Calibration device and calibration method of shock wave overpressure optical measurement system based on shock tube

Abstract

The present application relates to a kind of calibration device and calibration method of shock wave overpressure optical measurement system based on shock tube, it is related to the field of shock wave overpressure test, wherein the calibration device includes: standard shock tube, visible measuring unit;Visible measuring unit includes: transparent quartz tube, first piezoelectric sensor, second piezoelectric sensor, third piezoelectric sensor;Transparent quartz tube one end opening, the other end is closed and is arranged;In the direction from the opening end of transparent quartz tube to closed end, first piezoelectric sensor and second piezoelectric sensor have interval and are embedded in the side wall of transparent quartz tube;Third piezoelectric sensor is embedded in the center of the closed end of transparent quartz tube.This scheme can simply, reliably produce theoretical solvable or accurately measured impact wave overpressure of various shock waves propagation process, can accurately and reliably cross-verify and error determination to the impact wave overpressure obtained in optical measurement process, can accurately calibrate the system error of optical observation wave front propagation process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of shock wave overpressure test, and in particular to a calibration device and method for a shock wave overpressure optical measurement system based on a shock tube. BACKGROUND

[0002] When the shock wave propagates in the medium, it will cause a sudden change in the physical parameters such as pressure and density of the medium at the wave front. The shock wave overpressure (i.e. the difference between the peak pressure of the wave front and the ambient pressure) is a key criterion for studying the propagation law of the shock wave, solving the parameters of the shock wave, and evaluating its damage effect on the target. Therefore, it is of great significance to realize the accurate measurement of the shock wave overpressure.

[0003] The traditional shock wave overpressure measurement methods mainly include target plate method, pressure tank method, probe method, biological test method and electrical measurement method. These methods have many limitations: the target plate method and the probe method have insufficient accuracy; the pressure tank method is difficult to obtain quantitative parameters; the biological test method has ethical controversy; the most widely used electrical measurement method requires precise instruments and long leads, and is costly in a strong interference environment. In 2020, a shock wave overpressure optical measurement system was proposed. The system uses high-speed photography to record the propagation process of the shock wave, calculates the shock wave wave front propagation speed by the position change of the wave front in adjacent images, combines the local sound speed, air polytropic index and shock wave front pressure, and obtains the shock wave overpressure based on the fluid mechanics formula: Although the decay law of the overpressure obtained by this optical measurement method has high consistency with the empirical formula, the system still has many inherent defects:

[0004] 1. Its core relies on the fluid mechanics formula to establish the mapping relationship between the shock wave wave front propagation speed and the shock wave overpressure.

[0005] 2. There is no device to accurately generate and output the known standard shock wave overpressure in the experimental process, and the theoretical relationship cannot be verified and calibrated in practice.

[0006] 3. Due to the lack of effective calibration measures for the optical measurement method, the test results are prone to have large deviations, which limits the measurement accuracy and reliability.

[0007] Therefore, an effective calibration scheme is urgently needed for the shock wave overpressure optical measurement system to solve the problem of system deviation. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a calibration device and method for a shock wave overpressure optical measurement system based on a shock tube.

[0009] To achieve the above-mentioned application purpose, the present application provides a calibration device for a shock wave overpressure optical measurement system based on a shock tube, comprising: a standard shock tube, and a visual measurement unit connected with the standard shock tube.

[0010] The visual measurement unit is sealed and connected with the outlet end of the standard shock tube;

[0011] The visual measurement unit comprises a transparent quartz tube, a first piezoelectric sensor, a second piezoelectric sensor and a third piezoelectric sensor.

[0012] The transparent quartz tube is provided with an open end and a closed end.

[0013] The first piezoelectric sensor and the second piezoelectric sensor are embedded on the side wall of the transparent quartz tube with a spacing in the direction from the open end to the closed end of the transparent quartz tube.

[0014] The third piezoelectric sensor is embedded in the center of the closed end of the transparent quartz tube.

[0015] According to one aspect of the present application, the first piezoelectric sensor and the second piezoelectric sensor are arranged on the equidivision position of the transparent quartz tube in the direction from the open end to the closed end of the transparent quartz tube.

[0016] According to one aspect of the present application, the wall thickness of the tube body of the transparent quartz tube is consistent with the wall thickness of the closed end.

[0017] According to one aspect of the present application, the inner diameter d1 of the tube body of the transparent quartz tube is consistent with the inner diameter of the outlet end of the standard shock tube.

[0018] The outer diameter D1 of the tube body of the transparent quartz tube satisfies 0.2m<D1<0.6m.

[0019] The axial length of the transparent quartz tube is 1m.

[0020] According to one aspect of the present application, the standard shock tube comprises a high-pressure section and a low-pressure section connected coaxially, and a diaphragm arranged between the high-pressure section and the low-pressure section.

[0021] The high-pressure section comprises a tubular high-pressure section body, a fourth piezoelectric sensor mounted on the high-pressure section body, a high-pressure section air inlet pump and a high-pressure section air outlet pump connected with the high-pressure section body.

[0022] The high-pressure section body is a hollow tube body with an open end and a closed end.

[0023] The fourth piezoelectric sensor is embedded on the side wall of the high-pressure section body.

[0024] The high-pressure section air inlet pump is connected with the closed end of the high-pressure section body, and the high-pressure section air outlet pump is connected with the side wall of the high-pressure section body.

[0025] According to one aspect of the present application, the low-pressure section comprises: a tubular low-pressure section body, a low-pressure section intake pump and a low-pressure section exhaust pump connected to the low-pressure section body;

[0026] The low-pressure section body is a hollow pipe body with open ends;

[0027] The low-pressure section intake pump and the low-pressure section exhaust pump are respectively connected to the side wall of the low-pressure section body, and the connection positions are arranged with intervals;

[0028] The end of the low-pressure section body connected to the high-pressure section is adjacent to the low-pressure section exhaust pump, and the end of the low-pressure section body away from the high-pressure section is adjacent to the low-pressure section intake pump.

[0029] To achieve the above-mentioned purposes, the present application provides a calibration method of a shock wave overpressure optical measurement system based on a shock tube, which is realized based on a calibration device of the shock wave overpressure optical measurement system based on the shock tube and comprises the following steps:

[0030] S1. Aligning a high-speed camera of the shock wave overpressure optical measurement system to be calibrated with a visual measurement unit, and adjusting the relative position of the high-speed camera and the visual measurement unit so that the visual measurement unit is completely within the field of view of the high-speed camera;

[0031] S2. Controllably generating a standard shock wave propagating in the visual measurement unit by using a standard shock tube; wherein the standard shock wave is at least one of an incident shock wave and a reflected shock wave;

[0032] S3. Synchronously photographing the propagation process of the shock wave in the visual measurement unit by using the shock wave overpressure optical measurement system based on the high-speed camera, so as to obtain an optical measurement shock wave overpressure;

[0033] S4. Obtaining a verification shock wave overpressure of the propagation process of the shock wave in the visual measurement unit based on the initial condition of the standard shock wave generated by the standard shock tube and / or a piezoelectric sensor in the visual measurement unit;

[0034] S5. Obtaining a system error of the shock wave overpressure optical measurement system based on the optical measurement shock wave overpressure and the verification shock wave overpressure;

[0035] S6. Constructing a judgment index for evaluating the system error, and evaluating whether the system error is abnormal based on the judgment index; if yes, modifying the shock wave overpressure optical measurement system based on the system error; if no, judging that the output result of the shock wave overpressure optical measurement system is accurate.

[0036] According to one aspect of the present application, in step S3, the step of synchronously photographing the propagation process of the shock wave in the visual measurement unit by using the shock wave overpressure optical measurement system based on the high-speed camera to obtain the optical measurement shock wave overpressure comprises:

[0037] Based on the propagation process of the collected shock wave in the visual measurement unit, continuous wave front images are recorded;

[0038] The displacement of adjacent frames of the wave front images is extracted, and a first propagation speed of the shock wave wave front in the visual measurement unit is calculated;

[0039] A first functional relationship between the shock wave wave front speed and the shock wave overpressure is obtained, and the first propagation speed is brought in to calculate the optical measurement shock wave overpressure; wherein the first functional relationship is represented as:

[0040] ;

[0041] Wherein, represents the shock wave overpressure, represents the shock wave front area pressure, represents the particle motion speed, represents the initial sound speed, represents the multi-party index of the propagation medium, represents the shock wave wave front speed, which is used to bring in the value of the first propagation speed.

[0042] According to one aspect of the present application, in step S4, based on the initial conditions of the standard shock wave generated by the standard shock tube and / or the verification shock wave overpressure obtained by the piezoelectric sensor in the visual measurement unit during the propagation process of the shock wave in the visual measurement unit, if the verification shock wave overpressure is obtained based on the initial conditions of the standard shock wave generated by the standard shock tube, then the verification shock wave overpressure is the theoretical shock wave overpressure obtained by solving the one-dimensional Riemann problem based on the initial conditions of the standard shock tube;

[0043] If the verification shock wave overpressure is obtained based on the piezoelectric sensor in the visual measurement unit, then the verification shock wave overpressure has three kinds, and they are respectively: the first verification shock wave overpressure and the second verification shock wave overpressure;

[0044] If the verification shock wave overpressure is the first verification shock wave overpressure, then it is obtained based on the following steps, which include:

[0045] The time difference of the signal take-off point of the adjacent piezoelectric sensors and the distance between the adjacent piezoelectric sensors are collected;

[0046] Based on the obtained time difference and distance, a second propagation speed of the shock wave wave front in the visual measurement unit (2) is calculated;

[0047] A first functional relationship between the shock wave wave front speed and the shock wave overpressure is obtained, and the second propagation speed is brought in to calculate the first verification shock wave overpressure;

[0048] If the verification shock wave overpressure is the second verification shock wave overpressure, then it is directly obtained based on the signal data output by the piezoelectric sensor.

[0049] According to an aspect of the present application, in step S6, the step of constructing a decision index for evaluating the system error is represented as:

[0050] ;

[0051] ;

[0052] ;

[0053] wherein, represents the average deviation of the system error in the shock wave overpressure optical measurement system, represents the standard deviation of the system error in the shock wave overpressure optical measurement system, represents a confidence interval factor, which is obtained by looking up a table, represents the system error, represents the number of the system error, the subscript represents the serial number of the system error, and .

[0054] According to an aspect of the present application, the present scheme can simply and reliably generate various shock wave overpressures that can be theoretically solved or accurately measured in the process of shock wave propagation. Based on this, the shock wave overpressure obtained by the optical measurement process can be accurately and reliably cross-verified and error-determined, and the system error existing in the process of propagating the wave front observed by the optical observation can be effectively and accurately calibrated.

[0055] According to an aspect of the present application, the present scheme fully utilizes the advantages of the standard shock tube, such as good repeatability, high reliability, and accurate theoretical solution of the generated shock wave by solving the Riemann problem. The present scheme provides an ideal reference source for the calibration of the shock wave overpressure, and thus realizes the accurate calibration of the wave speed-overpressure relationship function obtained by the optical measurement system by synchronously recording the high-speed photographic image of the shock wave wave front and the electric measurement sensor signal, and takes into account the advantages of simplicity and precision.

[0056] According to an aspect of the present application, the present scheme provides a simple, reliable and high-precision calibration scheme, establishes the mapping function between the wave front propagation speed and the shock wave overpressure of the shock wave overpressure optical measurement system through experimental verification and correction, and thus significantly improves the measurement accuracy of the optical measurement shock wave overpressure system under different environmental conditions.

[0057] According to an aspect of the present application, the present scheme fully utilizes the advantages of the standard shock tube as a fast and accurate shock generator by optimizing and improving the standard shock tube, and thus achieves the accurate calibration of the shock wave overpressure optical measurement system, and provides a new idea for the calibration of the shock wave overpressure optical measurement system.

[0058] According to one scheme of the present application, the scheme can realize air in-situ calibration simultaneously by using theoretical solution and various methods of electric measuring sensor, the calibration process is more flexible, and the scheme with high reliability can be selected for comparison and verification according to actual situation, so that the correction accuracy of system error is greatly improved, and the calibration precision of the scheme is improved.

[0059] According to one scheme of the present application, the scheme adds an air inlet pump and an air outlet pump to the low-pressure section of the standard shock tube, which is beneficial to simulate different air pressures, temperatures and altitudes, quickly obtain the applicability of the optical shock wave overpressure testing device under different test conditions, greatly expand the calibration range of the optical shock wave overpressure testing system, and make the applicability of the scheme more extensive. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 The structure diagram of the calibration device of one embodiment of the present application is shown in the figure.

[0061] Figure 2 The principle diagram of the propagation process of the shock wave in the transparent quartz tube based on light measurement of one embodiment of the present application is shown in the figure.

[0062] Figure 3 The shock wave propagation wave system diagram in the standard shock tube of one embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0063] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor based on these drawings.

[0064] When describing the embodiments of the present application, the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" express the orientation or positional relationship based on the orientation or positional relationship shown in the relevant drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation of the present application.

[0065] The present application will be described in detail below in combination with the drawings and specific embodiments, and the embodiments cannot be described one by one here, but the embodiments of the present application are not limited to the following embodiments.

[0066] As Figure 1As shown, according to an embodiment of the present application, a calibration device of a shock wave overpressure optical measurement system based on a shock tube of the present application comprises: a standard shock tube 1, and a visual measurement unit 2 connected with the standard shock tube 1; in this embodiment, the standard shock tube 1 and the visual measurement unit 2 are coaxially arranged, wherein the standard shock tube 1 can controllably generate repetitive and reliable shock waves (shock waves) under different initial parameters, and the output end of the standard shock tube 1 is input into the visual measurement unit 2, and then the propagation process of the shock wave wavefront can be collected in multiple ways through the visual measurement unit 2, so that the calibration of the shock wave overpressure optical measurement system to be calibrated can be realized through the collection results.

[0067] In this embodiment, in order to realize the stable transmission of the shock wave wavefront generated by the standard shock tube 1 to the visual measurement unit 2, the visual measurement unit 2 is sealed and connected with the output end of the standard shock tube 1, so as to effectively avoid the leakage at the connection position during the propagation process of the shock wave wavefront, which is more beneficial to ensure the calibration accuracy of the present scheme.

[0068] In this embodiment, the visual measurement unit 2 comprises: a transparent quartz tube 21, a first piezoelectric sensor 22, a second piezoelectric sensor 23, and a third piezoelectric sensor 24; wherein the transparent quartz tube 21 is open at one end and closed at the other end; in this embodiment, the outside of the open end of the transparent quartz tube 21 is provided with a quartz tube connecting flange to facilitate the connection with the outlet end of the standard shock tube 1; specifically, a threaded connecting piece is used to connect the quartz tube connecting flange with the outlet end flange of the outlet end of the standard shock tube 1, and an annular sealing piece is arranged between the quartz tube connecting flange and the outlet end flange, so as to ensure the sealing property of the connection position. Further, in order to ensure the smoothness and continuity of the open end of the transparent quartz tube 21 and the outlet end of the standard shock tube 1 at the connection position, a certain embedded groove can be arranged between the quartz tube connecting flange and the outlet end flange to facilitate the installation of the annular sealing piece, and under the condition that the annular sealing piece can be reliably installed, the quartz tube connecting flange and the outlet end flange can be closely arranged, so as to realize the smoothness and continuity at the connection position, thereby ensuring the continuity and stability of the propagation process of the shock wave wavefront.

[0069] In the embodiment, the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are arranged at intervals on the side wall of the transparent quartz tube 21 in the direction from the open end to the closed end of the transparent quartz tube 21; wherein, the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are oppositely arranged along the length direction of the transparent quartz tube 21, and the first piezoelectric sensor 22 is arranged close to the open end of the transparent quartz tube 21, and the second piezoelectric sensor 23 is arranged close to the closed end of the transparent quartz tube 21, so that the accurate measurement of the shock wave wave front in the same direction of the propagation direction is realized, and the consistency and reliability of the measurement result are ensured. Further, the third piezoelectric sensor 24 is embedded in the center of the closed end of the transparent quartz tube 21, so that for the propagated shock wave wave front, the third piezoelectric sensor 24 can correspond to the center position of the shock wave wave front based on the structural symmetry of the transparent quartz tube 21, so that the effect of accurately collecting the shock wave wave front data at the closed end of the transparent quartz tube 21 can be achieved.

[0070] In the embodiment, in order to facilitate the installation of the piezoelectric sensor, three embedded mounting holes can be arranged on the circumferential side wall and the closed end side wall of the transparent quartz tube 21, wherein the hole diameter of the embedded mounting hole is matched with the radial dimension of the piezoelectric sensor, and a sealing structure can be further arranged at the connecting position to effectively ensure the air tightness of the whole transparent quartz tube 21, so as to be more beneficial to ensure the detection accuracy of the scheme. In addition, the end of the piezoelectric sensor extending into the transparent quartz tube 21 is arranged flush with the inner wall surface of the transparent quartz tube 21, so as to fully avoid the influence of the end of the piezoelectric sensor on the propagation of the shock wave wave front; and in order to further ensure the flatness between the end of the piezoelectric sensor extending into the transparent quartz tube 21 and the inner wall surface of the transparent quartz tube 21, a filling fixing glue or a pre-set corresponding filling structure can be used to further ensure the stable propagation of the shock wave wave front, so as to fully improve the calibration accuracy of the scheme.

[0071] As shown in Figure 1 According to an embodiment of the present application, the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are arranged at the equal division positions of the transparent quartz tube 21 in the direction from the open end to the closed end of the transparent quartz tube 21; specifically, the transparent quartz tube 21 is divided into three equal parts along the length direction of the transparent quartz tube 21, so that there are two mounting piezoelectric sensor hole positions in the direction from the open end to the closed end of the transparent quartz tube 21, and the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are sequentially embedded in the hole positions, so as to realize the accurate installation of the piezoelectric sensor.

[0072] As shown in Figure 1As shown, according to an embodiment of the present application, the tube wall thickness of the transparent quartz tube 21 is consistent with the thickness of the closed end wall; thus, the structural strength of the entire transparent quartz tube 21 is effectively ensured to be uniform, and the optical performance of the entire transparent quartz tube 21 is consistent based on the uniform thickness, so that the image precision and consistency collected by the high-speed camera in the shock wave overpressure optical measurement system are more beneficial to accurately obtain the system error of the shock wave overpressure optical measurement system.

[0073] As shown in the figure, Figure 1 As shown, according to an embodiment of the present application, the inner diameter d1 of the tube body of the transparent quartz tube 21 is consistent with the inner diameter of the outlet end of the standard shock wave tube 1; for ensuring the consistency between the internal dimensions of the standard shock wave tube 1, realizing the consistency of the shock wave wavefront transmission environment, and ensuring the accuracy of the calibration process.

[0074] As shown in the figure, Figure 1 As shown, according to an embodiment of the present application, the outer diameter D1 of the tube body of the transparent quartz tube 21 satisfies: 0.2m<D1<0.6m; and the axial length of the transparent quartz tube 21 is 1m.

[0075] Through the above setting, it is fully ensured that the transparent quartz tube 21 has sufficient space to realize the internal propagation of the shock wave wavefront, thereby fully ensuring the effectiveness of data acquisition.

[0076] As shown in the figure, Figure 1 As shown, according to an embodiment of the present application, the standard shock wave tube 1 comprises: a high-pressure section 11 and a low-pressure section 12 coaxially connected, and a diaphragm arranged between the high-pressure section 11 and the low-pressure section 12; wherein the high-pressure section 11 comprises: a tubular high-pressure section body 111, a fourth piezoelectric sensor 112 mounted on the high-pressure section body 111, a high-pressure section air inlet pump and a high-pressure section air outlet pump connected with the high-pressure section body 111; in this embodiment, the high-pressure section body 111 is a hollow tube body with one end open and the other end closed; specifically, the high-pressure section body 111 as a whole can be made of stainless steel, and a high-pressure section connecting flange can be arranged at the open end for facilitating installation with the low-pressure section 12. Further, the fourth piezoelectric sensor 112 is embedded on the side wall of the high-pressure section body 111 for detecting the pressure in the high-pressure section body 111, and the high-pressure section air inlet pump is connected with the closed end of the high-pressure section body 111, and the high-pressure section air outlet pump is connected with the side wall of the high-pressure section body 111; based on the high-pressure section air inlet pump and the high-pressure section air outlet pump, the dynamic and accurate control of the pressure in the high-pressure section body 111 is realized, and the accurate and repeated generation of the standard shock wave is effectively ensured.

[0077] As shown in the figure, Figure 1As shown, according to an embodiment of the present application, the low-pressure section 12 comprises: a tubular low-pressure section body 121, a low-pressure section intake pump and a low-pressure section exhaust pump connected to the low-pressure section body 121; wherein the low-pressure section body 121 is a hollow pipe body with both ends open, and the low-pressure section body 121 is also made of stainless steel; and the opposite ends of the low-pressure section body 121 are provided with low-pressure section connecting flanges, so that the low-pressure section connecting flanges can be connected to the high-pressure section 11 and the transparent quartz tube 21 respectively, effectively improving the installation convenience of the present application.

[0078] Further, the low-pressure section intake pump and the low-pressure section exhaust pump are connected to the side wall of the low-pressure section body 121, and the connection positions are spaced apart; specifically, the end of the low-pressure section body 121 connected to the high-pressure section 11 is adjacent to the low-pressure section exhaust pump, and the end of the low-pressure section body 121 away from the high-pressure section 11 is adjacent to the low-pressure section intake pump.

[0079] Further, the low-pressure section intake pump and the low-pressure section exhaust pump can be externally connected to cooling facilities for regulating the air pressure and air temperature in the low-pressure section 12 and the visual measurement unit 2, that is, the environment under different temperature and air pressure conditions (such as a conventional environment and a highland environment) can be fully simulated, so that the calibration accuracy of the present application is more excellent, and the scenarios that can be adapted are more flexible and extensive.

[0080] In the present embodiment, a diaphragm is mounted between the high-pressure section 11 and the low-pressure section 12, which can be locked and fixed between the high-pressure section 11 and the low-pressure section 12 in a clamped diaphragm structure, or directly fixed based on the connecting flanges between the high-pressure section 11 and the low-pressure section 12. Thus, the high-pressure section 11 can be closed based on the diaphragm, so that the formation of a standard shock wave in the standard shock tube 1 can be realized while the diaphragm is ruptured by controlling the size of the air pressure in the high-pressure section 11 and the characteristics (such as thickness and material) of the diaphragm.

[0081] In the present embodiment, the diaphragm can be a PET film. The diaphragm has good mechanical properties, the impact strength is 3-5 times that of other films, has good folding resistance, oil resistance, acid and alkali resistance, resistance to most solvents, low gas and water vapor permeability, excellent air, water, oil and odor resistance, non-toxic, odorless, and good sanitary safety.

[0082] According to an embodiment of the present application, a calibration method of a shock wave overpressure optical measurement system based on a shock tube, which is realized based on the calibration device of the shock wave overpressure optical measurement system based on a shock tube, and comprises the following steps:

[0083] S1. Align the high-speed camera of the shock wave overpressure optical measurement system to be calibrated with the visual measurement unit 2, and adjust the relative position of the high-speed camera and the visual measurement unit 2 so that the visual measurement unit 2 is completely within the field of view of the high-speed camera.

[0084] S2. A standard shock wave is generated by a controlled standard shock tube 1 and propagates in a visual measurement unit 2; wherein the standard shock wave is at least one of an incident shock wave and a reflected shock wave;

[0085] S3. The shock wave overpressure optical measurement system is based on a high-speed camera to simultaneously capture the propagation process of the shock wave in the visual measurement unit 2, so as to obtain the optical measurement of the shock wave overpressure.

[0086] S4. Verification of shock wave overpressure based on the initial conditions for generating a standard shock wave using a standard shock tube 1 and / or the propagation process of the shock wave within the visual measurement unit 2 obtained by the piezoelectric sensor in the visual measurement unit 2;

[0087] S5. Obtain the system error of the shock wave overpressure optical measurement system based on optical measurement of shock wave overpressure and verification of shock wave overpressure;

[0088] S6. Construct a judgment index for evaluating system error, and evaluate whether the system error is abnormal based on the judgment index. If it is abnormal, correct the shock wave overpressure optical measurement system based on the system error. If not, determine that the output result of the shock wave overpressure optical measurement system is accurate.

[0089] like Figure 1 As shown, according to one embodiment of the present invention, in step S1, in the step of aligning the high-speed camera of the shock wave overpressure optical measurement system to be calibrated with the visual measurement unit 2 and adjusting the relative position of the high-speed camera and the visual measurement unit 2 so that the visual measurement unit 2 is completely within the field of view of the high-speed camera, the high-speed camera and the transparent quartz tube 21 of the visual measurement unit 2 can be arranged at intervals facing each other, and the orientation of the high-speed camera is different from the installation direction of the first piezoelectric sensor 22 and the second piezoelectric sensor 23 (for example, the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are installed in the vertical direction, while the orientation of the high-speed camera is in the horizontal direction). This can fully avoid the influence of the first piezoelectric sensor 22 and the second piezoelectric sensor 23 on the acquired image, which is more beneficial for accurately identifying the position of the shock wave front.

[0090] like Figure 1As shown, according to an embodiment of the present application, in the step of controlling the standard shock tube 1 to generate a standard shock wave propagating in the visual measurement unit 2, the initial conditions of the standard shock tube 1 can be set according to the intensity of the shock wave to be generated, wherein the initial conditions are: the pressure of the high-pressure gas injected into the high-pressure section 11, the pressure of the low-pressure gas injected into the low-pressure section 12, the type of the high-pressure gas, and the type of the low-pressure gas. In this embodiment, the pressure difference between the pressure of the high-pressure gas and the pressure of the low-pressure gas is just enough to make the diaphragm rupture, and at the same time of the diaphragm rupture, a stable standard shock wave is formed in the low-pressure section 12 and transmitted into the transparent quartz tube 21 of the visual measurement unit 2.

[0091] In this embodiment, the standard shock wave is at least one of an incident shock wave and a reflected shock wave; wherein the incident shock wave is a shock wave propagating from the open end to the closed end of the transparent quartz tube 21, and the reflected shock wave is a shock wave transmitted from the incident shock wave to the closed end of the transparent quartz tube 21 and propagating from the closed end to the open end.

[0092] According to an embodiment of the present application, in the step of synchronously capturing the propagation process of the shock wave in the visual measurement unit 2 by the high-speed camera to obtain the light-measured shock wave overpressure, the high-speed camera collects the propagation process of the shock wave at a preset shooting frame rate, and it includes:

[0093] Based on the collected propagation process of the shock wave in the visual measurement unit 2, continuous wave front images are recorded; in this embodiment, the continuous wave front images are obtained based on an image difference algorithm or an edge recognition algorithm.

[0094] The adjacent frame displacement of the wave front image is extracted, and the first propagation speed of the shock wave wave front in the visual measurement unit 2 is calculated; in this embodiment, since the preset shooting frame rate of the wave front image is fixed, the first propagation speed of the shock wave wave front in the visual measurement unit 2 can be obtained based on the extracted adjacent frame displacement and combined with the corresponding preset shooting frame rate; see Figure 2 As shown, it shows the propagation process of the shock wave in the transparent quartz tube 21 based on Ls-Dyna simulation. Assuming that at time and , the wave fronts of the incident shock wave are located at and respectively, then the first propagation speed of the shock wave wave front can be expressed as .

[0095] In the embodiment, when the first propagation speed of the incident shock wave is needed to be collected, the first function relation between the shock wave front speed and the shock wave overpressure is obtained based on the wave front image of the incident propagation process, and when the first propagation speed of the reflected shock wave is needed to be collected, the first function relation between the shock wave front speed and the shock wave overpressure is obtained based on the wave front image of the reflected propagation process, and the reflected propagation process starting from the closed end of the transparent quartz tube 21 can be used for calculation.

[0096] The first function relation between the shock wave front speed and the shock wave overpressure is obtained, and the first propagation speed is brought in to calculate the light-measured shock wave overpressure; wherein the first function relation is expressed as:

[0097] (1)

[0098] wherein, represents the shock wave overpressure, represents the shock wave front zone pressure, represents the particle motion speed, represents the initial sound speed, represents the polytropic index of the propagation medium, represents the shock wave front speed, which is used to bring in the value of the first propagation speed.

[0099] According to an embodiment of the present application, in step S4, based on the initial condition of the standard shock wave generated by the standard shock tube 1 and / or the piezoelectric sensor in the visual measurement unit 2, the step of obtaining the verification shock wave overpressure of the propagation process of the shock wave in the visual measurement unit 2, if the verification shock wave overpressure is obtained based on the initial condition of the standard shock wave generated by the standard shock tube 1, the verification shock wave overpressure is the theoretical shock wave overpressure obtained by solving the one-dimensional Riemann problem based on the initial condition of the standard shock tube 1; wherein the theoretical shock wave overpressure is the theoretical incident shock wave overpressure or the theoretical reflected shock wave overpressure;

[0100] In the embodiment, the wave system diagram of the standard shock tube 1 can be known based on the theoretical solvability of the standard shock tube 1, that is, Figure 3 as shown, for the incident shock wave, when the pressure of the high-pressure gas initially injected in the high-pressure section 11 is , and the pressure of the low-pressure gas initially injected in the low-pressure section 12 is , the diaphragm breaks, and the shock wave generated in the low-pressure section 12 is , which can be solved by the following equation:

[0101] (2)

[0102] wherein, represents the sound speed of the high-pressure gas, represents the specific heat ratio of the high-pressure gas, represents the post-shock pressure of the incident shock wave, represents the pressure of the high-pressure gas, represents the pressure of the low-pressure gas, represents the specific heat ratio of the low-pressure gas, represents the initial density of the low-pressure gas.

[0103] As can be seen from equation (2), where only the post-shock pressure of the incident shock wave is an unknown quantity, which can be solved accurately, and thus, equation (2) can be solved accurately based on the initial conditions of the standard shock tube 1, and further, based on the obtained post-shock pressure of the incident shock wave , the theoretical incident shock wave overpressure can be obtained, and is represented as: .

[0104] Further, for the reflected shock wave, after the post-shock pressure of the incident shock wave is calculated, the wall surface of the closed end of the transparent quartz tube 21 is regarded as a rigid wall surface, and then the post-shock pressure of the reflected shock wave can be calculated by the following equation:

[0105] (3)

[0106] wherein, represents the post-shock pressure of the reflected shock wave, represents the post-shock pressure of the shock wave.

[0107] Further, based on the obtained post-shock pressure of the reflected shock wave , the theoretical reflected shock wave overpressure can be obtained, and is represented as: .

[0108] In the present embodiment, if the calibration shock wave overpressure is obtained based on the piezoelectric sensor in the visual measurement unit 2, the calibration shock wave overpressure has three kinds, and are respectively: the first calibration shock wave overpressure and the second calibration shock wave overpressure.

[0109] If the calibration shock wave overpressure is the first calibration shock wave overpressure, wherein the first calibration shock wave overpressure is the first calibration incident shock wave overpressure or the first calibration reflected shock wave overpressure; it is obtained based on the following steps, which includes:

[0110] The time difference of the signal jump point of the adjacent piezoelectric sensor and the interval of the adjacent piezoelectric sensor are collected; in the embodiment, for the incident shock wave, since the propagation direction of the incident shock wave is from the open end of the transparent quartz tube 21 to the closed end, the time difference of the signal jump point of the first piezoelectric sensor 22 and the second piezoelectric sensor 23 is collected in sequence, so that the propagation time of the incident shock wave front can be obtained, and since the first piezoelectric sensor 22 and the second piezoelectric sensor 23 are installed at the bisecting position of the transparent quartz tube 21, the interval between the first piezoelectric sensor 22 and the second piezoelectric sensor 23 is also fixed.

[0111] For the reflected shock wave, since the propagation direction of the reflected shock wave is from the closed end of the transparent quartz tube 21 to the open end, the time difference of the first signal jump point of the third piezoelectric sensor 24 and the second signal jump point of the second piezoelectric sensor 23 is collected in sequence, so that the propagation time of the reflected shock wave front can be obtained, and since the second piezoelectric sensor 23 is installed at the bisecting position of the transparent quartz tube 21 and the third piezoelectric sensor 24 is installed at the end of the transparent quartz tube 21, the interval between the third piezoelectric sensor 24 and the second piezoelectric sensor 23 is also fixed.

[0112] Based on the obtained time difference and interval, the second propagation speed of the shock wave front in the visible measuring unit 2 is calculated; wherein the corresponding second propagation speed can be obtained based on the ratio of the interval to the time difference; in the embodiment, if the interval between the first piezoelectric sensor 22 and the second piezoelectric sensor 23 and the time difference of the signal jump point are used, the second propagation speed of the incident shock wave is obtained; if the interval between the third piezoelectric sensor 24 and the second piezoelectric sensor 23 and the time difference of the signal jump point are used, the second propagation speed of the reflected shock wave is obtained.

[0113] The first function relationship between the shock wave front speed and the shock wave overpressure is obtained, and the second propagation speed is brought in to calculate the first verification shock wave overpressure; wherein if the second propagation speed of the incident shock wave is brought in, the first verification incident shock wave overpressure is obtained, and if the second propagation speed of the reflected shock wave is brought in, the first verification reflected shock wave overpressure is obtained.

[0114] In the embodiment, if the verification shock wave overpressure is the second verification shock wave overpressure, it is directly obtained based on the signal data output by the piezoelectric sensor; wherein the second verification shock wave overpressure is the second verification incident shock wave overpressure or the second verification reflected shock wave overpressure; specifically, for the incident shock wave, the second verification incident shock wave overpressure is represented by the signal peak value of the first piezoelectric sensor 22 and the second piezoelectric sensor 23, and the second verification reflected shock wave overpressure is represented by the signal peak value of the third piezoelectric sensor 24.

[0115] According to one embodiment of the present application, in step S5, the system error of the shock wave overpressure optical measurement system is obtained based on the optical measurement shock wave overpressure and the calibration shock wave overpressure, and the system error calculation formula for the incident shock wave and the reflected shock wave is consistent, but the data used is different. For the incident shock wave, the system error is obtained based on the optical measurement shock wave overpressure and the calibration shock wave overpressure obtained in the transmission process of the incident shock wave. For the reflected shock wave, the system error is obtained based on the optical measurement shock wave overpressure and the calibration shock wave overpressure obtained in the transmission process of the reflected shock wave. Specifically, for the incident shock wave, the system error is represented as:

[0116] ;

[0117] wherein, represents the system error, represents the optical measurement shock wave overpressure of the incident shock wave obtained based on the first function relationship, represents the calibration shock wave overpressure of the incident shock wave, which specifically adopts at least one of the theoretical incident shock wave overpressure, the first calibration incident shock wave overpressure, and the second calibration incident shock wave overpressure, and subscript represents the type mark of the calibration shock wave overpressure of the incident shock wave, and when the value is 1, it represents the theoretical incident shock wave overpressure, when the value is 2, it represents the first calibration incident shock wave overpressure, and when the value is 3, it represents the second calibration incident shock wave overpressure, and subscript represents the mark of the obtained optical measurement shock wave overpressure and calibration shock wave overpressure;

[0118] For the reflected shock wave, the system error is represented as:

[0119] ;

[0120] wherein, represents the system error, represents the optical measurement shock wave overpressure of the reflected shock wave obtained based on the first function relationship, represents the calibration shock wave overpressure of the reflected shock wave, which specifically adopts at least one of the theoretical reflected shock wave overpressure, the first calibration reflected shock wave overpressure, and the second calibration reflected shock wave overpressure, represents the type mark of the calibration shock wave overpressure of the reflected shock wave, and when the value is 1, it represents the theoretical reflected shock wave overpressure, when the value is 2, it represents the first calibration reflected shock wave overpressure, and when the value is 3, it represents the second calibration reflected shock wave overpressure, and subscript represents the mark of the obtained optical measurement shock wave overpressure and calibration shock wave overpressure.

[0121] According to one embodiment of the present application, in step S6, the step of constructing the judgment index for evaluating the system error comprises:

[0122] According to the obtained system error , the average deviation of the shock wave overpressure optical measurement system to be calibrated and the standard deviation are calculated, so that the determination index of the system error of the shock wave overpressure optical measurement system to be calibrated can be obtained based on the average deviation and the standard deviation, which is expressed as: .

[0123] Therefore, the determination index is expressed as:

[0124] ;

[0125] ;

[0126] ;

[0127] wherein represents the average deviation of the system error in the shock wave overpressure optical measurement system, represents the standard deviation of the system error in the shock wave overpressure optical measurement system, represents a confidence interval factor, which is obtained by looking up a table, represents the system error, represents the number of the system error, and the subscript represents the serial number of the system error, and .

[0128] Further, based on the statistical principle, it can be analyzed and determined whether the system error is abnormal (i.e., whether the system error exists and / or deviates from the preset value), if it is abnormal, the shock wave overpressure optical measurement system is corrected based on the system error, if not, it is determined that the output result of the shock wave overpressure optical measurement system is accurate.

[0129] In the embodiment, the determination index can be compared with a preset threshold to determine whether the system error is abnormal.

[0130] Through the above setting, the present scheme can flexibly select the system error involved in the obtained determination index to accurately calibrate the entire shock wave overpressure optical measurement system, effectively improving the calibration accuracy and effectiveness of the present scheme.

[0131] In the embodiment, if the system error of the shock wave overpressure optical measurement system is abnormal, the system error is corrected based on the following steps, specifically including:

[0132] Based on the shock wave overpressure optical measurement system, a series of optical measurement shock wave overpressures under different preset environments are obtained ;

[0133] A series of calibration shock wave overpressures corresponding to the photo-measured shock wave overpressures are obtained in the process of collecting the photo-measured shock wave overpressures by the photo-measurement system of shock wave overpressure . The calibration shock wave overpressures adopt at least one of the theoretical reflected shock wave overpressure, the first calibration reflected shock wave overpressure and the second calibration reflected shock wave overpressure.

[0134] A coordinate system is established with the different environments as the horizontal coordinates and the shock wave overpressures as the vertical coordinates, and the series of photo-measured shock wave overpressures and the calibration shock wave overpressures are unified into the coordinate system to form at least two two-dimensional data point graphs, one of which is formed based on the photo-measured shock wave overpressures and the rest of the two-dimensional data point graphs are formed based on the calibration shock wave overpressures The number of data types adopted generates the two-dimensional data point graphs (for example, if only the theoretical reflected shock wave overpressure is adopted, there is only one two-dimensional data point graph, and if the theoretical reflected shock wave overpressure, the first calibration reflected shock wave overpressure and the second calibration reflected shock wave overpressure are adopted in combination, there are two or three two-dimensional data point graphs).

[0135] Based on the line trends of the different data points, it is determined whether there is a linear or high-order systematic error, and the shock wave front speed in the first function relationship is corrected by the following high-order polynomial form, so that the absolute error between the photo-measured result of the shock wave overpressure photo-measurement system and the theoretical solution is minimized; wherein the high-order polynomial form is:

[0136] .

[0137] wherein, , , , are fitting coefficients, is the order, which can be selected based on the fitting degree between the different data points (i.e., the photo-measured shock wave overpressures and the calibration shock wave overpressures ), and is a constant.

[0138] In this embodiment, a set of , , , with the minimum fitting error is obtained through the fitting process between the different data points based on the set high-order polynomial form, and the error correction can be realized by inputting the set into the shock wave overpressure photo-measurement system.

[0139] To further illustrate the scheme, further examples are provided.

[0140] Embodiment 1

[0141] For the incident shock wave:

[0142] S1. Align the high-speed camera of the shock wave overpressure optical measurement system to be calibrated with the visual measurement unit 2, and adjust the relative position of the high-speed camera and the visual measurement unit 2 so that the visual measurement unit 2 is completely within the field of view of the high-speed camera; in this embodiment, the parameters of the high-speed camera are obtained based on the shock wave overpressure optical measurement system to be calibrated, and are set in the simulation environment.

[0143] S2. The standard shock wave propagating in the visual measurement unit 2 is generated by the standard shock tube 1 under control; wherein the standard shock wave is at least one of the incident shock wave and the reflected shock wave; in this embodiment, different initial conditions of the standard shock tube 1 can be changed to generate standard shock waves of different intensities (covering the expected overpressure range), thereby realizing full-range calibration of the shock wave overpressure optical measurement system to be calibrated, and fully improving the calibration comprehensiveness and accuracy of the present scheme.

[0144] S3. The shock wave overpressure optical measurement system synchronously photographs the propagation process of the shock wave in the visual measurement unit 2 based on the high-speed camera to obtain the optical measurement shock wave overpressure; in this embodiment, the optical measurement shock wave overpressure of the incident shock wave obtained by the shock wave overpressure optical measurement system to be calibrated can be expressed as: , , .

[0145] S4. Based on the initial condition of the standard shock wave generated by the standard shock tube 1 and / or the verification shock wave overpressure of the propagation process of the shock wave in the visual measurement unit 2 obtained by the piezoelectric sensor in the visual measurement unit 2; in this embodiment, the obtained verification shock wave overpressure adopts a combination mode of the theoretical incident shock wave overpressure and the second verification incident shock wave overpressure, wherein the theoretical incident shock wave overpressure can be expressed as: , , , and the second verification incident shock wave overpressure can be expressed as: , , .

[0146] S5. Obtain the system error of the shock wave overpressure optical measurement system based on the optical measurement shock wave overpressure and the verification shock wave overpressure; in this embodiment, the obtained system error can be expressed as:

[0147] .

[0148] S6. Constructing a judgment index for evaluating system error, and evaluating whether the system error is abnormal based on the judgment index, if yes, correcting the shock wave overpressure optical measurement system based on the system error, if no, judging that the output result of the shock wave overpressure optical measurement system is accurate; in the embodiment, one system error can be used for constructing the judgment index, or multiple system errors can be used for constructing the judgment index, and the specific construction manner is consistent with the foregoing steps, and thus is not described herein.

[0149] The system error can be evaluated based on the obtained judgment index, and thus is not described herein.

[0150] For the reflected shock wave, the calibration process is consistent with the foregoing steps, and thus is not described herein.

[0151] The foregoing is only an example of the specific scheme of the present application, and for the devices and structures not described in detail, it should be understood that the general devices and general methods in the art are used to implement them.

[0152] The above only describes one scheme of the present application, and is not used to limit the present application, and the present application can have various changes and variations for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A calibration method for a shock-wave overpressure optical measurement system based on a shock tube, characterized in that, The calibration device is realized by using a shock wave overpressure optical measurement system based on a shock tube, and the calibration device comprises: a standard shock tube (1), and a visual measurement unit (2) connected with the standard shock tube (1); The visual measurement unit (2) is in sealed butt joint with the outlet end of the standard shock tube (1); The visual measurement unit (2) comprises: a transparent quartz tube (21), a first piezoelectric sensor (22), a second piezoelectric sensor (23), and a third piezoelectric sensor (24); The transparent quartz tube (21) is provided with an open end and a closed end; In the direction from the open end to the closed end of the transparent quartz tube (21), the first piezoelectric sensor (22) and the second piezoelectric sensor (23) are embedded on the side wall of the transparent quartz tube (21) with a spacing; The third piezoelectric sensor (24) is embedded in the center of the closed end of the transparent quartz tube (21); The calibration method comprises the following steps: S1. Align the high-speed camera of the shock wave overpressure optical measurement system to be calibrated with the visual measurement unit (2), and adjust the relative position of the high-speed camera and the visual measurement unit (2) so that the visual measurement unit (2) is completely within the field of view of the high-speed camera; S2. The standard shock tube (1) generates a standard shock wave propagating in the visual measurement unit (2) under control; wherein the standard shock wave is at least one of an incident shock wave and a reflected shock wave; S3. The shock wave overpressure optical measurement system synchronously captures the propagation process of the shock wave in the visual measurement unit (2) based on the high-speed camera, to obtain an optical measurement shock wave overpressure; S4. Based on the initial conditions of the standard shock tube (1) generating the standard shock wave and / or the piezoelectric sensors in the visual measurement unit (2), a verification shock wave overpressure of the propagation process of the shock wave in the visual measurement unit (2) is obtained; S5. The system error of the shock wave overpressure optical measurement system is obtained based on the optical measurement shock wave overpressure and the verification shock wave overpressure; S6. A judgment index for evaluating the system error is constructed, and whether the system error is abnormal is evaluated based on the judgment index; if so, the shock wave overpressure optical measurement system is corrected based on the system error; if not, it is judged that the output result of the shock wave overpressure optical measurement system is accurate.

2. The calibration device for a shock tube based shockwave overpressure optical measurement system according to claim 1, characterized in that, In the direction from the open end to the closed end of the transparent quartz tube (21), the first piezoelectric sensor (22) and the second piezoelectric sensor (23) are arranged at the equidivision position of the transparent quartz tube (21).

3. The calibration device for a shock tube based light measurement system of shock wave overpressure according to claim 2, characterized in that, The wall thickness of the tube body of the transparent quartz tube (21) is consistent with the wall thickness of the closed end.

4. The calibration device for a shock tube based shockwave overpressure optical measurement system according to claim 3, characterized in that The inner diameter d1 of the tube body of the transparent quartz tube (21) is consistent with the inner diameter of the outlet end of the standard shock tube (1); The outer diameter D1 of the tube body of the transparent quartz tube (21) satisfies: 0.2m < D1 < 0.6m; The axial length of the transparent quartz tube (21) is 1m.

5. The calibration device of a shock tube based optical measurement system of shock wave overpressure according to any one of claims 1 to 4, characterized in that, The standard shock tube (1) comprises: a high-pressure section (11) and a low-pressure section (12) connected coaxially, and a diaphragm arranged between the high-pressure section (11) and the low-pressure section (12); The high-pressure section (11) comprises a tubular high-pressure section body (111), a fourth piezoelectric sensor (112) mounted on the high-pressure section body (111), and a high-pressure section air inlet pump and a high-pressure section air outlet pump connected with the high-pressure section body (111); The high-pressure section body (111) is a hollow pipe body with one open end and the other closed end; The fourth piezoelectric sensor (112) is embedded on the sidewall of the high-pressure section body (111); The high-pressure section air inlet pump is connected with the closed end of the high-pressure section body (111), and the high-pressure section air outlet pump is connected with the sidewall of the high-pressure section body (111).

6. The calibration device for a shock tube based shockwave overpressure optical measurement system according to claim 5, characterized in that The low-pressure section (12) comprises a tubular low-pressure section body (121), and a low-pressure section air inlet pump and a low-pressure section air outlet pump connected with the low-pressure section body (121); The low-pressure section body (121) is a hollow pipe body with both ends open; The low-pressure section air inlet pump and the low-pressure section air outlet pump are respectively connected with the sidewall of the low-pressure section body (121), and the connection positions are arranged with intervals; The end of the low-pressure section body (121) connected with the high-pressure section (11) is adjacent to the low-pressure section air outlet pump, and the end of the low-pressure section body (121) away from the high-pressure section (11) is adjacent to the low-pressure section air inlet pump.

7. The method of calibrating a shock tube based shockwave overpressure optical measurement system of claim 1, wherein, In step S3, the shock wave overpressure optical measurement system synchronously photographs the propagation process of the shock wave in the visible measurement unit (2) based on the high-speed camera, to obtain the shock wave overpressure in the step of optical measurement, which comprises: Based on the propagation process of the shock wave in the visible measurement unit (2), a continuous wave front image is recorded; The adjacent frame displacement of the wave front image is extracted, and the first propagation speed of the shock wave wave front in the visible measurement unit (2) is calculated; The first function relationship between the shock wave wave front speed and the shock wave overpressure is obtained, and the first propagation speed is brought in to calculate the optical measurement shock wave overpressure; wherein the first function relationship is represented as: wherein, represents the shock wave overpressure, represents the shock wave front zone pressure, represents the particle motion velocity, represents the initial sound speed, represents the propagation medium polytropic exponent, represents the shock wave front velocity, used to bring in the value of the first propagation velocity.

8. The method of calibrating a shock tube based shockwave overpressure optical measurement system of claim 7, wherein, In step S4, based on the initial condition of the standard shock tube (1) generating the standard shock wave and / or the piezoelectric sensor in the visible measurement unit (2) obtaining the propagation process of the shock wave in the visible measurement unit (2), the step of verifying the shock wave overpressure, if the verification shock wave overpressure is obtained based on the initial condition of the standard shock tube (1) generating the standard shock wave, then the verification shock wave overpressure is the theoretical shock wave overpressure obtained by solving the one-dimensional Riemann problem based on the initial condition of the standard shock tube (1); If the verification shock wave overpressure is obtained based on the piezoelectric sensor in the visible measurement unit (2), then the verification shock wave overpressure has three kinds, and they are respectively: the first verification shock wave overpressure and the second verification shock wave overpressure; If the verification shock wave overpressure is the first verification shock wave overpressure, then it is obtained based on the following steps, which comprises: The time difference of the signal take-off point of the adjacent piezoelectric sensors and the distance between the adjacent piezoelectric sensors are collected; Based on the obtained time difference and distance, the second propagation speed of the shock wave wave front in the visible measurement unit (2) is calculated; The first function relationship between the shock wave wave front speed and the shock wave overpressure is obtained, and the second propagation speed is brought in to calculate the first verification shock wave overpressure; If the check shock wave overpressure is a second check shock wave overpressure, the signal data output by the piezoelectric sensor is directly used.

9. The method of calibrating a shock tube based shockwave overpressure optical measurement system of claim 8, wherein, In step S6, a decision index for evaluating the system error is constructed, and the decision index is expressed as: wherein represents the average deviation of the system error in the optical measurement system of the shock wave overpressure, represents the standard deviation of the system error in the optical measurement system of the shock wave overpressure, represents the confidence interval factor, which is obtained by looking up a table, represents the system error, represents the number of system errors, the subscript represents the serial number of the system error, and .

Images