Diffuser section structure of hypersonic high-temperature engine test stand nozzle and manufacturing method

Abstract

The application provides a hypersonic high-temperature engine test bench nozzle diffusion section structure and a manufacturing method, and belongs to the technical field of hypersonic high-temperature engine test bench nozzles. The application solves the problem of how to improve the reliability of the engine test bench nozzle diffusion section under the working conditions of hypersonic speed, long time high temperature and high heat flow, ensure the aerodynamic profile precision of the diffusion section under the high temperature environment, and improve the heat exchange performance. Different sealing methods and different forging materials are adopted in the high-temperature nozzle structure, the process characteristics of the engine test bench under the high temperature and high heat flow are considered, and the machining process of the outer circular water channel and the manufacturing process of the assembly of the inner shell assembly are considered. The application can guarantee the manufacturing quality of the high-heat-flow diffusion section of the hypersonic high-temperature engine test bench, realize the manufacturing of the high-heat-flow diffusion section of the hypersonic high-temperature engine test bench nozzle, increase the overall sealing property of the engine test bench, and improve the overall sealing property and reliability of the engine test bench.

Description

Technical Field

[0001] This invention belongs to the field of nozzle technology for hypersonic high-temperature engine test benches, and specifically relates to a diffuser section structure and manufacturing method for a hypersonic high-temperature engine test bench nozzle. Background Technology

[0002] Hypersonic high-temperature engine test rigs are important ground facilities for the research and development of various aircraft and for fundamental aerodynamic research. Their function is to simulate the airflow environment during hypersonic flight. The engine nozzle is its core component, and the design precision of the nozzle determines the uniformity of the hypersonic airflow field at the specific Mach number required for ground testing.

[0003] Currently, there is a lack of research and design for large-scale engine test rigs that combine hypersonic and high-temperature characteristics. Compared to traditional hypersonic engine test rigs, hypersonic high-temperature engine test rigs have longer operating times, nozzle exit diameters greater than 1 meter, effective blowing durations exceeding 20 minutes, total temperatures exceeding 1400 K, and total pressures exceeding 10 MPa. The design of the nozzle diffuser section in traditional hypersonic engine test rigs is not suitable for hypersonic high-temperature engine test rigs. The high heat flux environment of hypersonic high-temperature engine test rigs places higher demands on the nozzle cooling system and the maintenance of aerodynamic profile accuracy under high-temperature conditions. Therefore, it is urgent to develop a hypersonic nozzle diffuser section structure and its manufacturing method suitable for high-temperature conditions to ensure its reliability in the high heat flux environment of hypersonic high-temperature engine test rigs. Summary of the Invention

[0004] The purpose of this invention is to improve the reliability of the nozzle diffuser section of a hypersonic engine test rig operating under hypersonic, long-term high-temperature, and high-heat-flux environments, ensuring its aerodynamic profile accuracy under high-temperature conditions and improving its heat transfer performance. Therefore, this invention proposes a structure and manufacturing method for the diffuser section of a hypersonic high-temperature engine test rig nozzle. Because the high-temperature nozzle structure employs different sealing methods and forging materials, the process characteristics of the engine test rig under high temperature and high heat flux conditions must be considered, along with the machining process of the outer circular water channel and its assembly with the inner shell. The innovative manufacturing process for the high-heat-flux diffuser section of the hypersonic high-temperature engine test rig in this invention ensures the manufacturing quality of the high-heat-flux diffuser section, achieves the manufacturing of the high-heat-flux diffuser section of the hypersonic high-temperature engine test rig nozzle, increases the overall sealing performance of the engine test rig, solves the problems of expansion deformation and cooling under the influence of high temperature and high heat flux, and improves the overall sealing performance and reliability of the engine test rig.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a nozzle diffuser section structure for a hypersonic high-temperature engine test bench, comprising a cylinder, a water channel cover, multiple longitudinal ribs, multiple annular ribs, an adjusting support frame, a front-end supplementary ring, a rear-end supplementary ring, and a pipe assembly. The cylinder is covered with a water channel cover and welded together to form a cooling water channel. Multiple longitudinal ribs and multiple annular ribs are staggered and welded in a mesh pattern on the water channel cover and the cylinder. An adjusting support frame is welded in the middle of the mesh formed by the longitudinal ribs and annular ribs. A front-end supplementary ring and a rear-end supplementary ring are welded at the front and rear ends of the cylinder, respectively.

[0006] Furthermore, the cylinder is formed by welding end flanges and an intermediate cylinder together.

[0007] Furthermore, the outer side of the middle cylinder of the cylinder is evenly distributed with water channels, and the axial cross-section of the middle cylinder is an isosceles trapezoid. On the end flange, from the axis outward, there are heat-insulating ring grooves, stop and sealing ring grooves. The heat-insulating ring grooves are filled with high-temperature resistant sealing material to act as a thermal barrier and prevent heat radiation generated by internal heat flow. Rubber polymer sealing strips are installed in the sealing ring grooves to achieve good air tightness and prevent convection caused by significant pressure difference. The stop is used for connection and positioning between the diffuser section and other sections.

[0008] Furthermore, the pipe assembly is mounted on the end flange of the cylinder, and the pipe assembly is connected to the internal cooling water channels through water passage holes on the outer shell of the cylinder.

[0009] Furthermore, the cylinder and waterway cover are made of 304 stainless steel.

[0010] Furthermore, the end flange is a forging, while the rest are steel plates.

[0011] A method for fabricating a diffuser section structure for a hypersonic high-temperature engine nozzle on a test rig, specifically including the following steps:

[0012] (1) Step 1: The forged blank of the end flange of the cylinder is processed by four steps: material handling, scribing, turning and fitter work.

[0013] (2) Step 2: The intermediate cylinder forging blank is processed through eight steps: material receiving, blanking, forming, welding, flaw detection, inspection, turning and fitter work.

[0014] (3) Step 3: The final diffusion section is processed through 22 steps including welding, flaw detection, scribing, rough turning, boring, milling, assembly welding, flaw detection, inspection, flaw detection, heat treatment, scribing, semi-finish turning, boring, inspection, finish turning, aging, inspection, welding, flaw detection, hydrostatic test and fitter work.

[0015] Furthermore, in step one, the turning process includes turning the inner and outer circles, end faces, step surfaces, and bevels.

[0016] Furthermore, in step two, the welding engineering content is welding the longitudinal seam; the turning process content is turning the welding bevel.

[0017] Furthermore, in step three, the welding process involves welding the end flanges of the cylinder to the intermediate cylinder; the rough turning process involves polishing the end faces to a smooth finish, serving as a reference for subsequent machining; the finish turning process involves polishing the water channel grooves on both end faces, the outer circular surface, and the inner circle to a smooth finish; the boring process involves drilling the oblique holes and radial pipe holes on both end faces; the milling process involves milling the water channel grooves on the outer circle of the cylinder; the assembly and welding process involves welding the water channel cover plate to the outside of the cylinder, welding the front and rear end rings, welding the outer wall stiffeners, and cooperating with the vertical lathe to weld the process head; the finish turning process involves finish turning the inner hole, outer circular plate, end faces, and various sealing grooves of the cylinder; and the water pressure test process involves conducting a water pressure test on the water channel.

[0018] Compared with the prior art, the beneficial effects of the nozzle diffuser section structure and manufacturing method of the hypersonic high-temperature engine test bench described in this invention are:

[0019] (1) The present invention improves the strength of the diffuser section by interlacing the ring ribs and longitudinal ribs welded to the inner shell flange and water channel cover plate of the diffuser section, so that the inner shell of the diffuser section can withstand greater pressure and axial force.

[0020] (2) The adjustment support frame of the present invention can facilitate the connection and installation of the diffuser section and the rest of the nozzle and provide support. After welding, the workpiece is subjected to solid solution treatment. S30408 ​​stainless steel with good high temperature performance, corrosion resistance and weldability is selected as the material, which can facilitate the welding between the components and also meet the high temperature performance requirements of the diffuser section. A certain number of water channels are designed on the outer shell to meet the heat exchange requirements of the diffuser section.

[0021] (3) The stop provided on the flanges at both ends of the present invention can realize the installation and positioning of the front and rear sections of the nozzle. The heat shield groove and sealing ring groove provided from the axis outward can ensure the airtightness of the installation connection. At the same time, the heat shield can effectively reduce the impact of high temperature on the performance and life of the sealing ring. Attached Figure Description

[0022] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0023] Figure 1 This is a front view of the nozzle diffuser section structure of the hypersonic high-temperature engine test bench according to the present invention.

[0024] Figure 2 This is a left view of the nozzle diffuser section structure of the hypersonic high-temperature engine test bench according to the present invention.

[0025] Figure 3This is a magnified view of a portion of the flange.

[0026] Figure 4 yes Figure 2 BB cross-sectional view.

[0027] In the figure: cylinder 1, end flange 1-1, intermediate cylinder 1-2, water channel cover 2, longitudinal rib 3, ring rib 4, adjusting support frame 5, front end supplementary ring 6, rear end supplementary ring 7, pipe assembly 8, heat-insulating ring groove 9, stop 10, sealing ring groove 11, water channel groove 12, weld 13. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0029] See Figure 1-4 This implementation method is described in conjunction with Figure 1 and Figure 2 This embodiment describes a diffuser section structure suitable for a hypersonic high-temperature engine test bench, comprising a cylinder 1, a water channel cover 2, multiple longitudinal ribs 3 and multiple annular ribs 4, an adjusting support frame 5, a front-end supplementary ring 6, a rear-end supplementary ring 7, and a pipe assembly 8. The diffuser section is a two-layer structure, with the cylinder 1 covered by the water channel cover 2, which is welded together to form a cooling water channel. The multiple longitudinal ribs 3 and multiple annular ribs 4 are staggered and arranged in a mesh, and are welded to the water channel cover 2 and the cylinder 1 by manual arc welding to improve the strength of the diffuser section, allowing the inner shell of the diffuser section to withstand greater pressure and axial force. An adjusting support frame 5 is welded in the middle of the mesh formed by the longitudinal ribs 3 and annular ribs 4 to facilitate the connection and installation of the diffuser section with the rest of the nozzle and to provide support. A front-end supplementary ring 6 and a rear-end supplementary ring 7 are welded at both ends of the cylinder 1. After all welding is completed, the workpiece is subjected to solution treatment.

[0030] Further integration Figure 2 , Figure 3 and Figure 4 In this embodiment, the cylinder 1 is formed by welding the end flange 1-1 and the intermediate cylinder 1-2. The material of the cylinder 1 is S30408 ​​stainless steel. The temperature of the diffuser section is not as high as that of the first few sections of the nozzle. S30408 ​​stainless steel, which has good high temperature performance, corrosion resistance and weldability, is selected as the material, which can facilitate the welding between the components and also meet the high temperature performance requirements of the diffuser section.

[0031] Water channels 12 are evenly distributed on the outer side of the intermediate cylinder 1-2. Since the temperature of the diffuser section is relatively lower, the number of water channels outside the intermediate cylinder 1-2 is relatively less, which can still meet the heat exchange requirements of the diffuser section. Furthermore, the axial cross-sectional shape of the channels in the intermediate cylinder 1-2 is an isosceles trapezoid. On the end flange 1-1, a heat-blocking ring groove 9, a stop 10, and a sealing ring groove 11 are arranged sequentially from the axis outward. The stop 10 provided on the end flange can realize the installation positioning of the front and rear sections of the nozzle. The heat-blocking ring groove 9 and the sealing ring groove 11 arranged from the axis outward can ensure the airtightness of the installation connection. At the same time, the heat-blocking ring groove 9 can effectively reduce the impact of high temperature on the performance and life of the sealing ring.

[0032] Further integration Figure 1 and Figure 2 In this embodiment, the pipe assembly 8 is installed on the end flange 1-1 of the cylinder 1, and the pipe assembly 8 is connected to the internal cooling water channel through the water channel hole on the outer shell of the cylinder 1.

[0033] The method for preparing the large-scale, long-duration hypersonic high-temperature engine test rig nozzle diffuser section structure of the present invention specifically includes the following steps:

[0034] (1) Step 1: The left / right flanges of the cylinder end flange 1-1 are processed through four steps: material handling, scribing, turning, and fitter work.

[0035] (2) Step 2: The intermediate cylinder 1-2 forging blanks are processed through 8 steps: material receiving, blanking, forming, welding, flaw detection, inspection, turning and fitter work.

[0036] (3) Step 3: The final diffusion section is processed through 22 steps including welding, flaw detection, scribing, rough turning, boring, milling, assembly welding, flaw detection, inspection, flaw detection, heat treatment, scribing, semi-finish turning, boring, inspection, finish turning, aging, inspection, welding, flaw detection, hydrostatic test and fitter work.

[0037] In step one, the turning process includes turning the inner and outer circles, end faces, step surfaces, and bevels.

[0038] In step two, the welding engineering content is welding the longitudinal seam; the turning process content is turning the welding bevel.

[0039] In step three, the welding process involves welding the end flange 1-1 of the cylinder to the intermediate cylinder 1-2; the rough turning process involves polishing the end face to a smooth finish, which serves as a reference for subsequent machining; the finish turning process involves polishing the water channel grooves 12 on both end faces, the outer circular surface, and the inner circle to a smooth finish; the boring process involves drilling the oblique holes and radial pipe holes on both end faces; the milling process involves milling the outer circular water channel groove 12 of the cylinder; the assembly and welding process involves welding the water channel cover plate 2 to the outside of the cylinder 1, welding the front and rear end rings, welding the outer wall stiffeners, and cooperating with the vertical lathe to weld the process head; the finish turning process involves finish turning the inner hole, outer circular plate, end face, and various sealing grooves of the cylinder; and the water pressure test process involves conducting a water pressure test on the water channel.

[0040] The specific process steps are as follows:

[0041] (1) Step 1: Prepare the forging blank for the end flange of the cylinder. Ensure that the dimensions of the blank meet the requirements, such as diameter and length. Use a suitable scribing tool to mark the area to be machined on the blank, i.e., the position of the left / right flange of the cylinder. Ensure that the scribing is accurate to ensure that the flange position is correct after machining. Clamp the scribing blank on the lathe. Use the lathe to perform turning machining to trim the outer diameter, inner diameter, and other dimensions of the blank to meet the required dimensions and surface roughness. Depending on the requirements, different tools and machining processes can be used, such as rough turning and finish turning, to obtain the required machining quality and surface roughness Ra=0.6. Perform bench work on the machined cylinder blank to complete the machining of the flange position. Bench work may include drilling, tapping, and other operations to meet the flange specification requirements.

[0042] (2) Step Two: The intermediate cylinder 1-2 forging blanks undergo preliminary processing through eight steps: incoming material, blanking, forming, welding, flaw detection, inspection, turning, and fitter work. Check the surface of the incoming cylinder blanks for obvious defects or damage, such as cracks or breaks. Check whether the dimensions of the incoming cylinder blanks meet the requirements of the drawings or specifications. According to the size requirements of the cylinder blanks, perform blanking operations to cut the blanks into workpieces of the required size. Use appropriate forming equipment, such as forging machinery or plastic processing equipment, to perform forming operations on the blanks. Perform welding operations on the formed cylinder blanks to connect the two parts of the cylinder. Perform flaw detection operations on the welded cylinders, and use ultrasonic testing to check whether there are defects in the weld and the inside of the cylinder. Perform visual inspection on the cylinders that have undergone flaw detection, and check the size and shape of the cylinders to ensure that there are no obvious defects in the appearance of the cylinders and that the size and shape meet the requirements. Perform turning operations on the inspected cylinders to obtain the required size and surface roughness. During the turning process, attention must be paid to the cutting speed, feed rate, and depth of cut to ensure that the turning quality and workpiece dimensional tolerances meet the drawing requirements. Depending on the needs, bench work such as drilling and tapping may be performed on the turned cylinder.

[0043] (3) Step 3: The final diffusion section is machined through 22 steps including welding, flaw detection, scribing, rough turning, boring, milling, assembly welding, flaw detection, inspection, flaw detection, heat treatment, scribing, semi-finish turning, boring, inspection, finish turning, aging, inspection, welding, flaw detection, hydrostatic testing, and fitter work. All components are welded, including the cylinder and clamping device. During welding, welding parameters must be controlled according to welding process specifications to ensure weld quality. The welded diffuser section undergoes flaw detection using methods such as ultrasonic testing to check for defects in the weld and localized areas. Lines are scribing the outer surface of the diffuser section as reference lines for further machining. The diffuser section is then rough-machined using tools such as lathes to achieve its preliminary geometric shape for subsequent processing. The diffuser section is then bored using equipment such as boring machines to obtain precise apertures and surface smoothness. The diffuser section is then milled using a milling machine to form the required complex shape and structure. Components or accessories to be installed (such as flanges, support structures, etc.) are welded to the diffuser section. A flaw detection test is then performed to verify that the welded parts meet requirements. The welded and machined diffuser section undergoes a visual inspection to ensure there are no obvious surface defects. The diffuser section is then heat-treated to improve its mechanical properties and microstructure. After repeated turning, boring, inspection, and flaw detection, the final step is a hydrostatic test to check its sealing and pressure resistance.

[0044] The parameters and operations of each process must comply with the process specifications and drawing requirements. Welding and weld flaw detection must meet the relevant welding process specifications and non-destructive testing standards. The dimensions, shape, and surface roughness of the processed diffuser section must meet the drawing or specification requirements. Inspection and testing must be comprehensive and accurate to ensure that the quality meets the requirements. After all processes are completed, the final product must undergo a hydrostatic test to ensure that its sealing and pressure resistance performance meet the requirements.

[0045] The following methods are needed to strictly ensure the dimensional accuracy of the cylinder during molding:

[0046] First, based on the inner diameter and thickness of the large and small ends of the cylinder cone, select the rolling or pressing method to make an inspection template, strictly control the forming dimensions of the cylinder, and require the ellipticity to be controlled within 5mm on one side.

[0047] Secondly, due to certain forming errors, a 20mm allowance was added to the plate thickness (in the direction of the inner diameter of the cylinder forming), which was removed during machining after assembly and welding. To ensure 100% RT flaw detection, manual arc welding, which is easier to guarantee quality, was selected for the welding of the cylinder itself and the welds between the cylinder and the left and right flanges, and ER308L welding material was selected.

[0048] When dealing with welding deformation, the following methods should be followed:

[0049] The main weld seam is radially fitted with a star-shaped tie rod, and the overall axial support rod is fitted with a support rod. The welding is carried out symmetrically to strictly control the welding deformation. The weld seam of the outer circular stiffening plate of the cylinder is welded in a segmented, skip-welding, and symmetrical manner.

[0050] Due to the large coefficient of linear expansion and low thermal conductivity of austenitic stainless steel, it is prone to generating large stress during welding. Therefore, it is necessary to select a smaller welding current and a faster welding speed, and strictly control the interpass temperature to be less than 150℃.

[0051] The welding process simulation and analysis software SYSWELD was used to analyze the stress and deformation of complex combined models after welding and to evaluate the welding weight.

[0052] To ensure precise control of the profile's shape, position, and dimensions, roughing, semi-finishing, and finishing processes are separated. Intermediate machining is performed strictly according to finish turning requirements, and the dimensional accuracy is met through program compensation based on coordinate measuring machine (CMM) feedback. High-precision CNC vertical lathes are used to machine the internal and external surfaces to guarantee the required shape and position tolerances. The surface cleanliness within the diffuser section is ≤200mg, and the cleanliness of the cooling water channels and pipes is ≤500mg.

[0053] After the diffuser section is installed, a vacuum air tightness test is conducted together with the equipment system to ensure the air tightness of the end faces of each nozzle section, the air-filled sealing structure, and the water pipes passing through the wall panels; and it is also necessary to ensure the air tightness of the diffuser section as a whole under thermal conditions during operation.

[0054] The innovative manufacturing process for the high heat flux diffusion section of the hypersonic high-temperature engine test rig in this invention can improve manufacturing quality through the following principles:

[0055] Material selection and treatment: Use appropriate high-temperature resistant materials and perform suitable surface treatments to improve the heat resistance and oxidation resistance of the materials, and maintain stable performance and structure in high-temperature and high-speed airflow environments.

[0056] Ingenious structural design: This invention improves the strength of the diffuser section by interlacing ring ribs and longitudinal ribs welded to the inner shell flange and water channel cover plate of the diffuser section, so that the inner shell of the diffuser section can withstand greater pressure and axial force.

[0057] The present invention adjusts the support frame to facilitate the connection and installation of the diffuser section and the rest of the nozzle and provides support. After welding, the workpiece is subjected to solution treatment. S30408 ​​stainless steel with good high temperature performance, corrosion resistance and weldability is selected as the material, which can facilitate the welding between the components and also meet the high temperature performance requirements of the diffuser section. A certain number of water channels are designed on the outer shell to meet the heat exchange requirements of the diffuser section.

[0058] The stop provided on the flanges at both ends of the present invention can realize the installation and positioning of the front and rear sections of the nozzle. The heat shield groove and sealing ring groove provided from the axis outward can ensure the airtightness of the installation connection. At the same time, the heat shield can effectively reduce the impact of high temperature on the performance and life of the sealing ring.

[0059] Precision machining and assembly: Advanced CNC machining technology is employed to ensure the geometric and dimensional accuracy of the high heat flux diffusion section, as well as the required surface quality. Precision machining and assembly guarantee a uniform flow field distribution in the high heat flux diffusion section, avoiding localized thermal stress and damage caused by uneven heat flux.

[0060] Testing and Quality Control: Establish a strict quality control system and use non-destructive testing methods (such as ultrasonic testing, infrared thermography, etc.) to test and evaluate the high heat flux diffusion section to ensure that the manufacturing quality meets the requirements.

[0061] By applying the above principles and methods, the innovative manufacturing process of this invention can improve the manufacturing quality of the high heat flux diffusion section of the hypersonic high-temperature engine test bench.

[0062] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A diffuser section structure for a hypersonic high-temperature engine test rig nozzle, characterized in that: The assembly includes a cylinder (1), a water channel cover (2), multiple longitudinal ribs (3), multiple annular ribs (4), an adjustment support frame (5), a front-end supplementary ring (6), a rear-end supplementary ring (7), and a pipe assembly (8). The cylinder (1) is covered with a water channel cover (2) and welded together to form a cooling water channel. Multiple longitudinal ribs (3) and multiple annular ribs (4) are staggered and welded in a mesh pattern on the water channel cover (2) and the cylinder (1). An adjustment support frame (5) is welded in the middle of the mesh formed by the longitudinal ribs (3) and the annular ribs (4). A front-end supplementary ring (6) and a rear-end supplementary ring (7) are welded at both ends of the cylinder (1).

2. The diffuser section structure of the nozzle of the hypersonic high-temperature engine test bench according to claim 1, characterized in that: The cylinder (1) is formed by welding together the end flange (1-1) and the intermediate cylinder (1-2).

3. The diffuser section structure of the nozzle of the hypersonic high-temperature engine test bench according to claim 2, characterized in that: Water channels (12) are evenly distributed on the outer side of the middle cylinder of the cylinder (1), and the axial cross-section of the middle cylinder is an isosceles trapezoid. On the end flange (1-1), a heat-blocking ring groove (9), a stop (10) and a sealing ring groove (11) are arranged sequentially from the axis outward. The heat-blocking ring groove (9) is filled with high-temperature resistant sealing material to act as a heat barrier and prevent the heat radiation generated by the internal heat flow. A rubber polymer sealing strip is installed in the sealing ring groove (11) to achieve good air tightness and prevent convection caused by significant pressure difference. The stop (10) is used for the connection and positioning of the diffusion section and other sections.

4. The diffuser section structure of the nozzle of the hypersonic high-temperature engine test bench according to claim 3, characterized in that: The pipe assembly (8) is installed on the end flange (1-1) of the cylinder (1), and the pipe assembly (8) is connected to the internal cooling water channel through the water channel hole on the outer shell of the cylinder (1).

5. The diffuser section structure of the nozzle of the hypersonic high-temperature engine test bench according to claim 4, characterized in that: The cylinder (1) and the waterway cover (2) are made of 304 stainless steel.

6. The diffuser section structure of the nozzle of the hypersonic high-temperature engine test bench according to claim 4, characterized in that: The end flange (1-1) is a forging, while the rest are steel plates.

7. A method for preparing the diffuser section structure of a hypersonic high-temperature engine test rig according to any one of claims 1-6, characterized in that: Specifically, the following steps are included: Step 1: Prepare the forging blank for the end flange of the cylinder body, ensuring that the dimensions of the blank meet the requirements. Use a scribing tool to mark the area to be machined on the blank, ensuring that the scribing is accurate to ensure that the flange position is correct after machining. Clamp the scribing blank on the lathe and use the lathe to perform turning machining. Trim the outer and inner diameter dimensions of the blank to meet the required dimensions and surface roughness. According to the requirements, obtain the required machining quality and surface roughness Ra=0.

6. Perform fitter machining on the machined cylinder blank to complete the machining of the flange position. Step Two: The intermediate cylinder (1-2) forging blank undergoes eight preliminary processes: material handling, blanking, forming, welding, flaw detection, inspection, turning, and fitter work. These include: inspecting the surface of the incoming cylinder blank for obvious defects or damage; checking if the dimensions of the incoming cylinder blank meet the drawings or specifications; blanking according to the blank's dimensions; forming the blank; welding the formed cylinder blank to connect the two parts; flaw detection of the welded cylinder, using ultrasonic testing to check for defects in the weld and internal structure; visual inspection of the flaw-detected cylinder, checking its dimensions and shape to ensure no obvious defects and that its dimensions and shape meet requirements; and turning the inspected cylinder to obtain the required dimensions and surface roughness. During turning, attention must be paid to the cutting speed, feed rate, and depth of cut to ensure the turning quality and workpiece dimensional tolerances meet the drawing requirements. Step 3: The final diffusion section is machined through 22 steps including welding, flaw detection, scribing, rough turning, boring, milling, assembly welding, flaw detection, inspection, flaw detection, heat treatment, scribing, semi-finish turning, boring, inspection, finish turning, aging, inspection, welding, flaw detection, hydrostatic testing, and fitter work. This involves welding all components, including the cylinder and clamping device, controlling welding parameters according to welding process specifications to ensure weld quality; performing flaw detection on the welded diffusion section using ultrasonic testing to check for defects in the weld and localized areas; scribing lines on the outer surface of the diffusion section as reference lines for machining; and rough turning the diffusion section. The diffusion section is machined to a preliminary geometry for subsequent processing. It is then bored to achieve precise aperture and surface smoothness. Milling is performed to create the required complex shape and structure. Components or accessories are welded to the diffusion section. A flaw detection test is conducted to ensure the welded parts meet requirements. The welded and machined diffusion section undergoes a visual inspection to ensure no obvious defects. Heat treatment is then applied to improve its mechanical properties and microstructure. After repeated turning, boring, inspection, and flaw detection, the final step involves a hydrostatic test to check its sealing and pressure resistance.

8. The method for preparing a diffuser section structure for a hypersonic high-temperature engine test bench nozzle according to claim 7, characterized in that, In step one, the turning process includes turning the inner and outer circles, end faces, step surfaces, and bevels.

9. The method for preparing a diffuser section structure for a hypersonic high-temperature engine test bench nozzle according to claim 7, characterized in that, In step two, the welding engineering content is welding the longitudinal seam; the turning process content is turning the welding bevel.

10. The method for preparing a diffuser section structure for a hypersonic high-temperature engine test bench according to claim 7, characterized in that, In step three, the welding process involves welding the end flange (1-1) of the cylinder to the middle cylinder (1-2); the rough turning process involves polishing the end face to serve as a reference for subsequent processing, and then finishing the water channel grooves (12) on both end faces, the outer circular surface, and the inner circle to polish; the boring process involves drilling the oblique holes and radial pipe holes on both end faces; the milling process involves milling the outer circular water channel grooves (12) of the cylinder; the assembly and welding process involves welding the water channel cover plate (2) to the outside of the cylinder (1), welding the front and rear end rings, welding the outer wall stiffeners, and cooperating with the vertical lathe to weld the process head; the finishing process involves finishing the inner hole, outer circular plate, end face, and sealing grooves of the cylinder; and the water pressure test process involves conducting a water pressure test on the water channel.

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