Large blast wave simulation shock tube sparse wave dynamic elimination device and method

Abstract

The invention relates to an explosive wave simulation shock tube auxiliary device and a working method, and provides a large explosive wave simulation shock tube opening sparse wave dynamic elimination device and method in order to solve the problem that the accuracy of a test result is reduced due to the fact that an existing shock tube sparse wave elimination device cannot eliminate interference of sparse waves on the test in real time. The eliminating device comprises an eliminating device body (5) and a feedback control system. The eliminating device is arranged at a tube opening of a low-pressure section of the shock tube. The eliminating device comprises a frame, X fan blades arranged on the frame and Y partition plates vertically arranged, X is larger than or equal to 1, and Y is larger than or equal to 0. The fan blades are arranged in rows, the number of the fan blades in each row is equal, fan blade rotating shafts are arranged on the two sides of each fan blade, each fan blade rotating shaft is connected with one transmission structure, and each fan blade is arranged between every two adjacent partition plates or between one partition plate and the inner side wall of the frame. Each transmission structure and the corresponding fan blade rotating shaft are used for controlling the rotating angle of the corresponding fan blade.

Description

Technical Field

[0001] The present invention relates to an auxiliary device and working method for simulating shock tubes with explosive waves, and particularly to a device and method for dynamically eliminating rarefaction waves at the nozzle of a large-scale explosive wave simulation shock tube. Background Art

[0002] A large-scale explosive wave simulation shock tube (hereinafter referred to as "shock tube") is an important device for conducting tests related to simulating explosive shock wave environments. Its test method is to pre-fill high-pressure gas in the driving section of the shock tube separated by a diaphragm or valve. At the moment when the diaphragm ruptures or the valve opens, the high-pressure gas contacts the atmospheric environment in the test section, generating a shock wave propagating towards the nozzle, and then acting on the test piece to be evaluated in the test section to achieve the assessment of the anti-shock ability of the test piece in an explosive environment. However, after the shock wave generated during the test propagates through the pipeline to the nozzle, due to the large pressure difference between the inside and outside of the nozzle, a rarefaction wave will be generated and transmitted back into the tube, causing the pressure history in the pipeline to drop rapidly, and the positive pressure action time is much shorter than the required simulation of the explosive wave. Therefore, the elimination of rarefaction waves at the nozzle is an urgent problem that must be solved in the construction of shock tubes.

[0003] Currently, domestic rarefaction wave elimination devices have adopted the method of arranging a grid-type baffle structure at the nozzle to weaken the influence of rarefaction waves. However, such structures can only appropriately extend the positive pressure action time in the test section within a certain pressure range and cannot eliminate the interference of rarefaction waves on the test in real time. And when the overpressure of the incident shock wave is lower than this range, this structure basically cannot play a role; when the overpressure of the incident wave is higher than this range, the post-wave airflow will be blocked at the outlet, forming a reflected wave propagating into the tube, causing the overpressure history to increase abnormally for a long time, and the overall deviation from the standard shock wave history is serious.

[0004] Therefore, designing a dynamic rarefaction wave elimination device that can dynamically adjust the nozzle blockage rate according to the overpressure of the incident wave, so that the outflow fluid at the nozzle is always sonic or the pressure is consistent with the external environment, and then realizing the real-time elimination of rarefaction waves, has an important role in ensuring the simulation ability of large-scale explosive wave simulation shock tubes. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem that the existing rarefaction wave elimination device of the shock tube cannot eliminate the interference of rarefaction waves on the test in real time, resulting in a decrease in the accuracy of the test results, and to provide a device and method for dynamically eliminating rarefaction waves at the nozzle of a large-scale explosive wave simulation shock tube.

[0006] To achieve the above purpose, the technical solution provided by the present invention is:

[0007] A device for dynamically eliminating rarefaction waves at the nozzle of a large-scale explosive wave simulation shock tube, characterized in that:

[0008] It includes an elimination device body disposed at the nozzle of the low-pressure section of the shock tube and a feedback control system connected to the elimination device body; the elimination device body includes a frame, X fan blades arranged on the frame, and Y vertical partitions, where X≥1, Y≥0, and both X and Y are positive integers;

[0009] The fan blades are arranged in columns, and the number of fan blades in each column is equal. Fan blade rotating shafts are provided on both sides of each fan blade, and each fan blade rotating shaft is connected to a transmission structure, and the transmission structure is installed on the side wall of the partition or the frame; each fan blade is arranged between two adjacent partitions, or between a partition and the inner side wall of the frame, or between two opposite inner side walls of the frame;

[0010] The frame is connected to the low-pressure section of the shock tube through a transition section;

[0011] Each of the transmission structures is connected to a control mechanism, and each of the transmission structures and the fan blade rotating shafts is used to control the rotation angle of the corresponding fan blade;

[0012] The feedback control system includes a power system with an output end electrically connected to each of the transmission structures, a control system with an output end connected to the input end of the power system, a synchronous machine with an output end connected to the input end of the control system, an oscilloscope with an output end connected to the input end of the synchronous machine, and a pressure sensor arranged on the inner wall of the low-pressure section of the shock tube; the pressure sensor is connected to the input end of the oscilloscope;

[0013] When the pressure sensor detects a shock wave, it sends a trigger signal to the control system; the control system is used to send a control signal to the power system, thereby controlling the working state of the power system; the power system is used to control the rotation state of each transmission structure, thereby adjusting the angle of the corresponding fan blade.

[0014] Further, the transition section includes a frame adapter flange connected to the frame, a transition section adapter flange connected to the frame adapter flange, a transition section cylinder body with one end connected to the transition section adapter flange, and a nozzle adapter flange connected to the other end of the transition section cylinder body, and the nozzle adapter flange is connected to the nozzle of the low-pressure section of the shock tube.

[0015] Further, the shape of the frame is rectangular or rhombic.

[0016] Further, the transmission structure is a gear.

[0017] Further, X = 30, Y = 2, and the distance between two adjacent fan blades in each column is equal; define the distance between two adjacent partitions as d1, and the distance between the partition on the side and the corresponding inner side wall of the frame as d2, d1 = d2, and the size of each fan blade is the same, and the size of each partition is the same.

[0018] At the same time, the present invention also provides a method for dynamically eliminating sparse waves in a large explosion wave simulation shock tube, which uses the above-mentioned large explosion wave simulation shock tube sparse wave dynamic elimination device, and its special feature is that it includes the following steps:

[0019] Step 1: Set the actual needs and determine the experimental conditions according to the actual needs; then determine the change process of the rarefaction wave in the shock tube simulated by the large explosion wave according to the experimental conditions;

[0020] Step 2: simulating the change process of the rarefaction wave in the shock tube according to the large explosion wave, calculating and writing the corresponding preset parameters and control program, and then inputting the preset parameters and control program into the control system;

[0021] Step 3, adjusting the initial angle of the fan blades, and setting the blocking rate of the sparse wave dynamic elimination device of the large explosion wave simulation shock tube to a value corresponding to the peak value p of the shock wave overpressure simulated by the test;

[0022] Step 4, start the test, start the large explosion wave simulation shock tube, and make the fan blades dynamically rotate by a preset angle according to the preset parameters and control program input in step 2 to achieve full dynamic elimination of sparse waves in the large explosion wave simulation shock tube.

[0023] Furthermore, in step 2, the preset parameters include the time t required for the wavefront of the explosion wave to be transmitted from the pressure sensor to the entrance of the elimination device body, and the delayed triggering time t of the power system. d , where t d =L / Vt i , L is the distance between the pressure sensor and the entrance of the elimination device, t i is the self-delay time for the power system to enter the working state after receiving the control signal from the power system, V is the wave velocity of the shock wave, a0 is the sound speed of the atmospheric environment, p0 is the atmospheric pressure, and γ is the specific heat ratio.

[0024] Furthermore, step 4 is specifically as follows:

[0025] The test begins by starting the large explosion wave simulation shock tube. When the incident shock wave front generated in the large explosion wave simulation shock tube is transmitted to the location of the pressure sensor, the pressure sensor generates a trigger signal, which passes through the oscilloscope and the synchronizer in turn and finally reaches the control system. Then the control system enters the standby state and after t d After a certain period of time, the control system sends a control signal to the power system. iAfter a certain period of time, the shock wave propagates to the entrance of the elimination device body, and the power system starts to control each transmission structure to drive the corresponding fan blade to rotate, so that the blockage rate of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device increases continuously with the attenuation of the shock wave overpressure until all the fan blades are completely closed; after the above process is completed, the fan blades are rotated to a preset final angle until the end of the test, realizing the whole process dynamic elimination of the rarefaction wave in the large explosion wave simulation shock tube.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] 1. The large explosion wave simulation shock tube nozzle rarefaction wave dynamic elimination device provided by the present invention can dynamically change the blocked area of the outlet of the low-pressure section of the shock tube, thereby greatly weakening the influence of the rarefaction wave on the internal flow field of the test section and ensuring the normal implementation of the test. This device has the characteristics of small floor area, convenient and flexible operation, high activity, relatively simple structure, etc., and is of great significance for the research of the effector under the action of the explosion shock wave;

[0028] 2. The large explosion wave simulation shock tube nozzle rarefaction wave dynamic elimination device provided by the present invention can adjust the blocked area of the large explosion wave simulation shock tube nozzle in real time according to a preset program and the incident shock wave overpressure, so that no rarefaction wave is generated at the outlet of the pipeline or the rarefaction wave cannot propagate back upstream, realizing the basic elimination of the rarefaction wave inside the test section;

[0029] 3. The large explosion wave simulation shock tube nozzle rarefaction wave dynamic elimination device provided by the present invention adopts a split-column design for the main body, and is a fan blade structure independently controlled by three groups of transmission structures in the horizontal direction, which can greatly reduce the power burden of the transmission structure in the power system and correspondingly improve the control accuracy of the control mechanism; the blocked areas of each column of the elimination device can be adjusted synchronously or independently according to a preset program, and can adapt to other waveforms other than the common exponential decay wave. Description of the Drawings

[0030] Figure 1 It is a schematic structural diagram of an embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0031] Figure 2 It is a schematic structural diagram of the elimination device body in an embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0032] Figure 3 It is an assembly schematic diagram of the elimination device body in an embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0033] Figure 4 It is a front view of the elimination device body in an embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0034] Figure 5 This is the rear view of the elimination device body in the embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0035] Figure 6 This is the side view of the elimination device body in the embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0036] Figure 7 This is the sectional view of the elimination device body in the embodiment of the large explosion wave simulation shock tube rarefaction wave dynamic elimination device of the present invention;

[0037] Explanation of reference numerals in the drawings:

[0038] 1 - Frame, 11 - Frame adapter flange; 21 - Fan blade, 22 - Fan blade rotating shaft; 3 - Transmission structure; 4 - Transition section, 41 - Pipe orifice adapter flange, 42 - Transition section cylinder, 43 - Transition section adapter flange; 5 - Elimination device; 6 - Low - pressure section of shock tube; 7 - Pressure sensor; 8 - Power system; 9 - Control system; 10 - Synchronous machine 11 - Oscilloscope. Detailed implementation manners

[0039] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0040] A large explosion wave simulation shock tube rarefaction wave dynamic elimination device, see Figures 1 to 7 ; It includes an elimination device body 5 arranged at the orifice of the low - pressure section 6 of the shock tube and a feedback control system connected to the elimination device body 5; The elimination device body 5 includes a rectangular frame 1, thirty fan blades 21 arranged on the frame 1, and two vertically arranged partitions 12;

[0041] The fan blades 21 are arranged in columns, the number of fan blades 21 in each column is equal, both sides of each fan blade 21 are provided with fan blade rotating shafts 22, each fan blade rotating shaft 22 is connected to a transmission structure 3, and each fan blade 21 is arranged between two adjacent partitions 12 or between a partition 12 and the inner wall of the frame 1; The distance between two adjacent fan blades 21 in each column is equal; Define the distance between two adjacent partitions 12 as d1, and the distance between the partition 12 on the side and the inner wall of the frame 1 as d2, d1 = d2, the size of each fan blade 21 is the same, and the size of each partition 12 is the same; Each transmission structure 3 and fan blade rotating shaft 22 are used to control the rotation angle of the corresponding fan blade 21;

[0042] The large-scale blast wave simulation shock tube rarefaction wave dynamic elimination device 5 is connected to the low-pressure section 6 of the shock tube by welding through the transition section 4; each transmission structure 3 is connected to an external control mechanism. The transition section 4 includes a frame adapter flange 11 connected to the frame 1, a transition section adapter flange 43 connected to the frame adapter flange 11, a transition section cylinder 42 with one end connected to the transition section adapter flange 43, and a pipe orifice adapter flange 41 connected to the other end of the transition section cylinder 42. The pipe orifice adapter flange 41 is connected to the pipe orifice of the low-pressure section 6 of the shock tube. In actual design, the shape of the pipe orifice adapter flange 41 can be changed so that the device can be installed on shock tubes with different shapes without changing the device structure.

[0043] The frame 1 is usually designed as a rectangle, a circle or its derivative structure. The inner diameter or inner side length of the frame 1 should be large enough so that when the large-scale blast wave simulation shock tube rarefaction wave dynamic elimination device 5 is installed at the pipe orifice of the low-pressure section 6 of the shock tube, it is not blocked by the frame 1 without the partition 12 within the positive projection range outside the pipe orifice. The partitions 12 should usually be arranged at equal intervals or symmetrically arranged with respect to the central axis of the frame 1.

[0044] The cross-sectional area of the fan blade 21 is usually designed as a rectangle or a rhombus according to specific needs. The characteristics of the rectangular cross-section are, first, the blockage ratio of the large-scale blast wave simulation shock tube rarefaction wave dynamic elimination device 5 starts to change when the fan blade 21 starts to rotate, which is beneficial to advancing the response time of the device; second, the processing cost is relatively low. The characteristics of the rhombus cross-section fan blade are, first, the blockage ratio of the large-scale blast wave simulation shock tube rarefaction wave dynamic elimination device 5 only starts to change after the fan blade rotates a certain angle, and the acceleration of the rotation of the fan blade 21 can be utilized during this stage, which is beneficial to reducing the response demand of the device power system; second, the moment of inertia of the fan blade 21 is small, which is beneficial to reducing the power demand of the power system. The length of the fan blade 21 should be designed so that the distance between it and the two side walls is the same. The width of the fan blade 21 should be designed so that when a row of fan blades 21 all rotate to be perpendicular to the ground, they can completely block the outflow channel where they are located. Usually, the design dimensions of each row of fan blades 21 should be exactly the same and arranged at equal intervals. The adjacent two rows of fan blades 21 should be staggered in the vertical direction with a small distance to avoid interference between the fan blade rotating shafts 22.

[0045] The transmission structure 3 is a gear. There is no specific requirement for the form of the transmission structure 3, and various forms such as gears and hinges can be adopted. Usually, an independent transmission structure 3 should be provided for a group of fan blades 21 in each outflow channel so that each row of fan blades 21 can rotate independently or in a coupled manner, thereby realizing a more adjustable time course of the change in the blockage ratio of the large-scale blast wave simulation shock tube rarefaction wave dynamic elimination device 5.

[0046] The feedback control system includes a power system 8 whose output end is electrically connected to each transmission structure 3, a control system 9 whose output end is connected to the input end of the power system 8, a synchronous machine 10 whose output end is connected to the input end of the control system 9, an oscilloscope 11 whose output end is connected to the input end of the synchronous machine 10, and a pressure sensor 7 disposed on the inner wall of the low-pressure section 6 of the shock tube; the pressure sensor 7 is connected to the input end of the oscilloscope 4;

[0047] When the pressure sensor 7 detects a shock wave, it sends a trigger signal to the control system 9; the control system 9 is used to send a control signal to the power system 8, thereby controlling the working state of the power system 8; the power system 8 is used to control the rotation state of each transmission structure 3, thereby adjusting the angle of the corresponding fan blade 21.

[0048] Meanwhile, this embodiment also provides a method for dynamically eliminating rarefaction waves in a large-scale explosion wave simulation shock tube. Using the above-mentioned large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device, it includes the following steps:

[0049] Step 1: Set the actual requirements. According to the actual requirements, determine the experimental conditions; then determine the change process of the rarefaction wave in the large-scale explosion wave simulation shock tube according to the experimental conditions;

[0050] Step 2: According to the change process of the rarefaction wave in the large-scale explosion wave simulation shock tube, calculate and compile the corresponding preset parameters and control programs, and then input the preset parameters and control programs into the control system 9; the preset parameters include the time t required for the wave front of the explosion wave to be transmitted from the pressure sensor 7 to the entrance of the elimination device body 5, and the delay trigger time t d of the power system 8, d where t i = L / V - t L is the distance between the pressure sensor 7 and the entrance of the elimination device body 5, t i is the self-delay time for the power system 8 to enter the working state after receiving the control signal sent by the power system 8, V is the wave speed of the shock wave, a0 is the speed of sound in the atmospheric environment, p0 is the atmospheric pressure, and γ is the specific heat ratio.

[0051] Step 3: Adjust the initial angle of the fan blade 21, and set the blockage ratio of the large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device 5 to a value corresponding to the overpressure peak p of the shock wave simulated in the test;

[0052] Step 4: Start the test. Start the large-scale explosion wave simulation shock tube. When the wave front of the incident shock wave generated in the large-scale explosion wave simulation shock tube is transmitted to the position where the pressure sensor 7 is located, the pressure sensor 7 generates a trigger signal. The trigger signal passes through the oscilloscope 11 and the synchronous machine 10 in sequence, and finally reaches the control system 9; then the control system 9 enters the waiting operation state, and after td After a certain time duration, the control system 9 sends a control signal to the power system 8. After a time duration of t i After a time duration of t, the shock wave propagates to reach the entrance of the shock wave elimination device body 5. The power system 8 starts to control each transmission structure 3 to drive the corresponding fan blade 21 to rotate, so that the blockage ratio of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 continuously increases with the attenuation of the shock wave overpressure until all the fan blades 21 are completely closed. After completing the above process, the fan blades 21 are rotated to a preset final angle until the end of the test, realizing the whole-process dynamic elimination of the rarefaction wave in the large explosion wave simulated shock tube.

[0053] The principle is as follows: The fan blade 21 can rotate 360° driven by the fan blade rotating shaft 22. When the plane of the fan blade 21 is parallel to the oncoming flow direction, the blockage ratio of the rarefaction wave elimination device is the smallest, about 10%. Among them, the blocked area of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 is the size of the orthographic projection area of the fan blade 21, the partition plate 12, and the transmission structure 3 inside the cross-sectional area of the low-pressure section 6 of the shock tube. The blockage ratio is the ratio of its blocked area to the cross-sectional area of the low-pressure section 6 of the shock tube. When the plane of the fan blade 21 is perpendicular to the oncoming flow direction, the blockage ratio of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 is the largest, which can reach 100%. The purpose of rotating the fan blade 21 to the open state with the minimum blockage ratio until the end of the experiment is to prevent the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 from being damaged by the large pressure difference between the inside and outside due to the larger pressure difference on both sides of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 after the incident wave enters the negative pressure area.

[0054] Table 1 is the corresponding relationship table between the shock wave overpressure and the blockage ratio of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5.

[0055] Table 1. Corresponding relationship table between shock wave overpressure and blockage ratio of large explosion wave simulated shock tube rarefaction wave dynamic elimination device

[0056]

[0057] Figure 4 In the figure, part a is the blocked part of the transmission structure, part b is the blocked part of the partition plate, and part c is the blocked part of the fan blade. The figure shows the situation when all the fan blades 21 of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 are completely open. The black shaded part inside the circular cross-section of the pipe orifice is the "orthographic projection of the fan blade 21, the partition plate 12, and the transmission structure 3 inside the circular cross-section of the shock tube". At this time, the blockage ratio of the large explosion wave simulated shock tube rarefaction wave dynamic elimination device 5 is the smallest, about 10%.

Claims

1. A device for dynamically eliminating rarefaction waves in a shock tube for large explosion wave simulation, characterized in that: It includes an elimination device body (5) arranged at the nozzle of the low-pressure section (6) of the shock tube and a feedback control system connected to the elimination device body (5); the elimination device body (5) includes a frame (1), X fan blades (21) arranged on the frame (1), and Y vertical partitions (12), where X≥1, Y≥0, and both X and Y are positive integers; The fan blades (21) are arranged in columns, and the number of fan blades (21) in each column is equal. On both sides of each fan blade (21), there are fan blade rotating shafts (22), and each fan blade rotating shaft (22) is connected to a transmission structure (3). The transmission structure (3) is installed on the side wall of the partition (12) or the frame (1); each fan blade (21) is arranged between two adjacent partitions (12), or between a partition (12) and the inner side wall of the frame (1), or between two opposite inner side walls of the frame (1); The frame (1) is connected to the low-pressure section (6) of the shock tube through a transition section (4); Each of the transmission structures (3) is connected to a control mechanism, and each of the transmission structures (3) and the fan blade rotating shafts (22) are used to control the rotation angle of the corresponding fan blade (21); The feedback control system includes a power system (8) whose output end is electrically connected to each of the transmission structures (3), a control system (9) whose output end is connected to the input end of the power system (8), a synchro (10) whose output end is connected to the input end of the control system (9), an oscilloscope (11) whose output end is connected to the input end of the synchro (10), and a pressure sensor (7) arranged on the inner wall of the low-pressure section (6) of the shock tube; the pressure sensor (7) is connected to the input end of the oscilloscope (4); When the pressure sensor (7) detects a shock wave, it sends a trigger signal to the control system (9); the control system (9) is used to send a control signal to the power system (8) to control the working state of the power system (8); the power system (8) is used to control the rotation state of each transmission structure (3) to adjust the angle of the corresponding fan blade (21).

2. The device for dynamically eliminating rarefaction waves in a shock tube for large explosion wave simulation according to claim 1, characterized in that: The transition section (4) includes a frame adapter flange (11) connected to the frame (1), a transition section adapter flange (43) connected to the frame adapter flange (11), a transition section cylinder (42) with one end connected to the transition section adapter flange (43), and a nozzle adapter flange (41) connected to the other end of the transition section cylinder (42). The nozzle adapter flange (41) is connected to the nozzle of the low-pressure section (6) of the shock tube.

3. The device for dynamically eliminating rarefaction waves in a shock tube for large explosion wave simulation according to claim 2, characterized in that: The shape of the frame (1) is rectangular or rhombic.

4. The device for dynamically eliminating rarefaction waves in a shock tube for large explosion wave simulation according to claim 3, characterized in that: The transmission structure (3) is a gear.

5. The large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device according to claim 4, characterized in that: X = 30, Y = 2, and the distances between adjacent two fan blades (21) in each column are equal; define the distance between adjacent two partition plates (12) as d1, and the distance between the partition plate (12) on the side and the inner side wall of the corresponding frame (1) as d2, d1 = d2, the sizes of each fan blade (21) are the same, and the sizes of each partition plate (12) are the same.

6. A method for dynamically eliminating rarefaction waves in a large-scale explosion wave simulation shock tube, which uses the large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device described in any one of claims 1-5, and is characterized in that, It includes the following steps: Step 1: Set the actual requirements, determine the working conditions of the experiment according to the actual requirements; then determine the change process of the rarefaction wave in the large-scale explosion wave simulation shock tube according to the working conditions of the experiment. Step 2: Calculate and compile the corresponding preset parameters and control programs according to the change process of the rarefaction wave in the large-scale explosion wave simulation shock tube, and then input the preset parameters and control programs into the control system (9). Step 3: Adjust the initial angle of the fan blade (21), and set the blockage ratio of the large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device (5) to a value corresponding to the peak overpressure p of the shock wave simulated in the test. Step 4: Start the test, start the large-scale explosion wave simulation shock tube, and make the fan blade (21) rotate dynamically by a preset angle according to the preset parameters and control programs input in Step 2, so as to achieve the full-process dynamic elimination of the rarefaction wave in the large-scale explosion wave simulation shock tube.

7. The large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination method according to claim 6, characterized in that: In step 2, the preset parameters include the time t required for the wave front of the blast wave to be transmitted from the pressure sensor (7) to the inlet of the elimination device body (5), and the delayed trigger time t of the power system (8). d , where L is the distance between the pressure sensor (7) and the inlet of the elimination device body (5), t i is the self-delay time for the power system (8) to enter the working state after receiving the control signal sent by the power system (8), V is the wave speed of the shock wave, a0 is the speed of sound in the atmospheric environment, p0 is the atmospheric pressure, and γ is the specific heat ratio.

8. The large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination method according to claim 7, characterized in that, Step 4 is specifically: Start the experiment and activate the large-scale explosion wave simulation shock tube. When the incident shock wave front generated in the large-scale explosion wave simulation shock tube transmits to the position where the pressure sensor (7) is located, the pressure sensor (7) generates a trigger signal. The trigger signal passes through the oscilloscope (11) and the synchronizer (10) in sequence, and finally reaches the control system (9). Then the control system (9) enters the standby state. After a time t d duration, the control system (9) sends a control signal to the power system (8). After a time t i duration, the shock wave propagates to the entrance of the elimination device body (5). The power system (8) starts to control each transmission structure (3) to drive the corresponding fan blade (21) to rotate, so that the blockage ratio of the large-scale explosion wave simulation shock tube rarefaction wave dynamic elimination device (5) continuously increases with the attenuation of the shock wave overpressure until all the fan blades (21) are completely closed. After the above process is completed, the fan blades (21) are rotated to a preset final angle until the end of the experiment, realizing the whole-process dynamic elimination of the rarefaction wave in the large-scale explosion wave simulation shock tube.

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