Centrifugal model test method for underwater explosion to determine the relative energy of explosives

Abstract

The present invention provides an underwater explosion centrifugal model test method for determining the relative energy of explosives. The method of the present invention comprises: (1) providing a centrifugal model test device, the centrifugal model test device comprising a model box and a centrifuge for causing the model box to perform centrifugal motion; (2) using the centrifugal model test device to place the water in the model box in a centrifugal environment, thereby generating a hypergravity field in the water; (3) using an initiator to initiate the explosive in the water under the centrifugal environment, while recording bubble pulsation and shock wave parameters; (4) calculating the explosive energy based on the parameters of step (3); (5) calculating or measuring the energy of the same mass of TNT explosives, and calculating the relative energy. The present invention can conveniently determine the shock wave energy and bubble energy of the explosive, thereby determining the relative energy of the explosive. When testing under a centrifugal environment, the boundary effect is small, the test accuracy is high, the test effect is good, the amount of explosive used is small, and it is relatively safe.

Description

Technical Field

[0001] The invention relates to a technique for measuring explosive relative energy, in particular to an underwater explosion centrifugal model test method for measuring explosive relative energy. Background Art

[0002] The determination of the relative energy of explosives is used in many engineering practices. Blasting operations are often required in mining, cofferdam removal, tunnel construction and other projects. The blasting design calculation requires knowing the power of various explosives, so as to accurately control the blasting effect. It is necessary to avoid repeated blasting due to too small power, and to prevent accidents such as landslides caused by excessive explosion power. Accidents such as oil and gas explosions or chemical explosions also often need to determine their equivalents for post-disaster loss assessment and responsibility determination. With the development of national defense, in order to achieve precise strikes, the country has carried out the development of high-energy materials. The determination of the power of new weapons requires a detailed understanding of their relative energy in order to formulate appropriate strategies and tactics. TNT equivalent is a common indicator for evaluating the relative energy of energetic materials such as explosives. At present, the methods for determining the relative energy of explosives include: blast pit method, air explosion method and underwater explosion method.

[0003] (1) Explosion pit method

[0004] When explosives explode underground or near the ground, a crater effect is usually produced, forming a crater on the ground. The explosion equivalent can be calculated by measuring the size of the crater. For accidental explosions in pipelines and chemical plants or nuclear weapons tests, it is usually difficult to deploy sensors on site to test the power of the explosion. The size of the crater becomes the most intuitive and effective data for evaluating the power of the explosion, and is therefore suitable for evaluating the power of sudden explosions such as production accidents.

[0005] However, due to the complex on-site environment, it is quite difficult to collect data such as the initial location of the explosion source. For example, the efficiency of converting explosive energy into blast pits is not consistent due to the different buried depths and layout locations of explosives. In addition, for different geotechnical materials, the empirical coefficients of the blast pit formula need to be re-filtered, and the results of filtering with small equivalent explosives are usually difficult to directly extend to large equivalent explosives. Therefore, the blast pit method is usually only suitable for roughly estimating the equivalent of disaster accidents.

[0006] (2) Air blast method

[0007] When explosives are far away from structures or the ground and explode in the air, due to the compressibility of air, the explosion will form a spherical shock wave that propagates in all directions. By measuring the waveform of the shock wave at different distances, the shock wave energy attenuation law can be obtained, and the shock wave energy of the explosive can be inferred. The explosive equivalent can be obtained based on the energy conversion efficiency.

[0008] However, the air explosion method only considers the shock wave energy and ignores the potential energy of the high-pressure gas generated by the explosion, which accounts for about half of the total energy of the explosion. Ignoring the gas potential energy will make the explosive equivalent measurement result smaller. For different forms of explosives, the proportion of shock wave energy is not consistent, and the accuracy cannot be guaranteed by simply using the energy conversion rate for correction.

[0009] (3) Underwater explosion method

[0010] When explosives explode underwater, the energy released by the explosion includes shock wave energy and bubble energy in the water. Similar to the air explosion method, the shock wave energy of the explosive can be calculated by measuring the waveform of the shock wave at different distances. The bubble energy can be calculated by measuring the bubble pulsation period and radius. It is generally believed that the sum of the initial shock wave energy and the bubble energy is the total energy of the explosive explosion in water. Therefore, the underwater explosion energy can be tested in a pool or explosion water tower.

[0011] However, for ground tests, the Mach number and the Froude number cannot simultaneously satisfy similarity, and the bubble energy cannot be similar. The bubble energy measured by the small-equivalent underwater explosion test cannot be directly extended to the large-equivalent explosive. When the amount of explosives used in the test is large, the results have a certain similarity, which invisibly increases the risk and cost of the test. In addition, due to the large explosive equivalent, the test is greatly affected by the boundary effect. According to the "GJB7692-2012 Explosive Explosion Relative Energy Evaluation Method-Underwater Explosion Method", it is recommended that when using 1.0kg explosives for testing, the water area must be greater than 9.5m and the depth should be greater than 12.6m; when using 5.0kg explosives for testing, the test water area must be greater than 16.2m and the depth should be greater than 21.6m. This undoubtedly increases the difficulty of the test. In addition, it is difficult to shoot the bubble pulsation process in the pool, and the bubble energy can only be calculated through the pulsation period measured by the pressure wave. Summary of the invention

[0012] In order to solve at least part of the technical problems in the prior art, the present invention provides an underwater explosion centrifugal model test method for determining the relative energy of explosives. Specifically, the present invention includes the following contents.

[0013] An underwater explosion centrifugal model test method for determining the relative energy of explosives comprises the following steps:

[0014] (1) providing a centrifugal model test device, the centrifugal model test device comprising a model box having a structure capable of containing water and a centrifuge designed to cause the model box to perform centrifugal motion;

[0015] (2) using the centrifugal model test device to place the water in the model box in a centrifugal environment, thereby generating a hypergravity field in the water;

[0016] (3) Detonate explosives in water using a detonation device in a centrifugal environment while recording bubble pulsation and shock wave parameters;

[0017] (4) calculating the explosive energy based on the parameters of step (3);

[0018] (5) Calculate or measure the energy of the same mass of TNT explosives and calculate the relative energy.

[0019] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the centrifugal model test device further includes a hanging basket, which is designed to enable the model box to be installed on the centrifuge, thereby causing the model box to rotate.

[0020] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the centrifugal model test device further includes a sensor assembly, which includes a sensor, a sensor bracket and a sensor mounting rod, wherein the sensor bracket is arranged in the model box in a manner that it can be basically parallel to the water surface, the sensor mounting rod is arranged in the model box in a manner that is basically perpendicular to the sensor bracket and extends along the depth direction of the water, the sensor is arranged on the sensor mounting rod, and the mounting rod and the sensor mounting rod are both marked with scales to facilitate determination of the horizontal distance between the explosive and the sensor and the depth of the sensor immersed in water.

[0021] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the model box is a rectangular parallelepiped, the sensor bracket is a cross-shaped bracket composed of four brackets, and the four brackets are fixed into a whole through the middle part of the cross-shaped bracket, and the two ends of each bracket are respectively fixed to the upper part of the model box.

[0022] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, there are multiple sensor mounting rods, and one end of each of the sensor mounting rods is installed on the same side of the sensor bracket in a basically vertical manner and is installed at a specified position of each bracket, a sensor is installed on the other end of each sensor bracket, and the detonating device is arranged below the middle part of the cross-shaped portion.

[0023] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the centrifugal model test device further includes a camera device, and the model box further includes a glass observation window, and the camera device is configured to rotate synchronously with the model box and can photograph changes in the model box through the glass observation window.

[0024] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the centrifugal model test device further includes a light source, and there is a glass wall on the opposite side of the glass observation window, and the light source is arranged on the outside of the glass wall to illuminate the background of the test model.

[0025] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the centrifugal acceleration is calculated by the following formula (I):

[0026]

[0027] At the same time, the acceleration should also satisfy the following equations (II) and (III):

[0028]

[0029] In formula (I) to formula (III), n represents centrifugal acceleration, W p is the mass of the explosive prototype to be simulated, [W m ] is the maximum amount of explosives allowed by the centrifuge and the model box, H represents the depth of the model box, d represents the depth of explosives entering the water, l min Indicates the length of the short side of the model box.

[0030] The actual explosive mass W used in the centrifuge test m for:

[0031] W m =W p / n 3

[0032] Preferably, the pressure sensor range should not be less than,

[0033]

[0034] Where R is the distance between the explosive and the sensor.

[0035] Preferably, in the underwater explosion centrifugal model test method for determining the relative energy of explosives of the present invention, the camera frequency of the camera device is determined by the following formula (IV):

[0036]

[0037] Where, f represents the camera frequency, T b represents the bubble cycle, i.e., the time it takes for the explosive to detonate, for the bubble to expand, and for it to shrink to its minimum volume. n represents the centrifugal acceleration, and W m is the mass of explosive actually used in the centrifuge test, and d represents the depth of the explosive into the water. Preferably, in the underwater explosion centrifuge model test method for determining the relative energy of explosives of the present invention, step (3) comprises:

[0038] (3-1) Calculate the shock wave time constant θ at each measuring point, corresponding to the shock wave pressure decaying to p m / e time, p m is the peak pressure, e≈2.718 is a natural constant;

[0039] (3-2) According to the shock wave curves measured at different positions, the energy flux density e at each measuring point is calculated by the following formula (V): s value:

[0040]

[0041] draw The test points can be fitted with a power function to obtain the following formula:

[0042]

[0043] Where R is the distance between the sensor and the explosive, K E With α E is the curve coefficient;

[0044] (3-3) The shock wave energy is calculated by the following formula (VII):

[0045]

[0046] a e is the equivalent explosive radius. For spherical charges, a e is the explosive radius; for cylindrical charges, a e It can be calculated based on volume equivalence;

[0047] (3-4) The bubble energy is calculated by the following formula (VI):

[0048]

[0049] Where p0 is the atmospheric pressure, about 101.3 kPa, ρ w is the density of water, which is 1000kg / m 3 ; n represents centrifugal acceleration, g = 9.8 m / s 2 , is the ground gravity acceleration; d is the depth of the explosive into the water; T b is the measured bubble pulsation period;

[0050] (3-5) Calculate the sum of the bubble energy and the shock wave energy to obtain the explosive energy.

[0051] A centrifugal model test device is used in the method of the present invention. The centrifugal model test device can be installed in a centrifuge and rotated, so that the centrifugal model test device can simulate a supergravity field, achieve the similarity of the Mach number and the Froude number at the same time, thereby simultaneously satisfying the similarity of the underwater explosion shock wave and the bubble pulsation. In the centrifugal model test, a small amount (a few grams) of explosives can be used to simulate the explosion power and effect of tons of explosives on the ground. According to the explosion similarity rate, 1 gram of explosives can simulate the explosion power of 1 ton of explosives under 100g centrifugal acceleration. In addition, under the supergravity field, the explosion energy is effectively constrained, and the test results in a limited space can simulate the underwater explosion effect consistent with the prototype. Therefore, measuring the relative energy of explosives in a centrifugal environment has the advantages of economy, safety, and repeatability.

[0052] Due to the additional hypergravity field, ground underwater explosion tests and test methods are not suitable for centrifuge model tests. The prototype mass simulated by the centrifuge test, the resulting shock wave and bubble pulsation results all need to be calculated using special methods, which are different from ground model tests. The current centrifuge model test methods are mainly used to focus on testing, controlling and detonating equipment, and do not include test methods for the relative energy of explosives. Therefore, it is necessary to propose an underwater explosion centrifuge model test method for determining the relative energy of explosives.

[0053] In the model box of the present invention, the size of the model box is determined according to the size of the centrifugal model test bench. Under the condition that space permits, the size of the model box should be as large as possible; under the condition that the centrifuge load is met, the water storage height should be as high as possible. The model box is provided with an adjustable sensor installation device, and the sensor installation device is provided with a sensor bracket and a plurality of parallel sensor installation rods. In order to avoid mutual interference between sensors and considering the limitation of the size of the test model box, the sensor bracket is a cross-shaped bracket engraved with a scale of distance to the center, and it has square grooves matching the sensor installation rods in all directions, and the sensor installation rods are fixed to the sensor bracket by buckles at the upper and lower ends. In addition, the cross-shaped bracket can also effectively restrain the deformation of the box body and increase the impact capacity of the model box.

[0054] The invention can conveniently determine the shock wave energy and bubble energy of the explosive, thereby determining the relative energy of the explosive. The test is conducted in a centrifugal environment, with high accuracy, good test effect, small amount of explosives used, and relative safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 A flow chart of an exemplary underwater explosion centrifugal model testing method is shown.

[0056] Figure 2 A cross-sectional view of a centrifuge showing an exemplary centrifuge model test apparatus used in the method of the present invention.

[0057] Figure 3 A cross-sectional view of a model box showing an exemplary centrifuge model testing apparatus used in the method of the present invention.

[0058] Figure 4 A top view of an exemplary mold box used in the method of the present invention is shown.

[0059] Description of reference numerals:

[0060] Model box 100, first side surface 111, second side surface 112, third side surface 113, fourth side surface 114, bottom surface 115, first plexiglass observation window 1111, second plexiglass observation window 1131, M-shaped bracket 120, first bracket 121, second bracket 122, third bracket 123, fourth bracket 124, middle part 125, sensor mounting rod 130, buckle 131, explosion water pressure sensor 140, explosive bracket 132, high-speed camera 150, constant light source 160. DETAILED DESCRIPTION

[0061] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0062] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art in the art to which the present invention relates.

[0063] The present invention is applicable to the physical simulation of the underwater explosion method for determining the relative energy of explosives. In order to facilitate the understanding of the technical purpose of the present invention, the physical simulation test of the underwater explosion centrifugal test method for determining the relative energy of explosives will be described below. In addition, in the following description, the term "centrifugal force" is used. However, from a physical point of view, the correct expression of this term should be "centripetal force". In order to comply with the customary usage in this field and so that the term "centrifugal force" will not cause any misunderstanding to those skilled in the art, "centrifugal force" is used in the description of this embodiment.

[0064] Example 1

[0065] This embodiment is a physical simulation test step of the underwater explosion centrifugal test method for determining the relative energy of explosives. Figure 1 The process shown is as follows.

[0066] (1) Design of the dimensions of the model box

[0067] According to the size of the centrifuge basket and the design model box, and the allowable load of the centrifuge, the test water storage height H is determined, and the water depth d=H / 2.

[0068] (2) Determine the model acceleration n

[0069] Considering the explosion resistance of the model box and centrifuge, according to the mass W of the simulated explosive prototype p , centrifuge and model box allow the maximum amount of medicine [W m ],in,

[0070]

[0071] Since the nature of the test explosive is unknown, the actual mass of the explosive can be used as an estimate of the TNT equivalent to calculate W p , or you can first conduct ground tests, make adjustments and corrections based on the preliminary test results, and then conduct fine tests. To meet the boundary effect, the centrifugal acceleration should also meet,

[0072]

[0073] Usually, the test centrifugal acceleration n is obtained by multiplying the minimum acceleration by 10, where H represents the depth of the model box, d represents the depth of the explosive entering the water, and l min Indicates the length of the short side of the model box.

[0074] (3) Determine the test explosive equivalent

[0075] The actual equivalent of the model test explosive is calculated according to the following formula:

[0076] W m =W p / n 3

[0077] (4) Making explosive devices

[0078] Spherical explosives are used, and the detonating cord is used for central detonation. The detonating cord is detonated by a micro-electric detonator, firmly bonded, and wrapped with a plastic wrap and heat-shrunk for waterproofing. If conditions permit, the same medicine ball can also be made of TNT of the same mass as a reference (standard) explosive. Spherical explosives are used in this embodiment, but it should be noted that those skilled in the art can understand that other types of explosives can be used freely without affecting the implementation of the present invention.

[0079] (5) Install test equipment

[0080] Usually, the shock wave pressure is tested at 5-8 different distances. If a high-speed camera is used, the sensor should not be placed between the lens and the explosive line. To avoid affecting the bubble pulsation, the distance between the sensor and the explosion source should be greater than the maximum bubble pulsation radius R. bm ,

[0081]

[0082] Where d is the depth of the explosive into the water. The pressure sensor range should not be less than:

[0083]

[0084] Where R is the actual distance between the explosive and the sensor. For high-energy explosives, the pressure sensor range should be further increased.

[0085] High-speed camera is fixed outside the glass window, and the height and left and right position are adjusted to make the explosion source in the center of the lens. The constant light source is arranged outside the model box on the opposite side. It can be debugged on the ground in advance to select the appropriate light source power and number of lights. The high-speed camera frequency f should meet at least 20 pictures per bubble pulsation cycle, so the camera frequency should not be less than:

[0086]

[0087] Before the test, it is advisable to use a ruler to calibrate the high-speed camera image in the model box. The image width is l p It should be greater than 2 times the maximum bubble radius;

[0088]

[0089] The high-speed camera recording time T should not be less than 10 times the bubble pulsation period T b , and set a certain negative delay to prevent emergencies.

[0090]

[0091] The period from the detonation of explosives, the expansion of bubbles, and their contraction to the minimum volume is defined as one bubble pulsation cycle. If high-speed video is not available, the time interval between the peak value of the bubble pulsation pressure and the peak value of the shock wave can be defined as the bubble pulsation cycle. To improve accuracy, the average value of the values ​​obtained by each sensor can be taken.

[0092] (6) Start testing of the equipment

[0093] After the equipment is installed, the weight is added and after preparation, the centrifuge is operated and the test is started to make the model reach the designed acceleration value.

[0094] (7) Data processing and analysis

[0095] First, calculate the shock wave time constant θ at each measuring point, corresponding to the shock wave pressure decaying to p m / e time, p m is the peak pressure, and e≈2.718 is a natural constant. Based on the high-speed video and pressure wave test results, the bubble pulsation period T is calculated.b . Calculate the energy flux density at each measuring point:

[0096] (8) Calculate the shock wave energy and bubble energy and obtain the total explosion energy.

[0097] According to the shock wave curves measured at different positions, the energy flux density e at each measuring point s value,

[0098]

[0099] Where p(t) is the shock wave time history curve, ρ w is the density of water, which is 1000kg / m 3 ;c w is the speed of sound in water, about 1498 m / s. s Value, draw The curve and test points can be fitted with a power function to obtain the following formula:

[0100]

[0101] Where R is the distance between the sensor and the explosive, K E With α E is the curve coefficient. The shock wave energy of the explosive can be calculated from the energy density at the radius of the explosive and the equivalent spherical area.

[0102]

[0103] Where R is the distance between the sensor and the explosive, α e is the equivalent explosive radius. For spherical charges, α e is the explosive radius; for cylindrical charges, α e It can be calculated based on volume equivalence. The bubble energy can be obtained based on the bubble pulsation period:

[0104]

[0105] Where p0 is the atmospheric pressure, about 101.3 kPa, ρ w is the density of water, which is 1000kg / m 3 ; n represents centrifugal acceleration, g = 9.8 m / s 2 , is the ground gravity acceleration; d is the depth of the explosive into the water; T b is the measured bubble pulsation period. In order to improve the accuracy, the test can be carried out under different gravitational acceleration or water depth to obtain the relationship between the underwater explosion radius and the equivalent water head, then

[0106]

[0107] Among them, K Tfor The slope of the curve.

[0108] The sum of the shock wave energy and the bubble energy is the energy of the explosive.

[0109] (9) Carry out the test using TNT of the same specification and calculate the TNT explosion energy based on the above steps 4 to 7. If there is no TNT medicine ball, it can be determined by empirical method, where the parameter K T =2.11, K E =83,α E =2.05.

[0110] (10) Calculate the relative energy using empirical parameters or test data of TNT explosives of the same specifications as in (9) above.

[0111] Example 2

[0112] This embodiment is a schematic cross-sectional view of a centrifuge of an exemplary centrifuge model test device used in the method of the present invention. Figure 2 As shown, the model box 100 in this embodiment is installed on one side of the centrifuge through a hanging basket, and the counterweight is installed in the hanging basket on the other side corresponding to it, so that the centrifuge drives the model box to rotate around the main axis of the centrifuge. The centrifuge and the hanging basket can use known products, wherein the centrifuge further includes an optoelectronic slip ring and an acquisition control system, the acquisition control system includes a blasting control device, a high-speed synchronous data acquisition and a signal conditioner, and the optoelectronic slip ring is an optical fiber data transmission device for the transmission of collected data. The optoelectronic slip ring and the acquisition control system in the centrifuge of the present invention are known products, which will not be repeated here, and the model box structure of the present invention will be described in detail below.

[0113] Figure 3 It is a cross-sectional view showing a model box of a centrifugal model test device. Figure 4 Figure 2 shows a top view of the model box structure. Figure 3 and Figure 4 As shown, the model box 100 of this embodiment is a rectangular parallelepiped structure, which can be spliced ​​by aluminum alloy plates. The model box 100 includes a first side surface 111, a second side surface 112, a third side surface 113 and a fourth side surface 114, and a bottom surface 115. Among them, the first side surface 111 and the third side surface 113 are arranged opposite to each other, and the second side surface 112 and the fourth side surface 114 are arranged opposite to each other. A first organic glass observation window 1111 is arranged on the first side surface 111, and a second organic glass observation window 1131 is arranged on the third side surface 113 for observing the situation inside the model box.

[0114] A cross-shaped bracket 120 is fixed above the model box 100, which includes a first bracket 121, a second bracket 122, a third bracket 123 and a fourth bracket 124. The four brackets are fixed in the middle part 125 in a cross-shaped shape to form an integral structure. One end of the first bracket 121 is fixed above the intersection of the first side 111 and the fourth side 114, and the other end of the first bracket 121 is fixed above the intersection of the second side 112 and the third side 113. One end of the second bracket 122 is fixed to the middle part above the first side 111, and the other end of the second bracket 122 is fixed to the middle part above the third side 113. One end of the third bracket 123 is fixed above the intersection of the first side 111 and the second side 112, and the other end of the third bracket 123 is fixed above the intersection of the third side 113 and the fourth side 114. One end of the fourth bracket 124 is fixed to the middle part above the second side, and the other end of the fourth bracket 124 is fixed to the middle part above the fourth side. The above structure of the cross-shaped bracket enables the bracket to be fastened to the side wall of the model box 100, thereby restraining the deformation of the model box 100, enhancing the impact resistance of the model box, and fixing the sensor mounting rod. At the same time, the cross-shaped structure is also conducive to avoiding mutual interference between multiple installed sensors. In addition, each bracket of the cross-shaped bracket is engraved with a scale of the distance to the center, and each direction is a square groove for fixing the sensor mounting rod 130, which is convenient for accurately determining the sensor position.

[0115] In an exemplary embodiment, the cross-shaped bracket 120 is composed of a rectangular steel frame with a cross section of 4 cm*6 cm. A 2 cm wide through slot is opened in the middle of the steel frame for fixing the sensor. The through slot is marked with scales to determine the position of the sensor. The cross-shaped bracket and the model box are connected by nuts. The sensor mounting rod is fixed with nuts. The scale is accurately positioned and then the upper and lower nuts are tightened. The explosive is hung in the center of the cross-shaped bracket, and each scale is 1 mm.

[0116] The model box 100 of this embodiment is provided with a plurality of sensor mounting rods 130, and these sensor mounting rods 130 are vertically arranged on the same side of the M-shaped sensor bracket 120. The sensor mounting rod 130 is a threaded rod, which is fastened to the sensor bracket 120 by a nut and a buckle 131. The sensor of this embodiment adopts an explosion water pressure sensor 140, which is a product known in the art and can be freely obtained through the market. The number of explosion water pressure sensors 140 is not particularly limited, and can be more than 2, for example, more than 5. The explosion water pressure sensor 140 can be fixed to the lower end of the mounting rod 130 by, for example, waterproof tape.

[0117] It should be noted that the installation position of the sensor is not particularly limited, but the distance between the sensor 130 and the boundary is generally less than 1 / 3 of the half side length. The sensor can be connected to the data acquisition device (not shown) via a cable through the sensor mounting rod 130. After the sensor is installed, the sensitive surface of the sensor is facing the center of the explosive for easy testing. The sensor mounting rod 130 adopts a standard length, which is convenient for unifying the scale with the upper threaded rod and convenient for adjusting the height of the sensor so that it is on the same horizontal plane as the explosive and the test sensitive surface is facing the explosion source.

[0118] In this embodiment, the explosive is suspended inside the model box 100 by cables, and is preferably arranged at the center of the model 100 to reduce the boundary effect. The explosive is suspended under the mounting hole, and the detonator fixing wire passes through the mounting hole and is suspended to the designed horizontal plane. Usually, the center of the explosive is at half the water depth to reduce the boundary effect between the bottom and the free liquid surface.

[0119] like Figure 4 As shown, a high-speed camera 150 is arranged outside the first organic glass observation window 1111, and it is arranged to be able to rotate synchronously with the model box 100. The high-speed camera 150 can be fixed on a hanging basket (not shown) for installing the model box 100. As known in the art, the high-speed camera 150 can also be fixed on the outside of the first organic glass observation window 1111 of the model box 100. A constant light source 160 is arranged on the side of the second organic glass observation window. The constant light source is arranged on the outside of the second side 112, and can be debugged on the ground in advance to select a suitable light source power and light quantity.

[0120] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. Various adjustments or changes may be made to the exemplary embodiments of the present specification without departing from the scope or spirit of the present invention. The scope of the claims should be based on the broadest interpretation to cover all modifications and equivalent structures and functions.

Claims

1. An underwater explosion centrifugal model test method for determining the relative energy of explosives, characterized in that: The following steps are involved: (1) Providing a centrifugal model test device, the centrifugal model test device comprising a model box capable of containing water, an explosive device and a sensor, and a centrifuge designed to make the model box perform centrifugal motion; (2) The centrifugal model test device is used to place the water in the model box in a centrifugal environment, thereby generating a hypergravity field in the water, so that the model reaches the designed acceleration value, and the acceleration is calculated by the following formula (I): Formula (I), at the same time, the acceleration should also satisfy the following formulas (II) and (III), Formula (II), Formula (III), in formula (I) to formula (III), n is the centrifugal acceleration, W p is the mass of the explosive prototype to be simulated, [ W m ] is the maximum amount of medicine allowed by the centrifuge and the model box, H represents the depth of the model box, d Indicates the depth of explosives entering water. l min Indicates the length of the short side of the model box; (3) Detonate explosives in water using an initiator in a centrifugal environment while recording bubble pulsation and shock wave parameters; (4) calculating the explosive energy based on the parameters of step (3); (5) Calculate or measure the energy of the same mass of TNT explosives and calculate the relative energy; Step (3) includes: (3-1) Calculate the shock wave time constant at each measuring point θ , corresponding to the shock wave pressure decaying to p m / e time, p m is the peak pressure, e ≈2.718 is a natural constant; (3-2) According to the shock wave curves measured at different positions, the energy flux density at each measuring point is calculated by the following formula (V): e s value: , formula (V), draw e s / - , the test points are fitted with a power function, and the following formula is obtained: , where R is the distance between the sensor and the explosive, K E and α E is the curve coefficient; (3-3) The shock wave energy is calculated by the following formula (VII): Formula (VII), a e is the equivalent explosive radius, for spherical charges, a e is the explosive radius; for cylindrical charges, a e It can be calculated based on volume equivalence; (3-4) The bubble energy is calculated by the following formula (VI): Formula (VI), wherein, p 0 is atmospheric pressure, 101.3 kPa, ρ w is the density of water, which is 1000kg / m 3 ; n is the centrifugal acceleration, g =9.8m / s 2 , is the ground gravity acceleration; d is the depth of explosives entering water; (3-5) Calculate the sum of the bubble energy and the shock wave energy to obtain the explosive energy.

2. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 1, characterized in that: The centrifugal model test device further comprises a hanging basket, which is designed to enable the model box to be installed on the centrifuge, so that the model box can perform a rotational motion.

3. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 1, characterized in that: The centrifugal model test device further includes a sensor assembly, which includes a sensor, a sensor bracket and a sensor mounting rod, wherein the sensor bracket is arranged in the model box in a manner that it can be basically parallel to the water surface, the sensor mounting rod is arranged in the model box in a manner that it is basically perpendicular to the sensor bracket and extends along the depth direction of the water, the sensor is arranged on the sensor mounting rod, and the mounting rod and the sensor mounting rod are both marked with scales to facilitate determination of the horizontal distance between the explosive and the sensor and the depth of the sensor entering the water.

4. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 3, characterized in that: The model box is in a rectangular shape, and the sensor bracket is in a cross-shaped shape composed of four brackets, and the four brackets are fixed into a whole through the middle part of the cross-shaped shape, and the two ends of each bracket are respectively fixed to the upper part of the model box.

5. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 4, characterized in that: There are multiple sensor mounting rods, and one end of each sensor mounting rod is installed on the same side of the sensor bracket in a basically vertical manner and installed at a specified position of each bracket. A sensor is installed on the other end of each sensor bracket, and the detonating device is arranged below the middle part of the cross shape.

6. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 1, characterized in that: The centrifugal model test device further includes a camera device, and the model box further includes a glass observation window. The camera device is configured to rotate synchronously with the model box and can capture changes in the model box through the glass observation window.

7. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 6, characterized in that: The centrifuge model test device further comprises a light source, and there is a glass wall on the opposite side of the glass observation window. The light source is arranged on the outside of the glass wall to illuminate the background of the image.

8. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 1, characterized in that: Actual Explosive Mass Used in Centrifuge Tests W m for: .

9. The underwater explosion centrifugal model test method for determining the relative energy of explosives according to claim 6, characterized in that: Its pressure sensor range [ p ] satisfies the following formula: , where R is the distance between the explosive and the sensor; The camera frequency of the camera device is determined by the following formula (IV): Formula (IV) in, f Indicates the camera frequency, T b represents the bubble cycle, i.e. the period during which the explosive detonates, the bubble expands, and shrinks to its minimum volume. K T express T b - The slope of the curve, n is the centrifugal acceleration, W m is the mass of explosive actually used in the centrifuge test, d Indicates the depth of explosives entering water.

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