A nozzle suitable for hypersonic continuously variable Mach number

Abstract

This application discloses a nozzle suitable for hypersonic continuously variable Mach number flight. The nozzle comprises: a nozzle body including an airflow inlet and an airflow outlet; an adjustment structure located within the nozzle body, arranged along the airflow direction, and forming an airflow channel with the nozzle body; the adjustment structure comprises an aerodynamic panel and a flat panel arranged vertically; translation of the flat panel changes the throat area and the outlet area of ​​the airflow channel; rotation of the aerodynamic panel changes the throat area while maintaining the outlet area of ​​the airflow channel; the nozzle is an entire rigid structure and can be provided with a water cooling mechanism throughout. This invention can simulate hypersonic total pressure and total temperature flight environments and a wide range of continuously variable Mach number inflows exceeding Mach 5.

Description

Technical Field

[0001] The present invention relates to the technical field of ground test of air-breathing engines, and more particularly to a nozzle suitable for hypersonic continuously variable Mach number. Background Art

[0002] With the emergence of scramjet technology, the study of combined cycle engines has become the main research direction of current flight dynamics. During the development of this type of equipment, there is a great demand for large-scale continuously variable Mach number technology, which is used to study phenomena such as engine "modal conversion" and boundary layer transition.

[0003] Variable Mach technology involves continuously changing the ratio of the nozzle throat area to the nozzle exit area. When this ratio changes continuously, the Mach number also changes continuously. Therefore, being able to continuously and accurately change the nozzle area ratio during testing while ensuring the quality of the nozzle exit flow field has become a key focus of variable Mach nozzle research. Currently, domestic variable Mach technology has been developed for speeds below Mach 5. However, excessive actuation distances for each nozzle can lead to a decrease in flow field quality. Therefore, a single nozzle can only be varied within a range of 1 to 2 Mach numbers. When the range of variable Mach numbers is larger, a combination of multiple nozzles is used to achieve continuous variation. Furthermore, the inflow temperature at hypersonic speeds exceeds the material's temperature resistance limit. Therefore, the design of a variable Mach nozzle also needs to consider the impact of the high inflow total temperature at hypersonic speeds on the nozzle, which places limitations on the nozzle's structure and profile design.

[0004] Currently, variable Mach number nozzles used in engine test benches include flexible-wall nozzles, semi-flexible-wall nozzles, rotating rigid-wall nozzles, and translating rigid-wall nozzles. To ensure flexibility, the steel plate thickness of flexible-wall nozzles generally does not exceed 5 mm, and they cannot be water-cooled. This makes them unable to withstand the high temperatures of the incoming flow, making them unsuitable for simulating hypersonic variable Mach flow fields. Rotating rigid-wall nozzles are currently widely used in the variable Mach number field, particularly in the Mach 2-4 range, and published data has been published. However, since the cross-sectional area at the center of the nozzle becomes larger than the exit area when the profile rotates from high to low Mach numbers, excessive rotation can severely degrade the flow field quality. Therefore, the variable Mach number range of rotating rigid-wall nozzles is limited, and they are suitable for Mach numbers within 2. Translational rigid-wall nozzles do not change their profile, but their mechanism results in low Mach efficiency at low Mach numbers, making them suitable for Mach numbers above 4.

[0005] Based on the above list and analysis of variable Mach nozzle technologies, we can see that the main requirements for current variable Mach technology are: the range of continuously variable Mach numbers for a single nozzle, the flow field quality within different Mach number ranges, and the temperature resistance of the variable Mach nozzle. Therefore, a new type of hypersonic continuously variable Mach number nozzle is expected to address these issues. Summary of the Invention

[0006] The purpose of the present invention is to propose a nozzle suitable for hypersonic continuously variable Mach number, which can be used for high-temperature incoming gas, simulate the real environment of high Mach number and high altitude, and widen the range of Mach number variation.

[0007] To achieve the above objectives, the present disclosure provides a nozzle suitable for hypersonic continuously variable Mach number operation, comprising:

[0008] a nozzle body, the nozzle body comprising an air flow inlet and an air flow outlet;

[0009] an adjusting structure, located inside the nozzle body, arranged along the airflow direction, and forming an airflow channel with the nozzle body;

[0010] The adjustment structure includes a pneumatic panel and a flat panel arranged up and down;

[0011] Translating the flat panel to change the throat area and the outlet area of ​​the airflow channel;

[0012] The pneumatic panel is rotated to change the throat area and maintain the outlet area of ​​the air flow channel.

[0013] In an optional solution, the nozzle body is barrel-shaped, comprising an upper wall plate, a lower wall plate, two side wall plates, a front wall plate and a rear wall plate connected to each other, the air flow inlet is provided on the front wall plate, and the air flow outlet is provided on the rear wall plate;

[0014] The side walls of the pneumatic panel and the flat panel are slidably and sealedly connected with the side wall plates of the nozzle body to form the airflow channel.

[0015] In an optional solution, the flat panel is driven by a first driving mechanism to move closer to or away from the pneumatic panel in a translational manner, so that the outlet area and the throat area change, and the ratio of the change of the outlet area and the throat area is different. When the flat panel moves away from the pneumatic panel, the ratio of the outlet area to the throat area increases, and vice versa.

[0016] The side of the pneumatic panel close to the airflow outlet is connected to the nozzle body through a rotating shaft; the pneumatic panel is driven by a second driving mechanism to rotate with the rotating shaft as the rotation axis to open and close in the direction of approaching or moving away from the flat panel.

[0017] In an optional solution, the pneumatic panel and the flat panel are provided with a water cooling jacket, a cooling water channel is provided between the inner and outer wall panels of the water cooling jacket, and a cooling water inlet and outlet are provided on the outer wall panel.

[0018] In an optional embodiment, the nozzle further includes an annular frame disposed around the outer periphery of the nozzle body. Screw elevators are provided on either side of the annular frame to move the two sidewall panels toward or away from each other, thereby clamping the flat panel and the pneumatic panel to form the nozzle body. The bottom edge of the annular frame is rigidly connected to the lower panel, thereby securing the relative positions of the various nozzle components during formation.

[0019] In an optional solution, the side wall plate is provided with a water cooling jacket, that is, a cooling water channel is provided between the inner and outer wall plates of the water cooling jacket, and a cooling water inlet and outlet are provided on the outer wall plate of the water cooling jacket.

[0020] In an optional solution, a plurality of air-cooling channels are provided on both the upper wall plate and the lower wall plate.

[0021] In an optional solution, the flat panel and the front wall panel are connected by a sliding seal via a first retractable movable panel, and the flat panel is above the first retractable movable panel; the connection between the first retractable movable panel and the flat panel is smoothly transitioned by designing a curved surface;

[0022] The pneumatic panel is connected to the front wall panel by a second retractable movable panel using a sliding seal. The pneumatic panel is below the second retractable movable panel. The connection between the second retractable movable panel and the pneumatic panel is smoothly transitioned by a designed curved surface.

[0023] In an optional solution, the first retractable movable plate and the second retractable movable plate are provided with water cooling jackets, and the outer wall plate is provided with a cooling water inlet and outlet.

[0024] In an optional solution, a first follower clamping mechanism is provided on the side of the first retractable movable plate away from the air flow channel; a second follower clamping mechanism is provided on the side of the second retractable movable plate away from the air flow channel; the first follower clamping mechanism and the second follower clamping mechanism can be spiral elevators.

[0025] In an optional solution, the pneumatic panel and the flat panel are divided into several sections along the airflow direction, and hard connections are used between adjacent sections. The connection positions need to be kept smooth with an error of no more than 0.1 mm.

[0026] In an optional solution, a first bracket is provided on a side of the flat panel away from the airflow channel for bearing the aerodynamic force exerted on the flat panel, and the first driving mechanism is mounted on the lower wall panel, and the first driving mechanism drives the flat panel to move by driving the first bracket;

[0027] A second bracket is provided on the side of the pneumatic panel away from the airflow channel for bearing the aerodynamic force exerted on the pneumatic panel. The second driving mechanism is installed on the upper wall panel and drives the pneumatic panel to move by driving the second bracket.

[0028] In an optional solution, the side walls of the pneumatic panel and the flat panel are slidingly sealed to the side wall plates of the nozzle body through a plurality of seals arranged along the direction of the air flow channel. The seals are arranged in the grooves of the side wall plates, and each seal is provided with a compressed air channel and an interface to cool the seals by air cooling.

[0029] In an optional solution, the side walls of the first retractable movable plate and the second retractable movable plate are slidingly sealed to the side wall plates of the nozzle body through a plurality of seals arranged along the direction of the air flow channel. The seals are arranged in the grooves of the side wall plates, and each seal is provided with a compressed air channel and an interface to cool the seals by air cooling.

[0030] In an optional solution, the upper cavity of the nozzle body is formed between the first retractable movable plate, the side wall plate of the nozzle body, the upper wall plate of the nozzle body, and the front wall plate and the rear wall plate of the nozzle body. The upper wall plate of the nozzle body is provided with air intake and exhaust interfaces, and the cavity is cooled by passing a small amount of cold air.

[0031] In an optional solution, the lower cavity of the nozzle body is formed between the second retractable movable plate, the side wall plate of the nozzle body, the lower wall plate of the nozzle body, and the front wall plate and the rear wall plate of the nozzle body. The lower wall plate of the nozzle body is provided with air intake and exhaust interfaces to cool the cavity by passing a small amount of cold air.

[0032] The beneficial effects of the present invention are:

[0033] The variable Mach nozzle of this invention utilizes a two-dimensional, semi-nozzle design. Its upper profile is the nozzle's aerodynamic profile, while its lower profile is a flat plate. At high Mach numbers, the flat plate is translated to achieve continuous Mach number variation. At low Mach numbers, the aerodynamic plate is rotated to achieve continuous Mach number variation. This nozzle boasts a Mach number variation range exceeding three Mach numbers, can simulate the total temperature of a realistic hypersonic incoming flow, and offers simplified actuation and control.

[0034] The present invention has other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain certain principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0036] Figure 1 A schematic diagram of the aerodynamic operation principle of the variable Mach nozzle is shown.

[0037] Figure 2 The corresponding relationship between the dimensionless translation distance of the flat panel of the variable Mach nozzle and the Mach number between Mach 3 and 6 is shown.

[0038] Figure 3 The corresponding relationship between the rotation angle of the variable Mach nozzle aerodynamic panel and the Mach number between Mach 2 and 3.5 is shown.

[0039] Figure 4 The dimensionless aerodynamic panel profile diagram of the variable Mach nozzle at Mach numbers 2.5 to 6 is shown.

[0040] Figure 5 A schematic diagram of the three-dimensional structure of the variable Mach nozzle is shown.

[0041] Figure 6 A schematic diagram of the internal three-dimensional structure of the variable Mach nozzle is shown.

[0042] Figure 7 A schematic diagram of the two-dimensional layout of the variable Mach nozzle adjustment section is shown.

[0043] Figure 8 A schematic diagram of the dynamic sealing structure of the variable Mach nozzle adjustment section is shown.

[0044] Figure 9 A schematic diagram of the cooling structure of the variable Mach nozzle throat profile block is shown.

[0045] Figure 10 A schematic diagram of the variable Mach nozzle air cooling position is shown.

[0046] Figure 11 A schematic diagram of the high-temperature dynamic seal and jacket water cooling structure of the variable Mach nozzle side wall plate is shown. DETAILED DESCRIPTION

[0047] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0048] Reference Figures 1-11 One embodiment of the present invention provides a nozzle suitable for hypersonic continuously variable Mach number, comprising:

[0049] a nozzle body, the nozzle body comprising an air flow inlet and an air flow outlet;

[0050] an adjusting structure, located inside the nozzle body, arranged along the airflow direction, and forming an airflow channel with the nozzle body;

[0051] The adjustment structure includes a pneumatic panel and a flat panel arranged up and down;

[0052] Translating the flat panel to change the throat area and the outlet area of ​​the airflow channel;

[0053] The pneumatic panel is rotated to change the throat area and maintain the outlet area of ​​the air flow channel.

[0054] The control structure adopts a two-dimensional semi-nozzle design, with an upper aerodynamic surface and a flat lower surface. At high Mach numbers, the flat panel is translated perpendicular to the airflow direction, changing the outlet and throat areas of the airflow channel. The proportions of these changes vary, resulting in a continuous change in the Mach number. At low Mach numbers, the upper surface is rotated using the intersection of the upper surface and the nozzle outlet as the axis of rotation, maintaining the outlet area of ​​the airflow channel while only changing the throat area, thus achieving continuous change in the Mach number. This variable Mach nozzle can extend the Mach number range to over 3 Mach numbers using a single nozzle, simulating flows above Mach 5 and extending the overall Mach number range to 2.5-6. A water cooling system can also be added to improve the nozzle's temperature resistance to hypersonic flows. Because both the aerodynamic and flat panels are rigid structures, the control structure's actuation consists of rotation and translation of the rigid body, making continuous actuation and control easier.

[0055] Reference Figure 5, the front wall panel of the nozzle is fixedly connected to the front end by a flange connection, and the rear wall panel extends deep into the test cabin and is sealed with the test cabin. The nozzle consists of several main parts, including the main frame system, the adjustment section system, and the wall panel system. Among them, the main frame and support are mainly composed of an annular welded frame and the upper, lower, front, rear, and side wall panels of the nozzle, etc., which serve as the support structure of the entire nozzle; the adjustment section system includes the first and second retractable movable panels, a rotating shaft, an adjustment plate drive mechanism, etc.; the wall panel system mainly includes a flat panel, a pneumatic panel, a first bracket, a second bracket, and the first and second drive systems, etc. The internal schematic diagram of the variable Mach nozzle is shown as follows Figure 6 shown.

[0056] Specifically, in this embodiment, the nozzle body is barrel-shaped, including an upper wall plate, a lower wall plate, two side wall plates (parallel to each other), a front wall plate and a rear wall plate that are connected to each other. The upper and lower wall plates, the front and rear wall plates and the frame are rigidly connected. The air flow inlet is provided on the front wall plate, and the air flow outlet is provided on the rear wall plate; the air flow channel is formed by a sliding seal connection between the pneumatic panel, the flat panel and the side wall plates of the nozzle body. The nozzle also includes an annular frame (an annular beam-column structure) arranged on the outer periphery of the nozzle body, and a spiral elevator is provided on the side of the annular frame. The spiral elevator is used to drive the two side wall plates closer to or away from each other, and is used to clamp the flat panel and the pneumatic panel to form the nozzle body. The bottom edge of the annular frame is rigidly connected to the lower wall plate, so that the relative positions of the various parts of the nozzle are fixed and formed. Since the flat panel, the pneumatic panel and the side wall need to directly contact the high-temperature gas in the nozzle, the side wall panel needs to be water-cooled for structural cooling. In this embodiment, the side wall panel is a water-cooled jacket structure with a cooling water inlet and outlet.

[0057] The upper wall plate and the lower wall plate are both provided with a plurality of cooling air channels to provide a cooling environment for the inside of the nozzle and protect the motor, the screw elevator and the supporting electrical components.

[0058] Reference Figure 6 and Figure 7 In this embodiment, an adjustment section is provided at the front end of each of the flat panel and the pneumatic panel, and the adjustment section and the front end of the pneumatic panel / flat panel are designed to be concentric arcs. The design must ensure that when the upper and lower panels of the nozzle move, there is a smooth transition between the adjustment section and the nozzle profile, so that air can pass through the joint between the adjustment section and the profile section without obstruction. A sliding seal is provided between the two moving parts. Here, because the retractable movable panel is designed with a jacketed water-cooling structure, the sliding seal can be a conventional high-temperature resistant sliding seal. See the high-temperature resistant structure. Figure 8Specifically, the flat panel and the front wall are connected by a first retractable movable panel using a sliding seal. The flat panel is located above the first retractable movable panel. The connection between the first retractable movable panel and the flat panel is smoothly transitioned by a designed curved surface. The pneumatic panel and the front wall are connected by a second retractable movable panel using a sliding seal. The pneumatic panel is located below the second retractable movable panel. The connection between the second retractable movable panel and the pneumatic panel is smoothly transitioned by a designed curved surface.

[0059] In this embodiment, the first and second retractable movable panels are equipped with water-cooling jackets, and the outer wall panels are provided with cooling water inlets and outlets. The sidewalls of the first and second retractable movable panels are slidably sealed to the sidewall panels of the nozzle body via a plurality of seals positioned along the airflow path. These seals are positioned within grooves in the sidewall panels, and each seal is provided with a compressed air channel and port, enabling air cooling of the seal.

[0060] In this embodiment, a first follower clamping mechanism is provided on the side of the first retractable movable plate away from the air flow channel; a second follower clamping mechanism is provided on the side of the second retractable movable plate away from the air flow channel; the first follower clamping mechanism and the second follower clamping mechanism can be screw elevators.

[0061] In this embodiment, the pneumatic panel and the flat panel are divided into several sections (such as 6 sections) along the airflow direction. The profile blocks of each section are processed separately. The two ends of the profile blocks are connecting flanges, and the adjacent sections are hard-connected. Each profile block is composed of an inner shell and an outer shell. The back side of the inner shell is processed with a cooling water channel. The upper part of the outer shell is provided with a cooling water inlet and outlet. The inner shell and the outer shell are tightly fitted together. The profile blocks are connected by bolts. The schematic diagram of the throat profile block is shown in FIG. Figure 9 shown.

[0062] In this embodiment, a first drive mechanism drives the flat panel toward or away from the pneumatic panel, thereby changing the outlet area and throat area, with the proportions of change varying between the outlet area and throat area. The side of the pneumatic panel near the airflow outlet is connected to the nozzle body via a rotating shaft. A second drive mechanism drives the pneumatic panel to open and close, rotating about the rotating shaft, toward or away from the flat panel. The first and second drive mechanisms may be screw elevators. When the pneumatic panel rotates about the terminal rotating shaft, the entire surface formed by each segment moves simultaneously.

[0063] In this embodiment, a first bracket is provided on the side of the flat panel away from the airflow channel for bearing the aerodynamic force exerted on the flat panel, and a first driving mechanism is installed on the lower wall panel, and the first driving mechanism drives the flat panel to move by driving the first bracket; a second bracket is provided on the side of the pneumatic panel away from the airflow channel for bearing the aerodynamic force exerted on the pneumatic panel, and a second driving mechanism is installed on the upper wall panel, and the second driving mechanism drives the pneumatic panel to move by driving the second bracket. Such a structural arrangement can ensure that the spiral elevators are not affected when lifting the profile of the pneumatic panel and the flat panel. These spiral elevators are uniformly controlled by a control system, and the extension of each spiral elevator is adjusted according to the different rotation angles.

[0064] In this embodiment, the two side walls of the pneumatic panel and the flat panel are connected to the two side wall plates in a sliding seal to form an air flow channel. The sliding seal structure is based on a high-temperature resistant braided strip seal, with auxiliary cooling air for cooling and pressure balance. The nozzle air cooling position is as follows: Figure 10 As shown, the high temperature dynamic sealing principle is as follows Figure 11 shown.

[0065] The upper cavity of the nozzle body is formed between the first retractable movable plate, the side wall plates of the nozzle body, the upper wall plate of the nozzle body, and the front and rear wall plates of the nozzle body. The upper wall plate of the nozzle body is provided with air intake and exhaust ports, and the cavity is cooled by a small amount of cold air. The lower cavity of the nozzle body is formed between the second retractable movable plate, the side wall plates of the nozzle body, the lower wall plate of the nozzle body, and the front and rear wall plates of the nozzle body. The lower wall plate of the nozzle body is provided with air intake and exhaust ports, and the cavity is cooled by a small amount of cold air.

[0066] Table 1 shows the corresponding parameters of the aircraft at Mach numbers 2.5 to 6. The flight range of Mach numbers 2.5 to 6 generally corresponds to an altitude of 15 to 30 km. To fully simulate the temperature and pressure environment at high altitude and speed, high total pressure and temperature of the incoming airflow are required, as well as long-term operation. At Mach 6, the incoming airflow temperature reaches 1500K. Since gas-fired heaters are generally used in engine test benches, the insulation coefficient is assumed to be 1.33. The nozzle walls are all rigid, and different metal materials are selected based on the incoming airflow temperature. For example, GH4169 can withstand long-term flow at 850K, while GH4099 can withstand long-term flow at 1050K. When the incoming airflow temperature exceeds the heat resistance limit of the metal, a high-pressure water cooling jacket can be installed to cool the wall temperature within the metal's temperature range using a cooling water system.

[0067] Table 1

[0068]

[0069] In view of the aerodynamic characteristics of the nozzle itself, the Mach number range corresponding to the upper and lower panels of the nozzle is bounded by Mach 3.3. Below Mach 3.3, the aerodynamic panel rotates, and above Mach 3.3, the flat panel translates. When the nozzle changes the Mach number range to Mach 2.5-6, the design reference Mach number of the nozzle is 3.8-4.2. Here, the nozzle outlet height y4 at Mach 4.0 is used as the benchmark for dimensionless conversion. The nozzle outlet height corresponding to Mach 4.0 is y t =y4 (unit: m), then other dimensions are dimensionless

[0070] The flat panel of the nozzle relies on translation to change the Mach number of Mach 3.3 and above. The corresponding relationship between the theoretical dimensionless translation distance and the Mach number in the range of Mach 3 to 6 is as follows: Figure 2 As shown, Figure 2 When the displacement distance is greater than 0, the corresponding flat panel moves downward, and vice versa. When the Mach number is 3.3, the corresponding displacement distance is The nozzle outlet height is When the Mach number is 6, the corresponding displacement distance is The nozzle outlet height is Therefore, the theoretical total displacement is The actual displacement is more affected by the boundary layer than the theoretical displacement. According to experience, the actual displacement is about 1.3 to 1.5 times the theoretical total displacement. t The larger the multiple is, the larger the multiple is. t =1m, it is recommended to take 1.4. t =0.1m, it is recommended to take 1.3.

[0071] The nozzle's aerodynamic panel relies on rotation to change the Mach number at Mach 3.3 and below. The corresponding relationship between its theoretical dimensionless translation distance and Mach number at Mach 2 to 3.5 is as follows: Figure 3 As shown, Figure 3 When the rotation angle is greater than 0, the corresponding aerodynamic panel rotates counterclockwise with the exit point as the axis, and vice versa. When calculating the rotation angle, it is necessary to know the distance L between the nozzle throat and the exit point along the airflow direction. According to the existing nozzle profile calculation method, L = (6~10×y t , in this calculation, L=8y t When the Mach number is 3.3, the corresponding rotation is The corresponding rotation angle is -0.208°, and when the Mach number is 2.5, the corresponding displacement distance is The corresponding rotation angle is -1.656°. Therefore, the theoretical total displacement is The actual displacement will be more affected by the boundary layer than the theoretical displacement. According to experience, the actual displacement is about 1.15 to 1.25 times the theoretical total displacement. As the distance L between the nozzle throat and the outlet along the airflow direction increases, the multiple increases. When L = 8y t , 1.2 is recommended.

[0072] Since the nozzle is a rigid body, the aerodynamic profile is a fixed profile. When the Mach number is 3.3 to 6, the profile does not change. When the Mach number is 2.5 to 3.3, the profile rotates with the actuation. The aerodynamic profile is calculated based on a reference Mach number of 4.0. The Sivells two-dimensional profile method is used to calculate the supersonic inviscid profile. The Maxwell method is used for viscous boundary layer correction. The Witoszynski curve is used to calculate the subsonic profile. When calculating the aerodynamic profile, it is necessary to calculate the profile while performing CFD simulation to achieve the following results:

[0073] The nozzle's non-stick profile has an outlet uniformity of within ±0.03% at the reference Mach number.

[0074] The nozzle has a profile with an outlet uniformity within ±0.3% at the reference Mach number.

[0075] The nozzle has a profile line with an outlet uniformity within ±0.5% at Mach numbers of 3.5 to 4.5;

[0076] The nozzle has a profile uniformity within ±0.95% at Mach numbers of 3-3.5 and 4.5-5.

[0077] The nozzle has a profile with an outlet uniformity within ±1.5% at Mach numbers of 2.5-3 and 5-5.5.

[0078] The nozzle has a profile line with an outlet uniformity within ±3.5% at Mach numbers of 5.5 to 6.

[0079] The uniformity area of ​​the nozzle accounts for more than 9 / 16 of the entire nozzle outlet area.

[0080] The dimensionless upper profile of the variable Mach number 2.5 to 6 nozzle is finally obtained as follows: Figure 4 If the upper limit of the variable Mach number range is changed, the reference Mach number is also changed according to the upper limit. The specific method is shown in Table 2. Table 2. Corresponding range of the variable Mach number nozzle and the reference Mach number.

[0081] Table 2

[0082] Upper limit of variable Mach number range 4.5 5 6 6.5 7 Base Mach number 3.2～3.5 3.5～3.8 3.8～4.2 4.2～4.6 4.6～4.9

[0083] In summary, an aerodynamic design method and profile selection method for a nozzle with a variable Mach number of 2.5 to 6 are proposed. The nozzle can simulate the total pressure and temperature of the real incoming flow at Mach 6, 15 to 30 km.

[0084] This embodiment has the following advantages:

[0085] (1) The nozzle actuation mode is only a unidirectional actuation of the rotation and translation of the rigid body, and does not require multi-point coordinated actuation, making the actuation mechanism and control method relatively simple.

[0086] (2) The nozzle wall is made of rigid body (high temperature alloy), so a water cooling system can be installed. It can be used for high temperature incoming gas and simulate the real environment of high Mach number and high altitude.

[0087] (3) By coordinating the two structural changes, the variable Mach range of the single nozzle is expanded to more than 3 Mach numbers while maintaining the nozzle exit flow field quality.

[0088] (4) When the design Mach number range is reasonable, the nozzle can simulate any Mach number above Mach 2.5.

[0089] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A nozzle suitable for hypersonic continuously variable Mach number, characterized in that: include: a nozzle body, the nozzle body comprising an air flow inlet and an air flow outlet; an adjusting structure, located inside the nozzle body, arranged along the airflow direction, and forming an airflow channel with the nozzle body; The adjustment structure includes a pneumatic panel and a flat panel arranged up and down; Translating the flat panel to change the throat area and the outlet area of ​​the airflow channel; Rotating the pneumatic panel to change the throat area and maintain the outlet area of ​​the airflow channel; The nozzle body is barrel-shaped and includes an upper wall plate, a lower wall plate, two side wall plates, a front wall plate, and a rear wall plate connected to each other. The air flow inlet is provided on the front wall plate, and the air flow outlet is provided on the rear wall plate. The upper wall plate and the lower wall plate are both provided with a plurality of air-cooling cooling air channels; The pneumatic panel is connected to the front wall panel via a first retractable movable panel, and the flat panel is connected to the front wall panel via a second retractable movable panel; The connection between the first retractable movable panel and the pneumatic panel is smoothly transitioned by a designed curved surface; The connection between the second retractable movable plate and the flat panel is smoothly transitioned by designing a curved surface; An upper cavity of the nozzle body is formed between the first retractable movable plate, the side wall plate of the nozzle body, the upper wall plate of the nozzle body, and the front wall plate and the rear wall plate of the nozzle body. The upper wall plate of the nozzle body is provided with air intake and exhaust interfaces, and the cavity is cooled by a small amount of cold air. A lower cavity of the nozzle body is formed between the second retractable movable plate, the side wall plate of the nozzle body, the lower wall plate of the nozzle body, and the front wall plate and the rear wall plate of the nozzle body. The lower wall plate of the nozzle body is provided with air intake and exhaust interfaces, and the cavity is cooled by a small amount of cold air.

2. The nozzle suitable for hypersonic continuously variable Mach number according to claim 1, characterized in that: The flat panel is driven by a first driving mechanism to move closer to or away from the pneumatic panel in a translational manner, so that the outlet area and the throat area change, and the proportions of the changes in the outlet area and the throat area are different; The side of the pneumatic panel close to the airflow outlet is connected to the nozzle body through a rotating shaft; the pneumatic panel is driven by a second driving mechanism to rotate with the rotating shaft as the rotation axis to open and close in the direction of approaching or moving away from the flat panel.

3. The nozzle suitable for hypersonic continuously variable Mach number according to claim 1, characterized in that: The nozzle further comprises an annular frame, which is arranged on the outer periphery of the nozzle body. Drive mechanisms are provided on both sides of the annular frame, and the drive mechanisms are used to drive the two side wall plates to move closer to or away from each other.

4. The nozzle suitable for hypersonic continuously variable Mach number according to claim 1, characterized in that: The side wall plate is provided with a water cooling jacket, a cooling water channel is provided between the inner and outer wall plates of the water cooling jacket, and a cooling water inlet and outlet are provided on the outer wall plate of the water cooling jacket.

5. The nozzle suitable for hypersonic continuously variable Mach number according to claim 1, characterized in that: The pneumatic panel and the flat panel are divided into several sections along the airflow direction, and adjacent sections are hard-connected, with smooth transition at the connection position and an error of no more than 0.1 mm.

6. The nozzle suitable for hypersonic continuously variable Mach number according to claim 2, characterized in that: A first bracket is provided on a side of the flat panel away from the air flow channel, and the first driving mechanism is mounted on the lower wall plate, and the first driving mechanism drives the flat panel to move by driving the first bracket; A second bracket is provided on a side of the pneumatic panel away from the airflow channel. The second driving mechanism is mounted on the upper wall plate. The second driving mechanism drives the pneumatic panel to move by driving the second bracket.

7. The nozzle suitable for hypersonic continuously variable Mach number according to claim 1, characterized in that: The side walls of the pneumatic panel and the flat panel and the side wall plates of the nozzle body, as well as the side walls of the first retractable movable panel and the second retractable movable panel and the side wall plates of the nozzle body are sealed and connected by a plurality of seals arranged along the direction of the airflow channel. The seals are arranged in the grooves of the side wall plates, and each seal is provided with a compressed air channel and an interface to cool the seal by air cooling.

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