A zero-stiffness support wind tunnel test method, system and timing control method

Abstract

The embodiments of the present invention relate to the field of wind tunnel test technology, and in particular to a zero-stiffness support wind tunnel test method, system and timing control method, wherein the timing control method includes: determining the time length t1 from the wind tunnel membrane rupture to the establishment of an effective flow field; determining the time length t2 required from triggering the model release device to completely releasing the model; starting the pulse wind tunnel; measuring the signal at the membrane rupture moment through the membrane rupture pressure sensor, and starting from the moment when the pressure value measured by the membrane rupture pressure sensor reaches a preset pressure threshold, after a delay t, using a release instruction to trigger the model release device. The present invention can accurately match the model release control and the wind tunnel operation timing to achieve zero-stiffness support aerodynamic measurement.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of wind tunnel testing, and in particular to a zero-rigidity support wind tunnel testing method and a system and timing control method. Background Art

[0002] Pulse wind tunnels are important equipment for conducting ground tests of hypersonic aircraft flight environments. Hypersonic aircraft aerodynamic measurements usually involve installing an aircraft model in a pulse wind tunnel, generating a flow field that meets simulation conditions through the wind tunnel to act on the model, and then measuring the aerodynamic loads on the model.

[0003] Compared with the common tail support internal balance aerodynamic measurement technology, the zero-stiffness support aerodynamic measurement technology can effectively improve the frequency response and data credibility of the aerodynamic signal measurement in the wind tunnel test. However, since the model will move during the zero-stiffness support aerodynamic measurement test, and the effective test time of the pulse wind tunnel is very short, in order to accurately achieve the measurement, it is necessary to ensure that the model is in the ideal position in the effective flow field within the effective test time window of the wind tunnel. Therefore, how to accurately match the model release control and wind tunnel operation timing has become a problem that needs to be solved urgently. Summary of the invention

[0004] In order to achieve accurate matching of model suspension release control and wind tunnel operation timing in a wind tunnel zero-stiffness support aerodynamic measurement test, an embodiment of the present invention provides a zero-stiffness support wind tunnel test method, system and timing control method.

[0005] In a first aspect, an embodiment of the present invention provides a zero-stiffness support wind tunnel test timing control method, comprising:

[0006] The timing control method is applied to a wind tunnel test system including a pulse-type wind tunnel and a model releasing device; the pulse-type wind tunnel includes a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test chamber, an upstream membrane and a downstream membrane are respectively provided between the membrane cavity and the high-pressure section and the low-pressure section, the outlet end of the low-pressure section is connected to the nozzle, and a third membrane is provided at the outlet end; the pulse-type wind tunnel is also provided with a membrane rupture pressure sensor for measuring a signal at the moment of membrane rupture; the model releasing device is used to suspend the model to be measured at an optimal test position in the test chamber in a preset posture by using a suspension line, and release the suspension constraint on the model in response to a received release command, or, to place the model to be measured at an optimal test position in the test chamber in a preset posture by lifting, and to evacuate to release the model in response to a received release command;

[0007] The timing control method comprises the following steps:

[0008] Determine the time length t1 from wind tunnel membrane breaking to effective flow field establishment;

[0009] Determine the time length t2 required from triggering the model release device to completely releasing the model;

[0010] Opening the pulse wind tunnel;

[0011] The signal of the membrane rupture moment is measured by the membrane rupture pressure sensor, and the moment when the pressure value measured by the membrane rupture pressure sensor reaches the preset pressure threshold is taken as the starting point. After a delay t, the model release device is triggered by a release instruction; the delay t is determined based on the time length t1 from wind tunnel membrane rupture to establishment of an effective flow field and the time length t2 required from triggering the model release device to completely releasing the model.

[0012] Optionally, the optimal test position is the axis of the nozzle.

[0013] Optionally, determining the time length t1 from wind tunnel film breaking to effective flow field establishment includes:

[0014] Through repeated tests, the time length t1 from wind tunnel membrane breaking to the establishment of effective flow field is determined.

[0015] Optionally, if the model releasing device uses a suspension line to suspend the model to be measured at an optimal test position in the test chamber in a preset posture, and releases the suspension constraint on the model in response to a received release instruction, the model releasing device suspends the model to be measured through at least two vertical lines.

[0016] Optionally, the model releasing device releases the suspension constraint on the model in response to the received release instruction by means of a fuse.

[0017] Optionally, the rupture membrane pressure sensor is arranged on the downstream side of the downstream diaphragm and is located at the most upstream of the low-pressure section.

[0018] In the second aspect, an embodiment of the present invention further provides a zero-stiffness support wind tunnel test method, which is implemented based on a wind tunnel test system including a pulse wind tunnel and a model release device, and uses the zero-stiffness support wind tunnel test timing control method described in any of the above items to match the timing of wind tunnel operation and model release, so as to open the wind tunnel and release the model to be measured.

[0019] In a third aspect, an embodiment of the present invention further provides a zero-stiffness support wind tunnel test system for implementing the above-mentioned zero-stiffness support wind tunnel test method;

[0020] The system includes: a pulse wind tunnel, a model release device and a host computer;

[0021] The pulse-type wind tunnel comprises a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test chamber. An upstream membrane and a downstream membrane are respectively arranged between the membrane cavity and the high-pressure section and the low-pressure section. The outlet end of the low-pressure section is connected to the nozzle, and a third membrane is arranged at the outlet end. A membrane rupture pressure sensor is also arranged in the pulse-type wind tunnel for measuring the signal at the membrane rupture moment.

[0022] The model release device is used to suspend the model to be measured in a preset posture at the optimal test position in the test chamber by using a suspension line, and release the suspension constraint on the model in response to a received release command, or to place the model to be measured in a preset posture at the optimal test position in the test chamber by lifting, and evacuate to release the model in response to a received release command;

[0023] The host computer is connected to both the pulse type wind tunnel and the model release device, and is used to generate a corresponding opening instruction and send it to the pulse type wind tunnel to open the pulse type wind tunnel, and to generate a corresponding release instruction and send it to the model release device to trigger the model release device.

[0024] An embodiment of the present invention provides a timing control method for a zero-rigidity support wind tunnel test. The timing control method first turns on a pulse wind tunnel, determines the exact membrane rupture moment, and then delays triggering a model release device so that the model to be measured can be released at the optimal test position in the test chamber. The method can accurately match the model suspension release control and the wind tunnel operation timing, thereby ensuring that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel.

[0025] An embodiment of the present invention also provides a zero-stiffness support wind tunnel test method, which adopts the above-mentioned timing control method to match the model suspension release control and the wind tunnel operation timing. The pulse wind tunnel is first turned on, and then the model to be measured is placed in the test cabin in a preset posture by suspension release or lifting and evacuation, so as to realize the zero-stiffness support wind tunnel test. Since the model to be measured is in the optimal test position in the test cabin with a preset posture at the beginning, it is easy to match accurately, and the test success rate is high. Compared with the existing supported aerodynamic measurement technology, it can effectively improve the measurement frequency response and data credibility of the aerodynamic signal of the wind tunnel test.

[0026] An embodiment of the present invention also provides a zero-stiffness support wind tunnel test system for implementing the above-mentioned zero-stiffness support wind tunnel test method; the system includes a pulse-type wind tunnel, a model release device and a host computer; the host computer is connected to both the pulse-type wind tunnel and the model release device, and is used to generate corresponding opening instructions and send them to the pulse-type wind tunnel to open the pulse-type wind tunnel, and to generate corresponding release instructions and send them to the model release device to trigger the model release device, which can realize automated control, ensure that the model suspension release control and the wind tunnel operation timing match, so as to ensure that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel, thereby realizing a zero-stiffness support wind tunnel test. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a step diagram of a timing control method for a zero-stiffness support wind tunnel test method provided by an embodiment of the present invention;

[0029] Figure 2 It is a schematic diagram of the diaphragm structure used in the pulse wind tunnel;

[0030] Figure 3 It is a schematic diagram of the structure of a pulse wind tunnel;

[0031] Figure 4 The present invention provides a flow chart of a timing control method for a zero-stiffness support wind tunnel test method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0033] As mentioned above, pulse wind tunnels are important equipment for conducting ground tests of hypersonic aircraft flight environments. Hypersonic aircraft aerodynamic measurement tests usually involve installing an aircraft model in a pulse wind tunnel, generating a flow field that meets the simulation conditions through the wind tunnel to act on the model, and then measuring the aerodynamic loads on the model. Compared with the common tail support internal balance aerodynamic measurement technology, zero-stiffness support aerodynamic measurement technology can effectively improve the frequency response of wind tunnel test aerodynamic signal measurement and data credibility. One zero-stiffness support aerodynamic measurement technology is to place the model in a wind tunnel in a preset posture by hanging or lifting it, and then release the model by releasing the hanging or lifting structure, so that the model is in the wind tunnel flow field in the form of zero-stiffness support. Since the model will move and the effective test time of the pulse wind tunnel is very short, in order to accurately achieve measurement, it is necessary to ensure that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel. Considering that it takes a certain amount of time to release the model, and it also takes a certain amount of time from the opening of the wind tunnel to the establishment of an effective flow field, and the lengths of these two time periods are not equal, how to accurately match the model release control and wind tunnel operation timing has become an urgent problem to be solved. In view of this, the present invention provides a zero-stiffness support wind tunnel test timing control method, for the model suspension release or lifting release zero-stiffness support aerodynamic measurement test, through calculation and judgment, to achieve the matching of model release and wind tunnel operation, so that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel.

[0034] The specific implementation of the above concept is described below.

[0035] Please refer to Figures 1 to 3The embodiment of the present invention provides a timing control method for a zero-stiffness support wind tunnel test (hereinafter referred to as the timing control method), which is applied to a wind tunnel test system including a pulse-type wind tunnel and a model release device; the pulse-type wind tunnel includes a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test cabin, and an upstream diaphragm 1 and a downstream diaphragm 2 are respectively arranged between the membrane cavity and the high-pressure section and the low-pressure section (that is, an upstream diaphragm 1 is arranged between the membrane cavity and the high-pressure section, and a downstream diaphragm 2 is arranged between the membrane cavity and the low-pressure section), the model is connected to the high-pressure section through a membrane cavity valve, and / or the model is connected to the low-pressure section through a membrane cavity valve. Then, the outlet end of the low-pressure section is connected to the nozzle, and a third diaphragm 3 is provided at the outlet end. The high-pressure section is filled with high-pressure driving gas, and the low-pressure section is filled with low-pressure test gas. The inflation pressure in the membrane cavity is between the high-pressure section and the low-pressure section, that is, there is a pressure difference P1 between the high-pressure section and the membrane cavity, and there is a pressure difference P2 between the membrane cavity and the low-pressure section; before the wind tunnel is opened, the test chamber is in a vacuum state. After the wind tunnel is opened, the upstream diaphragm 1, the downstream diaphragm 2 and the third diaphragm 3 are all broken (that is, the wind tunnel membrane is broken), and the test gas is injected into the test chamber through the nozzle, forming an effective flow field for the test in the test chamber. The specific structure of the pulse-type wind tunnel can refer to the existing technology and will not be further described. The pulse-type wind tunnel is also provided with a membrane rupture pressure sensor for measuring the signal at the moment of membrane rupture. The model release device is used to suspend the model to be measured in the optimal test position in the test chamber with a preset posture by using a suspension line, and release the suspension constraint on the model in response to the received release command, or to place the model to be measured in the optimal test position in the test chamber with a preset posture by lifting, and evacuate to release the model in response to the received release command, so that the model is in the wind tunnel flow field in the form of zero-stiffness support. In other words, the model release device can adopt a suspension structure to suspend the model in the optimal test position, or a lifting structure to lift the model in the optimal test position. After receiving the release command, the suspension or lifting structure should be quickly released to avoid affecting the zero-stiffness support state of the model in the wind tunnel flow field.

[0036] The timing control method comprises the following steps:

[0037] Step 100, determining the time length t1 from the wind tunnel membrane breaking to the effective flow field establishment;

[0038] Step 102, determining the time length t2 required from triggering the model release device to completely releasing the model;

[0039] t2 is the time length required from the time when the model release device receives the release command to the time when the model completely exists in the flow field in the form of zero-stiffness support;

[0040] Step 104, starting the pulse wind tunnel;

[0041] This step 104 triggers the operation of the wind tunnel, which can be opened by inflating or deflation.

[0042] Step 106, measuring the signal of the membrane rupture moment by the membrane rupture pressure sensor, and starting from the moment when the pressure value measured by the membrane rupture pressure sensor reaches the preset pressure threshold, after a delay t, triggering the model release device by using a release instruction; the delay t is determined based on the time length t1 from the wind tunnel membrane rupture to the establishment of the effective flow field and the time length t2 required from triggering the model release device to completely releasing the model.

[0043] Step 106 triggers the model release device with a release command after a delay, thereby releasing the suspension constraint on the model. The delay t is determined based on the time length t1 from the wind tunnel membrane breaking to the establishment of an effective flow field and the time length t2 required from triggering the model release device to completely releasing the model. Preferably, t = t1-t2-Δt, Δt is the time consumed by signal acquisition, judgment, issuing commands and signal transmission, and Δt can be used to debug and calibrate the actual system before the test.

[0044] At the moment of membrane rupture, the pressure value measured by the membrane rupture pressure sensor will have a significantly increased peak, and the membrane rupture moment can be determined by a preset pressure threshold. The specific preset pressure threshold can be adjusted according to actual needs.

[0045] The timing control method provided by the present invention is applied to a wind tunnel test system including a pulse wind tunnel and a model release device, and the main purpose is to ensure that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel through timing control. The wind tunnel test system suspends or lifts the model to be measured in the test cabin in a preset posture. Considering that the starting point of releasing the model is at the optimal test position in the test cabin and the time required to release the model is usually short, the pulse wind tunnel is first turned on, and after a period of delay, the model release device is triggered, which can accurately match the model release control and the wind tunnel operation timing.

[0046] From the start of the pulse-type wind tunnel to the establishment of an effective flow field, it can be divided into two stages, the first stage is from the start of the pulse-type wind tunnel to the completion of membrane breaking, and the second stage is from the completion of membrane breaking to the establishment of an effective flow field. The time required for the completion of membrane breaking to the establishment of an effective flow field in stage two is generally relatively stable, with a deviation of the order of 0.1ms, while the time required for the start of the pulse-type wind tunnel to the completion of membrane breaking in stage one is related to the actual performance of the diaphragm used (i.e., the upstream diaphragm and the downstream diaphragm). Due to factors such as material uniformity and processing tolerance, there will be a certain deviation in the membrane breaking pressure difference between diaphragms of the same specification but different sizes, which will lead to a certain deviation in the membrane breaking time (i.e., the time required for stage one). The present invention first opens the wind tunnel, and uses a membrane breaking pressure sensor to identify the membrane breaking moment, thereby determining the exact moment of membrane breaking completion, and then triggers the model release after a delay. The implementation method is simple and reliable, which can avoid the uncertainties introduced in stage one and improve the success rate of the experiment. The model falls freely in a predetermined posture inside the wind tunnel. Since the model's displacement in the direction of gravity and the axial direction are very small in the initial stage of falling, the model can be approximately suspended in the flow field. In particular, the effective test time of the pulse wind tunnel is very short, and the aerodynamic load on the model in the uniform area of ​​the wind tunnel flow field can be considered to be constant.

[0047] Optionally, the optimal test position is the axis of the nozzle.

[0048] The flow field near the nozzle axis is highly uniform, so the best test position is usually set at or near the nozzle axis. The model is suspended on the nozzle axis in a preset posture, and the model can be considered to have almost no displacement at the initial release stage, which can ensure that the model will not deviate from the uniform effective flow field during the effective test time, and is also conducive to ensuring accurate matching of model release control and wind tunnel operation timing.

[0049] Optionally, step 100 further includes:

[0050] Through repeated tests, the time length t1 from wind tunnel membrane breaking to the establishment of effective flow field is determined.

[0051] Optionally, if the model releasing device uses a suspension line to suspend the model to be measured in a preset posture at the optimal test position in the test chamber, and releases the suspension constraint on the model in response to a received release instruction, the model releasing device suspends the model to be measured by at least two vertical lines.

[0052] Suspending the model to be measured by at least two vertical lines is conducive to keeping the model in a preset posture before being released, and when the suspension constraint on the model is released, the posture of the model will not be significantly affected.

[0053] Furthermore, the model release device releases the suspension constraint of the model in response to the received release command by means of fusing. That is to say, in order to achieve rapid suspension release, the model release device can disconnect the suspension wire by means of fusing, such as electric explosion wire and fuse. When the model release device suspends the model to be measured by multiple vertical lines, the fusing method can ensure that each vertical line breaks at the same time, avoiding the time of line breaking being misaligned. In other embodiments, the model release device can also cut the suspension wire.

[0054] Optionally, the rupture membrane pressure sensor is arranged on the downstream side of the downstream diaphragm 2, at the most upstream of the low-pressure section.

[0055] The above embodiment places the pressure sensor as close to the membrane cavity as possible, so that the moment of wind tunnel membrane rupture can be determined more accurately, thereby triggering the model release device in time with a release instruction.

[0056] In a specific embodiment, Figure 4 As shown, the time length t1=30ms from the rupture of the wind tunnel membrane to the establishment of the effective flow field is determined, and the time length t2=20ms from the triggering of the model release device to the complete release of the model is determined. When the test is triggered, the pulse wind tunnel is first turned on (i.e., the membrane rupture is triggered), and the membrane rupture is completed and the signal of the membrane rupture moment is measured by the membrane rupture pressure sensor. The moment when the pressure value measured by the membrane rupture pressure sensor reaches the preset pressure threshold is taken as the starting point. After a delay of t=t1-t2=10ms, the model release device is triggered to release the model.

[0057] The present invention also provides a zero-stiffness support wind tunnel test method, which is implemented based on a wind tunnel test system including a pulse wind tunnel and a model release device. The zero-stiffness support wind tunnel test method uses the zero-stiffness support wind tunnel test timing control method described in any of the above embodiments to match the timing of wind tunnel operation and model release, so as to open the wind tunnel and release the model to be measured.

[0058] The above-mentioned zero-stiffness support wind tunnel test method uses a suspension line to suspend the model to be measured in a preset posture at the optimal test position in the test chamber, and releases the suspension constraint on the model in response to the received release command, or, the model to be measured is placed in the optimal test position in the test chamber in a preset posture by lifting, and evacuates to release the model in response to the received release command. The timing of wind tunnel operation and model release is matched by the above-mentioned timing control method, which can effectively eliminate the time difference between the two actions of opening the wind tunnel and triggering the model, so as to ensure that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel, and the test success rate is high. Compared with the existing supported aerodynamic measurement technology, it can effectively improve the measurement frequency response and data credibility of aerodynamic signals in wind tunnel tests.

[0059] Preferably, the zero-stiffness support wind tunnel test method comprises the following steps:

[0060] Obtaining wind tunnel flow field parameters and model entity parameters of the model to be measured; the model is embedded with an accelerometer combination and an offline data acquisition device, the accelerometer combination includes a plurality of accelerometers, and the offline data acquisition device is connected to each of the accelerometers for acquiring and storing the measurement results of the accelerometers;

[0061] Based on the wind tunnel flow field parameters and the model entity parameters, estimating the magnitude of the aerodynamic force acting on the model in the wind tunnel flow field through finite element simulation;

[0062] Calculating the attitude angle variation range of the model in the wind tunnel flow field based on the estimated magnitude of the aerodynamic force on the model in the wind tunnel flow field, the model entity parameters and the effective test time of the wind tunnel flow field;

[0063] Determine whether the attitude angle change range of the model in the wind tunnel flow field does not exceed a preset angle change threshold, and if yes, continue;

[0064] Determine the accelerometer combination parameters embedded in the model; the accelerometer combination parameters include the final measurement parameters, installation positions, measurement ranges and measurement accuracy corresponding to each of the accelerometers; the final measurement parameters include one or more of axial force, normal force, lateral force, pitch moment, yaw moment and roll moment;

[0065] The timing control method for the zero-stiffness support wind tunnel test described in any one of the above embodiments is used to match the timing of the wind tunnel operation and the model release, so as to open the wind tunnel and release the model to be measured, so that the model falls freely in the wind tunnel flow field;

[0066] Recovering the model and obtaining measurement results of all the accelerometers within the effective test time;

[0067] Based on the obtained measurement results of all the accelerometers and the accelerometer combination parameters, the actual aerodynamic force exerted on the model in the wind tunnel flow field is solved.

[0068] The above embodiments take into account the lack of support structure, and the model has a higher degree of freedom in the flow field. In order to avoid obvious changes in the model's attitude, which leads to distortion of the measurement results, a preferred zero-rigidity support wind tunnel test method provided by the present invention first obtains the wind tunnel flow field parameters and the model entity parameters of the model to be measured, estimates the attitude angle changes that may occur in the model during the wind tunnel test, and compares them with the preset angle change threshold, so as to determine whether the current model is suitable for zero-rigidity support to measure aerodynamics, so as to obtain more accurate and reliable measurement results. The model to be measured is embedded with an accelerometer combination and an offline data acquisition device. The actual value of the final measurement parameter is calculated through the measurement results of the accelerometer combination, and the corresponding measurement results can be obtained without the need for obvious displacement of the model. The zero-rigidity support wind tunnel test method can break the frequency response limitation of the cantilever beam configuration and effectively improve the measurement frequency response. Compared with the frequency response of about 20Hz of the tail support internal balance aerodynamic measurement technology, the frequency response of the zero-rigidity support wind tunnel test method provided by the present invention can be increased to more than 1000Hz.

[0069] The present invention also provides a zero-stiffness support wind tunnel test system, which is used to implement the zero-stiffness support wind tunnel test method described in any one of the above embodiments; the system comprises: a pulse wind tunnel, a model release device and a host computer;

[0070] The pulse-type wind tunnel comprises a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test chamber. An upstream membrane and a downstream membrane are respectively arranged between the membrane cavity and the high-pressure section and the low-pressure section. The outlet end of the low-pressure section is connected to the nozzle, and a third membrane is arranged at the outlet end. A membrane rupture pressure sensor is also arranged in the pulse-type wind tunnel for measuring the signal at the membrane rupture moment.

[0071] The model release device is used to suspend the model to be measured in a preset posture at the optimal test position in the test chamber by using a suspension line, and release the suspension constraint on the model in response to a received release command, or to place the model to be measured in a preset posture at the optimal test position in the test chamber by lifting, and evacuate to release the model in response to a received release command;

[0072] The host computer is connected to both the pulse type wind tunnel and the model release device, and is used to generate a corresponding opening instruction and send it to the pulse type wind tunnel to open the pulse type wind tunnel, and to generate a corresponding release instruction and send it to the model release device to trigger the model release device.

[0073] By adopting the above embodiment, the host computer can be used to complete the zero-stiffness support wind tunnel test timing control method, so as to automatically execute the action of first opening the wind tunnel and then triggering the model release device. In addition, in the above embodiment, the zero-stiffness support wind tunnel test system used for measurement has a more compact structure and higher stiffness, which can reduce the interference of difficult-to-handle low-frequency interference on the model aerodynamic measurement signal, improve data credibility, and thus more accurately measure the millisecond-level instantaneous aerodynamic signal.

[0074] In summary, an embodiment of the present invention provides a timing control method for a zero-stiffness support wind tunnel test. The timing control method first turns on the pulse wind tunnel, determines the exact membrane rupture time, and then delays the triggering of the model release device so that the model to be measured can be released at the optimal test position in the test cabin. This method can accurately match the model suspension release control and the wind tunnel operation timing, thereby ensuring that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel.

[0075] An embodiment of the present invention also provides a zero-stiffness support wind tunnel test method, which adopts the above-mentioned timing control method to match the model suspension release control and the wind tunnel operation timing. The pulse wind tunnel is first turned on, and then the model to be measured is placed in the test cabin in a preset posture by suspension release or lifting and evacuation, so as to realize the zero-stiffness support wind tunnel test. Since the model to be measured is in the optimal test position in the test cabin with a preset posture at the beginning, it is easy to match accurately, and the test success rate is high. Compared with the existing supported aerodynamic measurement technology, it can effectively improve the measurement frequency response and data credibility of the aerodynamic signal of the wind tunnel test.

[0076] An embodiment of the present invention also provides a zero-rigidity support wind tunnel test method, which first estimates the attitude angle changes that may occur to the model during the wind tunnel test, and compares them with a preset angle change threshold, so as to determine whether the current model is suitable for zero-rigidity support form to measure aerodynamics, so as to obtain more accurate and reliable measurement results.

[0077] An embodiment of the present invention also provides a zero-stiffness support wind tunnel test system for implementing the above-mentioned zero-stiffness support wind tunnel test method; the system includes a pulse-type wind tunnel, a model release device and a host computer; the host computer is connected to both the pulse-type wind tunnel and the model release device, and is used to generate corresponding opening instructions and send them to the pulse-type wind tunnel to open the pulse-type wind tunnel, and to generate corresponding release instructions and send them to the model release device to trigger the model release device, which can realize automated control, ensure that the model suspension release control and the wind tunnel operation timing match, so as to ensure that the model is in an ideal position in the effective flow field within the effective test time window of the wind tunnel, thereby realizing a zero-stiffness support wind tunnel test.

[0078] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0079] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A timing control method for a zero-stiffness support wind tunnel test, characterized in that: The timing control method is applied to a wind tunnel test system including a pulse-type wind tunnel and a model releasing device; the pulse-type wind tunnel includes a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test chamber, an upstream membrane and a downstream membrane are respectively provided between the membrane cavity and the high-pressure section and the low-pressure section, the outlet end of the low-pressure section is connected to the nozzle, and a third membrane is provided at the outlet end; the pulse-type wind tunnel is also provided with a membrane rupture pressure sensor for measuring a signal at the moment of membrane rupture; the model releasing device is used to suspend the model to be measured at an optimal test position in the test chamber in a preset posture by using a suspension line, and release the suspension constraint on the model in response to a received release command, or, to place the model to be measured at an optimal test position in the test chamber in a preset posture by lifting, and to evacuate to release the model in response to a received release command; The timing control method comprises the following steps: Determine the time length t1 from wind tunnel membrane breaking to effective flow field establishment; Determine the time length t2 required from triggering the model release device to completely releasing the model; Opening the pulse wind tunnel; The signal of the membrane breaking moment is measured by the membrane breaking pressure sensor, and the moment when the pressure value measured by the membrane breaking pressure sensor reaches the preset pressure threshold is taken as the starting point, and after a delay t, the model release device is triggered by a release instruction; The delay t is determined based on the time length t1 from the breaking of the wind tunnel membrane to the establishment of the effective flow field and the time length t2 required from triggering the model release device to completely releasing the model.

2. The method according to claim 1, characterized in that: The optimal test position is the axis of the nozzle.

3. The method according to claim 1, characterized in that Determining the time length t1 from wind tunnel membrane breaking to effective flow field establishment includes: Through repeated tests, the time length t1 from wind tunnel membrane breaking to the establishment of effective flow field is determined.

4. The method according to claim 1, characterized in that: If the model releasing device uses a suspension line to suspend the model to be measured at the optimal test position in the test chamber in a preset posture, and releases the suspension constraint on the model in response to the received release instruction, the model releasing device suspends the model to be measured through at least two vertical lines.

5. The method according to claim 4, characterized in that The model release device releases the suspension constraint on the model in response to the received release instruction by means of a fuse.

6. The method according to claim 1, characterized in that The ruptured membrane pressure sensor is arranged on the downstream side of the downstream diaphragm and is located at the most upstream of the low-pressure section.

7. A zero-stiffness support wind tunnel test method, characterized in that: Based on a wind tunnel test system including a pulse wind tunnel and a model releasing device, the zero-stiffness support wind tunnel test timing control method described in any one of claims 1 to 6 is used to match the timing of wind tunnel operation and model release to open the wind tunnel and release the model to be measured.

8. A zero-stiffness support wind tunnel test system, characterized in that: Used to implement the zero-stiffness support wind tunnel test method described in claim 7; The system includes: a pulse wind tunnel, a model release device and a host computer; The pulse-type wind tunnel comprises a high-pressure section, a membrane cavity, a low-pressure section, a nozzle and a test chamber. An upstream membrane and a downstream membrane are respectively arranged between the membrane cavity and the high-pressure section and the low-pressure section. The outlet end of the low-pressure section is connected to the nozzle, and a third membrane is arranged at the outlet end. A membrane rupture pressure sensor is also arranged in the pulse-type wind tunnel for measuring the signal at the membrane rupture moment. The model release device is used to suspend the model to be measured in a preset posture at the optimal test position in the test chamber by using a suspension line, and release the suspension constraint on the model in response to a received release command, or to place the model to be measured in a preset posture at the optimal test position in the test chamber by lifting, and evacuate to release the model in response to a received release command; The host computer is connected to both the pulse type wind tunnel and the model release device, and is used to generate a corresponding opening instruction and send it to the pulse type wind tunnel to open the pulse type wind tunnel, and to generate a corresponding release instruction and send it to the model release device to trigger the model release device.

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