Shock wave measuring device and measuring method based on anemometer

Abstract

The application discloses a kind of based on air flow meter Shockwave measuring device and measuring method, purpose is to solve the current measuring device layout difficult, data processing complex and other problems.Measuring device is composed of attenuation tube, air flow meter, ventilation warehouse, air flow meter is composed of impeller type probe and signal acquisition instrument.Attenuation tube, impeller type probe, ventilation warehouse are coaxially assembled from left to right.Measuring method is to calibrate first overpressure peak value and specific impulse conversion equation, attenuation tube attenuates shock wave, impeller type probe is driven to rotate after sensing shock wave, and the number of revolutions of impeller is output to signal acquisition instrument in the form of electric pulse, signal acquisition instrument converts electric pulse into wind speed signal, and stores corresponding instantaneous wind speed at different time;The overpressure peak value and specific impulse are obtained by the maximum wind speed and cumulative air volume output by signal acquisition instrument and overpressure peak value and specific impulse conversion equation.The device of the application is simple to lay out, and the measuring method is not disturbed by environment, which can be used for rapid and accurate measurement of shock wave.

Description

TECHNICAL FIELD

[0001] The present application belongs to a kind of shock wave measuring device and measuring method, more particularly to a kind of measuring device and measuring method that can measure air shock wave overpressure peak value and specific impulse simultaneously. BACKGROUND

[0002] Blasting ammunition still occupies a very large proportion in modern ammunition system, and accurately predicting the damage ability of explosion air shock wave is an important work of blasting ammunition identification test. The main parameters of air shock wave include overpressure peak value, positive pressure action time and impulse, wherein overpressure peak value and specific impulse are the key parameters for evaluating the damage power of shock wave, and are the main input parameters of existing shock wave damage criterion.

[0003] On the basis of a large number of experiments, scholars at home and abroad have summarized many damage criteria based on peak overpressure and impulse. The existing shock wave damage criteria mainly include overpressure criterion, impulse criterion and overpressure-impulse criterion. The overpressure-impulse damage criterion is a damage criterion based on the shock wave overpressure and specific impulse. Compared with the overpressure or impulse criterion, it has the advantages of comprehensive consideration, accurate evaluation and wide applicability (Wang Fang, "Overpressure-impulse" damage criterion and its equal damage curve, Journal of Rockets, Missiles and Guidance, Vol. 23, No. 2, January 2003, p. 126). On the basis of the overpressure-impulse damage criterion, the damage degree of the shock wave to personnel, vehicles, buildings and other targets can be evaluated by measuring the local shock wave overpressure peak and impulse, and then the killing power of the weapon ammunition can be evaluated. At present, the main methods for measuring air shock wave are electrical measurement, high-speed schlieren method, equivalent measurement method, biological effect method, etc. The electrical measurement method converts the shock wave pressure into an electrical signal based on the piezoelectric or piezoresistive effect of the sensitive element, and then outputs the signal to the recorder through the signal conditioning circuit. According to the measurement principle of the sensitive element, the electrical measurement sensor can be divided into piezoelectric sensor and piezoresistive sensor. According to the signal recording method, the electrical measurement sensor can be divided into lead type, storage type and remote sensing type. Since the electrical measurement method can measure the pressure time history curve of the shock wave, the data information is rich, and it is widely used in the test of shock wave. However, the electrical measurement method has some disadvantages, such as easy to produce parasitic output, complex data processing, difficult to lay out, high cost, limited by foreign technology, etc., which is not conducive to the efficient and rapid evaluation of shock wave in complex terrain. The high-speed schlieren method obtains the motion trajectory of the wave front based on high-speed photography technology, and then calculates the shock wave overpressure based on the basic relationship of shock wave and the state equation. The high-speed schlieren method has wide measurement range and intuitive results, but it also has some problems, such as complex installation of test equipment, easy to be disturbed by environment, etc. The equivalent measurement method evaluates the damage power of shock wave by measuring the deformation or motion characteristic parameters of equivalent target under shock wave loading. Common equivalent objects include equivalent target plate, impulse pendulum, pressure tank, etc. The equivalent measurement method has the advantages of simple installation, low cost and strong environmental adaptability, but it is difficult to evaluate some irregular deformations, and the obtained shock wave information is less. The biological effect method evaluates the killing power of shock wave by observing the physiological characteristics of some animals after shock wave loading. The evaluation results are more suitable for the real situation, but the biological samples have large individual differences, and it is difficult to accurately evaluate quantitatively.

[0004] In summary, among the existing shock wave measurement methods, the measurement method that can obtain relatively rich information parameters of explosion shock wave has the problems of complex installation, high cost and easy to be disturbed by test environment, such as electrical measurement method. The test method that has relatively simple installation, low test cost and strong anti-environmental interference ability cannot simultaneously invert the overpressure peak and impulse of shock wave, and cannot accurately evaluate the damage power of shock wave by "overpressure-impulse" criterion.

[0005] How to integrate the advantages of the above measurement methods to realize the efficient and accurate evaluation of the damage power of air explosion shock wave is the main problem that the technical personnel in the field are extremely concerned about. SUMMARY

[0006] The technical problem to be solved by the present application is to provide an impact wave measuring device and method based on a wind meter, which solves the problems of current measuring device layout difficulty, environmental interference, complex data processing, high cost and the like, has the characteristics of simple installation, reusability, rich impact wave information acquisition and the like, and can be used for fast and accurate measurement of the overpressure peak value and specific impulse of an explosion shock wave in air.

[0007] The technical scheme of the present application is:

[0008] The impact wave measuring device based on the wind meter is in a whole cylindrical shape, which is composed of an attenuation pipe, a wind meter and a ventilation bin. The wind meter is composed of an impeller type probe and a signal acquisition instrument. The right end of the attenuation pipe assembled with the wind meter is defined as the right end, and the end away from the wind meter is defined as the left end. The attenuation pipe, the impeller type probe and the ventilation bin are coaxially assembled from left to right. The impeller type probe is connected with the signal acquisition instrument through a signal line. The signal acquisition instrument is located at any position outside the attenuation pipe and the ventilation bin, as long as it can communicate with the probe.

[0009] The attenuation pipe is made of hard metal, and the hard metal requires a yield strength σ1>100MPa. The attenuation pipe as a whole is a cylinder with different inner diameters in sections, and the outer diameter is D1, 30mm<D1<300mm. The outer side wall of the right end of the attenuation pipe is engraved with external threads, and the length of the external threads is L1, 10mm<L1<20mm. The attenuation pipe 1 is divided into four sections according to different inner diameters, and is recorded as the first section, the second section, the third section and the fourth section from left to right. The inner diameter of the first section is d1, 5mm<d1<D1 / 2mm, and the length of the first section is l 11 , 1mm<l 11 <500mm. The inner diameter of the second section increases linearly from left to right, the inner diameter of the leftmost end of the second section is d2, d2=d1, the inner diameter of the rightmost end of the second section is d3, 1.5d1<d3<D1-5mm, and the length of the second section is l 12 , (d3-d2) / 2cot10°<l 12 <(d3-d2) / 2cot60°. The inner diameter of the third section is d4, d4=d3, and the length of the third section is l 13 , 10mm<l 13 <500mm. The inner diameter of the fourth section is d5, 5mm<d5<d4, and the length of the fourth section is l 14 , 10mm<l 14 <30mm. The center of the fourth section is embedded with the impeller type probe of the wind meter.

[0010] The air flow meter uses a split impeller air flow sensor (such as the micro pipeline wind speed sensor model FM-W-FS produced by Handan Tengyu Electronic Technology Co., Ltd.). The minimum wind speed that can be measured is required to be less than 1 m / s, the maximum wind speed that can be measured is required to be greater than 10 m / s, and the measurement resolution is less than 0.2 m / s. The air flow meter consists of an impeller probe and a signal acquisition instrument, and the impeller probe and the signal acquisition instrument are connected by a signal line. After the impeller probe senses the wind speed, it drives the impeller to rotate, and outputs the number of impeller rotation cycles to the signal acquisition instrument in the form of electrical pulses. The signal acquisition instrument converts the electrical pulses output by the impeller probe into wind speed signals and stores the instantaneous wind speeds corresponding to different times. The signal acquisition instrument requires a sampling frequency of electrical pulses greater than 100 Hz. The impeller probe is cylindrical as a whole, with a maximum diameter of d6, d6 < d4, and a length of l2, l2 < l 13 . The impeller probe is coaxially assembled in the fourth section of the attenuation tube and is fastened to the inner wall of the fourth section of the attenuation tube by screws. One end of the signal line is connected to the impeller probe, and the other end passes through the central through hole of the ventilation chamber and is connected to the signal acquisition instrument.

[0011] The ventilation chamber is made of hard metal, and the required yield strength σ2 > 100 MPa; the shape of the ventilation chamber is a cylinder, with a diameter of D2, satisfying D1 + 5 mm < D2 < D1 + 20 mm, and the length of the ventilation chamber is l 31 , 40 mm < l 31 < 300 mm. A cylinder is dug out at the left end of the ventilation chamber. The diameter of the dug-out cylinder is d7, d7 = D1, and the length is l 32 , satisfying l 31 - 25 mm < l 32 < l 31 < - 1 mm. Internal threads are engraved on the inner side wall of the left end of the ventilation chamber, and the length of the internal threads is L2, L2 = L1. Five circular through holes are dug on the right end face of the ventilation chamber for the signal line to pass through or ventilation. A central through hole is arranged at the center of the right end face of the ventilation chamber. Taking the central through hole as the base point, four through holes (let them be the second through hole, the third through hole, the fourth through hole, and the fifth through hole) are arranged circumferentially at 90° intervals. The diameters of the five through holes are all d8, d8 = 0.1D2, and the distance between the central through hole and the four circumferentially arranged through holes is l 33 l 33 = 6d8. The ventilation chamber is connected to the fourth section of the attenuation tube through internal threads.

[0012] The method for measuring the shock wave of an air explosion using a shock wave measuring device based on an air flow meter is as follows:

[0013] First, the air shock tube technology (Zhang Dayou, Shock tube in pressure sensor dynamic performance calibration and experimental application, Aerospace Measurement and Control Technology, Vol. 24, No. 4, August 2004, pp. 24-27) is used to calibrate the shock wave measurement device based on the air flow meter, that is, to establish the peak pressure conversion equation and specific impulse conversion equation of the shock wave measurement device based on the air flow meter. The method is as follows:

[0014] 1.1 Let the experiment number n = 1, and let the total number of experiments be N, where N is a positive integer and N ≥ 5. Initialize the pressure F of the nth shock tube high-pressure gas chamber n = 0.1 MPa;

[0015] 1.2 Fix the shock wave measurement device based on the air flow meter and the wall-mounted pressure sensor (with a range greater than 50 MPa and a rise time less than 4 μs) on a steel plate, ensuring that the leftmost end of the shock wave measurement device based on the air flow meter and the pressure-sensitive surface of the wall-mounted pressure sensor are in the same plane. Place the steel plate at the pressure outlet of the shock tube (with a maximum step pressure greater than 3.1 MPa and a pipe diameter greater than D1), with the plane of the steel plate perpendicular to the direction of shock wave propagation and the steel plate fixed to the ground. The thickness of the steel plate is greater than 5 mm.

[0016] 1.3 At the moment the shock tube is turned on, the high-pressure gas in the shock tube high-pressure gas chamber propagates to the low-pressure area, exerting a step pressure (with a certain attenuation during propagation in the shock tube, so the amplitude of the step pressure is less than F n , and increases with Fn) on the shock wave measurement device based on the air flow meter and the wall-mounted pressure sensor. After the step pressure is attenuated by the attenuation tube and reaches the impeller probe of the air flow meter, the signal acquisition instrument of the air flow meter outputs the nth maximum wind speed V n and the nth cumulative air volume Q n , while the wall-mounted pressure sensor measures the nth peak overpressure p n and the nth specific impulse I n under the loading pressure.

[0017] 1.4 Let n = n + 1, if n ≤ N, let F n = F n-1 + 0.2 MPa, and go to 1.2; if n > N, it means that N experiments have been completed, and the data points composed of the first N maximum wind speeds and the first N peak overpressures, i.e. (V1, p1), …, (V n , p n ), …, (V N , p N ), are obtained, as well as the data points composed of the first N cumulative air volumes and the first N specific impulses, i.e. (Q1, I1), …, (Q n , I n ), …, (QN , I N ), turn 1.5.

[0018] 1.5(V1, p1), …, (V n , p n ), …, (V N , p N ) are plotted in a rectangular coordinate system, and the distribution of data points is observed. If a linear relationship is presented, linear fitting is performed, otherwise high-order polynomial fitting is performed, to obtain the peak overpressure conversion equation of the air flow meter-based shock wave measuring device, which is p = f1(V), where p is the peak overpressure, and V is the maximum wind speed measured by the impeller probe and the signal acquisition instrument.

[0019] 1.6(Q1, I1), …, (Q n , I n ), …, (Q N , I N ) are plotted in a rectangular coordinate system, and the distribution of data points is observed. If a linear relationship is presented, linear fitting is performed, otherwise high-order polynomial fitting is performed, to obtain the specific impulse conversion equation of the air flow meter-based shock wave measuring device, which is I = f2(Q), where I is the specific impulse, and Q is the cumulative air flow measured by the impeller probe 21 and the signal acquisition instrument.

[0020] Second step, design a bracket to fix the air flow meter-based shock wave measuring device on the ground. The bracket is an elongated rod, and a circular hoop is installed at the upper end of the bracket. The bracket and the circular hoop are made of alloy steel. The length of the bracket is determined by the height of the explosion point, to ensure that the air flow meter-based shock wave measuring device is installed horizontally on the bracket, and the explosion point is on the extension line of the axis of the attenuation pipe 1. The lower end of the bracket is fixed to the ground or a heavy support;

[0021] Third step, fix the center of gravity of the air flow meter-based shock wave measuring device on the circular hoop on the bracket. The proportional distance from the left end face of the air flow meter-based shock wave measuring device to the explosion center (i.e. the ratio of the distance from the left end face of the air flow meter-based shock wave measuring device to the explosion point to the cube root of the explosion equivalent) is R, 0.1m / kg 1 / 3 <R<5m / kg 1 / 3 Turn on the switch of the signal acquisition instrument to make it in recording state.

[0022] Fourth step, detonate the explosive.

[0023] Fifth step, the attenuation pipe attenuates the shock wave generated by the detonated explosive, the method is:

[0024] 5.1 The first section of the attenuation tube captures the shock wave in the micro-section with diameter d1. The first section dissipates the energy of the shock wave under the action of the viscous force of the inner wall of the first section, and the peak overpressure and the particle velocity after the wave gradually decrease.

[0025] 5.2 When the shock wave enters the second section of the attenuation tube, the peak pressure and the particle velocity after the wave are further reduced by the attenuation tube, and the shock wave is attenuated into a pressure wave with slow pressure rise.

[0026] 5.3 When the pressure wave enters the third section of the attenuation tube, the impeller probe embedded in the fourth section of the attenuation tube starts to rotate after monitoring the wind speed, and converts the wind speed into an electrical signal which is transmitted to the signal acquisition instrument through a signal line.

[0027] 5.4 The signal acquisition instrument converts the electrical signal into the instantaneous wind speed V(t) at different times, finds the maximum value of the instantaneous wind speed V(t) at different times to obtain the maximum wind speed V, integrates the instantaneous wind speed V(t) to obtain the cumulative wind volume Q, and outputs the maximum wind speed V and the cumulative wind volume Q to the display screen of the signal acquisition instrument.

[0028] 5.5 The gas flowing through the impeller probe is discharged from the ventilation chamber through the ventilation chamber, the second through hole, the third through hole, the fourth through hole and the fifth through hole. The ventilation chamber can avoid the interference of the diffracted shock wave outside the measuring device on the impeller probe.

[0029] Step 6: After the explosion, read the maximum wind speed V and the cumulative wind volume Q output by the signal acquisition instrument.

[0030] Step 7: Calculate the peak overpressure p of the shock wave, p = f1(V), and the specific impulse I of the shock wave, I = f2(Q).

[0031] Based on the overpressure-impulse damage criterion, the damage degree of the shock wave to various targets can be determined by p and I, and the damage power of the weapon ammunition can be predicted.

[0032] Compared with the prior art, the present application can achieve the following beneficial effects:

[0033] 1. Compared with the electric measuring sensor, the measuring device of the present application has low cost, simple layout, is not affected by the environment, and is easy to process data, and can be used for rapid and accurate measurement of the peak overpressure and specific impulse of the shock wave in the air.

[0034] 2. Compared with the passive equivalent test method, the measuring device of the present application can more comprehensively obtain the shock wave parameters, and in combination with the overpressure-impulse damage criterion, the damage effect of the shock wave on different targets can be more accurately predicted. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is the schematic diagram of the overall structure of the device of the present application;

[0036] Figure 2 is the right view of the present application. DETAILED DESCRIPTION

[0037] The present application will be further described below in conjunction with the drawings.

[0038] The overall structure of the shock wave measuring device based on the air flow meter of the present application is in a cylindrical shape, which is composed of an attenuation tube 1, an air flow meter 2, and a ventilation bin 3. The air flow meter 2 is composed of a vane type probe 21 and a signal acquisition instrument 22. The right end of the attenuation tube 1 is defined as the end where the air flow meter 2 is assembled, and the left end is defined as the end away from the air flow meter 2. The attenuation tube 1, the vane type probe 21, and the ventilation bin 3 are coaxially assembled from left to right. The vane type probe 21 is connected to the signal acquisition instrument 22 through a signal line. The signal acquisition instrument 22 is located at any position outside the attenuation tube 1 and the ventilation bin 3, as long as it can communicate signals with the probe 21.

[0039] The attenuation tube 1 is made of hard metal, which requires a yield strength σ1>100MPa. The overall structure of the attenuation tube 1 is a cylinder with different internal diameters in different sections, and the outer diameter is D1, 30mm<D1<300mm. The outer side wall of the right end of the attenuation tube 1 is engraved with external threads, and the length of the external threads is L1, 10mm<L1<20mm. The attenuation tube 1 is divided into four sections according to the different internal diameters, which are referred to as the first section, the second section, the third section, and the fourth section from left to right. The internal diameter of the first section is d1, d1<D1, and the preferred value is 5mm<d1<D1 / 2. The length of the first section is l 11 , 1mm<l 11 <500mm. The internal diameter of the second section increases linearly from left to right. The internal diameter of the leftmost end of the second section is d2, d2=d1. The internal diameter of the rightmost end of the second section is d3, d1<d3<D1, and the preferred value is 1.5d1<d3<D1-5mm. The length of the second section is l 12 , (d3-d2) / 2cot10°<l 12 <(d3-d2) / 2cot60°. The internal diameter of the third section is d4, d4=d3. The length of the third section is l 13 , 10mm<l 13 <500mm. The internal diameter of the fourth section is d5, 5mm<d5<d4. The length of the fourth section is l 14 , 10mm<l 14 <30mm. The vane type probe 21 of the air flow meter 2 is nested in the center of the fourth section. The function of the attenuation tube 1 is to attenuate the shock wave generated by the detonation of explosives.

[0040] The air volume meter 2 adopts a split impeller type air volume sensor (for example, a micro-pipeline air speed sensor of FM-W-FS produced by Handan Tengyu Electronic Technology Co., Ltd.), which requires that the minimum air speed that can be measured is less than 1 m / s, the maximum air speed that can be measured is greater than 10 m / s, and the measurement resolution is less than 0.2 m / s. The air volume meter 2 is composed of an impeller type probe 21 and a signal acquisition instrument 22, and the impeller type probe 21 and the signal acquisition instrument 22 are connected through a signal line. After the impeller type probe 21 senses the attenuated shock wave signal, it drives the impeller to rotate, and the number of rotations of the impeller is output to the signal acquisition instrument 22 in the form of an electric pulse. The signal acquisition instrument 22 converts the electric pulse output by the impeller type probe 21 into a wind speed signal, and stores the instantaneous wind speed corresponding to different time points. The signal acquisition instrument 22 requires that the sampling frequency of the electric pulse is greater than 100 Hz. The impeller type probe 21 is in the form of a cylinder as a whole, with a maximum diameter d6, d6 < d4, and a length l2, l2 < l 13 . The impeller type probe 21 is coaxially assembled in the fourth segment of the attenuation pipe 1 and is fastened to the inner wall of the fourth segment of the attenuation pipe 1 by a screw. One end of the signal line of the signal acquisition instrument 22 is connected to the impeller type probe 21, and the other end passes through the central through hole 31 of the ventilation bin 3 and is connected to the signal acquisition instrument 22.

[0041] The ventilation bin 3 is made of hard metal, which requires that the yield strength σ2 > 100 MPa; the ventilation bin 3 is a cylinder with a bottom, with an outer diameter D2, satisfying D1 + 5 mm < D2 < D1 + 20 mm, and an inner diameter d7, d7 = D1, and the length of the ventilation bin 3 is l 31 , 40 mm < l 31 < 300 mm. The left end of the ventilation bin 3 is provided with internal threads on the inner side wall, and the length of the internal threads is L2, L2 = L1. The left end of the ventilation bin 3 is sleeved on the outer side of the fourth segment of the attenuation pipe 1 and is connected to the fourth segment of the attenuation pipe 1 through the internal threads. The right end face of the ventilation bin 3 is 1-25 mm thick, and five circular through holes are dug for signal lines to pass through or ventilation. The central through hole 31 is arranged at the center of the right end face of the ventilation bin 3, and four through holes (the second through hole 32, the third through hole 33, the fourth through hole 34, and the fifth through hole 35) are arranged in a ring around the central through hole 31 at an interval of 90°. The diameters of the five through holes are all d8, d8 = 0.1D2, and the distance between the central through hole 31 and the four through holes arranged in a ring around it is l 33 , l 33 = 6d8. The length of the empty bin inside the ventilation bin 3 (i.e. l 31 minus the thickness of the right end face) is l 32 , satisfying l 32 < l 31 , preferably l 31 -25 mm < l 32 < l 31-1mm. Venting bin 3 will pass into the attenuation tube 1 gas and timely discharge, avoid the diffraction of shock wave interference on vane type probe 21.

[0042] One embodiment of the measuring device of the application is:

[0043] The attenuation tube 1 is made of 304 stainless steel, D1 = 65mm, L1 = 15mm, d1 = 20mm, l 11 = 30mm, d2 = 20mm, d3 = 56mm, l 12 = 40mm, d4 = 56mm, l 13 = 72mm, d5 = 10mm, l 14 = 15mm; air flow meter 2 is made of Handan Tengyu Electronics Technology Co., Ltd. The type of FM-W-FS miniature duct air velocity sensor, d6 = 55mm, l2 = 70mm; Venting bin 3 is made of 304 stainless steel, D2 = 71mm, d7 = 65mm, l 31 = 41mm, L2 = 15mm, d8 = 7.1mm, l 33 = 42.6mm, l 32 = 38mm.

[0044] The method for measuring the shock wave of air explosion by using the above-mentioned shock wave measuring device based on air flow meter is:

[0045] First, calibrate the shock wave measuring device based on air flow meter by referring to air shock tube technology, that is, establish the overpressure peak conversion equation and specific impulse conversion equation of the shock wave measuring device based on air flow meter. The method is:

[0046] 1.1 Let the experiment number n = 1, let the total experiment number N, N is a positive integer, N = 5. Initialize the pressure F n = 0.05MPa;

[0047] 1.2 Fix the shock wave measuring device based on air flow meter and wall type pressure sensor (KD2004-01 type wall type sensor produced by Yangzhou Kedong Co., Ltd., range 10MPa, rise time 4us) on the 6mm thick steel plate, ensure that the leftmost end of the shock wave measuring device based on air flow meter and the pressure sensitive surface of the wall type pressure sensor are in the same plane. The steel plate is placed at the pressure outlet of the shock tube (maximum step pressure greater than 3MPa, pipe diameter greater than D1), the plane where the steel plate is located is perpendicular to the direction of shock wave propagation, and the steel plate is fixed on the ground.

[0048] 1.3 At the moment of opening the shock tube, the high pressure gas in the high pressure chamber of the shock tube spreads to the low pressure area, and exerts a step pressure (the amplitude of the step pressure is less than F n , and increases with the increase of Fn) on the impingement wave measuring device based on the air flow meter and the wall pressure sensor. After the step pressure is transmitted to the impeller probe of the air flow meter through the attenuation tube, the signal acquisition instrument of the air flow meter outputs the nth maximum wind speed V n and the nth cumulative air flow Q n , while the wall pressure sensor measures the nth overpressure peak value p n and the nth specific impulse I n .

[0049] 1.4 Let n = n + 1, if n ≤ N, let F n = F n-1 + 0.2MPa, turn 1.2; if n > N, it means that N experiments have been completed, and the data points composed of the first to Nth maximum wind speed and the first to Nth overpressure peak value, i.e. (V1, p1), …, (V n , p n ), …, (V N , p N ) (this embodiment is (8.4m / s, 0.05MPa), (46.0m / s, 0.25MPa), (90.9m / s, 0.45MPa), (152.5m / s, 0.65MPa), (240.1m / s, 0.85MPa)) are obtained, and the data points composed of the first to Nth cumulative air flow and the first to Nth specific impulse, i.e. (Q1, I1), …, (Q n , I n ), …, (Q N , I N ) (this embodiment is (2.1m, 3.30Pa.s), (6.5m, 13.12Pa.s), (11.1m, 19.92Pa.s), (19.1m, 25.51Pa.s), (48.7m, 31.50Pa.s)) are also obtained. Turn 1.5.

[0050] 1.5 Draw (V1, p1), …, (V n , p n ), …, (V N , p N ) in the rectangular coordinate system, and observe the distribution of the data points. If it is linear, perform linear fitting, otherwise perform exponential fitting, to obtain the overpressure peak conversion equation of the impingement wave measuring device based on the air flow meter. The equation obtained in this embodiment is p = 1.28 (1-exp -0.005V), p is the peak overpressure, unit is MPa, V is the maximum wind speed measured by the impeller probe 21 and the signal acquisition instrument 22, unit is m / s.

[0051] 1.6 Draw (Q1, I1), (Q2, I2), …, (Qn, In) in the rectangular coordinate system, observe the distribution of data points, if it is linear, linear fitting is performed, otherwise exponential fitting is performed, to obtain the specific impulse conversion equation of the wind meter based shock wave measuring device, in the embodiment, the equation is I = 40.42 (1-exp n , I n ), …, (Q N , I N ) in the rectangular coordinate system, observe the distribution of data points, if it is linear, linear fitting is performed, otherwise exponential fitting is performed, to obtain the specific impulse conversion equation of the wind meter based shock wave measuring device, in the embodiment, the equation is I = 40.42 (1-exp -0.053Q ), I is the specific impulse, unit is Pa.s, Q is the cumulative wind volume measured by the impeller probe 21 and the signal acquisition instrument 22, unit is m.

[0052] Second step, design a support to fix the wind meter based shock wave measuring device on the ground, the support is an elongated rod, a circular hoop is installed at the upper end of the support, the support and the circular hoop are made of alloy steel, the length of the support is determined by the height of the explosion point, to ensure that when the wind meter based shock wave measuring device is horizontally installed on the support, the explosion point is on the extension line of the axis of the attenuation pipe 1, and the lower end of the support is fixed on the ground or a heavier support;

[0053] Third step, fix the center of gravity of the wind meter based shock wave measuring device on the circular hoop on the support, the proportional distance of the left end surface of the wind meter based shock wave measuring device to the explosion center is R = 1.63 m / kg 1 / 3 Turn on the switch of the signal acquisition instrument 22, so that the signal acquisition instrument 22 is in a recording state;

[0054] Fourth step, detonate explosives (1 kg of TNT).

[0055] Fifth step, the attenuation pipe 1 attenuates the shock wave generated by the detonated explosives, the method is:

[0056] 5.1 The first section of the attenuation pipe 1 captures the shock wave in the tiny cross section with a diameter of d1 in the space, under the action of the viscous force on the inner wall surface of the first section pipe, the first section continuously dissipates the energy of the shock wave transmitted into the first section, and the peak pressure and the post-wave particle velocity of the shock wave gradually decrease.

[0057] 5.2 When the shock wave enters the second section of the attenuation pipe 1, the inner diameter of the second section of the attenuation pipe 1 continuously expands, the attenuation pipe 1 further reduces the peak pressure and the post-wave particle velocity of the shock wave, and attenuates the shock wave into a pressure wave with slow pressure rise.

[0058] 5.3 When the pressure wave enters the third section of the attenuation tube 1, the impeller-type probe 21 embedded in the fourth section of the attenuation tube 1 detects the wind speed and starts to rotate, converting the wind speed into an electrical signal, which is then transmitted to the collector 22 through the signal line.

[0059] 5.4 The collector 22 converts the electrical signal into instantaneous wind speed V(t) at different times, finds the maximum value of the instantaneous wind speed V(t) at different times to obtain the maximum wind speed V, integrates the instantaneous wind speed V(t) to obtain the cumulative air volume Q, and outputs the maximum wind speed V and the cumulative air volume Q to the display screen of the collector 22.

[0060] 5.5 The gas flowing through the impeller probe 21 is directed to the ventilation chamber 3. The second through hole 32, the third through hole 33, the fourth through hole 34, and the fifth through hole 35 discharge the gas that has passed through the impeller probe 21 into the ventilation chamber 3. The ventilation chamber 3 can prevent shock wave diffraction from interfering with the impeller probe 21.

[0061] Step 6: After the explosion, read the maximum wind speed V and cumulative air volume Q output by the signal acquisition instrument 22. In this embodiment, they are 50.1 m / s and 122 m, respectively.

[0062] Step 7: Calculate the peak overpressure p of the shock wave, p = 1.28(1 - exp[-1 / 2]). -0.005V Given a pressure of 0.28 MPa, calculate the specific impulse I of the shock wave: I = 40.42(1-exponential). -0.053Q = 40.36 Pa·s.

Claims

1. A shock wave measuring device based on an anemometer, characterized in that... The shock wave measuring device based on the anemometer is cylindrical in shape and consists of an attenuation tube (1), an anemometer (2), and a ventilation chamber (3). The anemometer (2) consists of an impeller probe (21) and a signal acquisition device (22). The end of the attenuation tube (1) where the anemometer (2) is assembled is defined as the right end, and the end away from the anemometer (2) is defined as the left end. The attenuation tube (1), the impeller probe (21), and the ventilation chamber (3) are coaxially assembled from left to right. The impeller probe (21) is connected to the signal acquisition device (22) through a signal line. The signal acquisition device (22) is located at any position outside the attenuation tube (1) and the ventilation chamber (3) and communicates with the impeller probe (21) via signal. The attenuation tube (1) is made of hard metal. The attenuation tube (1) is a cylinder with unequal inner diameters in segments as a whole, with an outer diameter of D1. There is an external thread engraved on the outer side wall of the right end of the attenuation tube (1), and the length of the external thread is L1. The attenuation tube (1) is divided into four segments according to different inner diameters, which are respectively recorded as the first segment, the second segment, the third segment and the fourth segment from left to right. The inner diameter of the first segment is d1, d1 < D1, and the length of the first segment is l 11 ; The inner diameter of the second segment increases linearly from left to right. The inner diameter at the leftmost end of the second segment is d2 = d1, and the inner diameter at the rightmost end of the second segment is d3, d1 < d3 < D1. The length of the second segment is l 12 ; The inner diameter of the third segment is d4, d4 = d3, and the length of the third segment is l 13 ; The inner diameter of the fourth segment is d5, d5 < d4, and the length of the fourth segment is l 14 ; The impeller probe (21) of the air flow meter (2) is nested in the center of the fourth segment; The function of the attenuation tube (1) is to attenuate the shock wave generated by the detonating explosive; The air volume meter (2) adopts a split impeller-type air volume sensor. After the impeller probe (21) senses the attenuated shock wave signal, it drives the impeller to rotate and outputs the number of impeller rotations in the form of electrical pulses to the signal acquisition instrument (22). The signal acquisition instrument (22) converts the electrical pulses output by the impeller probe (21) into wind speed signals and stores the instantaneous wind speeds corresponding to different times. The impeller probe (21) is cylindrical in shape and is coaxially mounted in the fourth section of the attenuation tube (1). It is fastened to the inner wall of the fourth section of the attenuation tube (1) by screws. One end of the signal line of the signal acquisition instrument (22) is connected to the impeller probe (21), and the other end passes through the central through hole (31) of the ventilation chamber (3) and is connected to the signal acquisition instrument (22). The ventilation chamber (3) is made of hard metal. The ventilation chamber (3) is a cylinder with a bottom. The outer diameter D2>D1 and the inner diameter d7=D1. The length of the ventilation chamber (3) is l. 31 The ventilation chamber (3) has an internal thread engraved on the inner side wall of its left end. The length of the internal thread is L2=L1. The left end of the ventilation chamber (3) is fitted onto the outer side of the fourth section of the attenuation tube (1) and connected to the fourth section of the attenuation tube (1) through the internal thread. The right end face of the ventilation chamber (3) has five circular through holes, namely the central through hole (31), the second through hole (32), the third through hole (33), the fourth through hole (34), and the fifth through hole (35), for signal lines to pass through or for ventilation. The length of the empty chamber inside the ventilation chamber (3) is l. 32 <l 31 The ventilation chamber (3) promptly discharges the gas that has entered the attenuation tube (1) to avoid the shock wave diffraction interfering with the impeller probe (21).

2. The shock wave measuring device based on an anemometer as described in claim 1, characterized in that... The outer diameter D1 of the attenuation tube (1) satisfies 30 mm < D1 < 300 mm; the length L1 of the external thread engraved on the outer side wall of the right end of the attenuation tube (1) satisfies 10 mm < L1 < 20 mm; the inner diameter d1 of the first section satisfies 5 mm < d1 < D1 / 2, and the length l 11 satisfies 1 mm < l 11 < 500 mm; the inner diameter d3 of the rightmost end of the second section satisfies 1.5d1 < d3 < D1 - 5 mm, and the length l 12 satisfies (d3 - d2) / 2cot10° < l 12 < (d3 - d2) / 2cot60°; the length l 13 of the third section satisfies 10 mm < l 13 < 500 mm; the inner diameter d5 of the fourth section satisfies 5 mm < d5 < d4, and the length l 14 satisfies 10 mm < l 14 < 30 mm.

3. The shock wave measuring device based on an anemometer as described in claim 1, characterized in that... The required minimum wind speed measured by the air flow meter (2) is less than 1 m / s, the maximum wind speed measured is greater than 10 m / s, and the measurement resolution is less than 0.2 m / s; the signal acquisition instrument (22) requires a sampling frequency for electrical pulses greater than 100 Hz; the maximum diameter d6 of the impeller-type probe (21) is < d4, and the length l2 < l 13 .

4. The shock wave measuring device based on an anemometer as described in claim 1, characterized in that... The outer diameter D2 of the ventilation bin (3) satisfies D1 + 5mm < D2 < D1 + 20mm, and the length l of the ventilation bin (3) 31 satisfies 40mm < l 31 < 300mm; the thickness of the right end face of the ventilation bin (3) is 1 - 25mm. A central through hole (31) is arranged at the center of the right end face of the ventilation bin (3). Taking the central through hole (31) as the base point, the second through hole (32), the third through hole (33), the fourth through hole (34), and the fifth through hole (35) are arranged circumferentially at 90° intervals. The diameter d8 of the 5 through holes is 0.1D2, and the distance l between the central through hole (31) and the 4 circumferentially arranged through holes 33 = 6d8; the length l of the internal empty bin of the ventilation bin (3) 32 satisfies l 31 - 25mm < l 32 < l 31 < - 1mm.

5. The shock wave measuring device based on an anemometer as described in claim 1, characterized in that... The hard metal used to prepare the attenuation tube (1) requires a yield strength of [missing information]. >100MPa; the hard metal used to prepare the ventilation chamber (3) requires a yield strength of >100MPa. >100MPa.

6. A method for measuring shock waves using the shock wave measuring device based on an anemometer as described in claim 1, characterized in that... Includes the following steps: The first step is to calibrate the shock wave measurement device based on an anemometer by referencing air shock tube technology, specifically by establishing the overpressure peak value conversion equation and specific impulse conversion equation for the anemometer-based shock wave measurement device. The method is as follows: Step 1.1 Let the number of experiments n=1, and the total number of experiments be N, where N is a positive integer; initialize the pressure F of the high-pressure gas chamber of the shock tube in the nth experiment. n =0.1MPa; Step 1.2 Fix the shock wave measuring device based on the air volume meter and the wall-mounted pressure sensor on the steel plate, ensuring that the leftmost end of the shock wave measuring device based on the air volume meter and the pressure sensing surface of the wall-mounted pressure sensor are on the same plane; place the steel plate at the pressure outlet of the shock tube, with the plane of the steel plate perpendicular to the direction of shock wave propagation, and fix the steel plate to the ground; Step 1.3 At the instant the shock tube is turned on, the high-pressure gas in the high-pressure chamber of the shock tube propagates to the low-pressure area, applying a step pressure to the shock wave measurement device based on the anemometer and the wall-mounted pressure sensor. The amplitude of this step pressure is less than F. n And with F n The step pressure increases with the increase of the pressure; after being attenuated by the attenuation tube, the pressure is transmitted to the impeller probe of the anemometer, and the signal acquisition instrument of the anemometer outputs the nth maximum wind speed V. n and the cumulative air volume Q of the nth time n Simultaneously, the wall-mounted pressure sensor measures the nth overpressure peak p under this step pressure. n The specific impulse I of the nth time n ; Step 1.4 Let n = n + 1. If n ≤ N, let F n =F n-1 +0.2MPa, go to 1.2; if n>N, it means that N experiments have been completed, and data points consisting of the maximum wind speed from the 1st to the Nth time and the overpressure peak from the 1st to the Nth time have been obtained, namely (V1, p1), ..., (V n p n ), ..., (V N p N ), and also obtained data points composed of the cumulative air volume from the 1st to the Nth time and the specific impulse from the 1st to the Nth time, namely (Q1, I1), ..., (Q n I n ), ..., (Q) N I N ), turn 1.5; Step 1.5 (V1, p1), ..., (V n p n ), ..., (V N p N Plot the data points in a rectangular coordinate system and observe the distribution of the data points. If they are linearly related, perform linear fitting; otherwise, perform high-order polynomial fitting to obtain the overpressure peak conversion equation of the shock wave measurement device based on the anemometer. Let the equation be p=f1(V), where p is the overpressure peak and V is the maximum wind speed measured by the impeller probe (21) and the signal acquisition instrument (22). Step 1.6 (Q1, I1), ..., (Q n I n ), ..., (Q) N I N Plot the data points in a rectangular coordinate system and observe the distribution of the data points. If they are linearly related, perform linear fitting; otherwise, perform high-order polynomial fitting to obtain the specific impulse conversion equation of the shock wave measurement device based on the air volume meter. Let the equation be I = f2(Q), where I is the specific impulse and Q is the cumulative air volume measured by the impeller probe (21) and the signal acquisition instrument (22). The second step is to design a support for fixing the shock wave measuring device based on the anemometer to the ground. The support is a slender rod with a circular clamp installed at the upper end. The support and the circular clamp are made of alloy steel. The length of the support is determined by the height of the explosion point. This ensures that when the shock wave measuring device based on the anemometer is installed horizontally on the support, the explosion point is on the extension line of the axis of the attenuation tube (1). The lower end of the support is fixed to the ground or a heavier support. The third step is to fix the center of gravity of the shock wave measuring device based on the anemometer onto the circular clamp on the bracket. The proportional distance between the left end face of the shock wave measuring device based on the anemometer and the explosion center, i.e., the ratio of the distance between the left end face of the shock wave measuring device based on the anemometer and the explosion point to the cube root of the explosion yield, is R, 0.1 m / kg. 1 / 3 <R<5m / kg 1 / 3 Turn on the switch of the signal acquisition device (22) to put the signal acquisition device (22) into recording mode; The fourth step is to detonate the explosives; Fifth step, the attenuation tube (1) attenuates the shock wave generated by the detonating explosive, the method is as follows: Step 5.1 The first section of the attenuation tube (1) captures the shock wave in a small cross section with a diameter of d1 in the space. Under the action of the viscous force on the inner wall of the first section, the energy of the shock wave transmitted into the first section is continuously dissipated, and the overpressure peak value of the shock wave and the velocity of the particles behind the wave gradually decrease. Step 5.2 When the shock wave enters the second section of the attenuation tube (1), as the inner diameter of the second section of the attenuation tube (1) continues to expand, the attenuation tube (1) further reduces the peak pressure and the velocity of the particles behind the shock wave, thus attenuating the shock wave into a pressure wave with a slow pressure rise. Step 5.3 When the pressure wave enters the third section of the attenuation tube (1), the impeller probe (21) embedded in the fourth section of the attenuation tube (1) detects the wind speed and starts to rotate, converting the wind speed into an electrical signal and transmitting it to the signal acquisition instrument (22) through the signal line; Step 5.4 The signal acquisition instrument (22) converts the electrical signal into instantaneous wind speed V(t) at different times, finds the maximum value of the instantaneous wind speed V(t) at different times to obtain the maximum wind speed V, integrates the instantaneous wind speed V(t) to obtain the cumulative air volume Q, and outputs the maximum wind speed V and the cumulative air volume Q to the display screen of the acquisition instrument. Step 5.5 The gas flowing through the impeller probe (21) is directed to the ventilation chamber. The second through hole (32), the third through hole (33), the fourth through hole (34), and the fifth through hole (35) discharge the gas through the impeller probe (21) into the ventilation chamber (3), thereby avoiding interference from the shock wave diffracted outside the measuring device to the impeller probe (21). Step 6: After the explosion, read the maximum wind speed V and cumulative wind volume Q output by the signal acquisition instrument (22); Step 7: Calculate the overpressure peak value p of the shock wave, p=f1(V), and calculate the specific impulse I of the shock wave, I=f2(Q).

7. The method for measuring shock waves using a shock wave measuring device based on an anemometer as described in claim 6, characterized in that... The total number of experiments N described in step 1.1 is a positive integer greater than or equal to 5.

8. The method for measuring shock waves using a shock wave measuring device based on an anemometer as described in claim 6, characterized in that... The wall-mounted pressure sensor described in step 1.2 requires a range greater than 50 MPa and a rise time less than 4 μs; the shock tube requires a maximum step pressure greater than 3.1 MPa and a pipe diameter greater than D1; and the steel plate thickness requires a thickness greater than 5 mm.

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