A ballistic target for a two-stage light gas gun driven by electromagnetic catapult

Abstract

The present invention provides a ballistic target for a two-stage light-gas gun driven by an electromagnetic catapult, comprising an electromagnetic catapult device, an armature, a piston, a high-pressure pump tube, a primary and secondary connecting mechanism, a projectile, a launch tube, an expansion tank, a test chamber, and a measurement and control system. The electromagnetic catapult device comprises an electromagnetic pump tube, a multi-stage drive coil wound around the electromagnetic pump tube, an excitation power supply for supplying power to the multi-stage drive coil, and a charger for charging the excitation power supply. The primary and secondary connecting mechanism comprises a secondary air chamber and a secondary diaphragm. The armature and piston are built into the inlet end of the electromagnetic pump tube. The projectile is built into the inlet end of the launch tube. The armature is subjected to electromagnetic force in the pulsed magnetic field of the electromagnetic catapult device, pushing the piston to compress the light gas. The high-temperature and high-pressure light gas breaks through the secondary diaphragm, driving the projectile to fly out of the launch tube at high speed through the expansion tank and into the test chamber. The present invention uses electromagnetic catapult as the primary drive of the two-stage light-gas gun, which improves the driving capacity by several times over that of traditional power sources, while being safer, cleaner, more efficient, and more controllable.

Description

Technical Field

[0001] The present application relates to the technical field of hypervelocity flight ground simulation test or hypervelocity collision loading test, and in particular to a ballistic target based on an electromagnetic catapult-driven two-stage light gas gun. Background Art

[0002] A ballistic target is an aerodynamic ground test device that enables aerodynamic test models to fly freely in static gas. It can simulate real flight flow conditions and can be used to conduct tests such as aerodynamic force / heat, aerodynamic physics, and hypervelocity collisions. The target mainly consists of a model launcher, a test system, and a measurement and control system. Traditional ballistic targets usually use a two-stage light gas gun as the core launch device and gunpowder as the driving source. The high-pressure gas after the gunpowder combustion drives the piston to move at high speed to compress the light gas (hydrogen or helium) in the pump tube to a high temperature and high pressure state. The high-pressure light gas is then used to drive the projectile to reach the required test speed. Due to the safety, uncertainty, and driving capacity limitations of gunpowder, the current launch speed of gunpowder-driven ballistic targets is usually in the range of 2km / s to 6km / s.

[0003] In recent years, China has strengthened research on the power source of two-stage light gas guns, and has successively developed two-stage light gas guns with new driving methods such as high-pressure gas and hydrogen-oxygen explosion.

[0004] The Chinese patent authorization announcement number is CN103322857B, and the authorization announcement date is December 17, 2014. The name of the invention is: A small two-stage light gas cannon. This patent authorizes a small two-stage light gas cannon with a first-stage drive using compressed air or helium and a second-stage drive using piston-compressed hydrogen. It is safer and more environmentally friendly than gunpowder drive, does not require gunpowder use qualifications, and provides great convenience for research in related fields; however, its shortcomings are that the energy density is not high enough and the driving ability is weak.

[0005] China's patent authorization announcement number is CN106679500B, and the authorization announcement date is August 17, 2018. The name of the invention is: A two-stage light gas cannon driven by hydrogen energy. The patent authorizes a light gas cannon that uses hydrogen-oxygen mixed gas detonation as the first-stage drive. Compared with the gunpowder drive method, it causes less damage to the cannon, does not produce particulate matter, is cleaner and more environmentally friendly, and has higher energy utilization than the compressed gas drive method; however, its shortcomings are that the domestic requirements for the management of flammable gases are strict, and the technical safety and experimental economy are not high.

[0006] In addition, gas gun systems driven by gunpowder gas, compressed gas, hydrogen-oxygen explosion, etc. generally have the inherent problem that the base pressure of the projectile drops rapidly after the projectile is launched and cannot provide a high average pressure for the projectile, and cannot guarantee excellent interior ballistic performance.

[0007] Chinese patent publication number CN108759559A, publication date November 6, 2018, is titled "A Two-Stage Light Gas Gun." The application discloses a two-stage light gas gun with an electromagnetic gun as the first-stage drive. The gun is safer and more environmentally friendly than gunpowder drive, mixed gas detonation, and other methods, and has stronger driving capability and a higher optimal firing speed than high-pressure gas drive. However, its shortcomings are the failure to provide an optimized control scheme for the timing triggering of the electromagnetic coil gun's multi-stage coils, and the inability to fully demonstrate whether the multi-stage electromagnetic coil gun can normally, reasonably, and feasibly fire projectiles at maximum speed. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems of weak driving capability and insufficient projectile launch speed of the existing two-stage light gas gun as the core launch device of the ballistic target, while exploring the potential of the electromagnetic catapult drive method. It provides a hypervelocity ballistic target scheme with a two-stage light gas gun driven by electromagnetic catapult as the launch device. It ensures that the driving capability is improved under the condition of high-speed projectile launch and the interior ballistic performance is improved at the same time, providing a safe, clean, efficient and controllable large-caliber test platform for aerodynamic / thermal, aerodynamic physics and hypervelocity collision tests.

[0009] In a first aspect, a ballistic target for a two-stage light gas gun driven by electromagnetic catapult is provided, which is characterized by comprising an electromagnetic catapult device, an armature, a piston, a high-pressure pump pipe, a primary and secondary connection mechanism, a projectile, a launch tube, an expansion tank, a test chamber, and a measurement and control system; wherein,

[0010] Each stage of the drive coil is connected to an independent excitation power supply, and the excitation power supply is triggered step by step to discharge the multi-stage drive coil step by step. The armature moves under the action of the electromagnetic force generated by the multi-stage drive coil and pushes the piston, and the piston flies out of the electromagnetic pump pipe and enters the high-pressure pump pipe;

[0011] The primary and secondary connection mechanism includes a secondary air chamber and a secondary diaphragm. The electromagnetic pump tube, the high-pressure pump tube, the secondary air chamber, and the launch tube are connected in sequence. The secondary diaphragm is provided between the secondary air chamber and the launch tube. The projectile is built into the inlet end of the launch tube, and the projectile is in front of the secondary diaphragm.

[0012] The electromagnetic pump tube, the high-pressure pump tube and the secondary air chamber in front of the piston are filled with light gas. The light gas in the electromagnetic pump tube, the high-pressure pump tube and the secondary air chamber breaks through the secondary diaphragm under the compression of the piston, pushing the projectile to fly out of the launch tube and pass through the expansion tank into the test chamber;

[0013] The measurement and control system is used to determine the triggering moment of each stage of the excitation power supply according to the moving speed and position of the armature.

[0014] In conjunction with the first aspect, in certain implementations of the first aspect, the electromagnetic catapult device satisfies at least one of the following:

[0015] The inner diameter of the electromagnetic pump tube is not less than 50mm;

[0016] The ratio of the piston mass to the cross-sectional area of ​​the electromagnetic pump tube is greater than 500 kg / m 2 ;

[0017] The maximum speed of the piston is 1.0 km / s;

[0018] The inner wall roughness of the electromagnetic pump tube is Ra≤1.6;

[0019] The number of stages of the multi-stage driving coil is n, where n≥3;

[0020] The structural parameters and electromagnetic parameters of the driving coils and excitation power supplies at each level are the same;

[0021] The ratio of the length of each stage driving coil to the inner diameter of the electromagnetic pump tube is 0.4 to 1.7;

[0022] The ratio of the distance between the end faces of adjacent driving coils to the inner diameter of the electromagnetic pump tube is 0.1 to 0.3.

[0023] In combination with the first aspect, in certain implementations of the first aspect, the excitation power supply includes an energy storage pulse capacitor group, a main switch, and a freewheeling switch; the energy storage pulse capacitor group is connected in series with the main switch and in parallel with the freewheeling switch at both ends of the drive coil, and the two ends of the energy storage pulse capacitor group are also connected to the two ends of the charger through a charging switch, and the conduction and disconnection of the main switch and the charging switch are controlled by the measurement and control system.

[0024] In conjunction with the first aspect, in certain implementations of the first aspect, the excitation power supply satisfies at least one of the following:

[0025] The energy storage pulse capacitor group is composed of a combination of metallized film self-healing pulse capacitors, and the energy volume ratio of the metallized film self-healing pulse capacitor is greater than or equal to 0.5MJ / m 3 , working life is greater than or equal to 1000 times;

[0026] The main switch is a spark gap switch or a high-voltage switch composed of a semiconductor thyristor;

[0027] The freewheeling switch is composed of a combination of semiconductor high-voltage diodes.

[0028] In conjunction with the first aspect, in certain implementations of the first aspect, the measurement and control system includes a central controller, a pulse trigger circuit, and a laser Doppler armature speed measurement device;

[0029] The laser Doppler armature speed measuring device includes an armature speed measuring device main body and an armature speed measuring device probe. The armature speed measuring device probe is installed at the pipe opening sealing portion at one end of the first-stage electromagnetic pump pipe. The armature speed measuring device main body and the armature speed measuring device probe are connected via an optical fiber.

[0030] The armature speed measuring device main body device transmits a laser signal to the armature through the armature speed measuring device probe and receives the laser signal reflected from the armature, and converts the laser signal into an electrical signal and transmits it to the central controller;

[0031] The central controller processes the electrical signal to obtain the armature position and instantaneous speed at each moment, and obtains the estimated triggering moment of the stage to be triggered;

[0032] At the expected triggering moment, the central controller sends a trigger control signal to the pulse triggering circuit, and the pulse triggering circuit outputs a power pulse to trigger the corresponding stage excitation power supply to be turned on.

[0033] In conjunction with the first aspect, in certain implementations of the first aspect, the central controller is configured to execute a timing trigger control method, and the timing trigger control method includes:

[0034] Step 1: i = 1, at time t i＝1 =0 triggers the first-stage excitation power supply to be turned on, and simultaneously controls the laser Doppler armature speed measuring device (1103) to emit laser light along the moving direction of the armature (2);

[0035] Step 2: i = 2, at time t i＝2 Triggering the conduction of the second stage excitation power supply, the time t2 satisfies: t m <t2<2t m , where t m is the time interval from when the discharge current of the driving coil changes from zero to when it reaches the maximum value; at the same time, the laser Doppler armature speed measuring device (1103) is controlled to perform measurement to obtain the position and speed of the armature (2) at time t2;

[0036] Step 3: Loop through the following steps 3-1 and 3-2 until the moment t at which the n-th stage excitation power supply is turned on is obtained. n :

[0037] Step 3-1: At time t i+1 Triggering the conduction of the i+1th level excitation power supply, the time t i+1 satisfy:

[0038] v i is time t iArmature (2) speed, a is the average acceleration of armature (2) motion, h is the distance between the centers of two adjacent driving coils;

[0039] Step 3-2: Let i=i+1.

[0040] In conjunction with the first aspect, in certain implementations of the first aspect, t m according to OK, L d It is the sum of all self-inductances of the discharge circuit before the discharge current of the driving coil is freewheeled by the diode, and C is the capacitance value of the energy storage capacitor group.

[0041] In combination with the first aspect, in certain implementations of the first aspect, before starting, the rear end surface of the armature is aligned with the center line of the first-stage drive coil.

[0042] In conjunction with the first aspect, in certain implementations of the first aspect, the high-pressure pump tube satisfies at least one of the following:

[0043] The high-pressure pump tube and the electromagnetic pump tube are coaxial with each other and have the same inner diameter, which is not less than 50 mm;

[0044] The inner wall roughness of the high-pressure pump tube Ra≤1.6;

[0045] In conjunction with the first aspect, in certain implementations of the first aspect, the secondary air chamber includes a large-diameter straight pipe section, a reducing diameter section, and a small-diameter straight pipe section, the convex stop of the large-diameter straight pipe section is adapted to the concave stop at the outlet end of the high-pressure pump tube, and the convex stop of the small-diameter straight pipe section is adapted to the concave stop at the inlet end of the launch tube;

[0046] The launch tube inlet end is provided with a concave stop, a secondary diaphragm groove, and a tapered groove in sequence along the center line. The diameter of the concave stop at the launch tube inlet end is larger than the secondary diaphragm groove, and the secondary diaphragm is placed in the secondary diaphragm groove; the diameter of the tapered groove gradually decreases from one end of the secondary diaphragm groove, the maximum diameter of the tapered groove is smaller than the diameter of the secondary diaphragm groove, and the minimum diameter of the tapered groove is equal to the inner diameter of the launch tube.

[0047] In conjunction with the first aspect, in certain implementations of the first aspect, the secondary air chamber satisfies at least one of the following:

[0048] The roughness of the secondary air chamber wall Ra≤0.8;

[0049] The ratio of the length of the large diameter straight pipe section to the diameter reducing section is 0.5 to 1.0;

[0050] The ratio of the length of the small diameter straight pipe section to the length of the variable diameter section is 0.3 to 0.6;

[0051] The diameter-changing section adopts a cone-shaped structure with a small cone angle of 6° to 15°;

[0052] The ratio of the length of the high-pressure pump tube to the length of the reducing section is 6 to 20;

[0053] The total pressure P of the light gas in the secondary gas chamber before the secondary diaphragm breaks 2x and total temperature T 2x The expression is:

[0054]

[0055] Where γ2 is the initial specific heat ratio of the light gas in the secondary chamber, P 20 is the initial pressure of the light gas in the secondary gas chamber, T 20 is the initial temperature of the light gas in the secondary chamber, V 20 is the initial total volume of the electromagnetic pump tube, high-pressure pump tube, and secondary air chamber in front of the piston, x is the distance between the armature and the piston, D is the inner diameter of the electromagnetic pump tube, V 2x (x) is the volume of light gas in the closed space between the piston and the secondary diaphragm when the piston moves a distance x.

[0056] In conjunction with the first aspect, in certain implementations of the first aspect, the transmitting tube satisfies at least one of the following:

[0057] The ratio of the inner diameter of the high-pressure pump tube to the inner diameter of the launch tube is 3 to 5;

[0058] The ratio of the launch tube length to the inner diameter is 280 to 560;

[0059] The inner wall roughness of the transmitting tube is Ra≤0.8.

[0060] In conjunction with the first aspect, in certain implementations of the first aspect, the ballistic target satisfies at least one of the following:

[0061] The armature structure is an integral solid cylinder or a hollow cylinder;

[0062] The material of the armature is aluminum or aluminum alloy;

[0063] The charger is an IGBT series resonant constant current charging power supply;

[0064] The light gas is hydrogen or helium, and the pressure of the hydrogen or helium is 0.01-1.0 MPa;

[0065] The electromagnetic pump tube is made of resin-based composite material, engineering plastic or ceramic material, and the maximum operating temperature of the electromagnetic pump tube is 260 degrees Celsius;

[0066] The high-pressure pump tube and the launch tube are made of gun steel;

[0067] When the high-pressure pump pipe, the electromagnetic pump pipe, and the launch pipe need to be connected to each other in sections using pipes of the same specifications, the sections are connected using a flange structure, a Hough nut structure, or a Hough clamp structure;

[0068] The piston structure is a whole cylindrical type or a three-section type with the piston head, steel counterweight and piston tail connected in sequence;

[0069] The piston head and piston tail are made of polyethylene or polytetrafluoroethylene;

[0070] The secondary diaphragm adopts a flat plate structure and is provided with a "cross" shaped four-petal groove or an "*" shaped six-petal groove;

[0071] The secondary diaphragm material is austenitic stainless steel with a tensile strength greater than 500 MPa;

[0072] The launch tube, expansion box and test chamber in front of the projectile are filled with test gas, which is air, and the air pressure is 10Pa~0.2MPa;

[0073] The projectile is a full-caliber projectile without a sabot or a combined projectile with a sabot. When the projectile is a full-caliber projectile without a sabot, the ratio of the projectile length to the diameter is greater than 0.5. After the projectile is launched, it passes through an expansion box and enters the test chamber. When the projectile is a combined projectile with a sabot, the combined projectile consists of a projectile body and a sabot. The sabot is a split-petal combination structure with two to eight petals, and the sabot material is polycarbonate, high-pressure polyethylene, or nylon. After the projectile is launched, the sabot and the projectile body are separated in the expansion box, and the projectile body enters the test chamber.

[0074] The expansion tank and the test chamber are equipped with a projectile velocity measurement system, a camera system for measuring the projectile position and posture, a shadow / schlieren instrument for flow field display, and a light radiation measurement system for measuring light radiation characteristics;

[0075] The ballistic target includes several supporting mechanisms and a track system. The supporting mechanisms are respectively located below the electromagnetic pump pipe, the high-pressure pump pipe, the launch tube, the expansion tank and the test chamber. The supporting mechanisms are installed on the track system and can move along the track.

[0076] In a second aspect, a timing trigger control method is provided, the method being applied to the ballistic target as described in any one of the implementations of the first aspect, the method comprising:

[0077] Step 1: i = 1, at time t i＝1 =0 triggers the first-stage excitation power supply to be turned on, and at the same time controls the laser Doppler armature speed measuring device to emit laser along the direction of movement of the armature;

[0078] Step 2: i = 2, at time t i＝2Triggering the conduction of the second stage excitation power supply, the time t2 satisfies: t m <t2<2t m , where t m is the time interval from when the discharge current of the driving coil changes from zero to when it reaches the maximum value; at the same time, the laser Doppler armature speed measuring device is controlled to perform measurement to obtain the position and speed of the armature at time t2;

[0079] Step 3: Loop through the following steps 3-1 and 3-2 until the moment t at which the n-th stage excitation power supply is turned on is obtained. n :

[0080] Step 3-1: At time t i+1 Triggering the conduction of the i+1th level excitation power supply, the time t i+1 satisfy:

[0081] v i is time t i Armature speed, a is the average speed of armature motion

[0082] speed, h is the center distance between two adjacent driving coils;

[0083] Step 3-2: Let i=i+1.

[0084] The beneficial effects of the present invention are:

[0085] (1) Light gas guns that use gunpowder, high-pressure gas, etc. as power sources have an upper limit on the launch speed. The first-stage drive of the launch device of the present invention adopts a multi-stage coil-type electromagnetic catapult device, which has the characteristics of axial distribution and multi-stage accumulation. Under the conditions of power supply, site, etc., the required total energy storage requirements can be calculated based on the required kinetic energy and energy conversion efficiency. By adding the excitation power supply and the number of drive coils along the axial direction, the electromagnetic drive capacity can be superimposed. The drive capacity can be at least several times higher than that of traditional power sources such as gunpowder, hydrogen-oxygen detonation, and high-pressure gas. Since there is a certain proportional relationship between the first-stage compression pipe and the inner diameter of the second-stage launch tube, the projectile launch speed can be greatly improved under the condition of a certain launch tube caliber or projectile size and mass; or under the condition of ensuring the same launch speed, the pump pipe and launch tube caliber can be greatly increased, and then the projectile (model) size and mass can be simultaneously increased, thereby improving the model's ultra-high-speed simulation effect.

[0086] (2) When the gas cannon is driven, the piston accelerates quickly at the beginning, but the bottom pressure drops rapidly, which leads to a lack of momentum and poor internal ballistic performance. To increase the driving force, the initial pressure can only be increased, but the increase in driving pressure is limited by the performance and safety of the equipment, and it is generally impossible to provide a high average pressure. The multi-stage coil-type electromagnetic catapult drive source used in the launch device of the present invention has the characteristics of axial multi-stage energy empowerment and single-stage independent adjustment. It can easily optimize and control the electromagnetic parameters of each level of circuit and the energy storage and empowerment scheme to form excellent controllable piston movement internal ballistic characteristics, and achieve efficient and smooth piston movement under high energy input.

[0087] (3) The first-stage drive of the present invention adopts the electromagnetic force generated by the discharge induction of multi-stage electromagnetic coils as a safe, clean and efficient power source, which can effectively replace gunpowder or hydrogen-oxygen detonation drive, causes less damage to the device, has higher structural sealing and safety, and does not generate toxic gases during the test, and does not pollute the environment.

[0088] (4) With the breakthrough of high energy density energy storage technology, high voltage switch technology and high strength new insulation material technology bottlenecks, the future synchronous electromagnetic coil propulsion device can be modularized, miniaturized, lightweight and intelligent. Electromagnetic thrust will have more and more advantages as an independent power source or an important part of the power source of light gas guns and ballistic targets. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] Figure 1 Schematic diagram of the ballistic target structure of a two-stage light gas gun driven by electromagnetic catapult.

[0090] Figure 2 Schematic diagram of the electromagnetic catapult device and timing trigger control system.

[0091] Figure 3 This is a schematic diagram of the flange connection structure between electromagnetic pump pipe sections.

[0092] Figure 4 This is a schematic diagram of the flange connection structure between the electromagnetic pump pipe and the high-pressure pump pipe.

[0093] Figure 5 This is a schematic diagram of the flange connection structure between high-pressure pump pipe sections.

[0094] Figure 6 It is a schematic diagram of the structure of the first and second level connection mechanism.

[0095] Figure 7 This is a schematic diagram of the flange connection structure between launch tube sections.

[0096] Figure 8 This is a top-down schematic diagram of the expansion tank, test chamber and related measurement and control equipment.

[0097] Description of Figure Numbers:

[0098] 1-Electromagnetic ejection device; 101-Plugging; 102-Electromagnetic pump tube; 10201-Section k of the first-stage electromagnetic pump tube; 10202-Section k+1 of the electromagnetic pump tube; 103-Drive coil; 104-Metal layer; 105-Excitation power supply; 10501-Energy storage pulse capacitor bank; 10502-Main switch; 10503-Freewheeling switch; 106-Charger; 10601-Charging switch; 107-Insulating flange connection mechanism A; 10701-Insulating flange pipe fitting Aa; 10702-Insulating flange pipe fitting Ab; 10703-Insulating bolt assembly Ac.

[0099] 2-Armature.

[0100] 3-Piston.

[0101] 4-Connection mechanism B; 401-Insulation flange pipe fitting Ba; 402-Steel flange pipe fitting Bb; 403-Bolt assembly Bc.

[0102] 5-high-pressure pump pipe; 501-high-pressure pump pipe section k; 502-high-pressure pump pipe section k+1; 503-steel flange connection mechanism C; 50301-steel flange pipe fitting Ca; 50302-steel flange pipe fitting Cb; 50303-steel bolt assembly Cc.

[0103] 6-primary and secondary connection mechanism; 601-secondary air chamber; 602-steel flange pipe fitting Da; 603-steel flange pipe fitting Db; 604-steel bolt assembly Dc; 605-secondary diaphragm.

[0104] 7-Projectile (acts as a model).

[0105] 8-launching tube; 801-launching tube section k; 802-launching tube section k+1; 803-steel flange connection mechanism G; 80301-steel flange pipe fitting Ea; 80302-steel flange pipe fitting Eb; 80303-steel bolt assembly Ec.

[0106] 9-Expansion tank; 901-Expansion tank and vacuum system interface; 902-Expansion tank side observation window; 903-Expansion tank top observation window.

[0107] 10-Test chamber; 1001-Interface between test chamber and vacuum system; 1002-Observation window on the side of test chamber; 1003-Observation window on the top of test chamber.

[0108] 11-Measurement and control system; 1101-Central controller; 1102-Pulse trigger circuit; 1103-Laser Doppler armature speed measuring device; 110301-Main equipment of armature speed measuring device; 110302-Armature speed measuring device probe; 1104-Excitation power supply voltage measuring device; 1105-Drive coil current measuring device; 1106-Projectile speed measuring device in expansion box; 1107-Binocular vision measurement system for expansion box; 1108-Projectile speed measuring device in test chamber; 1109-Test chamber schlieren instrument; 1110-Test chamber binocular vision measurement system; 1111-Test chamber optical radiation measuring instrument.

[0109] 12-Support mechanism.

[0110] 13-Track system. DETAILED DESCRIPTION

[0111] The present invention will be described more clearly and completely below with reference to the accompanying drawings, and those skilled in the art will be able to implement the present invention based on these descriptions.

[0112] The word "exemplary" is used exclusively herein to mean "serving as an example, example, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0113] like Figure 1 、 Figure 2 As shown, a ballistic target of a two-stage light gas gun driven by electromagnetic catapult includes an electromagnetic catapult device 1, an armature 2, a piston 3, a high-pressure pump pipe 5, a primary and secondary connecting mechanism 6, a projectile 7, a launch tube 8, an expansion tank 9, a test chamber 10 and a measurement and control system 11.

[0114] The electromagnetic ejection device 1 includes an electromagnetic pump tube 102, a multi-stage drive coil 103 wound around the electromagnetic pump tube 102, an excitation power supply 105 for supplying power to the multi-stage drive coil 103, and a charger 106 for charging the excitation power supply 105. In one embodiment, the charger 106 is an IGBT series resonant constant current charging power supply.

[0115] The electromagnetic pump tube 102, high-pressure pump tube 5, primary and secondary connection mechanism 6, launch tube 8, expansion tank 9, and test chamber 10 are connected in sequence. The electromagnetic pump tube 102 and high-pressure pump tube 5 are connected via connection mechanism B4. In one embodiment, the high-pressure pump tube 5 is made of a metal material, preferably gun steel; the electromagnetic pump tube 102 is made of an insulating material, preferably a high-strength resin-based composite material, special engineering plastics, or high-strength ceramic material. The maximum operating temperature of the electromagnetic pump tube 102 is 260 degrees Celsius.

[0116] The inlet end of the electromagnetic pump tube 102 houses an armature 2 and piston 3, with the armature 2 positioned behind the piston 3. The electromagnetic ejection device 1 generates a pulsed current and a pulsed magnetic field through discharge from a multi-stage drive coil 103. Through electromagnetic induction, the armature 2 experiences an electromagnetic force that propels the piston 3 forward. The piston 3 accelerates within the electromagnetic pump tube 102, exiting the tube and moving toward the high-pressure pump tube 5.

[0117] In one embodiment, Figure 2 As shown, the number of stages of the multi-stage drive coils 103 of the electromagnetic catapult device 1 is n, where n ≥ 3. Under the conditions of the set basic parameters such as the piston peak velocity, average acceleration, and pump tube diameter, the acceleration length, electric energy-to-kinetic energy conversion efficiency, and expected total energy are reasonably estimated. Furthermore, the number of stages of the drive coils 103 is determined after comprehensive consideration, taking into account the extreme parameters of the single-stage drive coils and the excitation power supply (voltage resistance, current resistance, stress, temperature rise, equipment cost, etc.), to achieve efficient and safe acceleration of the armature 2 and piston 3. If the number of stages of the drive coils 103 is too small, the energy per stage is too large, affecting the safety, technical difficulty, and cost of the drive coils 103 and the excitation power supply 105. If the number of stages of the drive coils 103 is too large, the energy per stage is too small and the acceleration length is too long, which is not conducive to achieving efficient and rapid acceleration of the armature 2 and greatly increases the equipment footprint and equipment cost.

[0118] In one embodiment, the ratio of the length of each stage of the electromagnetic catapult device 1 to the inner diameter of the electromagnetic pump tube 102 is 0.4 to 1.7, and the ratio of the distance between the facing end faces of the adjacent stages of the drive coils 103 to the inner diameter of the electromagnetic pump tube 102 is 0.1 to 0.3. By properly setting the length of the drive coils 103, it is beneficial to keep the mutual inductance gradient and overall driving capacity of the drive coils 103 and the armature 2 within a reasonable range.

[0119] In one embodiment, Figure 2 As shown, each stage of the electromagnetic catapult device 1 is connected to an independent excitation power supply 105. The excitation power supply 105 includes an energy storage pulse capacitor bank 10501, a main switch 10502, and a freewheeling switch 10503. The energy storage pulse capacitor bank 10501 can be connected in series with the main switch 10502 and connected in parallel with the freewheeling switch 10503 at both ends of the drive coil 103. The two ends of the energy storage pulse capacitor bank 10501 are also connected to the two ends of the charger 106 through a charging switch 10601.

[0120] The charger 106 is connected to the energy storage pulse capacitor group 10501 through the charging switch 10601; before the excitation power supply 105 works, the charging switch 10601 is turned on, and the charger 106 charges the energy storage pulse capacitor group 10501. When the energy storage pulse capacitor group 10501 is charged to a predetermined voltage, the charging switch 10601 is turned off, and the charger 106 stops charging.

[0121] In one embodiment, the structural and electromagnetic parameters of the drive coils 103 and excitation power supplies 105 at each stage are identical. Consequently, multiple drive coils 103 and excitation power supplies 105 from the same batch can be uniformly installed outside the electromagnetic pump tube 102, reducing the cost of manufacturing and assembling the drive coils 103 and excitation power supplies 105. While maintaining the same hardware parameters, the excitation timing of each stage of the drive coils 103 can be controlled by software to adapt to flight tests of different projectiles.

[0122] The measurement and control system 11 monitors the voltage information of the excitation power supply 105, the current information of the drive coil 103, the pressure and temperature information of the light gas and the test gas, the motion information of the armature 2 and the piston 3, the motion information of the launch tube 8, the expansion tank 9, and the projectile in the test chamber 10, as well as the aerodynamic / thermal information, aerodynamic physical information or high-speed collision information of the projectile in the test chamber 10 through sensors.

[0123] The excitation power supply 105 is controlled by a timing trigger method through the measurement and control system 11 to achieve step-by-step discharge. The measurement and control system 11 includes a central controller 1101, a pulse trigger circuit 1102, and a laser Doppler armature speed measuring device 1103. The laser Doppler armature speed measuring device 1103 includes an armature speed measuring device main unit 110301 and an armature speed measuring device probe 110302. The armature speed measuring device probe 110302 is installed at the end of the electromagnetic pump tube 102 at the pipe plug 101. The armature speed measuring device main unit 110301 and the armature speed measuring device probe 110302 are connected via an optical fiber. The armature speed measuring device main unit 110301 transmits a laser signal to the armature 2 through the armature speed measuring device probe 110302 and receives the laser signal reflected from the armature 2. The laser signal is converted into an electrical signal and transmitted to the central controller 1101.

[0124] Central controller 1101 is preferably a digital signal processor (DSP) or a field programmable gate array (FPGA). It processes electrical signals to determine the position and instantaneous velocity of armature 2 at each moment and, through a pre-programmed calculation, determines the predicted triggering moment of the triggering stage. At the predicted triggering moment, central controller 1101 sends a trigger control signal to pulse trigger circuit 1102, which then outputs a power pulse to turn on main switch 10502.

[0125] When the main switch 10502 is turned on, the energy storage pulse capacitor bank 10501 can discharge into the drive coil 103. When the voltage of the energy storage pulse capacitor bank 10501 drops to zero, the freewheeling switch 10503 turns on, the main switch 10502 turns off, and the drive coil 103 continues to flow through the freewheeling switch 10503 until the discharge current drops to zero. Each level of the excitation power supply operates in a similar manner. This prevents reverse charging of the energy storage pulse capacitor bank 10501 and improves the service life of the energy storage pulse capacitor bank 10501.

[0126] Furthermore, the energy storage pulse capacitor group 10501 is composed of a combination of metallized film self-healing pulse capacitors, and the energy volume ratio of the metallized film self-healing pulse capacitor is greater than or equal to 0.5MJ / m 3 , working life is greater than or equal to 1000 times.

[0127] Furthermore, the main switch 10502 is a spark gap switch or a high-voltage switch composed of a semiconductor thyristor.

[0128] Furthermore, the freewheeling switch 10503 is composed of a combination of semiconductor high-voltage diodes.

[0129] like Figure 2 As shown, the measurement and control system 11 may further include an excitation power supply voltage measuring device 1504 and a drive coil current measuring device 1505. The excitation power supply voltage measuring device 1504 may be used to monitor the voltage of the energy storage pulse capacitor bank 10501. The drive coil current measuring device 1505 may be used to monitor the current of the drive coil 103.

[0130] Example of the connection mechanism A107 between the sections of the electromagnetic pump tube 102:

[0131] like Figure 3 As shown, electromagnetic pump pipe section k 10201 and electromagnetic pump pipe section k+1 10202 are adjacent and connected by an insulating flange connection mechanism A107. An insulating flange pipe fitting Aa10701 with a concave stop and an insulating flange pipe fitting Ab10702 with a convex stop are respectively bonded to the outer surface of the left end of electromagnetic pump pipe section k 10701 and the outer surface of the right end of electromagnetic pump pipe section k+1 10702. The two are connected and fastened by an insulating bolt assembly Ac10703.

[0132] Example B4 of the connection mechanism between the electromagnetic pump tube 102 and the high-pressure pump tube 5:

[0133] like Figure 4As shown, the electromagnetic pump tube 102 has the same inner diameter as the high-pressure pump tube 5. Generally, the wall thickness of the high-pressure pump tube 5 is larger, while the wall thickness of the electromagnetic pump tube 102 is smaller. The electromagnetic pump tube 102 is connected to the high-pressure pump tube 5 via a connecting mechanism B4. The connecting mechanism B4 includes an insulating flange pipe fitting Ba401, a steel flange pipe fitting Bb402, and a bolt assembly Bc403. The insulating flange pipe fitting Ba401 is fixed to the outer surface of the right end of the electromagnetic pump tube 102 by bonding, and the steel flange pipe fitting Bb402 is fixed to the outer surface of the left end of the high-pressure pump tube 5 by threading or welding. The insulating flange pipe fitting Ba401 and the steel flange pipe fitting Bb402 are connected and tightened by the bolt assembly Bc403.

[0134] In one embodiment, the electromagnetic pump tube 102 and the high-pressure pump tube 5 are coaxial with each other and have the same inner diameter, which is not less than 50 mm.

[0135] In one embodiment, the inner wall roughness of the electromagnetic pump tube 102 and the high-pressure pump tube 5 is Ra ≤ 1.6. This relatively smooth inner wall helps reduce wear and tear on the piston 3 during movement; it also helps improve the seal between the gas on both sides of the piston 3.

[0136] In one embodiment, the ratio of the mass of the piston 3 to the cross-sectional area of ​​the electromagnetic pump tube 102 is greater than 500 kg / m 2 ; The maximum speed of piston 3 is 1.0 km / s.

[0137] Example of the connection mechanism 503 between the sections of the high-pressure pump tube 5:

[0138] like Figure 5 As shown, the high-pressure pump pipe section k 501 and the high-pressure pump pipe section k+1 502 are adjacent, and the concave stop provided at the right end of the high-pressure pump pipe section k 501 is adapted to the convex stop provided at the left end of the high-pressure pump pipe section k+1 502; the steel flange pipe fitting Ca50301 and the steel flange pipe fitting Cb50302 are respectively fixed to the outer surface of the right end of the high-pressure pump pipe section k 501 and the outer surface of the left end of the high-pressure pump pipe section k+1 502 by threads or welding, and the two are connected and fastened by a steel bolt assembly Cc50303.

[0139] Example of the primary and secondary connection mechanism 6 of the high-pressure pump tube 5 and the launch tube 8:

[0140] like Figure 6As shown, the primary and secondary connecting mechanism 6 includes a secondary air chamber 601 and a secondary diaphragm 605. The high-pressure pump tube 5 is connected to the secondary air chamber 601. The secondary air chamber 601 is connected to the launch tube 8 with a secondary diaphragm 605 disposed therebetween. A projectile 7 is built into the inlet end of the launch tube 8, and the projectile 7 is located in front of the secondary diaphragm 605. The electromagnetic pump tube 102 in front of the piston 3, the high-pressure pump tube 5, and the secondary air chamber 601 are filled with a light gas. In one embodiment, the launch tube 8 is made of a metal material, preferably gun steel.

[0141] After exiting the electromagnetic pump tube 102, the piston 3 decelerates within the high-pressure pump tube 5 and eventually stops within the secondary air chamber 601 of the primary-secondary connecting mechanism 6. The light gas originally contained within the electromagnetic pump tube 102, the high-pressure pump tube 5, and the secondary air chamber 601 is compressed by the piston 3 to a high-temperature, high-pressure state. Upon reaching a predetermined pressure, it breaks through the secondary diaphragm 605, propelling the projectile 7 at high speed out of the launch tube 8, through the expansion tank 9, and into the test chamber 10.

[0142] The total pressure of light gas in the secondary air chamber 601 before the secondary diaphragm 605 ruptures is P 2x and total temperature T 2x The expression is:

[0143]

[0144] Wherein, γ2 is the initial specific heat ratio of the light gas in the secondary gas chamber 601, P 20 is the initial pressure of the light gas in the secondary gas chamber 601, T 20 is the initial temperature of the light gas in the secondary gas chamber 601, V 20 is the initial total volume of the electromagnetic pump tube 102, high-pressure pump tube 5, and secondary air chamber 601 in front of the piston 3, x is the distance moved by the armature 2 and the piston 3, D is the inner diameter of the electromagnetic pump tube 102, V 2x (x) is the volume of light gas in the closed space between the piston 3 and the secondary diaphragm 605 when the piston 3 moves a distance x.

[0145] In one embodiment, the piston 3 uses a near isentropic compression mode to compress the light gas in the front electromagnetic pump tube 102, the high-pressure pump tube 5 and the secondary air chamber 601. The light gas can be hydrogen or helium, and the initial pressure of hydrogen or helium is 0.01~1.0MPa; the launch tube 8, the expansion tank 9 and the test chamber 10 in front of the projectile 7 are filled with air as the test gas, and the air pressure is 10Pa~0.2MPa.

[0146] In one embodiment, Figure 6 As shown, the secondary air chamber 601 includes a large diameter straight pipe section, a reducing section and a small diameter straight pipe section; the large diameter straight pipe section and the small diameter straight pipe section are respectively provided with convex stoppers; the reducing section adopts a conical cylinder structure with a small taper angle, and the taper angle of the reducing section is 6° to 15°.

[0147] Further, if Figure 6 As shown, the outlet of the high-pressure pump tube 5 is provided with a concave stopper; the convex stopper of the large-diameter straight section of the secondary air chamber 601 mates with the concave stopper at the outlet of the high-pressure pump tube 5. The inlet of the launch tube 8 is provided with a concave stopper, a secondary diaphragm groove, and a tapered groove, sequentially arranged along the centerline. The convex stopper of the small-diameter straight section of the secondary air chamber 601 mates with the concave stopper at the inlet of the launch tube 8. The diameter of the concave stopper of the launch tube 8 is larger than the secondary diaphragm groove, which houses the secondary diaphragm 605. The diameter of the tapered groove gradually decreases from one end of the secondary diaphragm groove, with the maximum diameter of the tapered groove being smaller than the diameter of the secondary diaphragm groove and the minimum diameter being equal to the inner diameter of the launch tube 8. When the secondary diaphragm 605 is ruptured, the multiple petals of the secondary diaphragm 605 can fit into the tapered surface of the reducing section, allowing the airflow from the secondary air chamber 601 to pass smoothly through the ruptured secondary diaphragm 605 and act on the projectile 7.

[0148] In one embodiment, the roughness of the inner wall of the secondary air chamber 601 is Ra≤0.8.

[0149] In one embodiment, the ratio of the length of the large-diameter straight pipe section of the secondary air chamber 601 to the length of the reduced-diameter section of the secondary air chamber 601 is 0.5 to 1.0.

[0150] In one embodiment, the ratio of the length of the small-diameter straight pipe section of the secondary air chamber 601 to the length of the reduced-diameter section of the secondary air chamber 601 is 0.3 to 0.6.

[0151] In one embodiment, the ratio of the length of the high-pressure pump tube 5 to the length of the reduced diameter section of the secondary air chamber 601 is 6-20.

[0152] In one embodiment, the ratio of the inner diameter of the high-pressure pump tube 5 to the inner diameter of the launch tube 8 is 3-5.

[0153] In one embodiment, the ratio of the length to the inner diameter of the launch tube 8 is 280-560.

[0154] In one embodiment, the roughness of the inner wall of the launch tube 8 is Ra≤0.8.

[0155] Example of the connecting mechanism 803 between segments of the launch tube 8:

[0156] like Figure 7 As shown, the launch tube section k 801 and the launch tube section k+1 802 are adjacent to each other, and the concave stop provided at the right end of the launch tube section k 801 is adapted to the convex stop provided at the left end of the launch tube section k+1 802; the steel flange pipe fitting Ea80301 and the steel flange pipe fitting Eb80302 are respectively fixed to the outer surface of the right end of the launch tube section k 801 and the outer surface of the left end of the launch tube section k+1 802 by threads or welding, and the two are connected and fastened by a steel bolt assembly Ec80303.

[0157] In one embodiment, the armature 2 structure is an integral solid cylinder or a hollow cylinder, and the armature 2 material is aluminum or an aluminum alloy; the piston 3 structure is an integral cylindrical type or a three-section type in which a piston head, a steel counterweight, and a piston tail are connected in sequence as one body, and the piston head and piston tail of the piston 3 are made of polyethylene or polytetrafluoroethylene; the secondary diaphragm 605 adopts a flat plate structure and is provided with a "cross" or "*" shaped groove, and the secondary diaphragm 605 material is austenitic stainless steel with a tensile strength greater than 500 MPa.

[0158] In one embodiment, the projectile 7 is a full-caliber projectile without a buttress or a combination projectile with a buttress; when the projectile 7 is a full-caliber projectile without a buttress, the ratio of the projectile length to the diameter is greater than 0.5, and after the projectile is launched, it passes through the expansion box 9 and enters the test chamber 10; when the projectile 7 is a combination projectile with a buttress, the combination projectile consists of a projectile body and a buttress, and the buttress is a split-petal combination structure with two to eight petals, and the buttress material is polycarbonate or high-pressure polyethylene or nylon. After the projectile 7 is launched, the buttress and the projectile body are separated in the expansion box 9, and the projectile body enters the test chamber 10.

[0159] In one embodiment, the expansion tank 9 and the test chamber 10 are equipped with a projectile velocity measurement system, a camera system for measuring the projectile position and posture, a shadow / schlieren device for displaying the flow field, and a light radiation measurement system for measuring light radiation characteristics.

[0160] Expansion tank, test chamber and related measurement and control device embodiments:

[0161] like Figure 8 As shown, the expansion tank 9 and the test chamber 10 are filled with air at a pressure range of 10 Pa to 0.2 MPa. The expansion tank 9 is provided with a vacuum system interface 901, multiple side optical windows 902, and a top optical window 903. Multiple expansion tank projectile velocity measuring devices 1106 are installed on the side. Multiple expansion tank binocular vision measurement systems 1107 for measuring the dynamic process of separation between the combined projectile sabot and the projectile body are installed on the side and top. The test chamber 10 is provided with a vacuum system interface 1001, multiple side optical windows 1002, and a top optical window 1003. Multiple test chamber projectile velocity measuring devices 1108, a flow field display schlieren instrument 1109, and an optical radiation measurement system 1111 for measuring optical radiation characteristics are installed on the side. A binocular vision measurement system 1110 for measuring the projectile flight posture is installed on the side and top.

[0162] In one embodiment, the ballistic target includes several support mechanisms 12 and a track system 13. The support mechanisms 12 are respectively located below the electromagnetic pump tube 102, the high-pressure pump tube 5, the launch tube 8, the expansion tank 9 and the test chamber 10. The support mechanisms 12 are installed on the track system 13 and can move along the track.

[0163] The working principle of the present invention is as follows:

[0164] Before the test, the armature 2 and the piston 3 are placed at appropriate positions inside the inlet end of the electromagnetic pump tube 102 (the preferred position is to align the rear end face of the armature 2 with the center line of the first-stage drive coil 103), with the armature 2 behind the piston 3; the projectile 7 is placed inside the inlet end of the launch tube 8 and in front of the secondary diaphragm 605; the electromagnetic pump tube 102, the high-pressure pump tube 5 and the secondary air chamber 601 in front of the piston 3 are filled with 0.01 to 1.0 MPa of hydrogen or helium; the launch tube 8, the expansion tank 9 and the test chamber 10 in front of the projectile 7 are filled with 10 Pa to 0.2 MPa of air; and each level of the energy storage pulse capacitor group 10501 is charged with a certain voltage.

[0165] During the test, the first-stage excitation power supply main switch is triggered, causing the first-stage energy storage pulse capacitor bank to discharge through the first-stage drive coil. After the voltage of the first-stage energy storage pulse capacitor bank drops to zero, the first-stage drive coil continues to flow through the first-stage freewheeling switch. The pulsed current excites a pulsed magnetic field, generating eddy currents in the armature 2. This electromagnetic force propels the piston 3 forward. The laser Doppler armature speed measuring device 1103 transmits a laser signal at a specific frequency to the armature 2 and receives the laser signal reflected from the armature 2. It converts the laser signal into an electrical signal and transmits it to the central controller 1101. The central controller 1101 processes the electrical signal to determine the position and instantaneous velocity of the armature 2 at each moment, and calculates the estimated triggering time for the second stage. Based on the predicted triggering moment of the second stage, the central controller 1101 sends a trigger control signal to the pulse trigger circuit 1102 after a specific delay. The pulse trigger circuit 1102 outputs a power pulse to turn on the second-stage excitation power supply main switch, causing the second-stage energy storage pulse capacitor bank to discharge through the second-stage drive coil. After the voltage of the second-stage energy storage pulse capacitor bank drops to zero, the second-stage drive coil continues to flow through the second-stage freewheeling switch. The pulse magnetic field jointly excited by the first stage (if the first stage discharge has not yet ended) and the second stage generates eddy currents in the armature 2, which, under the action of electromagnetic force, propels the piston 3 forward. Similarly, the multi-stage excitation power supply 105 discharges pulse currents through the drive coils step by step, thereby generating a pulse magnetic field, causing eddy currents to be generated within the armature 2 and subjected to electromagnetic force. Under the action of electromagnetic force, the armature 2 moves and propels the piston 3 at high speed to fly out of the electromagnetic pump tube 102. The piston 3 enters the secondary gas chamber 601 through the high-pressure pump tube 5, simultaneously compressing the light gas to a high temperature and high pressure state. The light gas high pressure breaks through the secondary diaphragm 605, propelling the projectile 7 at high speed to fly out of the launch tube 8. When the projectile 7 is a full-caliber projectile without a sabot, it passes through the expansion box 9 and enters the test chamber 10 after being fired; when the projectile 7 is a combined projectile with a sabot, the sabot and the projectile body are separated in the expansion box 9, and the projectile body enters the test chamber 10.

[0166] When the armature 2 and the piston 3 pass through the drive coil 103 close to the side of the blockage 1, the movement speed of the armature 2 and the piston 3 can be relatively slow. When the armature 2 and the piston 3 pass through the drive coil 103 close to the side of the high-pressure pump tube 5, the movement speed of the armature 2 and the piston 3 can be relatively fast. The embodiment of the present application provides an optimized timing trigger control method that can achieve the maximum speed of the armature and the piston, so that the multi-stage drive coil 103 is excited in time sequence, so that the armature 2 can be efficiently driven by the corresponding drive coil 103 when passing through each stage of the drive coil 103. The specific steps are as follows.

[0167] (1) For an n-stage electromagnetic catapult device with the same parameters at each stage, before starting, the rear end surface of the armature 2 is placed at an appropriate position near the center line of the first-stage drive coil. Preferably, the rear end surface of the armature 2 is aligned with the center line of the first-stage drive coil.

[0168] (2) The central controller 1101 triggers the first-stage excitation power supply 105-1 through the pulse trigger circuit 1102, and at the same time, the laser Doppler armature speed measuring device 1103 emits laser along the movement direction of the armature 2. This time is taken as time 0, that is, the triggering time of the first-stage excitation power supply 105-1 is t1=0.

[0169] (3) The armature 2 moves forward, and the central controller 1101 triggers the second-stage excitation power supply 105-2 to turn on at time t2 through the pulse trigger circuit 1102. At time t2, the following conditions are met: m <t2<2t m , where t m is the time interval from when the discharge current of the driving coil 103 changes from zero to when it reaches the maximum value, L d is the sum of all self-inductances of the first-stage discharge circuit before freewheeling, and C is the capacitance of the energy storage pulse capacitor bank. Simultaneously, the laser Doppler armature speed measuring device 1103 and the central controller 1101 measure and process the position and speed of the armature 2 at time t2.

[0170] (4) The armature 2 continues to move forward, and the central controller 1101 triggers the third-stage excitation power supply to be turned on at time t3 through the pulse trigger circuit 1102. At time t3, the following conditions are satisfied:

[0171] Wherein, v2 is the speed of armature 2 at time t2, a is the average acceleration of armature 2, h is the center distance between two adjacent driving coils 103, t m It is the time interval from when the discharge current of the driving coil 103 changes from zero to when it reaches the maximum value.

[0172] (5) Similarly, the armature 2 continues to move forward, and the central controller 1101 triggers the pulse circuit 1102 at time t i+1 Triggering the conduction of the i+1th level excitation power supply, time ti+1 satisfy:

[0173]

[0174] Among them, v i is time t i Armature 2 speed, a is the average acceleration of armature 2 movement, h is the center distance between two adjacent drive coils 103, t m It is the time interval from when the discharge current of the driving coil 103 changes from zero to when it reaches the maximum value.

[0175] (6) In the above steps, the armature 2 speed v at each triggering moment i The laser Doppler velocity measuring device 703 measures and the central controller 701 processes and solves the signal to obtain t m It is calculated by the structural parameters and electromagnetic parameters of a given circuit, where h is the given structural parameter and a is reasonably estimated based on the maximum electromagnetic force of the single-stage coil pushing the armature 2 and piston to move. Specifically, the maximum acceleration of the armature 2 and piston 3 in the first-stage drive coil and the second-stage drive coil can be obtained through simulation or experiment. This acceleration can be related to the total mass of the armature 2 and piston 3. Through the above steps, the optimal multi-stage trigger timing [t1, t2, t3, ... t i ,t i+1 ,…t n ], which can achieve higher electrical energy-kinetic energy conversion efficiency.

[0176] The present invention has been described in detail above with reference to specific embodiments and exemplary embodiments. However, these descriptions and embodiments are merely illustrative and not restrictive, and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the appended claims.

Claims

1. A ballistic target based on electromagnetic catapult driven two-stage light gas gun, characterized in that: The invention comprises an electromagnetic ejection device (1), an armature (2), a piston (3), a high-pressure pump pipe (5), a primary and secondary connection mechanism (6), a projectile (7), a launch tube (8), an expansion tank (9), a test chamber (10) and a measurement and control system (11); wherein, The electromagnetic ejection device (1) comprises a plug (101), an electromagnetic pump tube (102), a multi-stage drive coil (103) wound on the electromagnetic pump tube (102), an excitation power supply (105) for supplying power to the multi-stage drive coil (103), and a charger (106) for charging the excitation power supply (105); the armature (2) and the piston (3) are built into the inlet end of the electromagnetic pump tube (102); the armature (2) is located behind the piston (3); and the electromagnetic pump tube (102) is connected to the high-pressure pump tube (5); Each stage of the driving coil (103) is connected to an independent excitation power supply (105), and the excitation power supply (105) is triggered step by step to discharge the multi-stage driving coil (103) step by step. The armature (2) moves under the action of the electromagnetic force generated by the multi-stage driving coil (103) and pushes the piston (3), and the piston (3) flies out of the electromagnetic pump tube (102) and enters the high-pressure pump tube (5); The primary and secondary connection mechanism (6) comprises a secondary air chamber (601), a secondary diaphragm (605), the electromagnetic pump tube (102), the high-pressure pump tube (5), the secondary air chamber (601), and the launch tube (8) are connected in sequence, the secondary diaphragm (605) is provided between the secondary air chamber (601) and the launch tube (8), the projectile (7) is built into the inlet end of the launch tube (8), and the projectile (7) is in front of the secondary diaphragm (605); The electromagnetic pump tube (102), the high-pressure pump tube (5) and the secondary air chamber (601) in front of the piston (3) are filled with light gas. The light gas in the electromagnetic pump tube (102), the high-pressure pump tube (5) and the secondary air chamber (601) breaks through the secondary diaphragm (605) under the compression of the piston (3), and pushes the projectile (7) to fly out of the launch tube (8) and enter the test chamber (10) through the expansion box (9); The measurement and control system (11) is used to determine the triggering time of each level of the excitation power supply (105) according to the moving speed and position of the armature (2); The measurement and control system (11) comprises a central controller (1101) and a laser Doppler armature speed measuring device (1103); the central controller (1101) is used to execute a timing trigger control method, and the timing trigger control method comprises: Step 1: i = 1, at time t i＝1 =0 triggers the first-stage excitation power supply to be turned on, and simultaneously controls the laser Doppler armature speed measuring device (1103) to emit laser light along the moving direction of the armature (2); Step 2: i = 2, at time t i＝2 Triggering the conduction of the second stage excitation power supply, the time t2 satisfies: t m <t2<2t m , where t m is the time interval when the discharge current of the driving coil changes from zero to the maximum value; at the same time, the laser Doppler armature speed measuring device (1103) is controlled to perform measurement to obtain the position and speed of the armature (2) at time t2; Step 3: Loop through the following steps 3-1 and 3-2 until the moment t at which the n-th stage excitation power supply is turned on is obtained. n : Step 3-1: At time t i+1 Triggering the conduction of the i+1th level excitation power supply, the time t i+1 satisfy: v i is time t i Armature (2) speed, a is the average acceleration of armature (2) motion, h is the distance between the centers of two adjacent driving coils; Step 3-2: Let i=i+1.

2. The ballistic target according to claim 1, wherein The electromagnetic catapult device (1) satisfies at least one of the following: The inner diameter of the electromagnetic pump tube (102) is not less than 50 mm; The ratio of the mass of the piston (3) to the cross-sectional area of ​​the electromagnetic pump tube (102) is greater than 500 kg / m 2 ; The maximum speed of the piston (3) is 1.0 km / s; The inner wall roughness of the electromagnetic pump tube (102) is Ra≤1.6; The multi-stage driving coil (103) has n stages, where n≥3; The structural parameters and electromagnetic parameters of the driving coils (103) and the excitation power supply (105) at each level are the same; The ratio of the length of each stage driving coil (103) to the inner diameter of the electromagnetic pump tube (102) is 0.4 to 1.7; The ratio of the distance between the facing end faces of the adjacent stage driving coils (103) to the inner diameter of the electromagnetic pump tube (102) is 0.1 to 0.

3.

3. The ballistic target according to claim 1, wherein The excitation power supply (105) comprises an energy storage pulse capacitor group (10501), a main switch (10502), and a freewheeling switch (10503); the energy storage pulse capacitor group (10501) is connected in series with the main switch (10502), and is connected in parallel with the freewheeling switch (10503) at both ends of the driving coil (103); the two ends of the energy storage pulse capacitor group (10501) are also connected to the two ends of the charger (106) via a charging switch (10601); the conduction and disconnection of the main switch (10502) and the charging switch (10601) are controlled by the measurement and control system (11).

4. The ballistic target according to claim 3, wherein The excitation power supply (105) satisfies at least one of the following: The energy storage pulse capacitor group (10501) is composed of a combination of metallized film self-healing pulse capacitors, and the energy volume ratio of the metallized film self-healing pulse capacitor is greater than or equal to 0.5MJ / m 3 , working life is greater than or equal to 1000 times; The main switch (10502) is a spark gap switch or a high-voltage switch composed of a semiconductor thyristor; The freewheeling switch (10503) is composed of a combination of semiconductor high-voltage diodes.

5. The ballistic target according to any one of claims 1 to 4, characterized in that The measurement and control system (11) further includes a pulse trigger circuit (1102); The laser Doppler armature speed measuring device (1103) comprises an armature speed measuring device main body (110301) and an armature speed measuring device probe (110302), wherein the armature speed measuring device probe (110302) is installed at a pipe end plug (101) of the electromagnetic pump pipe (102), and the armature speed measuring device main body (110301) and the armature speed measuring device probe (110302) are connected via an optical fiber. The armature speed measuring device main body (110301) transmits a laser signal to the armature (2) through the armature speed measuring device probe (110302) and receives the laser signal reflected from the armature (2), and converts the laser signal into an electrical signal and transmits it to the central controller (1101); The central controller (1101) processes the electrical signal to obtain the position and instantaneous speed of the armature (2) at each moment, and obtains the estimated triggering moment of the stage to be triggered; At the expected triggering moment, the central controller (1101) sends a trigger control signal to the pulse triggering circuit (1102), and the pulse triggering circuit (1102) outputs a power pulse to trigger the corresponding stage excitation power supply (105) to turn on.

6. The ballistic target according to claim 1, wherein t m according to OK, L d It is the sum of all self-inductances of the discharge circuit before the discharge current of the driving coil is freewheeled by the diode, and C is the capacitance value of the energy storage capacitor group.

7. The ballistic target according to claim 1 or 6, characterized in that Before starting, the rear end surface of the armature (2) is aligned with the center line of the first-stage driving coil.

8. The ballistic target according to claim 1, wherein The high-pressure pump tube (5) satisfies at least one of the following: The high-pressure pump tube (5) and the electromagnetic pump tube (102) are coaxial with each other and have the same inner diameter, which is not less than 50 mm; The inner wall roughness of the high-pressure pump tube (5) is Ra≤1.6; The inlet end of the high-pressure pump tube (5) is connected to the outlet end of the electromagnetic pump tube (102) via a flange structure.

9. The ballistic target according to claim 1, wherein The secondary air chamber (601) comprises a large-diameter straight pipe section, a reduced-diameter section, and a small-diameter straight pipe section, wherein the convex stop of the large-diameter straight pipe section is adapted to the concave stop of the outlet end of the high-pressure pump pipe (5), and the convex stop of the small-diameter straight pipe section is adapted to the concave stop of the inlet end of the launch tube (8); The inlet end of the launch tube (8) is provided with a concave stop, a secondary diaphragm groove, and a tapered groove in sequence along the center line. The diameter of the concave stop at the inlet end of the launch tube (8) is larger than the secondary diaphragm groove, and the secondary diaphragm (605) is placed in the secondary diaphragm groove. The diameter of the tapered groove gradually decreases from one end of the secondary diaphragm groove. The maximum diameter of the tapered groove is smaller than the diameter of the secondary diaphragm groove, and the minimum diameter of the tapered groove is equal to the inner diameter of the launch tube (8).

10. The ballistic target according to claim 9, wherein The secondary air chamber (601) satisfies at least one of the following: The inner wall roughness of the secondary air chamber (601) is Ra≤0.8; The ratio of the length of the large diameter straight pipe section to the diameter reducing section is 0.5 to 1.0; The ratio of the length of the small diameter straight pipe section to the length of the variable diameter section is 0.3 to 0.6; The diameter-changing section adopts a cone-shaped structure with a small cone angle of 6° to 15°; The ratio of the length of the high-pressure pump tube (5) to the length of the variable diameter section is 6 to 20; The total pressure P of the light gas in the secondary gas chamber (601) before the secondary diaphragm (605) breaks 2x and total temperature T 2x The expression is: Wherein, γ2 is the initial specific heat ratio of the light gas in the secondary gas chamber (601), P 20 is the initial pressure of the light gas in the secondary gas chamber (601), T 20 is the initial temperature of the light gas in the secondary gas chamber (601), V 20 is the initial total volume of the electromagnetic pump tube (102), high-pressure pump tube (5), and secondary air chamber (601) in front of the piston (3), x is the distance moved by the armature (2) and the piston (3), D is the inner diameter of the electromagnetic pump tube (102), V 2x (x) is the volume of the light gas in the closed space between the piston (3) and the secondary diaphragm (605) when the piston (3) moves a distance x.

11. The ballistic target according to claim 1, wherein The transmitting tube (8) satisfies at least one of the following conditions: The ratio of the inner diameter of the high-pressure pump tube (5) to the inner diameter of the launch tube (8) is 3 to 5; The ratio of the length to the inner diameter of the launch tube (8) is 280 to 560; The inner wall roughness of the transmitting tube (8) is Ra≤0.

8.

12. The ballistic target according to claim 1, wherein The ballistic target satisfies at least one of the following: The armature (2) is in the form of an integral solid cylinder or a hollow cylinder; The material of the armature (2) is aluminum or aluminum alloy; The charger (106) is an IGBT series resonant constant current charging power supply; The light gas is hydrogen or helium, and the pressure of the hydrogen or helium is 0.01-1.0 MPa; The electromagnetic pump tube (102) is made of resin-based composite material, engineering plastics or ceramic material, and the maximum operating temperature of the electromagnetic pump tube (102) is 260 degrees Celsius; The high-pressure pump tube (5) and the launch tube (8) are made of gun steel; When the high-pressure pump tube (5), the electromagnetic pump tube (102), and the launch tube (8) need to be connected to each other in sections using pipes of the same specification, each section is connected using a flange structure, a half nut structure, or a half clamp structure; The piston (3) is of an integral cylindrical structure or a three-section structure in which a piston head, a steel counterweight, and a piston tail are sequentially connected as one body; The piston head and piston tail of the piston (3) are made of polyethylene or polytetrafluoroethylene; The secondary diaphragm (605) adopts a flat plate structure and is provided with a "cross" shaped four-petal groove or an "*" shaped six-petal groove; The secondary diaphragm (605) is made of austenitic stainless steel with a tensile strength greater than 500 MPa; The launch tube (8), expansion box (9) and test chamber (10) in front of the projectile (7) are filled with test gas, which is air, and the air pressure is 10Pa to 0.2MPa; The projectile (7) is a full-caliber projectile without a buttstock or a combined projectile with a buttstock. When the projectile (7) is a full-caliber projectile without a buttstock, the ratio of the length to the diameter of the projectile (7) is greater than 0.

5. After the projectile (7) is fired, it passes through an expansion box (9) and enters a test chamber (10). When the projectile (7) is a combined projectile with a buttstock, the combined projectile consists of a projectile (7) body and a buttstock. The buttstock is a split-petal combination structure with two to eight petals. The buttstock material is polycarbonate, high-pressure polyethylene, or nylon. After the projectile (7) is fired, the buttstock and the projectile (7) body are separated in the expansion box (9), and the projectile (7) body enters the test chamber (10). The expansion tank (9) and the test chamber (10) are equipped with a projectile (7) velocity measurement system, a camera system for measuring the position and posture of the projectile (7), a shadow / schlieren instrument for flow field display, and a light radiation measurement system for measuring light radiation characteristics; The ballistic target includes several supporting mechanisms and a track system. The supporting mechanisms are respectively located below the electromagnetic pump tube (102), the high-pressure pump tube (5), the launch tube (8), the expansion tank (9) and the test chamber (10). The supporting mechanisms are installed on the track system and can move along the track.

13. A timing trigger control method, characterized in that: The method is applied to a ballistic target of a two-stage light gas gun driven by electromagnetic catapult, wherein the ballistic target comprises an electromagnetic catapult device (1), an armature (2), a piston (3), a high-pressure pump pipe (5), a primary and secondary connecting mechanism (6), a projectile (7), a launch tube (8), an expansion tank (9), a test chamber (10), and a measurement and control system (11); wherein, The electromagnetic ejection device (1) comprises a plug (101), an electromagnetic pump tube (102), a multi-stage drive coil (103) wound on the electromagnetic pump tube (102), an excitation power supply (105) for supplying power to the multi-stage drive coil (103), and a charger (106) for charging the excitation power supply (105); the armature (2) and the piston (3) are built into the inlet end of the electromagnetic pump tube (102); the armature (2) is located behind the piston (3); and the electromagnetic pump tube (102) is connected to the high-pressure pump tube (5); Each stage of the driving coil (103) is connected to an independent excitation power supply (105), and the excitation power supply (105) is triggered step by step to discharge the multi-stage driving coil (103) step by step. The armature (2) moves under the action of the electromagnetic force generated by the multi-stage driving coil (103) and pushes the piston (3), and the piston (3) flies out of the electromagnetic pump tube (102) and enters the high-pressure pump tube (5); The primary and secondary connection mechanism (6) comprises a secondary air chamber (601), a secondary diaphragm (605), the electromagnetic pump tube (102), the high-pressure pump tube (5), the secondary air chamber (601), and the launch tube (8) are connected in sequence, the secondary diaphragm (605) is provided between the secondary air chamber (601) and the launch tube (8), the projectile (7) is built into the inlet end of the launch tube (8), and the projectile (7) is in front of the secondary diaphragm (605); The electromagnetic pump tube (102), the high-pressure pump tube (5) and the secondary air chamber (601) in front of the piston (3) are filled with light gas. The light gas in the electromagnetic pump tube (102), the high-pressure pump tube (5) and the secondary air chamber (601) breaks through the secondary diaphragm (605) under the compression of the piston (3), and pushes the projectile (7) to fly out of the launch tube (8) and enter the test chamber (10) through the expansion box (9); The measurement and control system (11) is used to determine the triggering time of each level of the excitation power supply (105) according to the moving speed and position of the armature (2); The measurement and control system (11) comprises a central controller (1101) and a laser Doppler armature speed measuring device (1103); and the method comprises: Step 1: i = 1, at time t i＝1 =0 triggers the first-stage excitation power supply to be turned on, and simultaneously controls the laser Doppler armature speed measuring device (1103) to emit laser light along the moving direction of the armature (2); Step 2: i = 2, at time t i＝2 Triggering the conduction of the second stage excitation power supply, the time t2 satisfies: t m <t2<2t m , where t m is the time interval from when the discharge current of the driving coil (103) changes from zero to when it reaches the maximum value; at the same time, the laser Doppler armature speed measuring device (1103) is controlled to perform measurement to obtain the position and speed of the armature (2) at time t2; Step 3: Loop through the following steps 3-1 and 3-2 until the moment t at which the n-th stage excitation power supply is turned on is obtained. n : Step 3-1: At time t i+1 Triggering the conduction of the i+1th level excitation power supply, the time t i+1 satisfy: v i is time t i Armature (2) speed, a is the average acceleration of armature (2) motion, h is the distance between the centers of two adjacent driving coils; Step 3-2: Let i=i+1.

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