Subsonic static pressure control method for semi-recirculation wind tunnel

Abstract

The present invention discloses a subsonic static pressure control method for an ejection semi-recirculation temporary wind tunnel, which relates to the field of aerospace wind tunnel testing, including: in a subsonic step-by-step test, a static pressure control center calculates a gate finger displacement value based on a static pressure control algorithm. cf , and cf The gate finger displacement command is sent to the gate finger control driving system; the gate finger control driving system controls the gate finger to move in place based on the received gate finger displacement command, so as to adjust the static pressure disturbance by changing the gate finger displacement. The present invention provides a subsonic static pressure control method for an ejector semi-recirculation temporary impingement wind tunnel, which eliminates the delay of the gate finger adjusting the static pressure disturbance by controlling the gate finger displacement, shortens the time for the gate finger to adjust the static pressure disturbance, reduces the time to complete a test, and reduces energy consumption.

Description

Technical Field

[0001] The invention relates to the field of aerospace wind tunnel tests, and in particular to a subsonic static pressure control method of an ejection semi-recirculation temporary impulse wind tunnel used for a subsonic step test. Background Art

[0002] During the subsonic step test in the semi-recirculation wind tunnel, when the Mach number control deviation is less than the given range, the collected test data is valid data. Ma Calculation formula:

[0003]

[0004] in P 0 is the total pressure value of the stable section; P s is the static pressure value of the test chamber. From the formula, we can know that: Ma It is determined by the ratio of total pressure to static pressure. During the test, the Mach number is adjusted by adjusting the total pressure and static pressure, in which the total pressure is adjusted by the pressure regulating valve and the static pressure is adjusted by the test section gate finger, both of which adopt the PID control method. During the Mach number adjustment process of the subsonic step test in the wind tunnel, the total pressure control part: the total pressure control accuracy can be maintained within 0.1% throughout the whole process; the static pressure control part: when the model angle of attack changes, it immediately causes disturbances to the gas flow, and then interferes with the static pressure, causing the Mach number control deviation to exceed the given range. After the angle of attack begins to change for a period of time, the gate finger displacement begins to change, and the static pressure is adjusted to reduce the Mach number control deviation to a given range. From the Mach number adjustment process, it can be found that the total pressure can be considered to remain unchanged. The Mach number control deviation exceeds the given value range due to the delay in the gate finger adjusting the static pressure disturbance. The key to the adjustment of the Mach number control deviation is to eliminate the delay in the gate finger adjusting the static pressure disturbance.

[0005] Adjusting the static pressure by changing the displacement of the gate fingers can bring the Mach number control deviation back to a given range and meet the test data collection requirements. However, since the static pressure regulation adopts the PID control method, there is a lag in the regulation and the regulation time is relatively long, which ultimately leads to a longer time to complete a test and causes higher energy consumption. Summary of the invention

[0006] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0007] In order to achieve these purposes and other advantages of the present invention, a subsonic static pressure control method for a semi-recirculating wind tunnel is provided, comprising: during a subsonic step test, a static pressure control center calculates a gate finger displacement value based on a static pressure control algorithm. cf, and cf It is sent to the gate finger control drive system as a gate finger displacement instruction;

[0008] The gate finger control driving system controls the gate finger to move into position based on the received gate finger displacement instruction, so as to adjust the static pressure disturbance through the gate finger displacement change;

[0009] in, cf Use the following formula to obtain:

[0010]

[0011] In the above formula, f ( α ) is the static pressure disturbance correction function, f (∆ cf ) is the gate finger displacement correction value I at the current moment obtained based on the gate finger calculation, f (∆ P s ) is the gate finger displacement correction value II at the current moment calculated based on the static pressure.

[0012] Preferably, f ( α ) is obtained using the following formula:

[0013]

[0014] In the above formula, a i is the function parameter, α is the model angle of attack, i =1, …,6;

[0015] f (∆ cf ) is obtained using the following formula:

[0016]

[0017] In the above formula, k cf is the gate deviation correction coefficient, cf t is the real-time gate finger displacement value, cf h is the theoretical gate finger displacement value;

[0018] f (∆ P s ) is obtained using the following formula:

[0019]

[0020] In the above formula, ∆ Ps ( k ) is the difference between the actual static pressure and the target static pressure at the current moment, ∆ P s ( k- 1) is the difference between the actual static pressure and the target static pressure at the previous moment, k p and k i is the static pressure deviation correction factor.

[0021] Preferably, the process of applying the static pressure control algorithm to adjust the static pressure is:

[0022] S1. Setting the parameters of the static pressure control algorithm based on given test parameters;

[0023] S2. Run the model angle of attack to the initial angle of attack of the angle of attack sequence α 0 , and remain unchanged, the static pressure control center is based on cf The formula calculates the real-time gate finger displacement value, which is used to adjust the static pressure;

[0024] S3, based on the judgment of Mach number control deviation and static pressure deviation, to obtain the real-time gate finger displacement value cf 0t ;

[0025] S4, the static pressure control center calculates the next angle of attack value in the angle of attack sequence α 1 The corresponding theoretical gate finger displacement value cf 1 , and in α 0 After the corresponding test data are collected, the model angle of attack is changed from α 0 Run to α 1 At, synchronously run the gate finger to cf 1 Department;

[0026] S5, after the model angle of attack and the gate fingers are in place, the model angle of attack remains unchanged, and the static pressure control center is based on cf The formula calculates the real-time gate finger displacement value, which is used to adjust the static pressure;

[0027] S6. Determine whether the model angle of attack has been traversed. If not, return to S3. If so, determine whether to collect test data or continue to adjust the static pressure based on the Mach number control deviation.

[0028] Preferably, in S1, the test parameters include: target Mach number Ma , target total pressure P 0 , target static pressureP s , model angle of attack operation sequence [ α 0 , α 1 , …, α n ], Mach number control deviation range ∆ Ma , static pressure control deviation range ∆ P s .

[0029] Preferably, in S2, the method of adjusting the static pressure includes:

[0030] S20, α 0 The corresponding theoretical gate finger displacement value cf 0 = f ( α 0 ), move the gate finger to cf 0 At f (∆ cf )and f (∆ P s ) The gate finger displacement correction values ​​outputted are all set to 0;

[0031] S21. Start the wind tunnel, and adjust the total pressure to a given range by the pressure regulating valve. During the subsequent tests, the total pressure is maintained within the given range.

[0032] S22, the static pressure control center is based on the real-time actual static pressure value P st calculate f (∆ P s ), then the real-time gate finger displacement value output by the static pressure control center is cf t = f ( α 0 )+ f (∆ P st ), the gate finger control drive system moves the gate finger to cf t Adjust the static pressure.

[0033] Preferably, in S3, the real-time gate finger displacement value cf nt The way to obtain is:

[0034] S30, determining in real time whether the Mach number control deviation is less than ∆Ma, if so, collecting test data, otherwise continuing to adjust the static pressure;

[0035] S31, real-time determination of whether the static pressure deviation is less than ∆ P s If so, the current real-time gate finger displacement value cf t Model angle of attack α 0 Corresponding real-time gate finger displacement value cf 0t .

[0036] Preferably, in S4, cf 1 Obtained by the following formula:

[0037] cf 1 = f (α 1 )+ f (∆ cf 0 )

[0038] In the above formula, f (α 1 ) is α 1 The corresponding theoretical gate finger displacement value is, f (∆ cf 0 ) is the angle of attack α 0 At this time, the actual gate finger value and the calculated gate finger value are used to calculate the gate finger displacement correction amount I at the current moment.

[0039] Preferably, in S5, the real-time gate finger displacement value output by the static pressure control center is cf t Obtained by the following formula:

[0040] cf t = f (α 1 )+ f (∆ cf 0 )+ f (∆ P st )

[0041] In the above formula, f (∆ P st ) is the gate finger displacement correction value II at the current moment calculated based on the actual static pressure and the target static pressure.

[0042] The present invention includes at least the following beneficial effects: the wind tunnel static pressure control method adopted by the present invention can eliminate the delay of the gate fingers in adjusting the static pressure disturbance by controlling the displacement of the gate fingers, shorten the time for the Mach number control deviation to return to a given range (i.e. shorten the time to complete a test), and can effectively reduce energy consumption.

[0043] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is the principle diagram of the static pressure control method in the present invention;

[0045] Figure 2 It is a schematic diagram of the upper half of the static pressure control process of the present invention;

[0046] Figure 3 For Figure 2 A matching middle section flow chart;

[0047] Figure 4 For Figure 3 A matching middle section flow chart;

[0048] Figure 5 For Figure 4 Matching lower part of the process diagram. DETAILED DESCRIPTION

[0049] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0050] The devices involved in the static pressure control method of the present invention mainly include: a static pressure control center and a gate finger control drive system.

[0051] Static pressure control center: responsible for running the static pressure control algorithm based on the static pressure function relationship, collecting real-time feedback information such as wind tunnel static pressure, model angle of attack, and finger displacement, calculating the finger displacement control value in real time, and sending it to the finger control drive system, using NI's PXI embedded real-time controller (PXIe-8119);

[0052] Fingers control drive system: The fingers control PLC adopts Rexroth MLC L45, which is responsible for receiving the command from the static pressure control center, controlling the fingers to run to the given displacement value, collecting the real-time displacement value of the fingers and sending it to the static pressure control center; the fingers mechanism adopts hydraulic cylinder drive, and the hydraulic servo drive is connected to MLC L45 through Sercos3 bus.

[0053] During the subsonic step test in the semi-recirculation wind tunnel, the principle of the static pressure control method is as follows: Figure 1 As shown, the static pressure control center is based on the target Mach number Ma , target static pressure P s , and the model angle of attack α The gate finger displacement is calculated in real time based on the test parameters such as the actual static pressure value fed back, and the gate finger displacement instruction is sent to the gate finger control drive system to operate the gate finger to the calculated value. The gate finger displacement change adjusts the static pressure disturbance caused by the change of the model angle of attack, so that the actual static pressure value returns to the given range.

[0054] The factors affecting static pressure include model angle of attack and finger displacement. Static pressure disturbance is caused by the change of model angle of attack and eliminated by the change of finger displacement. During the test, the static pressure disturbance is adjusted by the finger displacement value calculated by the static pressure control algorithm. cf Obtained by the following formula:

[0055]

[0056]

[0057]

[0058]

[0059] In the formula, a i is the function parameter, k cf is the gate finger deviation correction coefficient, and its value range is [0,1], which can be determined through test debugging. cf t is the real-time gate finger displacement value, cf h is the theoretical finger displacement value, ∆ P s ( k ) is the difference between the actual static pressure and the target static pressure at the current moment, ∆ P s ( k- 1) is the difference between the actual static pressure and the target static pressure at the previous moment, k p and k i It is the static pressure deviation correction factor, which can be determined through test debugging.

[0060] f ( α ) is the static pressure disturbance correction function, that is, the model angle of attack runs to α , the corresponding gate finger displacement is cfWhen the static pressure reaches the target static pressure, f ( α ) can be obtained by converting the model angle of attack-static pressure transfer function and the gate finger displacement-static pressure transfer function. f ( α ) can calculate the theoretical displacement value of the gate finger corresponding to the model attack angle α. Due to the uncertain influencing factors in the test process, it is necessary to f ( α ) to correct the theoretical gate finger displacement value calculated, f (∆ cf )and f (∆ P s ) both output the gate finger displacement correction value, where f (∆ cf ) The gate finger displacement correction value I at the current moment is calculated by the difference between the actual gate finger value and the calculated gate finger value at a certain moment. f (∆ P s ) The gate finger displacement correction amount II at the current moment is calculated by the difference between the actual static pressure and the target static pressure at the current moment and the previous moment.

[0061] Example:

[0062] like Figures 2 - 5 As shown in the figure, in the subsonic step test of the semi-recirculation wind tunnel, the static pressure control process includes the following steps:

[0063] Step 1: Given the test parameters, including the target Mach number Ma , target total pressure P 0 , target static pressure P s , model angle of attack operation sequence [ α 0 , α 1 , …, α n ], Mach number control deviation range ∆ Ma , static pressure control deviation range ∆ P s ;

[0064] Step 2: The static pressure control center adjusts the target Mach number Ma and target total pressure P 0 , automatically set the static pressure control algorithm parameters;

[0065] Step 3: Run the model angle of attack to the initial angle of attack α 0 , and remain unchanged, the static pressure control center is based on cfFormula to calculate initial angle of attack α 0 The corresponding theoretical gate finger displacement value cf 0 = f ( α 0 ), move the gate finger to cf 0 At this time f (∆ cf ) and f (∆ P s ) The gate finger displacement correction values ​​outputted are all set to 0;

[0066] Step 4: Start the wind tunnel, and adjust the total pressure to a given range by the pressure regulating valve, and keep the total pressure within the given range during the subsequent tests;

[0067] Step 5: The static pressure control center will calculate the actual static pressure value based on the real-time static pressure value. P st calculate f (∆ P s ), real-time gate finger displacement value output by the static pressure control center cf t = f ( α 0 )+ f (∆ P st ), move the gate finger to cf t Adjust static pressure;

[0068] Step 6: Determine in real time whether the Mach number control deviation (the difference between the actual Mach number and the target Mach number) is less than ∆Ma. If it is less than ∆Ma, collect test data; otherwise, continue to adjust the static pressure.

[0069] Step 7: Real-time determination of static pressure deviation (the difference between actual static pressure and target static pressure). P s When the current real-time gate finger displacement value is cf t Model angle of attack α 0 Corresponding real-time gate finger displacement value cf 0t ;

[0070] Step 8: The static pressure control center sets the next value according to the model angle of attack sequence. α 1 , cf 0t and cf 0Calculate separately f (α 1 )and f (∆ cf 0 ), then the model angle of attack α 1 The corresponding theoretical gate finger displacement value cf 1 = f (α 1 )+ f (∆ cf 0 );

[0071] Step 9: Model Angle of Attack α 0 After the corresponding test data are collected, the model angle of attack is changed from α 0 Run to α 1 At, synchronously run the gate finger to cf 1 Department;

[0072] Step 10: When both are in place, the model angle of attack remains unchanged, and the static pressure control center adjusts the static pressure value according to the real-time actual static pressure value. P st calculate f (∆ P s ), real-time gate finger displacement value output by the static pressure control center cf t = f (α 1 )+ f (∆ cf 0 )+ f (∆ P st ), the gate finger control drive system adjusts the gate finger to run to cf t Adjust static pressure;

[0073] Step 11: According to the model angle of attack sequence, determine whether the model angle of attack is α n , not for α n , then repeat steps 5 to 9 in sequence;

[0074] Step 12: When the model angle of attack reaches α n When the Mach number control deviation is less than ∆Ma, it is judged in real time whether it is less than ∆Ma. If it is less than ∆Ma, the test data is collected, otherwise the static pressure is continued to be adjusted;

[0075] Step 13: After data collection is completed, the model returns to zero and the vehicle is shut down, ending the test.

[0076] From the above process, it can be seen that the present invention controls the displacement of the gate finger through the static pressure control method, eliminates the delay of the gate finger adjusting the static pressure disturbance, shortens the time of the gate finger adjusting the static pressure disturbance, reduces the time to complete a test, and reduces energy consumption.

[0077] The above solution is only an illustration of a preferred embodiment, but is not limited thereto. When implementing the present invention, appropriate replacement and / or modification can be performed according to user needs.

[0078] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A subsonic static pressure control method for a semi-recirculating wind tunnel, characterized in that: include: During the subsonic step test, the static pressure control center calculated the gate finger displacement value based on the static pressure control algorithm. cf , and cf It is sent to the gate finger control drive system as a gate finger displacement instruction; The gate finger control driving system controls the gate finger to move into position based on the received gate finger displacement instruction, so as to adjust the static pressure disturbance through the gate finger displacement change; in, cf Use the following formula to obtain: In the above formula, f ( α ) is the static pressure disturbance correction function, f (∆ cf ) is the gate finger displacement correction value I at the current moment obtained based on the gate finger calculation, f (∆ P s ) is the gate finger displacement correction value II at the current moment calculated based on the static pressure; f ( α ) is obtained using the following formula: In the above formula, a i is the function parameter, α is the model angle of attack, i =1, …,6; f (∆ cf ) is obtained using the following formula: In the above formula, k cf is the gate deviation correction coefficient, cf t is the real-time gate finger displacement value, cf h is the theoretical gate finger displacement value; f (∆ P s ) is obtained using the following formula: In the above formula, ∆ P s ( k ) is the difference between the actual static pressure and the target static pressure at the current moment, ∆ P s ( k- 1) is the difference between the actual static pressure and the target static pressure at the previous moment, k p and k i is the static pressure deviation correction factor; The process of applying the static pressure control algorithm to adjust the static pressure is as follows: S1. Setting the parameters of the static pressure control algorithm based on given test parameters; S2. Run the model angle of attack to the initial angle of attack of the angle of attack sequence α 0 , and remain unchanged, the static pressure control center is based on cf The formula calculates the real-time gate finger displacement value, which is used to adjust the static pressure; S3. Based on the judgment of Mach number control deviation and static pressure deviation, the real-time gate finger displacement value corresponding to the angle of attack is obtained. cf nt ; S4, the static pressure control center calculates the next angle of attack value in the angle of attack sequence α 1 The corresponding theoretical gate finger displacement value cf 1 , and in α 0 After the corresponding test data are collected, the model angle of attack is changed from α 0 Run to α 1 At, synchronously run the gate finger to cf 1 Department; S5, after the model angle of attack and the gate fingers are in place, the model angle of attack remains unchanged, and the static pressure control center is based on cf The formula calculates the real-time gate finger displacement value, which is used to adjust the static pressure; S6. Determine whether the model angle of attack has been traversed. If not, return to S3. If so, determine whether to collect test data or continue to adjust the static pressure based on the Mach number control deviation.

2. The subsonic static pressure control method of the ejection semi-recirculation temporary wind tunnel according to claim 1 is characterized in that: In S1, the test parameters include: target Mach number Ma , target total pressure P 0 , target static pressure P s , model angle of attack operation sequence [ α 0 , α 1 , …, α n ], Mach number control deviation range ∆ Ma , static pressure control deviation range ∆ P s .

3. The subsonic static pressure control method of the jet semi-recirculation temporary wind tunnel according to claim 1, characterized in that: In S2, the methods for adjusting static pressure include: S20, α 0 The corresponding theoretical gate finger displacement value cf 0 = f ( α 0 ), move the gate finger to cf 0 At f (∆ cf )and f (∆ P s ) The gate finger displacement correction values ​​outputted are all set to 0; S21. Start the wind tunnel, and adjust the total pressure to a given range by the pressure regulating valve. During the subsequent tests, the total pressure is maintained within the given range. S22, the static pressure control center is based on the real-time actual static pressure value P st calculate f (∆ P s ), then the real-time gate finger displacement value output by the static pressure control center is cf t = f ( α 0 )+ f (∆ P st ), the gate finger control drive system moves the gate finger to cf t Adjust the static pressure.

4. The subsonic static pressure control method of the ejection semi-recirculation temporary wind tunnel according to claim 1, characterized in that: In S3, the real-time gate displacement value cf nt The way to obtain is: S30, determining in real time whether the Mach number control deviation is less than ∆Ma, if so, collecting test data, otherwise continuing to adjust the static pressure; S31, real-time determination of whether the static pressure deviation is less than ∆ P s If so, the current real-time gate finger displacement value cf t Model angle of attack α 0 Corresponding real-time gate finger displacement value cf 0t .

5. The subsonic static pressure control method of the jet semi-recirculation temporary wind tunnel according to claim 1, characterized in that: In S4, cf 1 Obtained by the following formula: cf 1 = f (α 1 )+ f (∆ cf 0 ) In the above formula, f (α 1 ) is α 1 The corresponding theoretical gate finger displacement value is, f (∆ cf 0 ) is the angle of attack α 0 The gate finger displacement correction amount I at the current moment is obtained by calculating the actual gate finger value and the gate finger calculated value.

6. The subsonic static pressure control method of the jet semi-recirculation temporary wind tunnel according to claim 1, characterized in that: In S5, the real-time gate finger displacement value output by the static pressure control center cf t Obtained by the following formula: cf t = f (α 1 )+ f (∆ cf 0 )+ f (∆ P st ) In the above formula, f (∆ P st ) is the gate finger displacement correction value II at the current moment calculated based on the actual static pressure and the target static pressure.

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