CN116118221A - Forming method of heat insulation layer of diffusion section of jet pipe of solid rocket engine - Google Patents

Abstract

The invention relates to the field of manufacturing of space solid rocket engines, and discloses a method for forming a heat insulation layer of a nozzle diffusion section of a solid rocket engine, which comprises the following steps: winding a mould, winding a carbon layer, machining, winding a high silica heat insulation layer, sealing a vacuum bag, curing, cleaning the vacuum bag, and adding the machine to the size of the diffusion section heat insulation layer blank after demoulding. According to the forming method of the diffusion section heat insulation layer of the solid rocket engine spray pipe, when the prepreg carbon fiber cloth tape is wound, the prepreg carbon fiber cloth tapes with different widths do not need to be replaced frequently, the production efficiency of the diffusion section heat insulation layer is effectively improved, and the product size and performance requirements are met.

Description

Forming method of heat insulation layer of diffusion section of jet pipe of solid rocket engine

Technical Field

The invention relates to the technical field of manufacturing of space solid rocket engines, in particular to a method for forming a heat insulation layer of a nozzle diffusion section of a solid rocket engine.

Background

The diffusion section heat insulation layer is an important component of the solid rocket engine spray pipe, and in the engine working process, the diffusion section heat insulation layer of the spray pipe is required to provide a stable pneumatic interface under the scouring action of high-temperature and high-condensation phase component air flow so as to ensure the thrust conversion efficiency of the engine. Meanwhile, the heat insulation layer of the spray pipe diffusion section also needs to have good heat insulation performance so as to ensure that the surface temperature is lower than 160 ℃ under the action of high-temperature fuel gas for a long time and ensure the working reliability of the engine.

With the rapid development of advanced functional composite material markets, more and more composite material preparation technologies are developed, and for reinforced fiber type composite materials, the quality and performance indexes of finished products are greatly affected by the molding process technology.

A certain type of solid rocket engine spray pipe diffusion section heat insulation layer adopts a presoaked fiber cloth tape winding forming process, carbon cloth/phenolic aldehyde is used as an ablation layer, and high silica cloth/phenolic aldehyde is used as a heat insulation layer to form the carbon cloth/high silica cloth reinforced phenolic resin composite winding product. As shown in figure 2, the taper of the inner and outer surfaces of the ablation-resistant carbon layer is alpha and beta respectively, the thickness dimension requirements are provided for the small end surface, the carbon layer at the position 65mm, 125mm and 205mm from the small end surface and the large end surface, the process is complex and low in efficiency due to the large variation span of the width of the prepreg fiber cloth belt, the smaller the width of the prepreg fiber cloth belt is, the slipping is easy to generate during winding, the thickness of the carbon layer is difficult to ensure, and the qualification rate of the product is low.

Disclosure of Invention

The invention aims at overcoming the defects of the technology, and provides a method for forming the diffusion section heat insulation layer of the solid rocket engine nozzle, so that the prepreg carbon fiber cloth belts with different widths do not need to be replaced frequently when being wound, the production efficiency of the diffusion section heat insulation layer is effectively improved, and the product size and performance requirements are met.

In order to achieve the purpose, the invention provides a method for forming a heat insulation layer of a diffusion section of a spray pipe of a solid rocket engine, which comprises the following steps:

a) Winding die installation: clamping the winding die to a numerical control prepreg fiber cloth belt winding machine, and uniformly coating a release agent on a working surface after clamping;

b) Winding a carbon layer: winding a prepreg carbon fiber cloth tape from the small end of the winding die to form a carbon layer, wherein the width of the prepreg carbon fiber cloth tape before being axially wound to the middle position of the winding die is b1, and then b2 is b1 > b2;

c) And (3) machining: machining the outer molded surface of the carbon layer to ensure that a compression allowance of 1-2 mm is reserved in the thickness direction of the carbon layer;

d) Winding a high silica heat insulation layer: winding a presoaked high silica fiber cloth belt from the small end outside the carbon layer to form a high silica heat insulation layer;

e) Vacuum bag sealing: placing a winding mould wound with the carbon layer and the high silica heat insulation layer into a vacuum bag for sealing;

f) Curing;

g) Cleaning the vacuum bag, and demolding and adding the vacuum bag to the size of the heat-insulating layer blank of the diffusion section.

Preferably, in the step a), impurities on the surface of the winding mold are removed, the radial runout of the winding mold is detected to be not more than 0.2mm, and the detection position comprises 3 sections of the small end, the middle part and the large end of the winding mold.

Preferably, in the step B), when the carbon layer is wound, the winding mould is preheated to 30-40 ℃, the winding tension is 3-5N/mm, the temperature of the hot roller is room temperature-70 ℃, and the pressure of the compression roller is 6-8N/mm.

Preferably, in the step B), the thickness of the carbon layer between the small end and the middle position of the winding mold is set to be h1, the thickness is set to be h2, h1 > h2, the thickness of the carbon layer at each point is larger than the thickness of the carbon layer at the corresponding position in the finished product of the diffusion section heat insulation layer, and the taper of the inner profile of the carbon layer is set to be α, b1=h1/sin α, and b2=h2/sin α.

Preferably, in the step C), according to the requirement on the thickness of the diffusion section heat insulation layer finished product, an outer contour line of the carbon layer in the diffusion section heat insulation layer finished product is formed, and after machining, the thickness of the carbon layer extends outwards by 1-2 mm relative to the outer contour line

Preferably, in the step C), the feeding amount F15mm/min is started from the small end of the winding mould by the machine, the first cutter rotating speed S150rpm, the second cutter starting rotating speed S100rpm, the starting feeding amount F10mm/min, then the feeding amount F7mm/min is decreased at a constant speed, and the rotating speed S70rpm is increased when the machine is added to the large end.

Preferably, in the step D), the winding tension is 1-2N/mm, the temperature of the hot roller is room temperature-70 ℃, the pressure of the pressing roller is 3-4N/mm, the width of the presoaked high silica fiber cloth belt is b3, the thickness of the high silica heat insulation layer is h3, the taper of the outer surface of the carbon layer in the finished product of the diffusion section heat insulation layer is beta, and b3=h3/sin beta.

Preferably, in the step D), the stripper ring with a thickness of 20-30 mm is wound around the tail ring at the large end of the winding mold after the winding is completed.

Preferably, in the step E), the autoclave vacuumizing nozzle is pre-buried into the vacuum bag, the vacuumizing pipe is connected with the autoclave vacuumizing nozzle pre-buried in the vacuum bag, the vacuum pump is opened for vacuumizing treatment, the vacuum pump is closed, the vacuum degree is checked after 15 minutes to be less than or equal to-0.09 MPa, if the vacuum degree is more than-0.09 MPa, the vacuum bag is checked, a leakage point is found, sealing is carried out, the vacuum pump is opened again after sealing, whether the vacuum bag is completely sealed or not is checked, and checking and sealing are repeated until the requirement that the vacuum pump is closed for 15 minutes is less than or equal to-0.09 MPa and the vacuum pump is stable and has no drop is met.

Preferably, in the step F), the vacuum degree of the vacuum bag is kept to be less than or equal to-0.09 MPa in the whole curing temperature rising and preserving period, the vacuum pumping is stopped after the preserving period at 165 ℃, the initial pressure is added at 0.8-1 MPa after the curing is started, the full pressure is added at 2.3-2.5 MPa after the preserving period at 80 ℃ for 60min, and the temperature is naturally reduced after the preserving period at 165 ℃ is finished, wherein the temperature is controlled as follows:

preserving the temperature at room temperature to 60 ℃ for 60min at 60 ℃;

preserving heat for 60min at 60-80 ℃ and 80 ℃;

preserving heat for 120min at 80-100 ℃ and 100 ℃;

preserving heat for 120min at 100-120 ℃ and 120 ℃;

preserving heat for 120min at 120-165 ℃ and 165 ℃;

heating up at 0.2 ℃/min, curing and preserving heat, cooling down at 0.3 ℃/min to less than or equal to 60 ℃, and discharging.

Compared with the prior art, the invention has the following advantages: after the winding of the carbon layer is completed, a machining process is added, so that the pre-impregnated carbon fiber cloth tapes with different widths do not need to be replaced frequently when the pre-impregnated carbon fiber cloth tapes are wound, the thickness size of the cured carbon layer can be effectively ensured, and the qualification rate and the production efficiency of products are improved.

Drawings

FIG. 1 is a schematic diagram of a forming structure of a diffusion section heat insulating layer in the present invention;

fig. 2 is a schematic diagram of a molding structure of a diffusion section heat insulating layer in the prior art.

The reference numerals of the components in the drawings are as follows:

winding a die 1, a carbon layer 2 and a high silica heat insulation layer 3.

Detailed Description

The invention will now be described in further detail with reference to the drawings and to specific examples.

Example 1

A method for forming a diffusion section heat insulation layer of a solid rocket engine nozzle comprises the following steps:

a) And (3) mounting a winding die 1: as shown in fig. 1, clamping a winding die 1 to a numerical control prepreg fiber cloth tape winding machine, and uniformly coating a release agent on a working surface after clamping;

b) Carbon layer 2 winding: winding a prepreg carbon fiber cloth tape from the small end of the winding die 1 to form a carbon layer 2, wherein the width of the prepreg carbon fiber cloth tape before being axially wound to the middle position of the winding die 1 is b1, and then b2 is b1 > b2;

c) And (3) machining: machining the outer surface of the carbon layer 2 to ensure that the carbon layer 2 is left with a compression allowance of 1-2 mm in the thickness direction;

d) Winding a high silica heat insulation layer 3: winding a presoaked high silica fiber cloth tape from the small end outside the carbon layer 2 to form a high silica heat insulation layer 3;

e) Vacuum bag sealing: placing the winding mould 1 wound with the carbon layer 2 and the high silica heat insulation layer 3 into a vacuum bag for sealing;

f) Curing;

g) Cleaning the vacuum bag, and demolding and adding the vacuum bag to the size of the heat-insulating layer blank of the diffusion section.

Example 2

A method for forming a diffusion section heat insulation layer of a solid rocket engine nozzle comprises the following steps:

a) And (3) mounting a winding die 1: clamping the winding die 1 to a numerical control prepreg fiber cloth belt winding machine, removing impurities on the surface of the winding die 1, detecting that the radial runout of the winding die 1 is not more than 0.2mm, wherein the detection position comprises 3 sections of the small end, the middle part and the large end of the winding die 1, and uniformly coating a release agent on the working surface after the clamping is finished;

b) Carbon layer 2 winding: when the winding of the carbon layer 2 is carried out, the winding die 1 is preheated to 30 ℃ and the winding tension is 3N/mm, the temperature of a hot roller is 70 ℃, the pressure of a press roller is 6N/mm, the width of the carbon fiber cloth belt before being axially wound to the middle position of the winding die 1 is b1, b2 is b1 & gtb 2, the thickness of the carbon layer 2 between the small end of the winding die 1 and the middle position is h1, the thickness of the carbon layer 2 is h2, h1 & gth 2, the thickness of the carbon layer 2 at each point is larger than the thickness of the carbon layer 2 corresponding to the position in a finished product of the diffusion section heat insulation layer, and the internal surface taper of the carbon layer 2 is alpha, b1=h1/sinalpha, b2=h2/sinalpha;

c) And (3) machining: machining the outer surface of the carbon layer 2 to ensure that the carbon layer 2 is left with a compression allowance of 1mm in the thickness direction, specifically, forming an outer contour line of the carbon layer 2 in the diffusion section heat insulation layer finished product according to the requirement on the diffusion section heat insulation layer finished product thickness, wherein after machining, the thickness of the carbon layer 2 extends outwards by 1mm relative to the outer contour line;

d) Winding a high silica heat insulation layer 3: winding a presoaked high silica fiber cloth belt outside the carbon layer 2 from a small end to form a high silica heat insulation layer 3, wherein winding tension is 1N/mm, the temperature of a hot roller is 70 ℃ below zero, the pressure of a pressing roller is 3N/mm, the width of the presoaked high silica fiber cloth belt is b3, the thickness of the high silica heat insulation layer 3 is h3, the taper of the outer surface of the carbon layer 2 in a finished product of the diffusion section heat insulation layer is beta, and b3=h3/sin beta;

e) Vacuum bag sealing: placing a winding mould 1 wound with a carbon layer 2 and a high silica heat insulation layer 3 into a vacuum bag for sealing, embedding a vacuum pumping nozzle of an autoclave into the vacuum bag, connecting the vacuum pumping pipe with the vacuum pumping nozzle of the autoclave embedded in the vacuum bag, opening a vacuum pump for vacuum pumping treatment, vacuumizing until the vacuum degree is less than or equal to-0.09 MPa, closing the vacuum pump, checking the vacuum degree after 15 minutes is less than or equal to-0.09 MPa, if the vacuum degree is more than-0.09 MPa, checking the vacuum bag, finding a leakage point, sealing, opening a vacuum pump for vacuum pumping again after sealing, checking whether the vacuum bag is completely sealed or not, and repeatedly checking and sealing until the vacuum pump is closed for 15 minutes and the requirement of stability and no reduction is met;

f) Curing, wherein the vacuum degree of the vacuum bag is kept to be less than or equal to minus 0.09MPa in the whole curing temperature rising and heat preserving stage, vacuumizing is stopped after heat preserving at 165 ℃, initial pressure is added at 0.8MPa after curing begins, full pressure is added at 2.3MPa after heat preserving at 80 ℃ for 60min, and natural depressurization is carried out after heat preserving at 165 ℃, wherein the temperature is controlled as follows:

preserving the temperature at room temperature to 60 ℃ for 60min at 60 ℃;

preserving heat for 60min at 60-80 ℃ and 80 ℃;

preserving heat for 120min at 80-100 ℃ and 100 ℃;

preserving heat for 120min at 100-120 ℃ and 120 ℃;

preserving heat for 120min at 120-165 ℃ and 165 ℃;

heating up at a rate of 0.2 ℃/min, curing and preserving heat, cooling down at a rate of 0.3 ℃/min to less than or equal to 60 ℃ and discharging from the furnace;

g) Cleaning the vacuum bag, and demolding and adding the vacuum bag to the size of the heat-insulating layer blank of the diffusion section.

Example 3

A method for forming a diffusion section heat insulation layer of a solid rocket engine nozzle comprises the following steps:

a) And (3) mounting a winding die 1: clamping the winding die 1 to a numerical control prepreg fiber cloth belt winding machine, removing impurities on the surface of the winding die 1, detecting that the radial runout of the winding die 1 is not more than 0.2mm, wherein the detection position comprises 3 sections of the small end, the middle part and the large end of the winding die 1, and uniformly coating a release agent on the working surface after the clamping is finished;

b) Carbon layer 2 winding: when the winding of the carbon layer 2 is carried out, the winding die 1 is preheated to 40 ℃ and the winding tension is 5N/mm, the temperature of a hot roller is room temperature, the pressure of a pressing roller is 8N/mm, the width of the carbon fiber cloth belt before being axially wound to the middle position of the winding die 1 is b1, b2 is b1 & gtb 2, the thickness of the carbon layer 2 between the small end of the winding die 1 and the middle position is h1, the thickness of the carbon layer 2 is h2, h1 & gth 2, the thickness of the carbon layer 2 at each point is larger than the thickness of the carbon layer 2 corresponding position in a diffusion section heat insulation layer finished product, the internal surface taper of the carbon layer 2 is alpha, b1=h1/sinalpha, and b2=h2/sinalpha;

c) And (3) machining: machining the outer surface of the carbon layer 2 to ensure that the carbon layer 2 is reserved with a compression allowance of 2mm in the thickness direction, specifically, forming an outer contour line of the carbon layer 2 in the diffusion section heat insulation layer finished product according to the requirement on the diffusion section heat insulation layer finished product thickness, wherein after machining, the thickness of the carbon layer 2 extends outwards by 2mm relative to the outer contour line;

d) Winding a high silica heat insulation layer 3: winding a presoaked high silica fiber cloth belt outside the carbon layer 2 from a small end to form a high silica heat insulation layer 3, wherein the winding tension is 2N/mm, the temperature of a hot roller is room temperature, the pressure of a compression roller is 4N/mm, the width of the presoaked high silica fiber cloth belt is b3, the thickness of the high silica heat insulation layer 3 is h3, the taper of the outer surface of the carbon layer 2 in a finished product of the diffusion section heat insulation layer is beta, b3=h3/sin beta, and a demoulding ring with the thickness of 20mm is wound on the tail part of the large end of the winding mould 1 after the winding is completed;

e) Vacuum bag sealing: placing a winding mould 1 wound with a carbon layer 2 and a high silica heat insulation layer 3 into a vacuum bag for sealing, embedding a vacuum pumping nozzle of an autoclave into the vacuum bag, connecting the vacuum pumping pipe with the vacuum pumping nozzle of the autoclave embedded in the vacuum bag, opening a vacuum pump for vacuum pumping treatment, vacuumizing until the vacuum degree is less than or equal to-0.09 MPa, closing the vacuum pump, checking the vacuum degree after 15 minutes is less than or equal to-0.09 MPa, if the vacuum degree is more than-0.09 MPa, checking the vacuum bag, finding a leakage point, sealing, opening a vacuum pump for vacuum pumping again after sealing, checking whether the vacuum bag is completely sealed or not, and repeatedly checking and sealing until the vacuum pump is closed for 15 minutes and the requirement of stability and no reduction is met;

f) Curing, wherein the vacuum degree of the vacuum bag is kept to be less than or equal to minus 0.09MPa in the whole curing temperature rising and heat preserving stage, vacuumizing is stopped after heat preserving at 165 ℃, initial pressure is added at the beginning of curing, full pressure is added at the end of heat preserving at 80 ℃ for 60min, the pressure is reduced naturally after heat preserving at 165 ℃, and the temperature is controlled as follows:

preserving the temperature at room temperature to 60 ℃ for 60min at 60 ℃;

preserving heat for 60min at 60-80 ℃ and 80 ℃;

preserving heat for 120min at 80-100 ℃ and 100 ℃;

preserving heat for 120min at 100-120 ℃ and 120 ℃;

preserving heat for 120min at 120-165 ℃ and 165 ℃;

heating up at a rate of 0.2 ℃/min, curing and preserving heat, cooling down at a rate of 0.3 ℃/min to less than or equal to 60 ℃ and discharging from the furnace;

g) Cleaning the vacuum bag, and demolding and adding the vacuum bag to the size of the heat-insulating layer blank of the diffusion section.

Example 4

A method for forming a diffusion section heat insulation layer of a solid rocket engine nozzle comprises the following steps:

a) And (3) mounting a winding die 1: clamping the winding die 1 to a numerical control prepreg fiber cloth belt winding machine, removing impurities on the surface of the winding die 1, detecting that the radial runout of the winding die 1 is not more than 0.2mm, wherein the detection position comprises 3 sections of the small end, the middle part and the large end of the winding die 1, and uniformly coating a release agent on the working surface after the clamping is finished;

b) Carbon layer 2 winding: when the winding of the carbon layer 2 is carried out, the winding die 1 is preheated to 35 ℃ and the winding tension is 4N/mm, the temperature of a hot roller is 55 ℃, the pressure of a press roller is 7N/mm, the width of the carbon fiber cloth belt before being axially wound to the middle position of the winding die 1 is b1, b2 is b1 & gtb 2, the thickness of the carbon layer 2 between the small end of the winding die 1 and the middle position is h1, the thickness of the carbon layer 2 is h2, h1 & gth 2, the thickness of the carbon layer 2 at each point is larger than the thickness of the carbon layer 2 corresponding to the position in a finished product of the diffusion section heat insulation layer, and the internal surface taper of the carbon layer 2 is alpha, b1=h1/sinalpha, b2=h2/sinalpha;

c) And (3) machining: machining the outer surface of the carbon layer 2 to ensure that the carbon layer 2 is left with a compression allowance of 1mm in the thickness direction, specifically, forming an outer contour line of the carbon layer 2 in the diffusion section heat insulation layer finished product according to the requirement on the diffusion section heat insulation layer finished product thickness, wherein after machining, the thickness of the carbon layer 2 extends outwards by 1mm relative to the outer contour line;

d) Winding a high silica heat insulation layer 3: winding a presoaked high silica fiber cloth belt outside the carbon layer 2 from a small end to form a high silica heat insulation layer 3, wherein the winding tension is 2N/mm, the temperature of a hot roller is 55 ℃, the pressure of a pressing roller is 3N/mm, the width of the presoaked high silica fiber cloth belt is b3, the thickness of the high silica heat insulation layer 3 is h3, the taper of the outer surface of the carbon layer 2 in a finished product of the diffusion section heat insulation layer is beta, b3=h3/sin beta, and a demoulding ring with the thickness of 30mm is wound on the tail part of the large end of the winding mould 1 after the winding is completed;

e) Vacuum bag sealing: placing a winding mould 1 wound with a carbon layer 2 and a high silica heat insulation layer 3 into a vacuum bag for sealing, embedding a vacuum pumping nozzle of an autoclave into the vacuum bag, connecting the vacuum pumping pipe with the vacuum pumping nozzle of the autoclave embedded in the vacuum bag, opening a vacuum pump for vacuum pumping treatment, vacuumizing until the vacuum degree is less than or equal to-0.09 MPa, closing the vacuum pump, checking the vacuum degree after 15 minutes is less than or equal to-0.09 MPa, if the vacuum degree is more than-0.09 MPa, checking the vacuum bag, finding a leakage point, sealing, opening a vacuum pump for vacuum pumping again after sealing, checking whether the vacuum bag is completely sealed or not, and repeatedly checking and sealing until the vacuum pump is closed for 15 minutes and the requirement of stability and no reduction is met;

f) Curing, wherein the vacuum degree of the vacuum bag is kept to be less than or equal to minus 0.09MPa in the whole curing temperature rising and heat preserving stage, vacuumizing is stopped after heat preserving at 165 ℃, initial pressure is added at 0.9MPa after curing begins, full pressure is added at the end of heat preserving at 80 ℃ for 60min, and the temperature is naturally reduced after heat preserving at 165 ℃ is finished, wherein the temperature is controlled as follows:

preserving the temperature at room temperature to 60 ℃ for 60min at 60 ℃;

preserving heat for 60min at 60-80 ℃ and 80 ℃;

preserving heat for 120min at 80-100 ℃ and 100 ℃;

preserving heat for 120min at 100-120 ℃ and 120 ℃;

preserving heat for 120min at 120-165 ℃ and 165 ℃;

heating up at a rate of 0.2 ℃/min, curing and preserving heat, cooling down at a rate of 0.3 ℃/min to less than or equal to 60 ℃ and discharging from the furnace;

g) Cleaning a vacuum bag, clamping and aligning the excircle of the large end and the small end of the winding mould 1, machining the large end face and the excircle of the diffusion section heat insulation layer, reserving demolding steps, and machining the diffusion section heat insulation layer blank after demolding.

Claims (10)

1. A method for forming a diffusion section heat insulation layer of a solid rocket engine nozzle is characterized by comprising the following steps of: the method comprises the following steps:

a) And (3) installing a winding die (1): clamping the winding die (1) to a numerical control prepreg fiber cloth tape winding machine, and uniformly coating a release agent on a working surface after clamping;

b) Winding a carbon layer (2): winding a prepreg carbon fiber cloth tape from the small end of the winding die (1) to form a carbon layer (2), wherein the width of the prepreg carbon fiber cloth tape before being axially wound to the middle position of the winding die (1) is b1, and then b2 is b1 > b2;

c) And (3) machining: machining the outer surface of the carbon layer (2) to ensure that the carbon layer (2) is left with a compression allowance of 1-2 mm in the thickness direction;

d) Winding a high silica heat insulation layer (3): winding a presoaked high silica fiber cloth belt outside the carbon layer (2) from the small end to form a high silica heat insulation layer (3);

e) Vacuum bag sealing: placing a winding mould (1) wound with a carbon layer (2) and a high silica heat insulation layer (3) into a vacuum bag for sealing;

f) Curing;

g) Cleaning the vacuum bag, and demolding and adding the vacuum bag to the size of the heat-insulating layer blank of the diffusion section.

2. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step A), impurities on the surface of the winding mould (1) are removed, the radial circle runout of the winding mould (1) is detected to be not more than 0.2mm, and the detection position comprises 3 sections of the small end, the middle part and the large end of the winding mould (1).

3. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step B), when the carbon layer (2) is wound, the winding mould (1) is preheated to 30-40 ℃, the winding tension is 3-5N/mm, the temperature of the hot roller is room temperature-70 ℃, and the pressure of the compression roller is 6-8N/mm.

4. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step B), the thickness of the carbon layer (2) from the small end of the winding mold (1) to the middle position is set to be h1, the thickness of the carbon layer (2) is set to be h2, h1 is larger than h2, the thickness of the carbon layer (2) at each point is larger than the thickness of the carbon layer (2) corresponding to the position in the finished product of the diffusion section heat insulation layer, and the taper of the inner surface of the carbon layer (2) is alpha, b1=h1/sin alpha, and b2=h2/sin alpha.

5. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step C), according to the requirement on the thickness of the diffusion section heat insulation layer finished product, forming the outer contour line of the carbon layer (2) in the diffusion section heat insulation layer finished product, and after machining, the thickness of the carbon layer (2) extends outwards by 1-2 mm relative to the outer contour line.

6. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step C), the feeding amount F15mm/min is started from the small end of the winding mould (1), the first cutter rotating speed S150rpm, the second cutter starting rotating speed S100rpm, the starting feeding amount F10mm/min and then the feeding amount F7mm/min are gradually decreased at a constant speed, and the rotating speed S70rpm is used when the winding mould is added to the large end.

7. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step D), the winding tension is 1-2N/mm, the temperature of a hot roller is room temperature-70 ℃, the pressure of a pressing roller is 3-4N/mm, the width of a pre-soaked high silica fiber cloth belt is b3, the thickness of a high silica heat insulation layer (3) is h3, the taper of the outer surface of a carbon layer (2) in a finished product of a diffusion section heat insulation layer is beta, and b3=h3/sin beta.

8. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step D), after the winding is completed, a demoulding ring with the thickness of 20-30 mm is wound on the tail ring at the large end of the winding mould (1).

9. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step E), the vacuumizing connector of the autoclave is pre-buried into the vacuum bag, the vacuumizing pipe is connected with the vacuumizing connector of the autoclave pre-buried in the vacuum bag, the vacuum pump is opened for vacuumizing treatment, the vacuum pump is closed until the vacuum degree is less than or equal to-0.09 MPa, the vacuum pump is checked after 15 minutes, if the vacuum degree is less than or equal to-0.09 MPa and is larger than-0.09 MPa, the vacuum bag is checked, a leakage point is found, sealing is carried out, the vacuum pumping is opened again after sealing, whether the vacuum bag is completely sealed or not is checked, and the checking and sealing are repeated until the requirement that the vacuum pump is closed for 15 minutes is less than or equal to-0.09 MPa and the vacuum pump is stable and has no drop is met.

10. The method for forming the heat insulation layer of the diffusion section of the nozzle of the solid rocket engine as claimed in claim 1, wherein the method comprises the following steps: in the step F), the vacuum degree of the vacuum bag is kept to be less than or equal to minus 0.09MPa in the whole curing temperature rising and heat preserving stage, the vacuum pumping is stopped after the heat preserving at 165 ℃ is finished, the initial pressure is added at 0.8-1 MPa after the curing is started, the heat preserving at 80 ℃ is finished for 60min, the full pressure is added at 2.3-2.5 MPa, the natural pressure is reduced after the heat preserving at 165 ℃ is finished, and the temperature is controlled as follows:

preserving the temperature at room temperature to 60 ℃ for 60min at 60 ℃;

preserving heat for 60min at 60-80 ℃ and 80 ℃;

preserving heat for 120min at 80-100 ℃ and 100 ℃;

preserving heat for 120min at 100-120 ℃ and 120 ℃;

preserving heat for 120min at 120-165 ℃ and 165 ℃;

heating up at 0.2 ℃/min, curing and preserving heat, cooling down at 0.3 ℃/min to less than or equal to 60 ℃, and discharging.

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