Ablation-resistant / heat-insulating integrated forming method for spray pipe

Abstract

The invention discloses an ablation-resistant / heat-insulating integrated forming method for a spray pipe, which comprises an ablation-resistant layer and a heat-insulating layer, the ablation-resistant layer is integrally formed by adopting a tungsten infiltrated copper material, and the integrated forming method specifically comprises the following steps: machining the outer molded surface of the ablation-resistant layer to the size, and leaving margins at the two ends and the inner molded surface; a high-silica cloth / phenolic aldehyde prepreg cloth belt is adopted, and an isometric deformation-width-imitating cloth belt is used for winding a trapezoidal ring area of the heat insulation layer. The heat insulation layer is directly formed on the outer surface of the integrated ablation-resistant layer, so that the assembly interface is reduced, the possibility of forming an internal gas channel is avoided, and the product quality is improved while the production efficiency is improved.

Description

Technical Field

[0001] This invention belongs to the field of nozzle heat insulation layer molding technology, specifically relating to an integrated molding method for nozzle ablation-resistant / heat insulation. Background Technology

[0002] The nozzle is a crucial component of a rocket engine. It's a device that accelerates airflow by altering the geometry of the inner wall of a tube section, serving as the outlet for the high-temperature, high-pressure combustion gases within the combustion chamber. In a rocket engine, the nozzle throat area controls the gas flow rate, maintaining a predetermined pressure within the combustion chamber to ensure proper combustion of the propellant. Simultaneously, the nozzle allows the propellant combustion products to expand and accelerate through the nozzle, fully converting their thermal energy into the kinetic energy of the combustion gases, thus providing the engine with propulsive power.

[0003] A typical traditional assembled nozzle structure can be divided into two parts: a support structure and an ablation-resistant / heat-insulating structure. The main function of the support structure is to support the convergent section, throat liner, and diffuser section, and to integrate them as a whole, bearing all loads except thermal loads (internal pressure, external loads, and local dynamic loads, etc.). The main function of the convergent section, throat liner, and diffuser section is to form the continuous internal profile of the nozzle, minimizing or eliminating changes to the aerodynamic design profile, and ensuring that the temperature of the support structure is controlled within allowable limits to ensure the safe and reliable operation of the nozzle structure. Figure 1 As shown, throat liner materials are generally made of ablation-resistant metals or composite materials such as graphite and C / C. The ablation-resistant materials for the convergent and diffuser sections are generally carbon / phenolic resins, and the thermal insulation materials are generally high-silica / phenolic resins. The molding method is generally composite winding or molding followed by machining assembly. Its structure is complex with many assembly interfaces, and the reliability of thermal protection is mainly ensured by the assembly gaps and the setting of labyrinth channels. At the same time, the trapezoidal area of ​​the tape winding during manufacturing is generally done by manual patching, and the winding tension cannot be accurately guaranteed, which not only results in low production efficiency but also poor internal quality of the product after molding. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems and provide an integrated molding method for ablation-resistant / heat-insulating nozzles that improves production efficiency while enhancing quality.

[0005] To achieve the above objectives, the present invention provides an integrated molding method for ablation-resistant / heat-insulating nozzles, comprising an ablation-resistant layer and a heat-insulating layer, wherein the ablation-resistant layer is integrally molded using tungsten-copper infiltrated material, and the integrated molding method specifically comprises: 1) Machin the outer surface of the ablation-resistant layer to the required dimensions, leaving allowances at both ends and on the inner surface; 2) High-silica cloth / phenolic prepreg tape is used, and the trapezoidal ring area of ​​the insulation layer is wrapped with equal-volume deformation-mimicking tape.

[0006] Further, the ablation-resistant layer comprises a throat insert, a converging section at the front end of the throat insert, and a diverging section at the rear end of the throat insert, and the outer profile surface of the integrally formed ablation-resistant layer comprises, in sequence from the converging section to the diverging section, a horizontal straight surface 1.1, a vertical straight surface, a first inclined surface, a horizontal surface, and a second inclined surface.

[0007] Further, the specific process of step 2) is as follows: 2a) Calculate the volume V of the circular ring containing the trapezoidal ring area by using the formula: V = π × D (R 2 -r 2 ), wherein D is the vertical length between the starting end of the first inclined surface and the ending end of the second inclined surface, R is the vertical distance between the central axis of the ablation-resistant layer and the starting end of the first inclined surface, and r is the vertical distance between the central axis of the ablation-resistant layer and the ending end of the first inclined surface; 2b) Calculate the outer radius of the cloth tape roll according to the volume V of the circular ring in step 2a): , wherein R' is the outer radius of the cloth tape roll required for the equal-volume profiling winding, and r' is the outer radius of the slitting and winding core; and the equal-width high-silica cloth / phenolic prepreg tape is slit and wound; 2c) According to the difference between the two sides of the trapezoidal ring area, i.e., the vertical length L1 between the starting end and the ending end of the first inclined surface and the vertical length L2 between the starting end and the ending end of the second inclined surface, the excess part of the slitted equal-width high-silica cloth / phenolic prepreg tape roll corresponding to the two sides is removed; 2d) Apply an elastic glue layer on the outer profile surface of the ablation-resistant layer before winding, and then perform the trapezoidal ring area profiling width winding.

[0008] Further, it further comprises: 3) After the trapezoidal ring area profiling width winding is completed, the outer equal-width high-silica / phenolic prepreg tape is flatly wound; 4) The permeable felt layer is uniformly wrapped on the outer layer of the wound material, and the pressure-sensitive adhesive tape is used for fixation; 5) The wound material is vacuum bag sealed and the sealing property is detected; 6) After the vacuum bag meets the sealing requirements, curing is performed; 7) After the curing is completed, the vacuum bag and the permeable felt are cleaned, and the ablation-resistant / heat-insulating integrally formed structure is machined and demolded.

[0009] Further, in step 3), the winding tension is 1-2 N / mm, the hot roller temperature is room temperature-70°C, and the pressure roller pressure is 3-4 N / mm.

[0010] Further, in the step 5), the specific process is: embedding the vacuum extraction nozzle into the vacuum bag, connecting the vacuum extraction pipe with the embedded vacuum extraction nozzle in the vacuum bag, opening the vacuum pump for vacuum extraction, extracting vacuum to a vacuum degree of ≤-0.092 MPa, closing the vacuum pump, checking the vacuum degree after 15-20 minutes, if the vacuum degree is greater than-0.092 MPa, it proves that the vacuum bag is not completely sealed, checking the vacuum bag to find the air leakage point and sealing; after sealing, opening the vacuum pump again for vacuum extraction, checking whether the vacuum bag is completely sealed; repeating the checking and sealing until the vacuum degree is ≤-0.092 MPa and stable without decline after closing the vacuum pump for 15-20 minutes.

[0011] Further, in the step 6), the curing system is as follows: Extracting vacuum from the bag before heating and curing to remove air and volatile matters; The vacuum degree during curing is controlled to be ≤-0.092 MPa, vacuum extraction is started at the beginning of curing, and the vacuum degree is kept to be ≤-0.092 MPa during the whole curing temperature rising and holding stage, and the vacuum extraction is stopped after holding at 165-180℃. The pressure system is: adding initial pressure of 0.8-1 MPa at the beginning of curing, holding at 80-100℃ for 60-90 min, adding full pressure of 2.3-2.5 MPa, and naturally reducing the pressure after holding at 165-180℃.

[0012] The temperature system is: Room temperature to 60℃, holding at 60℃ for 60 min; 60℃ to 80℃, holding at 80℃ for 60 min; 80℃ to 100℃, holding at 100℃ for 120 min; 100℃ to 120℃, holding at 120℃ for 120 min; 120℃ to 165℃, holding at 165℃ for 120 min.

[0013] Further, in the step 6), the temperature rising rate is controlled to be 0.3-0.5℃ / min, and the temperature falling rate is controlled to be 0.2-0.4℃ / min after holding at the end of curing to ≤60℃.

[0014] Compared with the prior art, the application has the beneficial effects that: the application directly forms the heat insulation layer on the integrated ablation-resistant layer outer shape, reduces the assembly interface, eliminates the possibility of forming internal gas channels, improves the production efficiency and improves the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a schematic diagram of the existing nozzle structure; Figure 2This is a schematic diagram of the integrated ablation-resistant / heat-insulating structure of the present invention; Figure 3 This is a schematic diagram of the equal-volume, deformation-simulating width fabric strip structure of the present invention; Figure 4 This is a schematic diagram of the winding structure of the present invention. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] The nozzle uses an integrated ablation-resistant / heat-insulating molding method, including an ablation-resistant layer 1 and a heat-insulating layer 2, such as... Figure 2 The ablation-resistant layer 1 shown is integrally formed using tungsten-copper infiltrated material, including a throat liner a, a converging section b at the front end of the throat liner, and a diffusing section c at the rear end of the throat liner. The outer surface of the integrally formed ablation-resistant layer 1, from the converging section to the diffusing section, includes a transverse straight surface 1.1, a vertical straight surface 1.2, a first inclined surface 1.3, a horizontal surface 1.4, and a second inclined surface 1.5. The specific integral forming method is as follows: 1) Machin the outer surface of the ablation-resistant layer to the required dimensions, leaving allowances at both ends and on the inner surface; 2) High-silica cloth / phenolic prepreg tape is used, and the trapezoidal ring area of ​​the insulation layer is wrapped with equal-volume deformation-conforming tape. Because the outer surface of the ablation-resistant layer is formed by offsetting the inner surface (Laval curve), and the initial winding area is a trapezoidal ring region, it is impossible to use conventional equal-width fabric tape for flat winding. Therefore, this invention uses equal-volume deformation-mimicking fabric tape for winding, as follows: 2a) Calculate the volume V of the annulus containing the trapezoidal ring region using the formula: V = π × D (R 2 -r 2 ), where D is the vertical length between the starting end of the first inclined plane and the ending end of the second inclined plane, R is the vertical distance between the central axis of the ablation-resistant layer and the starting end of the first inclined plane, and r is the vertical distance between the central axis of the ablation-resistant layer and the ending end of the first inclined plane; 2b) Calculate the outer radius of the fabric roll based on the annular volume V from step 2a): Where R′ is the outer radius of the fabric roll required for equal volume contour winding, and r′ is the outer radius of the core 3 for slitting and winding; and equal width and height silicone / phenolic prepreg fabric tape is slitted and wound up; 2c) Based on the difference between the two sides of the trapezoidal ring region, i.e., the vertical length L1 between the starting end and the ending end of the first inclined plane and the vertical length L2 between the starting end and the ending end of the second inclined plane, machine the excess parts on both sides of the equal-width and high-height silica / phenolic prepreg rolls cut in step 2a), such as... Figure 3 As shown.

[0018] 2d) In order to improve the deformation matching of the ablation-resistant layer and the heat-insulating layer interface, an elastic glue layer is brushed on the outer surface of the ablation-resistant layer before winding, and then the width of the trapezoidal ring area is profiled and widened; 3) After the trapezoidal ring area profiled and widened winding is completed, the outer part is flatly stacked and wound with equal-width high-silica / phenolic pre-impregnated cloth tape, as shown in Figure 4 The winding tension is 1-2 N / mm, the hot roller temperature is room temperature-70°C, and the pressure roller pressure is 3-4 N / mm.

[0019] 4) The wound blank is uniformly wrapped with 3-5 layers of air-permeable felt, and is fixed with pressure-sensitive adhesive tape; 5) The blank is vacuum bag sealed, the hot press tank is connected to the vacuum bag, the vacuum pipe is connected to the vacuum bag, the vacuum pump is opened for vacuumizing treatment, the vacuum degree is ≤-0.092 MPa, the vacuum pump is closed, and the vacuum degree is checked after 15-20 minutes. If the vacuum degree is greater than-0.092 MPa, it means that the vacuum bag is not completely sealed, and the leak point is found and sealed. After sealing, the vacuum pump is opened again for vacuumizing, and the vacuum bag is checked for complete sealing. Repeat the checking and sealing until the vacuum pump is closed for 15-20 minutes and the vacuum degree is ≤-0.092 MPa and stable without decline. 6) After the vacuum bag meets the sealing requirements, it is cured according to the following requirements: Before heating and curing, the bag is vacuumized to remove air and volatile matter; The vacuum degree during curing is controlled to be ≤-0.092 MPa. Vacuumizing starts at the beginning of curing, and the vacuum degree is maintained at ≤-0.092 MPa during the curing temperature rising and holding stages. The vacuum is stopped after the 165-180°C holding is completed. The pressure system is as follows: initial pressure 0.8-1 MPa is added at the beginning of curing; full pressure 2.3-2.5 MPa is added after 80-100°C holding for 60-90 min; and the pressure is naturally reduced after the 165-180°C holding is completed.

[0020] Temperature system: Room temperature-60°C, 60°C holding for 60 min; 60°C-80°C, 80°C holding for 60 min; 80°C-100°C, 100°C holding for 120 min; 100°C-120°C, 120°C holding for 120 min; 120°C-165°C, 165°C holding for 120 min; The temperature rising rate is controlled to be 0.3-0.5°C / min. After the solidification and heat preservation end, the cooling rate is controlled to be 0.2~0.4 ℃ / min to ≤60 ℃ to discharge the furnace; 7) After the solidification is completed, the vacuum bag and the air-permeable felt are cleaned, and after machining and demolding, the machining is performed to the ablation-resistant / heat-insulating integrated forming structure.

[0021] The abutment surfaces of multiple heat insulation members of the existing nozzle are prone to form airflow channels during the working process of the engine, which causes fire penetration. The ablation-resistant / heat-insulating integrated forming structure is a whole without fire penetration channels, which reduces the fire penetration risk of the nozzle during the working process of the engine. Meanwhile, the equal-volume profiling and width-changing tape winding ensures high winding tension and winding efficiency, and the internal quality of the formed product is good.

Claims

1. A method for forming an integrated ablation-resistant / insulating nozzle, comprising an ablation-resistant layer (1) and an insulating layer (2), characterized in that: The ablation-resistant layer (1) is integrally formed by using tungsten copper material, and the integrally forming method is specifically as follows: 1) machining the outer surface of the ablation-resistant layer to the size, and leaving a margin at both ends and the inner surface; 2) using high-silicon cloth / phenolic pre-impregnated cloth tape, and winding the trapezoidal ring area through equal-width profiled width cloth tape.

2. The ablation-resistant / heat-insulating integrated molding method for nozzles according to claim 1, characterized in that: The ablation-resistant layer (1) comprises a throat liner (a), a converging section (b) at the front end of the throat liner, and a diverging section (c) at the rear end of the throat liner, and the outer surface of the integrally formed ablation-resistant layer (1) comprises, in sequence from the converging section to the diverging section, a horizontal straight surface (1.1), a vertical straight surface (1.2), a first inclined surface (1.3), a horizontal surface (1.4), and a second inclined surface (1.5).

3. The method for integrally forming an ablation-resistant / heat-insulating nozzle according to claim 2, characterized by: The specific process of step 2) is as follows: 2a) Calculate the volume of the torus including the trapezoidal ring area with the formula: V = π x D (R 2 -r 2 ), where D is the vertical length between the first ramp start and the second ramp end, R is the vertical distance between the center axis of the ablative layer and the first ramp start, and r is the vertical distance between the center axis of the ablative layer and the first ramp end; 2b) calculating the outer radius of the cloth tape roll according to the circular ring volume V in step 2a): Wherein, R' is the outer radius of the volume profiling winding required tape roll, r' is the outer radius of the slitting winding core (3); and the high-silica cloth / phenolic pre-impregnated tape with equal width is slitted and wound. 2c) machining the excess part of the equal-width high-silicon cloth / phenolic pre-impregnated cloth tape roll cut in step 2a) according to the difference between the two sides of the trapezoidal ring area, i.e. the vertical length L1 between the starting end and the terminal end of the first inclined surface, and the vertical length L2 between the starting end and the terminal end of the second inclined surface; 2d) applying an elastic glue layer on the outer surface of the ablation-resistant layer before winding, and then winding the trapezoidal ring area with profiled width.

4. The method of claim 3, wherein the method is characterized by: Further comprising: 3) after the trapezoidal ring area profiled width winding is completed, performing flat stacking and winding of the equal-width high-silicon / phenolic pre-impregnated cloth tape on the outside; 4) uniformly wrapping the permeable felt layer on the outer layer of the wound material, and fixing it with pressure-sensitive adhesive tape; 5) vacuum bag sealing of the wound material and detection of the sealing property; 6) curing after the vacuum bag meets the sealing requirement; 7) cleaning the vacuum bag and the permeable felt after the curing is completed, and machining and demolding to the ablation-resistant / heat-insulating integrally formed structure.

5. The method of claim 4, wherein the method is characterized by: In step 3), the winding tension is 1-2 N / mm, the hot roller temperature is room temperature-70°C, and the pressure roller pressure is 3-4 N / mm.

6. The method of claim 4, wherein the method is characterized by: In step 5), the specific process is as follows: embedding the vacuum extraction nozzle into the vacuum bag, connecting the vacuum extraction pipe with the embedded vacuum extraction nozzle in the vacuum bag, opening the vacuum pump for vacuum extraction, and extracting the vacuum to a vacuum degree of ≤-0.092 MPa, then closing the vacuum pump, checking the vacuum degree after 15-20 minutes, and if the vacuum degree is greater than -0.092 MPa, it is proved that the vacuum bag is not completely sealed, the vacuum bag is checked to find the air leakage point, and the sealing is performed; after sealing, the vacuum pump is opened again for vacuum extraction, and the vacuum bag is checked to see whether it is completely sealed; the checking and sealing are repeated until the vacuum degree is ≤-0.092 MPa and stable without decline after the vacuum pump is closed for 15-20 minutes.

7. The method of claim 4, wherein the method is characterized by: In step 6), the curing system is performed according to the following requirements: Before heating and curing, the bag is vacuumed to remove air and volatile substances; During curing, the vacuum degree is controlled to be ≤-0.092 MPa, the vacuum extraction is started at the beginning of curing, the vacuum degree is maintained to be ≤-0.092 MPa during the whole process of temperature rising and holding, and the vacuum extraction is stopped after the holding at 165-180°C is completed. Pressure regime: initial pressure 0.8~1MPa at the beginning of curing; 80~100℃ for 60~90min, then full pressure 2.3~2.5MPa, 165~180℃ for 60~90min, then natural pressure reduction; Temperature regime: Room temperature~60℃, 60℃ for 60min; 60℃~80℃, 80℃ for 60min; 80℃~100℃, 100℃ for 120min; 100℃~120℃, 120℃ for 120min; 120℃~165℃, 165℃ for 120min.

8. The method of claim 7, wherein the method is characterized by: The temperature rising rate in step 6) is controlled at 0.3~0.5℃ / min; after the curing and holding, the temperature falling rate is controlled at 0.2~0.4℃ / min to ≤60℃ for discharging.

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