature resistance.

[0004] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a thermal protection sleeve for the combustion chamber shell of a solid rocket engine, the thermal protection sleeve comprising a structural layer, interlayer fibers and a heat insulation layer arranged sequentially from the outside to the inside; The structural layer is woven as a whole using 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving. The heat insulation layer is a preform formed by combining quartz glass mesh or high silica glass mesh with needle punching. The interlayer fibers are introduced between the structural layer and the heat insulation layer by stitching or needle punching, and the stitching depth only reaches the surface of the heat insulation layer.

[0005] Furthermore, the structural layer is made of high-strength quartz glass fiber or high-silica glass fiber material; the heat insulation layer is made of quartz glass fiber / high-silica glass fiber mesh and chopped fiber reinforcement; and the interlayer fibers are made of quartz glass fiber yarn or high-silica glass fiber yarn.

[0006] Furthermore, the heat protection sleeve is fully permeated with liquid resin using resin transfer molding (RTM), vacuum injection, or vacuum infusion processes; the liquid resin is barium phenolic resin or other modified ablation-resistant resin with good fluidity, and the temperature is set to 60~120℃ and the curing time to 1~4h according to the resin system requirements.

[0007] Secondly, the present invention provides an external protective structure for the combustion chamber shell of a solid rocket engine, including a thermal protection sleeve and a buffer layer arranged from the outside to the inside. The thermal protection sleeve includes a structural layer, interlayer fibers, and a thermal insulation layer arranged sequentially from the outside to the inside; The structural layer is woven as a whole using 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving. The heat insulation layer is formed into a preform using quartz glass mesh or high silica glass mesh combined with needle punching. The interlayer fibers are introduced between the structural layer and the heat insulation layer by stitching or needle punching, and the stitching depth only reaches the surface of the heat insulation layer. The buffer layer comprises a 0.5-1mm PI foam layer and a 0.1mm epoxy film arranged from the outside to the inside; an epoxy adhesive is applied to the surface of the PI foam layer, and it is left to dry for 10-20 minutes until it reaches a semi-cured state; the gap between the heat protection sleeve and the PI foam layer of the buffer layer is adjusted to <0.1mm, and it is then pressurized and cured at 60℃ for 2-4 hours.

[0008] Thirdly, the present invention provides a method for forming an external protective structure for a solid rocket engine combustion chamber shell as described in the second aspect, comprising the following steps: Step S1: Use 2.5D weaving, three-way orthogonal weaving, or three-dimensional four-way weaving technology to create the overall woven structural layer; Step S2: The preform is formed by combining a quartz glass mesh or a high-silica glass mesh with a needle punching process; Step S3: Introduce normal fibers between the structural layer and the insulation layer by suturing or needle punching. The suturing depth should only reach the surface of the insulation layer and avoid penetrating it. Step S4: Use resin transfer molding (RTM), vacuum infusion, or vacuum infusion processes to fully penetrate the preform with liquid resin, and set the temperature to 60~120℃ and the curing time to 1~4h according to the resin system requirements. Step S5: Grinding and cleaning the surface of the combustion chamber composite shell, including using a pneumatic grinder to coarsely grind the surface of the fiber winding layer, using 400-600 grit sandpaper for fine finishing in some areas, and wiping with acetone or isopropanol to remove floating dust and ensure the substrate is clean; Step S6: Lay a 0.1mm epoxy film, lay a 0.5~1mm PI foam layer, apply epoxy adhesive to the surface of the PI foam layer, and let it dry for 10~20 minutes until it is semi-cured; Step S7: Pre-install the heat protection sleeve, apply continuous pressure using the kit tooling to align it with the skirt end face, adjust the gap between the heat protection sleeve and the PI foam layer to <0.1mm, and pressurize at 60℃ for 2~4h; Step S8: Cut off the excess material at both ends on a lathe to make the thermal protective sleeve flush with the end faces of the front and rear skirts, with an accuracy of ±0.05mm.

[0009] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: the use of integral woven prefabrication and RTM / vacuum infusion process to replace traditional spraying achieves integrated molding, and the production cycle of the overall engine housing is shortened by more than 30%; the use of PI buffer layer and kit tooling for precise assembly controls the gap between the heat protection sleeve and the housing to <0.1mm, reducing the rework rate; The thermal protective sleeve adopts a 2.5D / triaxial orthogonal braided structure to ensure continuous fiber distribution and avoid delamination and peeling problems in the spraying process; low-pressure resin impregnation (viscosity ≤200cP) ensures 100% density of the composite material and eliminates the porosity defects of traditional spraying. One-time molding avoids the manpower and energy consumption of multiple spraying processes; near-net-shape preforms reduce machining allowances, requiring only the cutting of the ends; automatic tooling alignment replaces manual adjustment, increasing assembly efficiency by 50%. The three-dimensional woven preform is directly manufactured into the final shape, reducing the complexity of subsequent processing; the quartz fiber melting and heat absorption (SiO2 phase change) works in conjunction with the resin carbonization layer to form a double thermal barrier; the integral protective sleeve structure has no seams or weak areas, eliminating the risk of localized failure at high temperatures.

[0010] Barium phenolic resin / modified resin has low VOC emissions and is more environmentally friendly than traditional solvent-based coatings; its high temperature resistance (1000°C) far exceeds that of epoxy / rubber coatings (up to 600°C). Attached Figure Description

[0011] Figure 1 This is a schematic diagram of an external protective structure for the combustion chamber shell of a solid rocket engine, provided as an embodiment of the present invention.

[0012] Figure 2 A flowchart illustrating a molding method for an external protective structure of a solid rocket engine combustion chamber shell, provided as an embodiment of the present invention.

[0013] In the diagram: 1. Thermal protective sleeve; 2. Structural layer; 3. Thermal insulation layer; 4. PI foam layer; 5. Epoxy film; 6. Buffer layer; 7. Combustion chamber shell. Detailed Implementation

[0014] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0015] like Figure 1As shown, this embodiment of the invention provides a thermal protection sleeve for the combustion chamber shell of a solid rocket engine. The thermal protection sleeve includes a structural layer, interlayer fibers, and a heat insulation layer arranged sequentially from the outside to the inside. The structural layer adopts a 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving to form an integral structure; the heat insulation layer adopts a quartz glass mesh or high silica glass mesh combined with needle punching to form a prefabricated body; the interlayer fibers are introduced into the structural layer and the heat insulation layer by stitching or needle punching, and the stitching depth only reaches the surface of the heat insulation layer.

[0016] The structural layer is made of high-strength quartz glass fiber or high-silica glass fiber; the thermal insulation layer is made of quartz glass fiber / high-silica glass fiber mesh + chopped fiber reinforcement; the interlayer fibers are made of quartz glass fiber yarn or high-silica glass fiber yarn.

[0017] The heat protection sleeve is made by resin transfer molding (RTM), vacuum injection, or vacuum infusion processes to fully penetrate the liquid resin. The liquid resin is made of barium phenolic resin or other modified ablation-resistant resin with good fluidity. The temperature is set to 60~120℃ and the curing time is set to 1~4h according to the resin system requirements.

[0018] In this embodiment, a method for preparing a thermal protective sleeve for a solid rocket engine combustion chamber includes the following steps.

[0019] First, the structural layer is woven. The structural layer is woven as a whole using 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving processes, along with high-strength quartz glass fiber or high-silica glass fiber materials.

[0020] Secondly, the insulation layer is formed. The process involves using a quartz glass mesh or high-silica glass mesh combined with a needle-punching process to form the preform. The materials used are quartz glass fiber / high-silica glass fiber mesh and chopped fiber reinforcement.

[0021] Furthermore, interlayer fiber reinforcement is used. In terms of process, normal fibers are introduced between the structural layer and the insulation layer using stitching or needle punching methods. The stitching depth only extends to the surface of the insulation layer, avoiding penetration. The materials used are quartz glass fiber yarn or high-silica glass fiber yarn.

[0022] Finally, resin impregnation and curing. RTM (Resin Transfer Molding), vacuum infusion, or vacuum infusion processes are used to ensure the liquid resin fully penetrates the preform. The resin system uses barium phenolic resin or other modified ablation-resistant resins with good flowability. The temperature (e.g., 60~120℃) and time (1~4h) are set according to the resin system requirements.

[0023] like Figure 1 As shown, this embodiment of the invention provides an external protective structure for the combustion chamber shell of a solid rocket engine, including a thermal protection sleeve and a buffer layer arranged from the outside in. The thermal protective sleeve includes, from the outside in, a structural layer, interlayer fibers, and a thermal insulation layer; The structural layer adopts a 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving to form an integral structure; the heat insulation layer adopts a quartz glass mesh or high silica glass mesh combined with needle punching to form a preform; the interlayer fibers are introduced into the structural layer and the heat insulation layer by stitching or needle punching. According to the functional requirements of the product in terms of mechanical and thermal properties, the stitching spacing or needle punching frequency and needle arrangement are determined by simulation or based on production practice experience. The spacing setting or needle punching frequency and needle arrangement should fully consider the stress distribution, and the stitching depth only reaches the surface of the heat insulation layer; The buffer layer consists of a 0.5-1mm PI foam layer and a 0.1mm epoxy film arranged from the outside to the inside; an epoxy adhesive is applied to the surface of the PI foam layer, and it is left to dry for 10-20 minutes until it is semi-cured; the gap between the heat protection sleeve and the PI foam layer of the buffer layer is adjusted to <0.1mm, and it is then pressurized and cured at 60℃ for 2-4 hours.

[0024] like Figure 2 As shown, this embodiment of the invention provides a method for forming an external protective structure for the combustion chamber shell of a solid rocket engine, comprising the following steps: Step S1: Use 2.5D weaving, three-way orthogonal weaving, or three-dimensional four-way weaving technology to create the overall woven structural layer; Step S2: The preform is formed by combining a quartz glass mesh or a high-silica glass mesh with a needle punching process; Step S3: Introduce normal fibers between the structural layer and the insulation layer using suturing or needle punching. The suturing interval is 2-20 mm or the needle punching frequency is 3-8 times / cm. 2 (The needle spacing is 2~10mm), and the suture depth is only to the surface of the insulation layer and avoids penetration; Step S4: Use resin transfer molding (RTM), vacuum infusion, or vacuum infusion processes to fully penetrate the preform with liquid resin, and set the temperature to 60~120℃ and the curing time to 1~4h according to the resin system requirements. Step S5: Grinding and cleaning the surface of the combustion chamber composite shell, including using a pneumatic grinder to coarsely grind the surface of the fiber winding layer, using 400-600 grit sandpaper for fine finishing in some areas, and wiping with acetone or isopropanol to remove floating dust and ensure the substrate is clean; Step S6: Apply a 0.1mm epoxy film to prevent direct contact between the carbon fiber layer and the PI foam. Lay a 0.5~1mm PI foam layer, an elastic material, to address thermal mismatch issues. Apply an epoxy adhesive to the surface of the PI foam layer and allow it to cure for 10~20 minutes. Step S7: Pre-install the heat protection sleeve, apply continuous pressure using the kit tooling to align it with the skirt end face, adjust the gap between the heat protection sleeve and the PI foam layer to <0.1mm, and pressurize at 60℃ for 2~4h; Step S8: Cut off the excess material at both ends on a lathe to make the thermal protective sleeve flush with the end faces of the front and rear skirts, with an accuracy of ±0.05mm.

[0025] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A thermal protection sleeve for the combustion chamber shell of a solid rocket motor, characterized in that, The thermal protection sleeve includes a structural layer, interlayer fibers, and a thermal insulation layer arranged sequentially from the outside to the inside; The structural layer is woven as a whole using 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving. The heat insulation layer is a preform formed by combining quartz glass mesh or high silica glass mesh with needle punching. The interlayer fibers are introduced between the structural layer and the heat insulation layer by stitching or needle punching, and the stitching depth only reaches the surface of the heat insulation layer.

2. The thermal protection sleeve for the combustion chamber shell of a solid rocket motor according to claim 1, characterized in that, The structural layer is made of high-strength quartz glass fiber or high-silica glass fiber material; the heat insulation layer is made of quartz glass fiber / high-silica glass fiber mesh and chopped fiber reinforcement; the interlayer fiber is made of quartz glass fiber yarn or high-silica glass fiber yarn.

3. The thermal protection sleeve for the combustion chamber shell of a solid rocket motor according to claim 1, characterized in that, The heat protection sleeve is made by resin transfer molding (RTM), vacuum injection, or vacuum infusion processes to fully permeate the liquid resin. The liquid resin is a barium phenolic resin or other modified ablation-resistant resin with good fluidity, and the temperature is set to 60~120℃ and the curing time is set to 1~4h according to the resin system requirements.

4. An external protective structure for the combustion chamber shell of a solid rocket motor, characterized in that, This includes a heat shield and a buffer layer arranged from the outside in; The thermal protection sleeve includes a structural layer, interlayer fibers, and a thermal insulation layer arranged sequentially from the outside to the inside; The structural layer is woven as a whole using 2.5D weaving, three-dimensional orthogonal weaving, or three-dimensional four-dimensional weaving. The heat insulation layer is formed into a preform using quartz glass mesh or high silica glass mesh combined with needle punching. The interlayer fibers are introduced between the structural layer and the heat insulation layer by stitching or needle punching, and the stitching depth only reaches the surface of the heat insulation layer. The buffer layer comprises a 0.5-1mm PI foam layer and a 0.1mm epoxy film arranged from the outside to the inside; an epoxy adhesive is applied to the surface of the PI foam layer, and it is left to dry for 10-20 minutes until it reaches a semi-cured state; the gap between the heat protection sleeve and the PI foam layer of the buffer layer is adjusted to <0.1mm, and it is then pressurized and cured at 60℃ for 2-4 hours.

5. A method for forming the outer protective structure of the solid rocket motor combustion chamber shell as described in claim 4, characterized in that, Includes the following steps: Step S1: Use 2.5D weaving, three-way orthogonal weaving, or three-dimensional four-way weaving technology to create the overall woven structural layer; Step S2: The preform is formed by combining a quartz glass mesh or a high-silica glass mesh with a needle punching process; Step S3: Introduce normal fibers between the structural layer and the insulation layer by suturing or needle punching. The suturing depth should only reach the surface of the insulation layer and avoid penetrating it. Step S4: Use resin transfer molding (RTM), vacuum infusion, or vacuum infusion processes to fully penetrate the preform with liquid resin, and set the temperature to 60~120℃ and the curing time to 1~4h according to the resin system requirements. Step S5: Grinding and cleaning the surface of the combustion chamber composite shell, including using a pneumatic grinder to coarsely grind the surface of the fiber winding layer, using 400-600 grit sandpaper for fine finishing in some areas, and wiping with acetone or isopropanol to remove floating dust and ensure the substrate is clean; Step S6: Lay a 0.1mm epoxy film, lay a 0.5~1mm PI foam layer, apply epoxy adhesive to the surface of the PI foam layer, and let it dry for 10~20 minutes until it is semi-cured; Step S7: Pre-install the heat protection sleeve, apply continuous pressure using the kit tooling to align it with the skirt end face, adjust the gap between the heat protection sleeve and the PI foam layer to <0.1mm, and pressurize at 60℃ for 2~4h; Step S8: Cut off the excess material at both ends on a lathe to make the thermal protective sleeve flush with the end faces of the front and rear skirts, with an accuracy of ±0.05mm.

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