A continuously variable pressure device and method for high speed flutter testing

Abstract

A continuous variable pressure device and method for high-speed flutter test belong to the technical field of continuous wind tunnel test, and aim to solve the problem that the traditional test equipment cannot change the Mach number while changing the continuous variable pressure. The device comprises an upper flexible wall group and a lower flexible wall group. The upper flexible wall group comprises a flexible wall plate and a plurality of servo action units. One end of the servo action units is connected with the upper end wall of a nozzle body. The servo action units are arranged at intervals along the airflow direction. The other end of the servo action units is connected with the flexible wall plate. The servo action units are respectively electrically connected with a servo controller group. A nozzle controller is connected with the servo controller group through a real-time bus. The left and right ends of the flexible wall plate are respectively and correspondingly slidably and sealingly matched with the left side wall and the right side wall of the nozzle body. The upper flexible wall group and the lower flexible wall group are the same in structure and are symmetrical. The flexible wall plate is used to adjust the Mach number, so that the problem that the traditional test equipment cannot change the Mach number while changing the continuous variable pressure can be solved.

Description

Technical Field

[0001] This invention belongs to the field of continuous wind tunnel testing technology, and particularly relates to a continuous variable speed pressure device and method for high-speed flutter testing. Background Technology

[0002] High-speed flutter testing is a type of wind tunnel testing aimed at obtaining the flutter characteristics of high-speed aircraft under specific operating conditions. Flutter is a specific physical phenomenon where an aircraft exhibits self-excited vibrations under certain operating conditions. The intensity of these vibrations is directly related to velocity-pressure. Therefore, high-speed flutter testing requires simultaneous control of both Mach number and velocity-pressure variables. To obtain the dynamic flutter characteristics of the aircraft, continuous velocity-pressure testing is necessary. Traditional testing equipment typically achieves continuous velocity-pressure changes at high speeds by fixing the nozzle profile and varying the total pressure, which cannot simultaneously change the Mach number. Summary of the Invention

[0003] The purpose of this invention is to simultaneously achieve Mach number changes while implementing continuous variable speed pressure conditions in high-speed flutter testing, thereby obtaining a wider range of aircraft flutter characteristics. The technical solution adopted in this invention is as follows:

[0004] A continuously variable pressure device for high-speed flutter testing includes an intake unit, an intake regulating valve, an intake shut-off valve, and a pressure regulating valve connected in sequence, as well as a stabilization section, a flexible wall nozzle, and a test section connected in sequence. The outlet of the pressure regulating valve is connected to the front end of the stabilization section, and the end of the test section is connected to the exhaust shut-off valve, the exhaust regulating valve, and the exhaust unit in sequence. A gas source pressure sensor is installed on the pipeline between the intake unit and the intake regulating valve, an intake pressure sensor is installed on the pipeline between the intake regulating valve and the intake shut-off valve, a total pressure sensor is installed on the stabilization section, a static pressure sensor is installed on the test section, an exhaust pressure sensor is installed on the pipeline between the test section and the exhaust shut-off valve, and an exhaust main pipe pressure sensor is installed on the pipeline between the exhaust regulating valve and the exhaust unit. The make-up air tower is connected to the pipeline between the exhaust shut-off valve and the exhaust pressure sensor through the make-up air regulating valve.

[0005] The flexible wall nozzle includes a nozzle body, an upper flexible wall assembly, and a lower flexible wall assembly. The nozzle body is a rectangular tube. The upper flexible wall assembly includes a flexible wall panel and several servo actuators. One end of each servo actuator is connected to the upper end wall of the nozzle body. The servo actuators are arranged at intervals along the airflow direction. The other end of each servo actuator is set downward and connected to the flexible wall panel. Each servo actuator is electrically connected to a servo controller group. The nozzle controller is connected to the servo controller group via a real-time bus. The left and right ends of the flexible wall panel are respectively slidably sealed to the left and right sides of the nozzle body. The upper and lower flexible wall assemblies have the same structure and are symmetrical. An airflow channel is formed between the flexible wall panels of the upper and lower flexible wall assemblies.

[0006] Furthermore, it also includes a central controller, which establishes signal connections with the nozzle controller and the valve controller respectively, and is electrically connected to the air source pressure sensor, the intake pressure sensor, the total pressure sensor, the static pressure sensor, the extraction pressure sensor and the extraction manifold pressure sensor respectively. The valve controller is electrically connected to the intake regulating valve, the intake shut-off valve, the pressure regulating valve, the extraction shut-off valve, the extraction regulating valve and the replenishment regulating valve respectively.

[0007] This invention also provides a continuous variable-speed pressure method for high-speed flutter testing, which is based on the aforementioned continuous variable-speed pressure device for high-speed flutter testing, and includes the following steps:

[0008] Step 1: Perform simulation calculations, select the exit Mach numbers of n flexible-wall nozzles as target Mach numbers, and label the n target Mach numbers as M1, M2, M3...M n Then, the position profiles of the n flexible panels corresponding one-to-one with the n target Mach numbers are successively named the 1st position profile, the 2nd position profile, the 3rd position profile, ... the nth position profile. All the calibrated position profiles are collectively referred to as the nozzle position profiles, and the correspondence between the target Mach number and the nozzle position profiles is established.

[0009] Step 2: Derive the formula relating the total pressure of the test section to the target Mach number. Since the total pressure of the stable section is equal to that of the test section, the static pressure of the test section is calculated using the following formula:

[0010] (1)

[0011] In the formula, P0 is the total pressure in the steady-state section, P ct The static pressure of the test section is M, and the exit Mach number of the flexible wall nozzle is M.

[0012] The rapid pressure Q of the test section is calculated using the following formula:

[0013] (2)

[0014] Combining equations (1) and (2), we have:

[0015] (3)

[0016] Step 3: Select the discrete values ​​of velocity pressure from n test sections as the target velocity pressure, and label them sequentially as Q1, Q2, Q3...Q n There is a one-to-one correspondence between the n target velocity pressures and the n target Mach numbers. By substituting the n pairs of target velocity pressures and target Mach numbers into equations (2) and (3) respectively, the n target static pressures P can be obtained. ct1 P ct2 P ct3 ...Pctn And the total pressure P of n targets 01 P 02 P 03 ...P 0n ;

[0017] Step 4: Change the opening of the intake regulating valve to adjust the downstream pressure P of the intake regulating valve. in The following conditions must be met:

[0018] P in >1.2*P 0max (4)

[0019] Among them, P 0max For the target total pressure P 01 P 02 P 03 ...P 0n The maximum value in;

[0020] Then the intake shut-off valve is opened to the fully open position;

[0021] Step 5: Open the suction shut-off valve to the fully open position, then change the opening of the suction regulating valve to 60%, and change the opening of the replenishment regulating valve to adjust the reading P of the suction pressure sensor. out The following conditions must be met:

[0022] P out <0.8*P ctmin (5)

[0023] Among them, P ctmin For the target static pressure P ct1 P ct2 P ct3 ...P ctn The minimum value in;

[0024] Step 6: Adjust the nozzle position profile according to the first discrete value M1 in the target Mach number sequence, then open the pressure regulating valve, and use PID control to make the actual total pressure of the test section equal to the first discrete value P in the target total pressure sequence. 01 The PID control formula is:

[0025] (6)

[0026] in, Let K be the opening increment of the pressure regulating valve at time k. p For proportional gain, K i Let e(k) be the integral gain, e(k) be the real-time reading P0 of the total pressure sensor at time k, and e(k-1) be the target total pressure P at time k-1. 01 Deviation;

[0027] Step 7: Measure the actual static pressure at this time using a static pressure sensor;

[0028] Step 8: Repeat steps 6 and 7 to complete the actual static pressure measurements at the remaining target Mach numbers, and label the n actual static pressures corresponding to the n target Mach numbers as P. sct1 P sct2 P sct3 ...P sct4 ;

[0029] Step 9: There is a one-to-one correspondence between the n actual static pressures and the n target Mach numbers. Substituting the n pairs of actual static pressures and target Mach numbers into equation (2) in sequence, we can obtain the n actual velocity pressures Q. s1 Q s2 Q s3 ...Q sn Ultimately, the actual continuous speed change pressure curve is obtained.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] To achieve continuous variable pressure testing, a method of dynamically changing the nozzle exit Mach number and the total pressure in the steady-state section is adopted. This is achieved through the real-time operation of the nozzle profile and the pressure regulating valve to effectively control the velocity-pressure sequence. First, the target velocity-pressure sequence and the target Mach number sequence are used as basic input conditions, and then the target total pressure sequence is calculated. In the specific experiment, the entire test process is completed through the coordinated movement of discrete points in the target Mach number sequence, the target velocity-pressure sequence, and the target total pressure sequence. This solves the problem in high-speed flutter testing where traditional testing equipment, in achieving continuous variable pressure at high speeds, often uses a fixed nozzle profile while varying the total pressure, failing to simultaneously change the Mach number. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0033] Figure 2 This is a schematic diagram of the flexible wall nozzle.

[0034] Figure 3 This is a control relationship diagram of the device of the present invention;

[0035] Figure 4 This is a flowchart of the method of the present invention.

[0036] In the diagram, 1. Intake unit, 2. Intake regulating valve, 3. Intake shut-off valve, 4. Pressure regulating valve, 5. Stabilization section, 6. Flexible wall nozzle, 7. Test section, 8. Extraction shut-off valve, 9. Extraction regulating valve, 10. Extraction unit, 11. Make-up air regulating valve, 12. Make-up air tower, 13. Air source pressure sensor, 14. Intake pressure sensor, 15. Total pressure sensor, 16. Static pressure sensor, 17. Extraction pressure sensor, 18. Extraction main pipe pressure sensor, 19. Nozzle controller, 20. Servo controller, 21. Upper flexible wall assembly, 22. Nozzle body, 23. Servo action unit, 24. Flexible wall panel, 25. Current profile, 26. Target profile, 27. Central controller, 28. Valve controller, 29. Nozzle position profile. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0038] The connections mentioned in this invention are divided into fixed connections and detachable connections. Fixed connections, also known as non-detachable connections, include but are not limited to conventional fixed connection methods such as folded connections, riveted connections, adhesive connections, and welded connections. Detachable connections include but are not limited to conventional disassembly methods such as bolted connections, snap-fit ​​connections, pin connections, and hinged connections. When a specific connection method is not explicitly defined, it is assumed that at least one existing connection method can be found to achieve this function, and those skilled in the art can choose according to their needs. For example, a welded connection can be chosen for fixed connections, and a bolted connection can be chosen for detachable connections.

[0039] The present invention will be further described in detail below with reference to the accompanying drawings. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0040] Example 1: As Figures 1-4As shown, a continuously variable pressure device for high-speed flutter testing is characterized by comprising an intake unit 1, an intake regulating valve 2, an intake shut-off valve 3, and a pressure regulating valve 4 connected in sequence, and a stabilizing section 5, a flexible wall nozzle 6, and a test section 7 connected in sequence. The outlet of the pressure regulating valve 4 is connected to the front end of the stabilizing section 5, and the end of the test section 7 is connected in sequence to an extraction shut-off valve 8, an extraction regulating valve 9, and an extraction unit 10. A gas source pressure sensor 13 is installed on the pipeline between the intake unit 1 and the intake regulating valve 2, an intake pressure sensor 14 is installed on the pipeline between the intake regulating valve 2 and the intake shut-off valve 3, a total pressure sensor 15 is installed on the stabilizing section 5, a static pressure sensor 16 is installed on the test section 7, an extraction pressure sensor 17 is installed on the pipeline between the test section 7 and the extraction shut-off valve 8, and an extraction main pipe pressure sensor 18 is installed on the pipeline between the extraction regulating valve 9 and the extraction unit 10. The gas replenishment tower 12 is connected to the pipeline between the extraction shut-off valve 8 and the extraction pressure sensor 17 through a gas replenishment regulating valve 11.

[0041] The flexible wall nozzle 6 includes a nozzle body 22, an upper flexible wall assembly 21, and a lower flexible wall assembly. The nozzle body 22 is a rectangular tube. The upper flexible wall assembly 21 includes a flexible wall panel 24 and several servo action units 23. One end of each servo action unit 23 is connected to the upper wall of the nozzle body 22. The several servo action units 23 are arranged at intervals along the airflow direction. The other end of each servo action unit 23 is set downwards and is driven by a motor through a reducer. The end of the lift is connected to the flexible wall panel 24. The several servo action units 23 are electrically connected to the servo controller group 20. The nozzle controller 19 is connected to the servo controller group 20 through a real-time bus. The left and right ends of the flexible wall panel 24 are respectively slidably sealed to the left and right walls of the nozzle body 22. The upper flexible wall assembly 21 and the lower flexible wall assembly have the same structure and are symmetrical. An airflow channel is formed between the flexible wall panel 24 of the upper flexible wall assembly 21 and the flexible wall panel 24 of the lower flexible wall assembly.

[0042] The airflow from both the intake unit 1 and the supplementary air tower 12 flows toward the extraction unit 10. The nozzle controller 19 drives all the servo action units 23 to move synchronously through the servo controller group 20, which can change the position and shape of the two flexible wall panels 24, thereby causing the exit Mach number of the flexible wall nozzle 6 to change, thus realizing the dynamic change of the exit Mach number of the flexible wall nozzle 6.

[0043] It also includes a central controller 27, which establishes signal connections with the nozzle controller 19 and valve controller 28 via an industrial Ethernet network. The central controller 27 is electrically connected to the air source pressure sensor 13, intake pressure sensor 14, total pressure sensor 15, static pressure sensor 16, extraction pressure sensor 17, and extraction manifold pressure sensor 18 via a PCI or PXI bus card. The valve controller 28 is electrically connected to the intake regulating valve 2, intake shut-off valve 3, pressure regulating valve 4, extraction shut-off valve 8, extraction regulating valve 9, and replenishment regulating valve 11. The central controller 27 collects the output pressure data of the intake unit 1 through the air source pressure sensor 13 and the outlet pressure of the intake regulating valve 2 through the intake pressure sensor 14. The data includes total pressure data of the stable section 5 collected by total pressure sensor 15, static pressure data of the test section 7 collected by static pressure sensor 16, end pressure data of the test section 7 collected by extraction pressure sensor 17, and front-end main pipe pressure data of the extraction unit 10 collected by extraction main pipe pressure sensor 18. The central controller 27 sends the target position profile of the flexible wall panel 24 to the nozzle controller 19, which can then control several servo action units 23 to change the two flexible wall panels 24 from the current profile 25 to the target profile 26. The central controller 27 sends a signal to the valve controller 28 to control the target opening degree of the intake regulating valve 2, intake shut-off valve 3, pressure regulating valve 4, extraction shut-off valve 8, extraction regulating valve 9, and replenishment regulating valve 11.

[0044] Example 2: Figures 1-4 As shown, a continuous variable-speed pressure method for high-speed flutter testing is implemented based on the continuous variable-speed pressure device for high-speed flutter testing described in Example 1, and includes the following steps:

[0045] Step 1: Perform simulation calculations, selecting the exit Mach numbers of n flexible-wall nozzles 6 as target Mach numbers, and labeling the n target Mach numbers sequentially as M1, M2, M3...M n Then, the position profiles of the n flexible wall panels 24 corresponding one-to-one with the n target Mach numbers are successively named the first position profile, the second position profile, the third position profile, ... the nth position profile. All the position profiles are collectively referred to as the nozzle position profiles 29, and the correspondence between the target Mach numbers and the nozzle position profiles 29 is established.

[0046] Step 2: Derive the formula relating the total pressure of the test section to the target Mach number. Since the total pressure of the stable section is equal to that of the test section, the static pressure of test section 7 is calculated using the following formula:

[0047] (1)

[0048] In the formula, P0 is the total pressure of the stable section 5, P ctM is the static pressure of test section 7, and M is the exit Mach number of the flexible wall nozzle 6.

[0049] The velocity pressure Q of test section 7 is calculated using the following formula:

[0050] (2)

[0051] Combining equations (1) and (2), we have:

[0052] (3)

[0053] Step 3: Select the discrete values ​​of velocity pressure from n test sections 7 as the target velocity pressure, and label them sequentially as Q1, Q2, Q3...Q n There is a one-to-one correspondence between the n target velocity pressures and the n target Mach numbers. By substituting the n pairs of target velocity pressures and target Mach numbers into equations (2) and (3) respectively, the n target static pressures P can be obtained. ct1 P ct2 P ct3 ...P ctn And the total pressure P of n targets 01 P 02 P 03 ...P 0n ;

[0054] Step 4: Change the opening of intake regulating valve 2 to increase the downstream pressure P of intake regulating valve 2. in The following conditions must be met:

[0055] P in >1.2*P 0max (4)

[0056] Among them, P 0max For the target total pressure P 01 P 02 P 03 ...P 0n The maximum value in;

[0057] Then, the intake shut-off valve 3 is opened to the fully open position;

[0058] Step 5: Open the suction shut-off valve 8 to the fully open position, then change the opening of the suction regulating valve 9 to 60%, and change the opening of the replenishment regulating valve 11, so that the reading P of the suction pressure sensor 17 is... out The following conditions must be met:

[0059] P out <0.8*P ctmin (5)

[0060] Among them, P ctmin For the target static pressure P ct1 Pct2 P ct3 ...P ctn The minimum value in;

[0061] Step 6: Adjust the nozzle position profile 29 according to the first discrete value M1 in the target Mach number sequence, then open the pressure regulating valve 4, and use PID control to make the actual total pressure of test section 7 equal to the first discrete value P in the target total pressure sequence. 01 The actual total pressure can be measured in real time by the total pressure sensor 15. The PID control formula is as follows:

[0062] (6)

[0063] in, Let K be the opening increment of pressure regulating valve 4 at time k. p For proportional gain, K i Let e(k) be the integral gain, e(k) be the real-time reading of the total pressure sensor 15 at time k, and e(k-1) be the target total pressure value P at time k-1. 01 Deviation;

[0064] Step 7: Measure the actual static pressure at this time using static pressure sensor 16;

[0065] Step 8: Repeat steps 6 and 7 to complete the actual static pressure measurements at the remaining target Mach numbers, and label the n actual static pressures corresponding to the n target Mach numbers as P. sct1 P sct2 P sct3 ...P sct4 ;

[0066] Step 9: There is a one-to-one correspondence between the n actual static pressures and the n target Mach numbers. Substituting the n pairs of actual static pressures and target Mach numbers into equation (2) in sequence, we can obtain the n actual velocity pressures Q. s1 Q s2 Q s3 ...Q sn Ultimately, the actual continuous speed change pressure curve is obtained.

[0067] To achieve continuous variable pressure testing, a method of dynamically changing the nozzle exit Mach number and the total pressure in the steady-state section is adopted. This is achieved through the real-time operation of the nozzle profile and the pressure regulating valve to effectively control the velocity-pressure sequence. First, the target velocity-pressure sequence and the target Mach number sequence are used as basic input conditions, and then the target total pressure sequence is calculated. In the specific experiment, the entire test process is completed through the coordinated movement of discrete points in the target Mach number sequence, the target velocity-pressure sequence, and the target total pressure sequence. This solves the problem in high-speed flutter testing where traditional testing equipment, in achieving continuous variable pressure at high speeds, often uses a fixed nozzle profile while varying the total pressure, failing to simultaneously change the Mach number.

[0068] The above embodiments are merely illustrative examples of the present invention and do not limit its scope of protection. Those skilled in the art can make partial changes to them, as long as they do not exceed the spirit and essence of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A continuously variable pressure device for high-speed flutter testing, characterized in that: The system includes an intake unit (1), an intake regulating valve (2), an intake shut-off valve (3), and a pressure regulating valve (4) connected in sequence, as well as a stabilization section (5), a flexible wall nozzle (6), and a test section (7) connected in sequence. The outlet of the pressure regulating valve (4) is connected to the front end of the stabilization section (5), and the end of the test section (7) is connected in sequence to the extraction shut-off valve (8), the extraction regulating valve (9), and the extraction unit (10). A gas source pressure sensor (13) is installed on the pipeline between the intake unit (1) and the intake regulating valve (2). The intake regulating valve (2) and the intake shut-off valve are connected in sequence. (3) An inlet pressure sensor (14) is installed on the pipeline between them. A total pressure sensor (15) is installed on the stable section (5). A static pressure sensor (16) is installed on the test section (7). A suction pressure sensor (17) is installed on the pipeline between the test section (7) and the suction shut-off valve (8). A suction main pipe pressure sensor (18) is installed on the pipeline between the suction regulating valve (9) and the suction unit (10). The gas replenishment tower (12) is connected to the pipeline between the suction shut-off valve (8) and the suction pressure sensor (17) through the gas replenishment regulating valve (11). The flexible wall nozzle (6) includes a nozzle body (22), an upper flexible wall assembly (21), and a lower flexible wall assembly. The nozzle body (22) is a rectangular tube. The upper flexible wall assembly (21) includes a flexible wall panel (24) and several servo action units (23). One end of each servo action unit (23) is connected to the upper wall of the nozzle body (22). Several servo action units (23) are arranged at intervals along the airflow direction. The other end of each servo action unit (23) is set downward and connected to the flexible wall panel (24). The dry servo action unit (23) is electrically connected to the servo controller group (20) respectively. The nozzle controller (19) is connected to the servo controller group (20) via a real-time bus. The left and right ends of the flexible wall panel (24) are respectively slidably sealed to the left and right sides of the nozzle body (22). The upper flexible wall group (21) and the lower flexible wall group have the same structure and are symmetrical. An airflow channel is formed between the flexible wall panel (24) of the upper flexible wall group (21) and the flexible wall panel (24) of the lower flexible wall group.

2. The continuously variable pressure device for high-speed flutter testing according to claim 1, characterized in that: It also includes a central controller (27), which establishes signal connections with the nozzle controller (19) and the valve controller (28) respectively. The central controller (27) is electrically connected to the air source pressure sensor (13), the intake pressure sensor (14), the total pressure sensor (15), the static pressure sensor (16), the extraction pressure sensor (17), and the extraction main pipe pressure sensor (18) respectively. The valve controller (28) is electrically connected to the intake regulating valve (2), the intake shut-off valve (3), the pressure regulating valve (4), the extraction shut-off valve (8), the extraction regulating valve (9), and the replenishment regulating valve (11) respectively.

3. A continuous variable-speed pressure method for high-speed flutter testing, implemented using the continuous variable-speed pressure device for high-speed flutter testing as described in claim 2, characterized in that... Includes the following steps: Step 1: Perform simulation calculations, select the exit Mach numbers of n flexible wall nozzles (6) as target Mach numbers, and label the n target Mach numbers as M1, M2, M3...M n Then, the position profiles of the n flexible wall panels (24) corresponding one-to-one with the n target Mach numbers are successively named the first position profile, the second position profile, the third position profile, ... the nth position profile. All the position profiles are collectively referred to as the nozzle position profiles (29), and the correspondence between the target Mach number and the nozzle position profiles (29) is established. Step 2: Derive the formula relating the total pressure of the test section to the target Mach number. Since the total pressure of the stable section is equal to that of the test section, the static pressure of the test section (7) is calculated using the following formula: ； (1) In the formula, P0 is the total pressure of the stable section (5), P ct M is the static pressure of the test section (7), and M is the exit Mach number of the flexible wall nozzle (6). The velocity pressure Q of test section (7) is calculated by the following formula: ；(2) Combining equations (1) and (2), we have: ；(3) Step 3: Select the velocity pressure discrete values ​​of n test sections (7) as the target velocity pressure, and label them sequentially as Q1, Q2, Q3...Q n There is a one-to-one correspondence between the n target velocity pressures and the n target Mach numbers. By substituting the n pairs of target velocity pressures and target Mach numbers into equations (2) and (3) respectively, the n target static pressures P can be obtained. ct1 P ct2 P ct3 ...P ctn And the total pressure P of n targets 01 P 02 P 03 ...P 0n ; Step 4: Change the opening of the intake regulating valve (2) to adjust the downstream pressure P of the intake regulating valve (2). in The following conditions must be met: P in >1.2*P 0max ;(4) Among them, P 0max For the target total pressure P 01 P 02 P 03 ...P 0n The maximum value in; Then open the intake shut-off valve (3) to the fully open position; Step 5: Open the suction shut-off valve (8) to the fully open state, then change the opening of the suction regulating valve (9) to 60%, and change the opening of the replenishment regulating valve (11) to make the reading P of the suction pressure sensor (17) increase. out The following conditions must be met: P out <0.8*P ctmin ;(5) Among them, P ctmin For the target static pressure P ct1 P ct2 P ct3 ...P ctn The minimum value in; Step 6: Adjust the nozzle position profile (29) according to the first discrete value M1 in the target Mach number sequence, and then open the pressure regulating valve (4). Use PID control to make the actual total pressure of the test section (7) equal to the first discrete value P in the target total pressure sequence. 01 The PID control formula is: ；(6) in, K represents the opening increment of the pressure regulating valve (4) at time k. p For proportional gain, K i Let e(k) be the integral gain, e(k) be the real-time reading of the total pressure sensor (15) at time k, and e(k-1) be the target total pressure value P at time k-1. 01 Deviation; Step 7: Measure the actual static pressure at this time using the static pressure sensor (16); Step 8: Repeat steps 6 and 7 to complete the actual static pressure measurements at the remaining target Mach numbers, and label the n actual static pressures corresponding to the n target Mach numbers as P. sct1 P sct2 P sct3 ...P sct4 ; Step 9: There is a one-to-one correspondence between the n actual static pressures and the n target Mach numbers. Substituting the n pairs of actual static pressures and target Mach numbers into equation (2) in sequence, we can obtain the n actual velocity pressures Q. s1 Q s2 Q s3 ...Q sn Ultimately, the actual continuous speed change pressure curve is obtained.

Images