Solid rocket engine divergent section and method of forming

Abstract

The present application relates to the field of solid rocket engine, specifically relates to a kind of solid rocket engine expansion section and its forming method, the expansion section includes carbon layer, the carbon layer includes carbon cloth tape / phenolic resin material layer;High silica layer, the high silica layer includes high silica cloth tape / phenolic resin material layer;The high silica layer is wound outside the carbon layer, the carbon layer and the high silica layer connection interface are conical surface;And the high silica layer and the carbon layer are integrally cured and formed;The expansion section product of the present application does not need multiple machine, and the carbon layer and the high silica layer interface of expansion section product are high in bonding strength, reduce the waste of carbon cloth tape / phenolic resin material layer and high silica cloth tape / phenolic resin material layer, while guaranteeing the thickness requirement of required carbon layer and high silica layer, meet the performance requirement of expansion section when bearing high temperature, ablation and mechanical load.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solid rocket engine, in particular to a solid rocket engine divergent section and a forming method thereof. BACKGROUND

[0002] The divergent section is a key component for improving energy conversion efficiency in the rocket engine nozzle. During the working process of the solid rocket engine, the nozzle divergent section needs to provide a stable aerodynamic interface under the scouring action of high-temperature and high-condensed-phase component gas flow to ensure the thrust conversion efficiency of the solid rocket engine. The divergent section needs to withstand the combined action of high temperature, ablation and mechanical load.

[0003] With the development of solid rocket engine technology, diversified technical requirements are put forward for the nozzle divergent section technology. The adiabatic layer of the divergent section is generally composed of carbon layer and high-silica layer, or composed of single carbon layer. The main function of the carbon layer is to resist ablation, and the main function of the high-silica layer is to insulate heat. Therefore, the resin-based divergent section has the advantages of high reliability, short production cycle and low cost, and is widely used in high-performance solid rocket engines at home and abroad.

[0004] However, the traditional winding method adopts the following process: first, winding the carbon layer, then machining once and winding the high-silica layer, or first winding the carbon layer, then pre-solidifying, machining once and winding the high-silica layer. There are problems of waste of carbon cloth / phenolic resin material layer and weak interfacial bonding force between the carbon layer and the high-silica layer, and the interlaminar shear strength is less than 10 MPa, which causes delamination. It cannot meet the performance requirements of the divergent section under high temperature, ablation and mechanical load.

[0005] Therefore, it is necessary to design a divergent section forming method to improve the above problems. SUMMARY

[0006] In order to solve the problems of the prior art, the present application provides a solid rocket engine divergent section, which comprises:

[0007] a carbon layer, the carbon layer comprising a carbon cloth / phenolic resin material layer;

[0008] a high-silica layer, the high-silica layer comprising a high-silica cloth / phenolic resin material layer; the high-silica layer is wound outside the carbon layer, the connection interface between the carbon layer and the high-silica layer is a conical surface, and the high-silica layer and the carbon layer are integrally solidified and formed.

[0009] Further, the thickness of the carbon layer and the high-silica layer is determined according to the actual working condition of the divergent section, and according to the heat transfer path, the thickness of the carbon layer at the outlet part of the solid rocket nozzle is gradually set to be smaller than the thickness of the carbon layer at the inlet part of the solid rocket nozzle.

[0010] Further, the thickness of the carbon layer at the exit portion of the solid rocket nozzle is less than the thickness of the carbon layer at the entrance of the solid rocket nozzle.

[0011] A solid rocket engine expansion section and a forming method thereof, comprising the following steps:

[0012] S1, carbon layer winding, the carbon layer includes carbon cloth tape / phenolic resin material layer, according to the carbon layer winding procedure, the carbon cloth tape / phenolic resin material layer is wound on the outside of the mandrel in a variable thickness manner;

[0013] S2, high silica layer winding, the high silica cloth tape / phenolic resin material layer is wound on the tapered section of the expansion section in a constant thickness manner and is combined with the carbon cloth tape / phenolic resin material layer of the trapezoidal region II of the straight section of the mandrel, so as to realize the integrated winding of the carbon layer and the high silica layer on the outside of the mandrel;

[0014] S3, after the winding is completed, the mandrel wrapped by the carbon layer and the high silica layer is obtained, then the mandrel is placed in a hot press tank for temperature rising and curing, after the curing is completed, the mandrel is demolded, an expansion section blank is obtained, and the expansion section blank is machined to obtain an expansion section product, and the forming pressure of the hot press tank is not greater than 3.0 MPa;

[0015] S4: the expansion section product is subjected to demolding inspection, and records are made;

[0016] Further, the carbon cloth tape / phenolic resin material layer is wound in a variable thickness manner, specifically including: first, the carbon cloth tape / phenolic resin material layer is overlapped on one side to the intersection of the straight section and the tapered section of the mandrel, the carbon layer winding procedure is executed, until the carbon cloth tape / phenolic resin material layer reaches the end of the tapered section of the mandrel, the procedure is ended, and the carbon layer winding of the region I is completed; then the carbon cloth tape / phenolic resin material layer is continuously overlapped, and the straight section trapezoidal region II of the mandrel is padded flat in a half overlapping manner;

[0017] Further, the high silica cloth tape / phenolic resin material layer is wound in a constant thickness manner, specifically including: the high silica cloth tape / phenolic resin material layer includes a first high silica cloth tape / phenolic resin material layer and a second high silica cloth tape / phenolic resin material layer, first, the first high silica cloth tape / phenolic resin material layer is overlapped on one side to the intersection of the carbon cloth tape / phenolic resin material layer of the trapezoidal region II of the straight section of the mandrel and the tapered section of the mandrel, the high silica layer winding procedure is executed, until the end of the tapered section of the mandrel, the procedure is ended, and the high silica layer winding of the region III of the tapered section of the mandrel is completed; then the second high silica cloth tape / phenolic resin material layer is reciprocally wound at the end of the tapered section of the mandrel in a half overlapping manner, and the high silica layer winding of the region IV of the tapered section of the mandrel is completed;

[0018] Further, the width of the carbon cloth / phenolic resin material layer is determined by the width of the intersection of the carbon layer taper section and the straight section of the mandrel, and the width of the high-silica cloth / phenolic resin material layer climbing section is determined by subtracting the width of the carbon cloth / phenolic resin material layer from the width of the intersection of the high-silica layer taper section and the straight section of the mandrel;

[0019] Further, in step S3, before curing and forming in the autoclave, the covered mandrel is packaged with a breathable film, a glue absorbing felt and a vacuum bag, and vacuumed to a vacuum degree less than -0.098 MPa;

[0020] Further, in step S3, the mandrel is placed in the autoclave for temperature rising and curing, and after curing, the mandrel is demolded to obtain the expansion section blank, and the expansion section blank is machined to obtain the expansion section product, specifically including:

[0021] at a rate of 1 ℃ / min and 0.03 MPa / min, the temperature is raised to 60-80 ℃ from room temperature, the pressure is raised to 0.8-1 MPa, and the temperature is kept for 1-2 h;

[0022] at a rate of 0.5 ℃ / min and 0.03 MPa / min, the temperature is raised to 100 ℃ from 80 ℃, the pressure is kept at 2 MPa, and the temperature is kept for 1.5-2 h;

[0023] at a rate of 0.5 ℃ / min and 0.03 MPa / min, the temperature is raised to 130 ℃ from 100 ℃, the pressure is kept at 2 MPa, and the temperature is kept for 2-3 h;

[0024] at a rate of 0.5 ℃ / min and 0.03 MPa / min, the temperature is raised to 160 ℃ from 130 ℃, the pressure is kept at 2 MPa, and the temperature is kept for 2-3 h; after curing, when the temperature in the autoclave is reduced to below 50 ℃, the mandrel to be cured is cooled to below 30 ℃ at room temperature, the carbon layer and the high-silica layer integrally formed expansion section blank are demolded and taken out, and the expansion section blank is machined to obtain the expansion section product;

[0025] Further, the carbon layer climbing program is provided in the carbon layer winding program, and the carbon layer in the carbon layer climbing program is fed by F: the axial length of the mandrel taper section is equally divided, and F=axial feed / cosα;

[0026] wherein the axial feed=width of the carbon cloth / phenolic resin material layer / number of layers; and α is the included angle between the carbon layer straight section and the taper section in region I;

[0027] The high-silica layer climbing program is provided in the high-silica layer winding program, and the high-silica layer is fed by F in each small program: the axial length of the mandrel taper section is equally divided, and F=high-silica cloth / phenolic resin material layer / sinα;

[0028] The beneficial effects of the present application are:

[0029] The forming method of the solid rocket engine expansion section of the present application adopts carbon layer and high silica layer to be wound on the outside of the core mold, and the carbon cloth tape / phenolic resin material layer is wound on the outside of the core mold in a variable thickness manner; after the carbon layer is wound, the high silica layer is directly wound, and the high silica cloth tape / phenolic resin material layer is wound on the cone section of the expansion section in a constant thickness manner and is compounded with the carbon cloth tape / phenolic resin material layer of the trapezoidal area II of the straight section of the core mold, after the winding is completed, the core mold wrapped by the carbon layer and the high silica layer is placed in a hot press tank for temperature rising and curing, and after the curing is completed, the core mold is demolded, the expansion section blank formed by the carbon layer and the high silica layer is obtained, and the expansion section product is obtained by machining the expansion section blank, without multiple machining, reducing the waste of the carbon cloth tape / phenolic resin material layer and the high silica cloth tape / phenolic resin material layer, and at the same time, the thickness requirements of the carbon layer and the high silica layer are ensured, so that the interface bonding strength of the carbon layer and the high silica layer of the expansion section product is high. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 The carbon layer winding and high silica layer winding in the embodiment of the present application are shown in the schematic diagram;

[0031] Figure 2 The carbon layer winding procedure in the embodiment of the present application is shown in the schematic diagram;

[0032] Figure 3 The structure of the expansion section product of the present application is shown in the schematic diagram. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0034] The present application provides a solid rocket engine expansion section, which comprises:

[0035] a carbon layer, the carbon layer comprising a carbon cloth tape / phenolic resin material layer;

[0036] a high silica layer, the high silica layer comprising a high silica cloth tape / phenolic resin material layer; the high silica layer is wound on the outside of the carbon layer, the connecting interface of the carbon layer and the high silica layer is a conical surface, and the high silica layer is integrally cured and formed with the carbon layer.

[0037] Further, the thickness of the carbon layer and the high silica layer is determined according to the actual working condition of the expansion section, and according to the heat transfer path, the thickness of the carbon layer at the outlet part of the solid rocket nozzle is set to be gradually smaller than the thickness of the carbon layer at the inlet part of the solid rocket nozzle.

[0038] Further, the thickness of the carbon layer at the exit portion of the solid rocket nozzle is less than the thickness of the carbon layer at the entrance of the solid rocket nozzle.

[0039] Referring to Figures 1-2 A solid rocket engine expansion section and a forming method thereof, comprising the following steps:

[0040] S1, carbon layer winding, the carbon layer comprising a carbon cloth tape / phenolic resin material layer, the carbon cloth tape / phenolic resin material layer being wound on the outside of the mandrel in a variable thickness manner according to a carbon layer winding program;

[0041] S2, high silica layer winding, the high silica cloth tape / phenolic resin material layer being wound on the tapered section of the expansion section in a constant thickness manner and being combined with the carbon cloth tape / phenolic resin material layer of the trapezoidal region II of the straight section of the mandrel, so as to realize integrated winding of the carbon layer and the high silica layer on the outside of the mandrel;

[0042] S3, after the winding is completed, the mandrel wrapped by the carbon layer and the high silica layer is obtained, then the mandrel is placed in a hot press tank for temperature rising and curing, the mandrel is demolded after the curing is completed, an expansion section blank is obtained, and the expansion section blank is machined to obtain an expansion section product, and the forming pressure of the hot press tank is not greater than 3.0 MPa;

[0043] S4: demolding inspection is performed on the expansion section product, and records are made;

[0044] Further, the carbon cloth tape / phenolic resin material layer is wound in a variable thickness manner, specifically including: first, the carbon cloth tape / phenolic resin material layer is overlapped on one side to the intersection of the straight section and the tapered section of the mandrel, the carbon layer winding program is executed, and the carbon cloth tape / phenolic resin material layer is moved to the end of the tapered section of the mandrel until the program is completed, the carbon layer winding of the region I is completed; then the carbon cloth tape / phenolic resin material layer is continuously overlapped, and the straight section trapezoidal region II of the mandrel is padded flat in a half overlapping manner;

[0045] Further, the high silica cloth tape / phenolic resin material layer is wound in a constant thickness manner, specifically including: the high silica cloth tape / phenolic resin material layer includes a first high silica cloth tape / phenolic resin material layer and a second high silica cloth tape / phenolic resin material layer, first, the first high silica cloth tape / phenolic resin material layer is overlapped on one side to the intersection of the carbon cloth tape / phenolic resin material layer of the trapezoidal region II of the straight section of the mandrel and the tapered section of the mandrel, i.e. the G point as shown; the high silica layer winding program is executed until the end of the tapered section of the mandrel, the program is completed, and the high silica layer winding of the region III of the tapered section of the mandrel is completed; then the second high silica cloth tape / phenolic resin material layer is reciprocally wound at the end of the tapered section of the mandrel in a half overlapping manner, and the high silica layer winding of the region IV of the tapered section of the mandrel is completed; Figure 1

[0046] ​Further, the width of the carbon cloth / phenolic resin material layer is determined by the width of the intersection of the carbon layer taper section and the straight section of the mandrel, and the width of the high-silicon cloth / phenolic resin material layer climbing section is determined by subtracting the width of the carbon cloth / phenolic resin material layer from the width of the intersection of the high-silicon layer taper section and the straight section of the mandrel;

[0047] Further, in step S3, before curing and forming in the autoclave, the covered mandrel is packaged with a breathable film, a glue absorbing felt and a vacuum bag, and vacuumed to a vacuum degree less than -0.098 MPa;

[0048] The vacuum packaging and vacuuming operation is performed before curing, which aims to remove air in the product and reduce the generation of air bubbles during curing, thereby improving the quality of the composite material;

[0049] Further, in step S3, the mandrel is placed in the autoclave for temperature rising and curing, and after curing is completed, the mandrel is demolded to obtain an expansion section blank, and the expansion section blank is machined to obtain an expansion section product, which specifically includes:

[0050] Rising from room temperature to 60-80℃ at a rate of 1℃ / min, 0.03 MPa / min, and rising to 0.8-1 MPa, and holding for 1-2 h;

[0051] Rising from 80℃ to 100℃ at a rate of 0.5℃ / min, 0.03 MPa / min, 2 MPa pressure holding, and holding for 1.5-2 h;

[0052] Rising from 100℃ to 130℃ at a rate of 0.5℃ / min, 0.03 MPa / min, 2 MPa pressure holding, and holding for 2-3 h;

[0053] Rising from 130℃ to 160℃ at a rate of 0.5℃ / min, 0.03 MPa / min, 2 MPa pressure holding, and holding for 2-3 h; after curing is completed, when the temperature in the autoclave drops to below 50℃, the mandrel to be cured is cooled to below 30℃ at room temperature, and the carbon layer and high-silicon layer integrally formed expansion section blank is demolded and taken out, and the expansion section blank is machined to obtain an expansion section product;

[0054] Further, the carbon layer climbing program is provided in the carbon layer winding program, and the carbon layer in the carbon layer climbing program is fed by F:

[0055] The axial length of the mandrel taper section is equally divided, and F=axial feed / cosα;

[0056] Wherein, the axial feed=width of the carbon cloth / phenolic resin material layer / number of layers; and α is the included angle between the carbon layer straight section and the taper section in region I;

[0057] The high-silica layer winding procedure is provided with a high-silica layer climbing procedure, and the feeding F of each small procedure of the high-silica layer is:

[0058] The axial length of the core mold taper section is equally divided, and F is the thickness of the high-silica cloth tape / phenolic resin material layer

[0059] / sinα;

[0060] In example 1, the autoclave forming pressure is 2.0 MPa, and the interface bonding strength between the carbon layer and the high-silica layer is required to be high, and the specific steps are as follows:

[0061] S1, carbon layer winding, the carbon layer includes a carbon cloth tape / phenolic resin material layer, and the carbon cloth tape / phenolic resin material layer is wound on the outside of the core mold in a variable thickness manner according to the carbon layer winding procedure;

[0062] As shown in Figure 1 , the carbon cloth tape / phenolic resin material layer with a width of 43 mm is overlapped to the intersection point A of the straight section and the taper section of the core mold, the carbon layer winding procedure is started to be executed, and the procedure is ended until the tape reaches the point B, and the carbon layer winding of the region I is completed; then the core mold small end is returned to continue to overlap the carbon cloth tape / phenolic resin material layer, and the core mold straight section trapezoidal region II is flattened in a half overlap manner;

[0063] The carbon layer winding procedure is provided with a carbon layer climbing procedure, and the feeding F of each small procedure of the carbon layer in the carbon layer climbing procedure is: the axial length of the core mold taper section is equally divided, and F is the axial feeding / cosα; wherein the axial feeding is the width of the carbon cloth tape / phenolic resin material layer / number of layers; and α is the included angle of the straight section and the taper section of the region I carbon layer;

[0064] Specifically, the feeding F refers to the distance that the carbon cloth tape / phenolic resin material layer or the high-silica cloth tape / phenolic resin material layer moves along the direction of the core mold taper section per revolution of the winding machine main shaft; the carbon layer winding procedure of the climbing section, as shown in Figure 2 , specifically includes: the axial length of the core mold AB section is equally divided, the number of equal divisions is determined according to the axial length of AB, the length of each section is ensured to be 10-40 mm, the number of equal divisions is controlled to be 10-30, the program control is accurate, the actual carbon layer size is appropriately increased according to the actual required carbon layer size, and the shrinkage of the carbon layer after curing is prevented, so that the actual design carbon layer size CE is obtained; Figure 2 , the radial length of 1-10 sections is taken, that is, the radial design thickness is L, and L / 0.2 (the thickness of the carbon cloth tape / phenolic resin material layer) = the number of layers;

[0065] The axial feeding is calculated as 43 (the width of the carbon cloth tape / phenolic resin material layer) / number of layers;

[0066] As shown in Figure 2 , the included angle α of the CE section and the AE section is taken, and the angle is α=15.86°;

[0067] Calculate the axial feed of each small program F = axial feed / cosα; based on the carbon layer, the axial length and radial length of each segment after the carbon layer AB segment is evenly divided; at this point, the carbon layer climbing program is complete;

[0068] S2, high silica layer winding, high silica cloth / phenolic resin material layer is wound on the taper section of the expansion section in the form of equal thickness with the carbon cloth / phenolic resin material layer of the trapezoidal area II of the straight section of the core mold, realizing the integrated winding of the carbon layer and the high silica layer on the outside of the core mold;

[0069] In the high silica layer winding process, the high silica cloth / phenolic resin material layer of different widths is set in different winding modes and paths in different regions, ensuring the coverage and structural strength of the high silica layer at different parts of the expansion section, so that it and the carbon layer together form a complete heat insulation layer shape, meeting the requirements of heat insulation and ablation resistance;

[0070] In the high silica layer winding process, the high silica cloth / phenolic resin material layer of different widths is set in different winding modes and paths in different regions, ensuring the coverage and structural strength of the high silica layer at different parts of the expansion section, so that it and the carbon layer together form a complete heat insulation layer shape, meeting the requirements of heat insulation and ablation resistance;

[0071] In the high silica layer winding process, the high silica cloth / phenolic resin material layer of different widths is set in different winding modes and paths in different regions, ensuring the coverage and structural strength of the high silica layer at different parts of the expansion section, so that it and the carbon layer together form a complete heat insulation layer shape, meeting the requirements of heat insulation and ablation resistance;

[0072] The high-silica layer winding procedure is provided with a high-silica layer climbing procedure, and the program feed F of each small procedure of the high-silica layer is: the axial length of the mandrel cone section is evenly divided, F = high-silica cloth tape / phenolic resin material layer thickness / sin a; specifically, in the high-silica layer winding step, the high-silica winding procedure of the climbing section is set as: program feed F = high-silica cloth tape / phenolic resin material layer thickness / sin a; the axial and radial coordinate changes of the GC section are obtained based on the program feed F of each small procedure of the high-silica layer;

[0073] S3, after winding is completed, a mandrel coated with the high-silica cloth tape / phenolic resin material layer / carbon cloth tape / phenolic resin material layer is obtained, and then curing and forming are performed in a hot press tank, and the forming pressure of the hot press tank is 2.0 MPa;

[0074] Before curing and forming in the hot press tank, the coated mandrel is packaged by vacuumizing with a breathable film, glue-absorbing felt and a vacuum bag, and vacuumizing is performed until the vacuum degree is less than -0.098 MPa;

[0075] The vacuum packaging and vacuumizing operation is performed before curing, and the purpose is to remove air in the product, reduce the generation of air bubbles in the curing process, and improve the quality of the composite material;

[0076] The mandrel is placed in the hot press tank for temperature rising and curing, and after curing is completed, demolding is performed to obtain an expansion section blank, and the expansion section blank is machined to obtain an expansion section product, and the specific steps include:

[0077] The temperature is raised from room temperature to 60-80℃ at a rate of 1℃ / min and 0.03 MPa / min, the pressure is raised to 0.8-1 MPa, and the temperature is kept for 1-2 h; the temperature is raised from 80℃ to 100℃ at a rate of 0.5℃ / min and 0.03 MPa / min, the pressure is kept at 2 MPa, and the temperature is kept for 1.5-2 h; the temperature is raised from 100℃ to 130℃ at a rate of 0.5℃ / min and 0.03 MPa / min, the pressure is kept at 2 MPa, and the temperature is kept for 2-3 h; the temperature is raised from 130℃ to 160℃ at a rate of 0.5℃ / min and 0.03 MPa / min, the pressure is kept at 2 MPa, and the temperature is kept for 2-3 h; after curing is completed, when the temperature in the hot press tank is reduced to below 50℃, the mandrel to be cured is cooled to below 30℃ at room temperature, the carbon layer and the high-silica layer integrally formed expansion section blank is demolded and taken out, the expansion section blank is machined to obtain an expansion section product; and then machining is performed to the size required by the nozzle expansion section;

[0078] It should be noted that the setting of the parameters such as the heating rate, the pressure increasing rate, the holding time and the temperature in the curing step is to ensure that the resin in the prepreg uniformly flows and sufficiently cures in the curing process, to avoid problems such as air bubbles, excessive internal stress, material cracking or deformation, and to improve the compactness, mechanical properties, heat resistance and dimensional stability of the composite material. The machining step is performed after curing, cooling and demolding, and is used to accurately adjust the size of the expansion section to the required final size of the product, so as to ensure that the size precision and performance of the product meet the design requirements.

[0079] S4: After curing, demolding inspection is performed. It is found through the demolding inspection that the interface bonding strength between the carbon layer and the high-silica layer is high, and the performance requirements of the expansion section under high temperature, ablation and mechanical load are met. The interlaminar shear strength of the carbon cloth tape / phenolic resin material layer is 16 MPa, and the interlaminar shear strength of the high-silica cloth tape / phenolic resin material layer is 19 MPa. The requirements of the GB 1450.1-2005 standard are met.

[0080] In example 2, the other conditions in the solid rocket engine expansion section and the forming method thereof are the same as in example 1, and the solid rocket engine expansion section is formed in a hot press tank. The forming pressure of the hot press tank is 2.0 MPa. After curing, demolding inspection is performed. It is found through the demolding inspection that the interface bonding strength between the carbon layer and the high-silica layer is high. The interlaminar shear strength of the carbon cloth tape / phenolic resin material layer is 15 MPa, and the interlaminar shear strength of the high-silica cloth tape / phenolic resin material layer is 17 MPa. The requirements of the GB 1450.1-2005 standard are met, and the performance requirements of the expansion section under high temperature, ablation and mechanical load are met.

[0081] It should be noted that in the forming method of the solid rocket engine expansion section, the carbon layer and the high-silica layer are integrally wound outside the core mold, and the carbon cloth tape / phenolic resin material layer is wound outside the core mold in a variable thickness manner. After the carbon layer is wound, the high-silica layer is directly wound. The high-silica cloth tape / phenolic resin material layer is wound on the cone section of the expansion section in a constant thickness manner and is combined with the carbon cloth tape / phenolic resin material layer in the trapezoidal area II of the straight section of the core mold. After winding is completed, the core mold wrapped with the carbon layer and the high-silica layer is placed in a hot press tank for heating and curing. After curing, the expansion section blank is demolded. The carbon layer and the high-silica layer are integrally formed. The expansion section blank is machined to obtain the expansion section product. Multiple machining is not required, the waste of the carbon cloth tape / phenolic resin material layer and the high-silica cloth tape / phenolic resin material layer is reduced, and the thickness requirements of the carbon layer and the high-silica layer are ensured, so that the interface bonding strength between the carbon layer and the high-silica layer of the expansion section product is high. The winding program of the carbon layer ensures the thickness of the carbon layer, and the thickness of the high-silica layer is ensured after curing and machining. The problem of multiple machining and winding in the existing composite winding process of the thermal insulation layer of the expansion section is solved.

[0082] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for forming the expansion section of a solid rocket motor, characterized in that, The molding method includes an expansion section, the expansion section comprising: The carbon layer includes a carbon cloth tape / phenolic resin material layer; A high-silica layer, comprising a high-silica tape / phenolic resin material layer; the high-silica layer is wound around the outside of the carbon layer, and the interface between the carbon layer and the high-silica layer is a conical surface; and the high-silica layer and the carbon layer are integrally cured and formed. The molding method includes the following steps: S1, carbon layer winding, the carbon layer includes carbon cloth tape / phenolic resin material layer, according to the carbon layer winding procedure, the carbon cloth tape / phenolic resin layer is wound on the outside of the mandrel in a variable thickness manner; S2, High silica layer winding: The high silica tape / phenolic resin material layer is wound together with the carbon tape / phenolic resin material layer in the trapezoidal area II of the straight section of the core mold in an equal thickness manner on the conical section of the expansion section, so as to realize that the carbon layer and the high silica layer are wound together on the outside of the core mold. S3. After winding, a core mold is obtained that is covered by the carbon layer and the high silica layer. Then, the core mold is placed in a hot autoclave for heating and curing. After curing, the mold is demolded to obtain an expanded section blank. The expanded section blank is then machined to obtain an expanded section product. The molding pressure of the hot autoclave is not greater than 3.0 MPa. S4: Perform demolding inspection on the expanded section products and keep records. The carbon fiber tape / phenolic resin material layer is wound using a variable thickness method, specifically including: first, overlapping one side of the carbon fiber tape / phenolic resin material layer to the intersection of the straight and conical sections of the mandrel, and executing the carbon layer winding procedure until the carbon fiber tape / phenolic resin material layer reaches the end of the conical section of the mandrel, at which point the procedure ends, completing the carbon layer winding of region I; then, continuing to overlap the carbon fiber tape / phenolic resin material layer, using a semi-overlapping method to flatten the trapezoidal region II of the straight section of the mandrel. The carbon layer winding program includes a carbon layer ramping program. The feed F for each small segment of the carbon layer in the carbon layer ramping program is: the axial length of the mandrel cone segment is evenly divided, F = axial feed / cosα. Where, axial feed = carbon layer tape / width of phenolic resin material layer / number of layers; α is the angle between the straight section and the conical section of the carbon layer in region I; The high silica layer winding program includes a high silica layer ramping program. The feed F for each small segment of the high silica layer program is: the axial length of the mandrel cone segment is evenly divided, F = high silica tape / phenolic resin material layer / sinα. The thicknesses of the carbon layer and the high-silica layer are determined based on the actual operating conditions of the expansion section, and according to the heat transfer path, the thickness of the carbon layer at the exit portion of the solid rocket nozzle is set to be gradually smaller than the thickness of the carbon layer at the inlet portion of the solid rocket nozzle.

2. The method for forming the expansion section of a solid rocket motor according to claim 1, characterized in that, The thickness of the carbon layer at the exit portion of the solid rocket nozzle is less than the thickness of the carbon layer at the inlet portion of the solid rocket nozzle.

3. The method for forming the expansion section of a solid rocket motor according to claim 1, characterized in that, The high-silica tape / phenolic resin material layer is wound in an equal-thickness manner, specifically including: the high-silica tape / phenolic resin material layer includes a first high-silica tape / phenolic resin material layer and a second high-silica tape / phenolic resin material layer. First, one side of the first high-silica tape / phenolic resin material layer is overlapped to the intersection of the carbon tape / phenolic resin material layer and the conical section of the mandrel in the trapezoidal region II of the straight section. The high-silica layer winding procedure is then performed until the end of the mandrel conical section, completing the high-silica layer winding in the conical section region III of the mandrel. Then, the second high-silica tape / phenolic resin material layer is wound in a semi-overlapping manner at the end of the mandrel conical section, completing the high-silica layer winding in the conical section region IV of the mandrel.

4. The method for forming the expansion section of a solid rocket motor according to claim 1, characterized in that, The width of the carbon tape / phenolic resin material layer is determined by the width of the intersection line between the conical section of the carbon layer and the straight section of the mandrel. The width of the ramp section of the high silica tape / phenolic resin material layer is determined by subtracting the width of the carbon tape / phenolic resin layer from the width of the intersection line between the conical section of the high silica layer and the straight section of the mandrel.

5. The method for forming the expansion section of a solid rocket motor according to claim 1, characterized in that, In step S3, before curing and molding in the autoclave, the core mold is vacuum-packed using a breathable membrane, absorbent felt, and vacuum bag, and the vacuum level is reduced to less than -0.098 MPa.

6. The method for forming the expansion section of a solid rocket motor according to claim 1, characterized in that, In step S3, the mandrel is placed in an autoclave for heating and curing. After curing, it is demolded to obtain an expanded section blank, which is then machined to obtain the expanded section product. Specifically, this includes: The temperature was increased from room temperature to 60-80℃ at a rate of 1℃ / min and 0.03MPa / min, and the pressure was increased by 0.8-1MPa, and the temperature was held for 1-2 hours. The temperature was increased from 80℃ to 100℃ at a rate of 0.5℃ / min and 0.03MPa / min, and held at 2MPa for 1.5-2 hours. The temperature was increased from 100℃ to 130℃ at a rate of 0.5℃ / min and 0.03MPa / min, and the pressure was maintained at 2MPa for 2-3 hours. The temperature was increased from 130℃ to 160℃ at a rate of 0.5℃ / min and 0.03MPa / min, and the pressure was maintained at 2MPa for 2-3 hours. After curing, when the temperature inside the autoclave drops to below 50°C, the core mold to be cured is removed. The core mold to be cured is then cooled to below 30°C at room temperature. The expanded section blank, which is integrally formed by the carbon layer and the high silica layer, is demolded and removed. The expanded section blank is then machined to obtain the expanded section product.

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