A method for maintaining the sound speed profile of a continuously operating transonic wind tunnel liquid control flexible nozzle

Abstract

This application relates to the technical field of wind tunnel flexible nozzle profile control devices, specifically, to a method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle. The method includes the following steps: calculating the total load on each support node of the flexible nozzle's sonic profile; assembling the node support mechanism onto the flexible plate of the flexible nozzle; the node support mechanism includes a mechanical locking device; returning each node to its mechanical zero position; and locking the mechanical locking device; giving the hydraulic servo control system a sonic nozzle forming command; unlocking the mechanical locking device; and allowing the flexible nozzle profile to move from its mechanical zero position to the sonic nozzle profile through coordinated control by the hydraulic servo system; when the dynamic adjustment of the sonic nozzle profile meets the control accuracy requirements, locking the mechanical locking device; the hydraulic servo system exits the dynamic adjustment state; and the mechanical locking device provides the locking force to maintain the sonic nozzle profile. This achieves the goal of maintaining a more stable sonic profile of the flexible nozzle.

Description

Technical Field

[0001] This application relates to the technical field of wind tunnel flexible nozzle profile control devices, specifically, to a method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle. Background Technology

[0002] In domestic wind tunnels, the traditional method for maintaining the sonic profile of flexible nozzles in hydraulically controlled transonic wind tunnels is as follows: After receiving the sonic profile forming command, a coordinated control method is used to achieve closed-loop control of the nozzle profile to a given profile accuracy (synchronous coordination accuracy 0.05mm, positioning accuracy 0.1mm). During the test, the nozzle profile is always in a closed-loop dynamic control and adjustment state, and the position control accuracy of the sonic nozzle profile is maintained by closed-loop dynamic adjustment. Therefore, the traditional sonic nozzle forming method is a closed-loop adjustment and maintenance method throughout the entire test process. Its main disadvantage is that in all wind tunnel tests using sonic nozzles, the nozzle profile needs to be dynamically closed-loop controlled and maintained. Under normal temperature and pressure, tests requiring sonic nozzle profiles can generally be extended to Mach 1.2. According to a rough statistical analysis of historical data, the number of such tests accounts for about 65% of all wind tunnel tests. Therefore, in order to achieve dynamic adjustment of the nozzle profile during the test, it is inevitable to consume human resources. At the same time, the hydraulic oil source system needs to maintain working pressure for a long time, which inevitably leads to energy consumption.

[0003] Currently, under normal temperature and pressure, the sonic velocity profile of hydraulically controlled flexible nozzles is maintained using a closed-loop dynamic adjustment method throughout the entire test. This method involves continuous adjustment by a hydraulic servo system to maintain the nozzle profile accuracy. However, this approach has several drawbacks: the hydraulic oil source needs to operate under pressure for extended periods, resulting in high energy consumption and equipment wear; the control system requires constant monitoring, leading to high labor costs; and the closed-loop adjustment inherently introduces slight fluctuations, affecting the stability and repeatability of test data. Therefore, there is an urgent need to develop an energy-efficient, stable, and high-precision method for maintaining the sonic velocity profile of flexible nozzles. Summary of the Invention

[0004] To further stabilize the sonic profile of a flexible nozzle, a method for maintaining the sonic profile of a hydraulically controlled flexible nozzle in a continuous transonic wind tunnel is provided, comprising the following steps:

[0005] S1. Calculate the total load on each support node of the sonic profile of the flexible nozzle;

[0006] S2. Based on the total load of each support node, assemble the node support mechanism onto the flexible plate of the flexible nozzle; the node support mechanism includes a mechanical locking device.

[0007] S3. Check the locking reliability of the mechanical locking device;

[0008] S4. Install the support mechanisms at each node. After achieving the synchronous and coordinated control requirements of the nozzle profile with the mechanical locking device unlocked, each node returns to the mechanical zero position and the mechanical locking device is locked.

[0009] S5. Given the sonic nozzle forming command from the hydraulic servo control system, the mechanical locker is unlocked, and the flexible nozzle profile moves from the mechanical zero position to the sonic nozzle profile through the coordinated control of the hydraulic servo system.

[0010] S6. When the control accuracy of the sonic nozzle profile reaches the control requirements, the hydraulic servo system continues to maintain the closed-loop state of dynamic adjustment of the sonic nozzle profile.

[0011] S7. When the dynamic adjustment of the sonic nozzle profile meets the control accuracy requirements, the mechanical locking device locks, the hydraulic servo system exits the dynamic adjustment state, and the mechanical locking device provides the locking force to maintain the sonic nozzle profile.

[0012] S8. Conduct wind tunnel testing. After the test, reset the equipment and wait for the next test.

[0013] The above technical solution achieves mechanical locking by setting a mechanical locking device, eliminating the need for continuous closed-loop adjustment of the hydraulic system during the test, thus significantly reducing hydraulic oil consumption and equipment wear. The mechanical locking provides rigid positioning, eliminating closed-loop adjustment fluctuations and significantly improving the stability of the sound velocity profile and the repeatability of test data. At the same time, it reduces the manpower required for the control system and achieves energy-saving, stable, and high-precision sound velocity profile maintenance.

[0014] Optionally, the method for calculating the load of each support node in S1 is as follows:

[0015] S101. Calculate the static load of each support node of the sonic profile of the flexible nozzle under the conditions of temperature 25℃ and pressure 1×105kPa.

[0016] S102. Calculate the aerodynamic loads of each support node when the flexible nozzle is in the sonic profile at a pressure of 1×10⁵ kPa, a temperature of 25℃, a wind speed of Mach number of 1.0.

[0017] S103. Summing the static load and the aerodynamic load yields the total load of each support node.

[0018] Optionally, the static load of the support node in S101 includes the self-weight of the node support mechanism, the weight of the flexible plate it bears, and the reaction force generated by the deformation of the flexible plate.

[0019] Optionally, the node support mechanism in S2 includes a servo cylinder and a lateral force guiding mechanism.

[0020] Through the above technical solutions, the servo cylinder provides precise axial drive and closed-loop adjustment, enabling rapid forming and high-precision positioning of the sonic profile; the lateral force guiding mechanism bears the lateral aerodynamic load during wind tunnel operation, prevents piston rod wear due to off-center load, ensures that the servo cylinder and mechanical locking device are coaxially stressed, and improves operational stability and service life.

[0021] Optionally, in S2:

[0022] The rated thrust of the servo cylinder is at least 1.3 times the total load of all support nodes;

[0023] The load-bearing capacity of the lateral force guiding mechanism is at least 10% of the total load of all support nodes;

[0024] The rated locking force of the mechanical locking device is at least 1.5 times the total load of each support node.

[0025] By using the above technical solutions, safety margins of 1.3 times, 10%, and 1.5 times are set according to the total load to ensure that the servo cylinder thrust is sufficient, the lateral guidance is reliable, and the mechanical locking is firm, so that no displacement, deformation, or failure occurs under the maximum design load, thus meeting the requirements for long-term safe operation in wind tunnel tests.

[0026] Optionally, the method for resetting the hydraulic servo control system in S8 is as follows:

[0027] S801. When a command is given to return the nozzle to the mechanical zero position, the mechanical locker is unlocked, the hydraulic servo control system is put into closed-loop control, and the flexible nozzle moves from the sonic nozzle profile to the mechanical zero position through the coordinated control of the hydraulic servo system. After the return to zero requirement is met, the mechanical locker is locked, the hydraulic servo system is disengaged, and the flexible nozzle profile is maintained at the mechanical zero position.

[0028] Optionally, the method for checking the locking reliability of the mechanical locking device in S3 is as follows:

[0029] Three tests were conducted, with the servo cylinder reaching positions of 0.9, 1.0, and 1.1 times the theoretical stroke of the sonic nozzle, respectively, with the mechanical locker unlocked. The test process included: locking the mechanical locker, applying a wind speed of Mach 1.0 to the servo cylinder at normal temperature and pressure, and loading it in both directions at 1.3 times the calculated total load of the sonic nozzle. The reliability of the mechanical locker was checked. If the mechanical locker could not lock reliably, the coaxiality of the locker and the lateral force guide mechanism was adjusted until the coaxiality requirement of 0.03 mm was met. If the locking force requirement was still not met, the mechanical locker was replaced until the locking force requirement was met in all three tests at each node.

[0030] During the dynamic adjustment of flexible nozzles, there are usually slight differences between the theoretical stroke and the actual stroke at each node. To ensure the locking reliability of the final determined stroke during dynamic adjustment, the above technical solution sets three different strokes for testing. This ensures that the mechanical locking device at each node can reliably lock under the full stroke and maximum load, eliminating the risk of locking failure from the source.

[0031] Optionally, the standard for checking the reliability of the mechanical locking device in S3 is as follows: if the piston rod of the servo cylinder does not move after being loaded with 1.3 times the total load for 0.5 hours, the mechanical locking device is reliable; if the piston rod of the servo cylinder moves, the mechanical locking device is unreliable.

[0032] Optionally, the assembly of the node support mechanism onto the flexible plate of the flexible nozzle in step S2 includes the following steps:

[0033] S201. Fix each support node shaft to the temporary fixture one by one, so that the piston rod of the servo cylinder of the support node and the guide rod of the lateral force guiding mechanism can be freely adjusted within the full stroke range in the vertical direction.

[0034] Optionally, during the S8 wind tunnel test, the position of the sonic nozzle profile is monitored in real time.

[0035] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0036] In all wind tunnel tests using sonic nozzles, the nozzle profile needs to be maintained through dynamic closed-loop control. At ambient temperature and pressure, tests requiring sonic nozzle profiles typically extend to Mach 1.2, accounting for approximately 65% ​​of all wind tunnel tests. Therefore, achieving dynamic nozzle profile adjustment during testing inevitably consumes manpower, and the hydraulic system must maintain operating pressure for extended periods, leading to energy consumption. By using a mechanical locking device to maintain the sonic profile of a flexible nozzle, continuous closed-loop adjustment of the hydraulic system is eliminated, significantly reducing hydraulic energy consumption and equipment wear. The mechanical locking provides rigid positioning, eliminating closed-loop adjustment fluctuations and significantly improving the stability of the sonic profile and the repeatability of test data. Simultaneously, it reduces the manpower required for control system operation, achieving energy-saving, stable, and high-precision sonic profile maintenance.

[0037] By setting the rated thrust of the servo cylinder to be at least 1.3 times the total load, the bearing capacity of the lateral force guiding mechanism to be at least 10% of the total load, and the rated locking force of the mechanical locker to be at least 1.5 times the total load, it is ensured that the servo cylinder has sufficient thrust, reliable lateral guidance, and firm mechanical locking, and that no displacement, deformation, or failure occurs under the maximum design load, thus meeting the requirements for long-term safe operation in wind tunnel tests.

[0038] During the dynamic adjustment of flexible nozzles, there are usually slight differences between the theoretical stroke and the actual stroke at each node. In order to ensure the locking reliability of the final determined stroke of the dynamic adjustment, this application sets three different strokes for testing to ensure that the mechanical locking device at each node can reliably lock under the full stroke and maximum load, thus eliminating the risk of locking failure from the source. Attached Figure Description

[0039] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0040] Figure 1 This is an overall structural cross-sectional view of the connection between the node support structure and the flexible plate in this application;

[0041] Figure 2 This is a partial structural diagram of the node support structure in this application;

[0042] Figure 3 This is a schematic diagram of the mechanical locking device in the state of being without oil.

[0043] Figure 4 This is a schematic diagram of the mechanical locking device in the oil-filled state.

[0044] Among them, 1. Servo cylinder; 2. Lateral force guiding mechanism; 3. Mechanical locking device; 4. Node support mechanism; 5. Flexible plate; 6. Guide clamping rod; 7. Clamping sleeve; 8. Housing; 9. Locking piston; 10. Spring; 11. Upper beam; 12. Lower beam; 13. Guide rod; 14. Rotating shaft; 15. Oil port. Detailed Implementation

[0045] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0046] Example 1

[0047] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0048] Reference Figure 1 and Figure 2 , Figure 1 The node support mechanism 4, whose midpoints are all omitted, is a method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle, comprising the following steps:

[0049] S1. Calculate the total load on each support node of the sonic profile of the flexible nozzle;

[0050] S2. Based on the total load of each support node, the node support mechanism 4 is assembled onto the flexible plate 5 of the flexible nozzle; the node support mechanism 4 includes a mechanical locking device 3.

[0051] S3. Check the locking reliability of the mechanical locking device 3;

[0052] S4. Install the support mechanism 4 at each node. After the nozzle profile is synchronized and coordinated with the mechanical locking device 3 in the unlocked state, each node returns to the mechanical zero position and the mechanical locking device 3 is locked.

[0053] S5. Given the sonic nozzle forming command of the hydraulic servo control system, the mechanical locker 3 is unlocked, and the flexible nozzle profile moves from the mechanical zero position to the sonic nozzle profile through the coordinated control of the hydraulic servo system.

[0054] S6. When the control accuracy of the sonic nozzle profile reaches the control requirements, the hydraulic servo system continues to maintain the closed-loop state of dynamic adjustment of the sonic nozzle profile.

[0055] S7. When the dynamic adjustment of the sonic nozzle profile meets the control accuracy requirements, the mechanical locker 3 locks, the hydraulic servo system exits the dynamic adjustment state, and the mechanical locker 3 provides the locking force to maintain the sonic nozzle profile.

[0056] S8. Conduct wind tunnel testing. After the test, reset the equipment and wait for the next test.

[0057] Mechanical locking is achieved by setting mechanical locking device 3, eliminating the need for continuous closed-loop adjustment of the hydraulic system during the test, which greatly reduces the energy consumption of hydraulic oil source and equipment wear; mechanical locking provides rigid positioning, eliminates closed-loop adjustment fluctuations, and significantly improves the stability of the sound velocity profile and the repeatability of test data; at the same time, it reduces the manpower required to operate the control system, and achieves energy-saving, stable and high-precision sound velocity profile maintenance.

[0058] Optionally, the method for calculating the load of each support node in S1 is as follows:

[0059] S101. Calculate the static load of each support node of the sonic profile of the flexible nozzle under the conditions of temperature 25℃ and pressure 1×105kPa.

[0060] S102. Calculate the aerodynamic loads of each support node when the flexible nozzle is in the sonic profile at a pressure of 1×10⁵ kPa, a temperature of 25℃, a wind speed of Mach number of 1.0.

[0061] S103. Summing the static load and the aerodynamic load yields the total load of each support node.

[0062] Optionally, the static load of the flexible nozzle sonic profile support node in S101 includes the self-weight of the node support mechanism 4, the weight of the flexible plate 5 it bears, and the reaction force generated by the deformation of the flexible plate 5.

[0063] Optionally, the node support mechanism 4 in S2 includes a servo cylinder 1 and a lateral force guiding mechanism 2.

[0064] Servo cylinder 1 provides precise axial drive and closed-loop adjustment, enabling rapid forming and high-precision positioning of the sonic profile; lateral force guiding mechanism 2 bears the lateral aerodynamic load during wind tunnel operation, prevents piston rod wear due to off-center load, ensures that servo cylinder 1 and mechanical locking device 3 are coaxially stressed, and improves operational stability and service life.

[0065] Optionally, in S2:

[0066] The rated thrust of the servo cylinder 1 is at least 1.3 times the total load of all support nodes;

[0067] The load-bearing capacity of the lateral force guiding mechanism 2 is at least 10% of the total load of all support nodes;

[0068] The rated locking force of the mechanical locking device 3 is at least 1.5 times the total load of each support node.

[0069] Safety margins of 1.3 times, 10%, and 1.5 times the total load are set to ensure that the servo cylinder 1 has sufficient thrust, reliable lateral guidance, and firm mechanical locking, and will not experience displacement, deformation, or failure under the maximum design load, thus meeting the requirements for long-term safe operation in wind tunnel tests.

[0070] Optionally, the method for resetting the hydraulic servo control system in S8 is as follows:

[0071] S801, given the command to return the nozzle to the mechanical zero position, the mechanical locker 3 is unlocked, the hydraulic servo control system is put into closed-loop control, the flexible nozzle moves from the sonic nozzle profile to the mechanical zero position through the coordinated control of the hydraulic servo system. After the return to zero requirement is met, the mechanical locker 3 is locked, the hydraulic servo system is disengaged, and the flexible nozzle profile is maintained at the mechanical zero position.

[0072] Optionally, the method for checking the locking reliability of the mechanical locking device 3 in S3 is as follows:

[0073] Three tests were conducted, with the servo cylinder 1 reaching positions of 0.9, 1.0, and 1.1 times the theoretical stroke of the sonic nozzle, respectively, with the mechanical locking device 3 unlocked. The test process included: locking the mechanical locking device 3, applying a wind speed of Mach 1.0 to the servo cylinder 1 at normal temperature and pressure, and loading it in both directions at 1.3 times the calculated total load of the sonic nozzle. The reliability of the mechanical locking device 3 was checked. If the mechanical locking device 3 could not lock reliably, the coaxiality between the locking device and the lateral force guide mechanism 2 was adjusted until the coaxiality requirement of 0.03 mm was met. If the locking force requirement was still not met, the mechanical locking device 3 was replaced until each mechanical locking device 3 met the locking force requirement in all three tests.

[0074] During the dynamic adjustment of the flexible nozzle, there may be slight differences between the theoretical stroke and the actual stroke at each node. To ensure the locking reliability of the final determined stroke during dynamic adjustment, three different strokes are set for testing to ensure that the mechanical locking device 3 at each node can reliably lock under the full stroke and maximum load, thus eliminating the risk of locking failure from the source.

[0075] Optionally, the standard for checking the reliability of the mechanical locking device 3 in S3 is as follows: if the piston rod of the servo cylinder 1 does not move after being loaded with 1.3 times the total load for 0.5 hours, the mechanical locking device 3 is reliable; if the piston rod of the servo cylinder 1 moves, the mechanical locking device 3 is unreliable.

[0076] Optionally, assembling the node support mechanism 4 onto the flexible plate 5 of the flexible nozzle in step S2 includes the following steps:

[0077] S201. Fix each support node shaft 14 to the temporary fixture one by one, so that the piston rod of the servo cylinder 1 of the support node and the guide rod 13 of the lateral force guiding mechanism 2 can be freely adjusted within the full stroke range in the vertical direction.

[0078] Optionally, during the S8 wind tunnel test, the position of the sonic nozzle profile is monitored in real time.

[0079] Example 2

[0080] Reference Figure 2 After the assembly of the support node mechanism is completed, the rotating shafts 14 on both sides of the upper beam 11 of each support node mechanism are fixed one by one on the temporary tooling, so that the piston rod and guide rod 13 of the servo cylinder 1, together with the connected lower beam 12, can be freely adjusted in the full stroke range in the vertical direction.

[0081] Example 3

[0082] Reference Figure 3 and Figure 4Based on the continuous transonic wind tunnel hydraulically controlled flexible nozzle sonic profile maintenance method described in Example 1 or 2, the mechanical locking device 3 comprises the following structure:

[0083] Guide clamping rod 6: The guide clamping rod is connected to the guide rod 13;

[0084] Clamping sleeve 7: Sleeves on the outside of guide clamping rod 6, used to clamp guide clamping rod 6;

[0085] Outer shell 8: It is fixedly connected to the upper small beam 11, and an oil passage 15 is provided on the surface of the outer shell 8;

[0086] Locking piston 9: It is slidably connected inside the housing 8. The side of the locking piston 9 near the clamping sleeve 7 is inclined, and a spring 10 is provided on the side of the locking piston 9 away from the clamping sleeve 7.

[0087] The operating principle of the mechanical locking device 3 is as follows: When unlocking is required, oil is supplied to the oil inlet 15. The oil pushes the locking piston 9 to compress the spring 10, causing the locking piston 9 to separate from the clamping sleeve 7. This eliminates the force exerted by the locking piston 9 on the clamping sleeve 7, and the clamping sleeve 7 releases the clamping rod to achieve unlocking. After unlocking, the cylinder piston rod and guide rod 13 and their connected components can be freely adjusted within the full stroke range under the control of the hydraulic servo system. When locking, the oil in the mechanical locking device 3 is discharged through the oil inlet 15, the spring 10 recovers appropriately, and the spring 10 presses the locking piston 9 against the outer surface of the clamping sleeve, causing the clamping sleeve 7 to clamp the guide clamping rod 6.

[0088] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0089] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for maintaining the sonic profile of a hydraulically controlled flexible nozzle in a continuous transonic wind tunnel, characterized in that, Includes the following steps: S1. Calculate the total load on each support node of the sonic profile of the flexible nozzle; S2. Based on the total load of each support node, the node support mechanism (4) is assembled onto the flexible plate (5) of the flexible nozzle; the node support mechanism (4) includes a mechanical locking device (3); S3. Check the locking reliability of the mechanical locking device (3); S4. Install the support mechanism (4) at each node. After the nozzle profile is synchronized and coordinated with the control requirements in the unlocked state of the mechanical locking device (3), each support node returns to the mechanical zero position and the mechanical locking device (3) is locked. S5. Given the sonic nozzle forming command of the hydraulic servo control system, the mechanical lock (3) is unlocked, and the flexible nozzle profile moves from the mechanical zero position to the sonic nozzle profile through the coordinated control of the hydraulic servo system. S6. When the control accuracy of the sonic nozzle profile reaches the control requirements, the hydraulic servo system continues to maintain the closed-loop state of dynamic adjustment of the sonic nozzle profile. S7. When the dynamic adjustment of the sonic nozzle profile meets the control accuracy requirements, the mechanical locker (3) locks, the hydraulic servo system exits the dynamic adjustment state, and the mechanical locker (3) provides the locking force to maintain the sonic nozzle profile. S8. Conduct wind tunnel testing. After the test, reset the equipment and wait for the next test. The node support mechanism (4) in S2 also includes a servo cylinder (1), a lateral force guiding mechanism (2), an upper beam (11), a lower beam (12), a guide rod (13), and a rotating shaft (14). In S2: The rated thrust of the servo cylinder (1) is at least 1.3 times the total load of each support node; The bearing capacity of the lateral force guiding mechanism (2) is at least 10% of the total load of each support node; The rated locking force of the mechanical locking device (3) is at least 1.5 times the total load of each support node; The method for checking the locking reliability of the mechanical locking device (3) in S3 is as follows: Three tests were conducted, and the servo cylinder (1) reached the positions of 0.9, 1.0 and 1.1 times the theoretical stroke of the sonic nozzle respectively in the unlocked state of the mechanical locker (3). The test process included: locking the mechanical locker (3), applying a wind speed of 1.0 Mach to the servo cylinder (1) at normal temperature and pressure, and loading it in both directions at 1.3 times the calculated total load of the sonic nozzle. Checking whether the mechanical locker (3) was reliable. If the mechanical locker (3) could not be locked reliably, the coaxiality of the mechanical locker (3) and the lateral force guide mechanism (2) was adjusted until the coaxiality requirement of 0.03 mm was met. If the locking force requirement was still not met, the mechanical locker (3) was replaced until the locking force requirement of the mechanical locker (3) at each node was met in all three tests. The mechanical locking device (3) has the following structure: Guide clamping rod (6): The guide clamping rod is connected to the guide rod (13); Clamping sleeve (7): Sleeve on the outside of guide clamping rod (6) for clamping guide clamping rod (6); Outer shell (8): It is fixedly connected to the upper small beam (11), and an oil passage (15) is provided on the surface of the outer shell (8). Locking piston (9): It is slidably connected inside the housing (8). The side of the locking piston (9) near the clamping sleeve (7) is inclined, and a spring (10) is provided on the side of the locking piston (9) away from the clamping sleeve (7).

2. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 1, characterized in that, The method for calculating the load of each support node in S1 is as follows: S101. Calculate the static load of each support node of the sonic profile of the flexible nozzle under the conditions of temperature 25℃ and pressure 1×105kPa. S102. Calculate the aerodynamic loads of each support node when the flexible nozzle is in the sonic profile at a pressure of 1×10⁵ kPa, a temperature of 25℃, a wind speed of Mach number of 1.

0. S103. Summing the static load and the aerodynamic load yields the total load of each support node.

3. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 2, characterized in that, The static load of the support node in S101 includes the self-weight of the node support mechanism (4), the weight of the flexible plate (5) it bears, and the reaction force generated by the deformation of the flexible plate (5).

4. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 1, characterized in that, The method for resetting the hydraulic servo control system in S8 is as follows: S801, given the command to return the nozzle to the mechanical zero position, the mechanical lock (3) is unlocked, the hydraulic servo control system is put into closed-loop control, the flexible nozzle moves from the sonic nozzle profile to the mechanical zero position through the coordinated control of the hydraulic servo system. After the return to zero requirement is met, the mechanical lock (3) is locked, the hydraulic servo system is disengaged, and the flexible nozzle profile is maintained at the mechanical zero position.

5. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 1, characterized in that, The standard for checking the reliability of the mechanical locking device (3) in S3 is as follows: if the piston rod of the servo cylinder (1) does not move after being loaded with 1.3 times the total load for 0.5 hours, the mechanical locking device (3) is reliable; if the piston rod of the servo cylinder (1) moves, the mechanical locking device (3) is unreliable.

6. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 1, characterized in that, The step of assembling the node support mechanism (4) onto the flexible plate (5) of the flexible nozzle in step S2 includes the following steps: S201. Fix each support node shaft (14) onto the temporary fixture one by one, so that the piston rod of the servo cylinder (1) of the support node and the guide rod (13) of the lateral force guiding mechanism (2) can be freely adjusted within the full stroke range in the vertical direction.

7. The method for maintaining the sonic profile of a continuous transonic wind tunnel hydraulically controlled flexible nozzle according to claim 1, characterized in that, During the S8 wind tunnel test, the position of the sonic nozzle profile was monitored in real time.

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