Solid rocket engine nozzle expansion section ablation examination structure and method
By combining the ladder plunger -type verification sample block and low -cost carbon fiber phenolic resin molding product expansion section, the problem of high ablation performance of the expansion of solid rocket engine in nozzles, the problem of high performance assessment costs, long construction period, and low efficiency of the solid rocket engine. High -efficiency imperfect performance assessment under real conditions.
Patent Information
- Application Number
- CN202411770128.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-04
- Publication Date
- 2025-01-24
AI Technical Summary
The existing methods used for the ablation performance assessment of the nozzle expansion section of solid rocket engines have problems such as high cost, long preparation period and low assessment efficiency. Especially the preparation period and high cost of the braided expansion section are severely restricted. Assessment.
Use the staircase plunger to abract the sample block and the low -cost carbon fiber phenolic resin molding section, to form a tortuous connection by adhesion and assembly, and protect it through the ink shell to achieve burning under the real conditions of real work conditions under the real conditions of real working conditions Eclipse performance assessment.
Effectively reduce the assessment costs of weaving and expanded materials, shorten the preparation cycle, improve the authenticity and efficiency of the assessment, and be able to assess the ablation performance of multiple expansion materials at one time.
Smart Images
Figure CN119353125A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of nozzle performance testing, and in particular to an ablation assessment structure and method for a solid rocket engine nozzle expansion section. Background Art
[0002] The nozzle of a solid rocket engine is mainly composed of a throat liner, an expansion section, a nozzle shell, an ablative insulation layer, etc. The expansion section is an important component of the nozzle and a key component that converts chemical energy into kinetic energy. Its working environment is high temperature, high pressure and high speed gas. The ablation of the expansion section material is affected by factors such as gas characteristics, air flow velocity, combustion chamber pressure, and the bulk properties of the material. At present, oxyacetylene ablation is the main method for ablation assessment of braided expansion section materials. It cannot truly reflect the ablation of the expansion section in a solid rocket engine, and thus cannot effectively verify the ablation characteristics of the expansion section under the actual working conditions of the solid rocket engine. Evaluating the ablation performance of the expansion section material through ablation tests in solid rocket engine tests has important guiding significance and engineering application value for the thermal structure design of the expansion section. However, although the ablation characteristics assessment of the expansion section material using a real solid rocket engine can reflect the actual working conditions of the expansion section, the preparation cycle is long and the assessment cost is high.
[0003] At present, the main method for evaluating the ablation performance of braided expansion section materials is to use the same batch of fibers and the same process to prepare a flat plate, then cut the ablation sample from the flat plate, and finally use the oxyacetylene ablation method to evaluate its ablation performance. The ablation environment of the oxyacetylene ablation method cannot truly simulate the two-phase flow caused by Al2O3 particles in solid rocket engines and the influence of factors such as gas components on ablation, so it is impossible to effectively verify the ablation characteristics of the expansion section under the actual working conditions of solid rocket engines. For this reason, an ablation test engine is used to evaluate the ablation of the expansion section, which has a very high similarity with the actual working conditions and is conducive to the evaluation of the ablation characteristics of the expansion section. However, the performance of the braided expansion section material or the expansion section preparation process needs to be verified through multiple solid rocket engine nozzle test runs, and solid rocket engines are expensive. In addition, the braided expansion segment is first prepared as a preform using fibers and carbon cloth, then impregnated with resin, pressurized and cured to form the final braided expansion segment product. The above process results in a long preparation cycle for the expansion segment from fibers to preforms and finally to blank forming, which is often one month or even more than half a year. The time and cost of test runs to evaluate the ablation performance of the expansion segment are extremely high. Summary of the invention
[0004] In view of this problem, the present invention proposes an ablation assessment structure for a solid rocket engine nozzle combination expansion section to solve the problems of high cost, long preparation period, low assessment efficiency, and especially the long preparation period and high cost of the braided expansion section, which seriously restricts the assessment of its ablation performance.
[0005] In order to solve the above-mentioned technical problems, one of the objects of the present invention is to provide an ablation test structure for the expansion section of the nozzle of a solid rocket engine. The ablation test sample adopts a stepped plunger structure. The bonding surface between the ablation test sample and the open hole expansion section is a stepped cylindrical surface, forming a tortuous docking surface, and is further protected by the nozzle shell on the outside to prevent fire.
[0006] Furthermore, the test sample is assembled with the nozzle expansion section in a way that the small diameter cylinder faces upward to avoid being washed away by high-speed airflow when the solid rocket engine is working.
[0007] Furthermore, the ablation test specimens are cut from a woven flat plate made from the same batch of fibers and using the same process, and bonded to a low-cost carbon fiber phenolic resin molded product, so as to realize the ablation performance test of the ablation test specimens under a real solid rocket engine.
[0008] Furthermore, the combined structure may use five, eight or other number of test blocks.
[0009] Furthermore, according to the size of the expansion section, more than two axial positions are selected to assemble the test sample along the annular opening.
[0010] Furthermore, the ablation test sample block may be cylindrical or conical in shape according to needs.
[0011] Based on the same inventive concept, the present invention also provides a method for evaluating the ablation evaluation structure of the expansion section of a solid rocket motor, and the specific steps are as follows:
[0012] S1: The same batch of fibers and the same preparation process were used to prepare two types of carbon fiber woven flat plates, T700 and T800. Then, six stepped plunger ablation specimens were cut from each of the woven flat plates.
[0013] S2: Low-cost carbon fiber phenolic resin molded products are used as the nozzle expansion section material. Holes corresponding to the stepped plunger test block are processed at two axial positions in a circumferentially uniform manner in the expansion section. Six holes are opened at each axial position and staggered at 30°.
[0014] S3: The cut stepped plunger test specimen is bonded and assembled with the open hole expansion section by means of HX98-1 adhesive, and the assembly method is that the small diameter cylindrical end of the stepped plunger test specimen faces the inner profile of the expansion section;
[0015] S4: After the adhesive between the stepped plunger specimen and the expansion section is cured for 48 hours, the external surface of the expansion section is processed;
[0016] S5: The expansion section with the ablation test sample is bonded to the nozzle shell 5 by HX98-1 adhesive to form a nozzle body;
[0017] S6: Install the throat liner (composed of a carbon / carbon throat liner 1 and an ablative insulation layer 2 bonded together) into the nozzle body to form a solid rocket engine nozzle that can be used for ground test and assessment.
[0018] Furthermore, the nozzle throat diameter is φ48.5 mm, the expansion ratio is 13.8, the maximum working pressure of the ground test solid rocket engine is 6.5 MPa, and the working time is not less than 12 s.
[0019] Furthermore, the stepped plunger test sample in S1 has an upper cylindrical diameter of Φ10 and a lower cylindrical diameter of Φ18, and a total thickness of 15 mm.
[0020] Furthermore, the test samples in S2 were taken at axial positions of the openings 37 and 98 away from the small end of the diffusion section, and the corresponding pressures were 0.32 MPa and 0.13 MPa, respectively.
[0021] Furthermore, after the ablation test structure of the solid rocket engine expansion section is tested on the ground, the remaining thickness of the ablation test sample is tested, and the ablation rate of the ablation test sample under the solid rocket engine working condition is obtained by (thickness before test-remaining thickness after test) / working time.
[0022] The above one or more technical schemes of the present invention have at least one or more of the following technical effects: the present invention proposes to cut a stepped plunger ablation test specimen of the braided expansion section to be tested from a flat plate material made from the same batch of fibers and the same process, and embed it into the expansion section of a low-cost carbon fiber phenolic resin molded product, thereby realizing the test of the ablation performance of the braided expansion section material under real working conditions. At the same time, it avoids the problems of long preparation cycle and high cost of the braided expansion section material, improves the authenticity and efficiency of the braided expansion section material test, and saves the test cost.
[0023] A stepped plunger ablation test specimen is placed in a low-cost expansion section material to be assembled into a nozzle, which enables the ablation performance test of different expansion section materials in a single test under real working conditions, reduces the test cost of the braided expansion section material, and improves the authenticity and efficiency of the test.
[0024] The ablation test sample is bonded and embedded into the nozzle expansion section. The interface between the ablation test sample and the opening expansion section is a stepped cylindrical surface, and the nozzle shell is bonded to the outer wall. The stepped matching structure + outer wall bonding nozzle shell is adopted. Firstly, the ablation test sample can be prevented from flying out when the solid rocket engine is working, and secondly, the gap between the expansion section and the interface can be prevented from piercing fire.
[0025] The ablation performance assessment of the braided expansion section material under real working conditions can be realized. Compared with the expansion section made entirely of braided products, the manufacturing cost is low and the cycle is short. At the same time, the ablation performance of at least two expansion section materials can be assessed at one time. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Figure 1 : Stepped plunger type test specimen;
[0027] Figure 2 : Schematic diagram of the opening expansion section;
[0028] Figure 3 : The front view and right view of the expansion section after processing;
[0029] Figure 4 : Exploded view after the expansion section is processed;
[0030] Figure 5 : Schematic diagram of nozzle body;
[0031] Figure 6 : Schematic diagram of nozzle structure;
[0032] Figure 7 : A combined expansion section structure with five test blocks evenly distributed in the annular direction;
[0033] Among them: 1-throat liner, 2-ablation insulation layer, 3-low-cost open hole expansion section, 4-ablation test sample, 5-nozzle shell. Specific implementation plan
[0034] The present invention proposes a method for evaluating the ablation performance of expansion section materials under actual solid rocket engine working conditions. The specific method is: the same batch of fiber materials are selected from the braided expansion section to be evaluated, and the expansion section flat plate is prepared by the same process method. According to the different objects to be evaluated, different compression rates and different fiber materials can be selected to prepare the expansion section flat plate, and then a stepped plunger ablation evaluation specimen is cut from the flat plate, and it is placed in a low-cost carbon fiber phenolic resin molded product expansion section product at one time, thereby shortening the preparation cycle of the braided expansion section to be evaluated and reducing the evaluation cost.
[0035] In order to avoid fire at the docking site during the test run, the ablation test specimen structure is designed as a stepped plunger type and placed at different axial positions of the nozzle expansion section. The stepped plunger type test specimens at the same axial position can be made of the same or different materials. Six ablation performance test specimens can be assembled at each axial position. After the ablation performance test specimens are bonded and cured, they are bonded to the nozzle shell to further limit the structure of the stepped plunger type ablation performance test specimen blocks to avoid flying out during the test run, and finally form a nozzle for test run assessment.
[0036] The present invention relates to an ablation test structure for a braided expansion section of a nozzle of a solid rocket engine. By embedding a plurality of stepped plunger-type test specimens into the expansion section of the nozzle, the ablation performance of the expansion section material under actual working conditions of the solid rocket engine can be tested, thereby improving the authenticity and efficiency of the expansion section material test.
[0037] At present, the main method for evaluating the ablation performance of braided expansion section materials is to use the same batch of fibers and the same process to prepare them into flat plates, then cut ablation samples from the flat plates, and finally use the oxyacetylene ablation method to evaluate their ablation performance. The ablation environment of the oxyacetylene ablation method cannot truly simulate the influence of factors such as the two-phase flow caused by Al2O3 particles in solid rocket engines and the composition of the gas on ablation, so it is impossible to effectively verify the ablation characteristics of the expansion section under the actual working conditions of solid rocket engines.
[0038] The present invention proposes an ablation test structure for a combined expansion section of a solid rocket engine nozzle. The expansion section consists of an ablation test sample block and a low-cost open-hole expansion section. The ablation performance of braided expansion section materials in two states can be tested at one time. In order to avoid gas ignition at the docking position, the test sample block adopts a stepped plunger structure to form a combination of a stepped plunger ablation sample block + an open-hole expansion section. The structure is installed in a nozzle shell to form a nozzle, and is connected to a real solid rocket engine. This can achieve the purpose of testing the ablation performance of multiple braided expansion section materials through a single solid rocket engine test under the same working conditions.
[0039] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the obtained embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.
[0040] The present invention proposes a solid rocket engine nozzle structure using a braided expansion section material;
[0041] The same batch of fibers and the same preparation process were used to prepare two types of carbon fiber woven flat plates, T700 and T800. Then, six stepped plunger ablation specimens were cut from each of the woven flat plates.
[0042] The diameter of the upper cylinder of the stepped plunger test specimen is Φ10 and the diameter of the lower cylinder is Φ18;
[0043] A low-cost carbon fiber phenolic resin molded product is used as the nozzle expansion section material. Holes corresponding to the stepped plunger test block are processed at two axial positions in the expansion section in a circumferentially uniform manner. Six holes are opened at each axial position and staggered at 30°. The axial positions of the openings are respectively 37 and 98 from the small end of the diffusion section, and the corresponding pressures are 0.32MPa and 0.13MPa, respectively. The structural form is as follows: Figure 1-2 As shown;
[0044] The cut stepped plunger test specimen is bonded and assembled with the opening expansion section by HX98-1 adhesive. The assembly method is that the small diameter cylindrical end of the stepped plunger test specimen faces the inner surface of the expansion section. Figure 3 41 is a stepped plunger specimen cut from a T800 carbon fiber woven flat product, and 42 is a stepped plunger specimen cut from a T700 carbon fiber woven flat product;
[0045] After the adhesive between the stepped plunger specimen and the expansion section is cured for 48 hours, the expansion section surface is processed. The exploded view of the expansion section after processing is shown in the figure below. Figure 4 As shown;
[0046] The expansion section with the ablation test sample is bonded to the nozzle shell 5 by HX98-1 adhesive to form a nozzle body. Figure 4 As shown;
[0047] The throat liner body composed of the throat liner 1 and the ablative insulation layer 2 bonded together is installed into the nozzle body to form a solid rocket engine nozzle that can be used for ground test and assessment. The nozzle structure is shown in FIG. Figure 5 ;
[0048] The nozzle throat liner is a three-dimensional woven carbon / carbon composite material, the ablative heat insulation layer is a high-silicon fiber phenolic resin molded product, the nozzle shell is a 30CrMnSi alloy steel material, the opening expansion section is a carbon fiber phenolic resin molded product, and the ablation test samples are stepped plunger samples cut from T700 and T800 carbon fiber woven flat products.
[0049] The shear strength of HX98-1 adhesive is ≥18.0MPa, the uneven and tearing strength is ≥22.0kN / m, and the curing time is ≥48h; the nozzle throat diameter is φ48.5mm, the maximum working pressure of the engine is 6.5MPa, and the effective working time is 12s.
[0050] Combined expansion section structure with five test blocks evenly distributed in the annular direction Figure 7 As shown, the combined structure uses five, eight or other number of test blocks, and the test blocks can also be assembled along the annular opening at more than two axial positions according to the size of the expansion section; the ablation test block can be cylindrical or conical as needed.
[0051] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A solid rocket engine nozzle expansion section ablation test structure, characterized in that: The ablation test specimen adopts a stepped plunger structure. The bonding surface between the ablation test specimen and the opening expansion section is a stepped cylindrical surface, forming a tortuous docking surface, and is protected externally by a nozzle shell to prevent fire.
2. The solid rocket engine expansion section ablation assessment structure according to claim 1, characterized in that: The test sample is assembled with the nozzle expansion section in a way that the small diameter cylinder faces upward to avoid being washed away by high-speed airflow when the solid rocket engine is working.
3. The solid rocket motor expansion section ablation assessment structure according to claim 1, characterized in that: The ablation test specimens are cut from woven flat plates made from the same batch of fibers and using the same process, and bonded to low-cost carbon fiber phenolic resin molded products to achieve ablation performance testing of the ablation test specimens under real solid rocket engines.
4. The solid rocket motor expansion section ablation assessment structure according to claim 1, characterized in that: The combination structure may use five, eight or other number of test blocks.
5. The solid rocket motor expansion section ablation assessment structure according to claim 1, characterized in that: According to the size of the expansion section, select two or more axial positions and assemble the test sample along the circumferential opening.
6. The solid rocket motor expansion section ablation assessment structure according to claim 1, characterized in that: The ablation test sample can be cylindrical or conical according to the needs.
7. The method for evaluating the ablation evaluation structure of the expansion section of a solid rocket motor according to any one of claims 1 to 6, characterized in that: The specific steps are as follows: S1: The same batch of fibers and the same preparation process were used to prepare two types of carbon fiber woven flat plates, T700 and T800. Then, six stepped plunger ablation specimens were cut from each of the woven flat plates. S2: Low-cost carbon fiber phenolic resin molded products are used as the nozzle expansion section material. Holes corresponding to the stepped plunger test block are processed at two axial positions in the expansion section in a circumferentially uniform manner. Six holes are opened at each axial position and staggered at 30°. S3: The cut stepped plunger test specimen is bonded and assembled with the open hole expansion section by means of HX98-1 adhesive, and the assembly method is that the small diameter cylindrical end of the stepped plunger test specimen faces the inner profile of the expansion section; S4: After the adhesive between the stepped plunger specimen and the expansion section is cured for 48 hours, the external surface of the expansion section is processed; S5: The expansion section with the ablation test sample is bonded to the nozzle shell 5 by HX98-1 adhesive to form a nozzle body; S6: Install the throat liner into the nozzle body to form a solid rocket engine nozzle that can be used for ground test and assessment.
8. The solid rocket motor expansion section ablation assessment method according to claim 7, characterized in that: The S1 stepped plunger test sample has an upper cylindrical diameter of Φ10, a lower cylindrical diameter of Φ18, and a total thickness of 15 mm.
9. The solid rocket motor expansion section ablation assessment method according to claim 7, characterized in that: The test samples in S2 were taken at axial positions of the openings 37 and 98 away from the small end of the diffusion section, and the corresponding pressures were 0.32 MPa and 0.13 MPa, respectively.
10. The solid rocket motor expansion section ablation assessment method according to claim 7, characterized in that: The nozzle throat diameter is φ48.5 mm, the expansion ratio is 13.8, the maximum working pressure of the solid rocket engine during ground test is 10 MPa, and the working time is not less than 15 s.
11. The solid rocket motor expansion section ablation assessment method according to claim 7, characterized in that: After the ablation test structure of the solid rocket engine expansion section is tested on the ground, the remaining thickness of the ablation test sample is tested, and the ablation rate of the ablation test sample under the solid rocket engine working condition is obtained by (thickness before test-remaining thickness after test) / working time.