A design method of a small electromagnetic rail launcher system

Abstract

The application provides a design method of a small electromagnetic railgun launcher system, and aims at solving the technical problems of electromagnetic rail launching technology, such as that the power supply is too large to be moved and installed at will, the working current is too large to cause serious rail ablation and affect the service life, and the speed of the armature out of the barrel is too large to require harsh material performance of the guide rail and the armature. The method is that the Ohm's law of the loop is written, the force analysis of the armature is carried out, the derivative of the expression of the electromotive force to the magnetic induction intensity is obtained, the derivative is equal to zero, and the minimum value of the electromotive force of the power supply is found through MATLAB drawing. The method discloses two specific modes of the electromagnetic rail launching system, and the specific configuration of the small electromagnetic rail weapon launching system is given by taking a light weapon as an example. The application enables people to configure the small electromagnetic rail launching system according to the demand, has higher dynamic efficiency, has lower requirement for the electromagnetic launching technology, has better realizability, and can avoid the rail ablation and improve the service life of the rail.

Description

Technical Field

[0001] This invention relates to electromagnetic orbital launch technology, and in particular to the design of a small electromagnetic orbital launcher system. Background Technology

[0002] Electromagnetic launch technology is a new concept of kinetic energy launch technology that emerged after chemical energy launch. Its essence is based on the principle of an electric motor, using electromagnetic energy to do work and converting electromagnetic energy into the kinetic energy of the payload. It has wide applications in scientific experiments, military, industry, transportation, and many other fields. Electromagnetic launch technology can be divided into electromagnetic rail launch technology and electromagnetic coil launch technology. With the vigorous efforts of countries around the world, electromagnetic rail launch technology has made great progress. The U.S. Navy launched an electromagnetic railgun development project in 2005, and on March 7, 2014, the Materials Testing Laboratory of the U.S. Naval Research Laboratory successfully test-fired a newly developed small-caliber electromagnetic railgun testbed, marking a new stage in electromagnetic railgun research.

[0003] However, under current technological conditions, some key technologies still require time to overcome. For example, the pulse power systems or rotating flux compression pulse generators commonly used in existing electromagnetic railguns are enormous, with volumes reaching hundreds of cubic meters and weights of tens of tons, making them difficult to move and install, thus limiting the widespread application of electromagnetic launch technology. On the other hand, the superior performance of electromagnetic railguns heavily depends on the performance of their power supply, requiring megaampere-level currents with high stability. However, such high operating currents can lead to rail ablation, severely impacting the rail's lifespan. Furthermore, the projectiles achieve muzzle velocities of several thousand meters per second, demanding that the rails and armature possess stringent requirements for high-temperature resistance, wear resistance, and high conductivity. Therefore, a design technology is urgently needed to address these technical challenges. Summary of the Invention

[0004] This invention aims to provide a design method for a small electromagnetic rail launcher system, which can solve the following technical problems: 1. The power supply is large and bulky, making it difficult to move and install, thus hindering the widespread application of electromagnetic rail launch technology in reality; 2. The rail ablation caused by the ultra-high operating current severely affects the service life of the electromagnetic rail launcher system; 3. The high armature ejection speed places stringent requirements on the high temperature resistance, wear resistance, and high conductivity of the guide rail and armature, which are difficult to achieve.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] 1. System structure composition:

[0007] The entire electromagnetic rail launcher system mainly consists of a power supply, wires, rails, an armature, and an electromagnet. The positive terminal of the DC power supply is at the bottom and the negative terminal is at the top. The electromagnet provides a uniform magnetic field. When the switch is closed, the power supply is turned on, and the current flows through the wires, rails, and armature to form a closed loop. When current flows through the armature, under the action of the uniform magnetic field, the armature accelerates between the two fixed rails.

[0008] 2. Find the minimum value of the power supply voltage.

[0009] For an electromagnetic orbiter system with known magnetic flux density, armature length, armature mass, and total loop resistance, its power supply voltage has a minimum value.

[0010] (1) According to Ohm's law and Newton's second law for closed circuits, the equation of motion of the projectile is given. (It should be noted here that the above derivation process takes into account the short track and ignores the effects of air resistance and frictional resistance, see details 5 and 6 of the invention). Substituting the initial values, the relationship between the projectile's velocity v and the power supply voltage E, magnetic induction intensity B, and acceleration time t in the system can be obtained as follows:

[0011] (2) Rewrite the expression for the velocity v of the projectile as the expression for E. Analysis of the graph of the expression reveals that the voltage E as a function of the magnetic induction intensity B has a minimum value.

[0012] (3) When the projectile velocity v, length L, mass m, total circuit resistance R, and time t are constant, differentiate the expression with respect to the magnetic induction intensity and set the derivative to zero to obtain: make Treat this expression as a function f(q) = e q When -2q-1 is zero, the zeros of f(q) can be obtained by plotting the function graph using MATLAB, and the corresponding magnetic flux density value at that point can also be determined. Therefore, the minimum value of this power supply voltage can be determined.

[0013] 3. Basic formulas for designing a small electromagnetic rail launcher system

[0014] Based on minimum voltage, acceleration time t, and muzzle velocity v c The direct relationship between the track length d and the track length d: k = 1 - e -q , The conclusion is This formula and The basic formulas for designing small electromagnetic rail launcher systems.

[0015] 4. Two specific modes for designing a small electromagnetic rail launcher system

[0016] Using the basic formulas, we obtain two specific modes of the electromagnetic rail launcher system: a launch mode with a set magnetic induction intensity and a launch mode with a set exit velocity.

[0017] The emission mode is set to be for each magnetic induction intensity B. m Given the track length d, t and v are calculated sequentially using the basic formulas of a small electromagnetic track launcher system. c and E m value.

[0018] The firing mode is set to a muzzle velocity of v. c Given the track length d, t and B are calculated sequentially using the basic formulas of a small electromagnetic track launcher system. m and E m value.

[0019] 5. In all the above derivations, the influence of frictional work was neglected due to the short trajectory, and the kinetic energy gained by the projectile upon exiting the barrel was calculated by substituting the relevant parameters of the small arms pistol's firing system. And the magnitude of work done by friction | W f |=μmgd, comparing the two, we can conclude that the work done by friction is much smaller than the bullet's muzzle kinetic energy, further confirming that the effect of friction on the bullet is negligible.

[0020] 6. In all the above derivations, the influence of air resistance work was neglected due to the short track length, and the equation was modified accordingly. Substitution The formula for calculating the work done by air resistance By substituting the relevant parameters of the firing system of a small arms pistol, the work done by air resistance was calculated. The results were compared with the muzzle kinetic energy of the projectile, and it was concluded that the work done by air resistance was much smaller than the muzzle kinetic energy of the projectile, further confirming that the effect of air resistance on the projectile is negligible.

[0021] 7. Design Methods for Small Electromagnetic Rail Launcher Systems

[0022] Based on the principles of setting the firing mode of magnetic induction intensity and setting the firing mode of muzzle velocity as described in step 4, select the weapon assembly, substitute the specific parameters required for the light weapon into the basic formula for designing the small electromagnetic rail launcher system, and obtain the specific configuration parameters of the small electromagnetic rail launcher, thereby completing the configuration method for setting the small electromagnetic rail launcher system.

[0023] Taking a pistol as an example, the configuration of the magnetic induction intensity firing mode is set: taking its muzzle velocity as the target, the mass and resistance of the aluminum projectile are calculated using formulas, and the total resistance of the entire circuit is estimated accordingly. Using the given magnetic induction intensity and air gap width provided by the electromagnet, as well as the track length, the acceleration time and projectile velocity are obtained. Substituting these into the derived formula for calculating the minimum power supply voltage, it is found that under a given magnetic induction intensity, after acceleration on a certain length acceleration track, the projectile can reach the target muzzle velocity, proving that the configuration of this small electromagnetic railgun weapon launcher system is indeed practically feasible.

[0024] The beneficial effects of this invention are as follows:

[0025] On the one hand, the power supply used in this invention is a constant voltage source, which has the following advantages compared to a constant current source:

[0026] 1. Stable power output: Constant voltage power supplies are linear power supplies, and their output voltage does not fluctuate with changes in load. Therefore, they have stable output characteristics and are suitable for applications that require high output voltage stability.

[0027] 2. Lower power supply cost. Compared to constant current power supplies, constant voltage power supplies have simpler circuit designs, resulting in lower costs.

[0028] 3. Simple and convenient to use: The constant voltage power supply has a simple structure and is easy to use. It does not require much adjustment and maintenance, and the maintenance cost is relatively low.

[0029] 4. Strong anti-interference capability: The constant voltage power supply does not contain switching components, so it will not generate strong electromagnetic interference due to the complexity of the circuit, unlike other power supplies. At the same time, its output voltage is stable and has strong anti-interference capability.

[0030] On the other hand, the present invention can significantly reduce the power supply voltage of the electromagnetic orbiter, which has the following advantages:

[0031] 1. The power supply system requirements are low. The device of the present invention can use a power supply system with low output voltage and low requirements for peak power, so a small-sized power supply system can be used.

[0032] 2. The projectile acquires relatively low kinetic energy, which reduces its wear and tear on the track and extends the track's lifespan.

[0033] 3. In the device of the present invention, the reduction of power supply voltage also means the reduction of track current, which can reduce track erosion under high current conditions and extend track life.

[0034] The dynamic efficiency of the electromagnetic railgun system designed according to this invention is significantly improved compared with that of traditional railguns and new railguns, by 42.13% and 38.05% respectively. Furthermore, the current linear density calculated according to this invention is much lower than the maximum current linear density that the current rail can withstand, which means that it will not cause rail ablation. This improves the service life of the electromagnetic railgun system, reduces the performance requirements of the rail and armature to a certain extent, has good economic benefits, and solves existing technical problems to a certain extent. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the electromagnetic track launcher system according to an embodiment of the present invention (electromagnets are omitted). In the diagram, "●" indicates the direction of the uniform magnetic field.

[0036] Figure 2 This is a side view of the electromagnetic track launcher system according to an embodiment of the present invention;

[0037] Figure 3 This is a front view of the electromagnetic track launcher system according to an embodiment of the present invention (ignoring the power supply system and the electromagnet device power supply system, etc.);

[0038] Figure 4 This is a top view of the electromagnetic track launcher system according to an embodiment of the present invention (ignoring the power supply system and the electromagnet device power supply system, etc.);

[0039] Figure label:

[0040] 1. Electromagnet power supply system; 2. Power supply; 3. Electromagnet connection and support part; 4. Wire; 5. Armature; 6. Guide rail; 7. Electromagnet body. Detailed Implementation

[0041] The specific embodiments of the present invention will be described in detail below with reference to specific circumstances.

[0042] In a specific implementation, the present invention provides a design method for a small electromagnetic orbital launcher system, comprising the following steps:

[0043] 1. System structure composition:

[0044] The entire electromagnetic rail launcher system, as shown in the attached diagram, mainly consists of an electromagnet power supply system 1, a power source 2, an electromagnet connection and support part 3, wires 4, an armature 5, rails 6, and an electromagnet 7. The positive terminal of the DC power source 2 is at the bottom, and the negative terminal is at the top. The electromagnet 7 provides a uniform magnetic field. When the switch is closed, the power source 2 is connected, and current flows through wires 4, rails 6, and armature 5 to form a closed loop. When current flows through the armature 5, under the action of the uniform magnetic field, the armature 5 accelerates between the two fixed rails 6.

[0045] 2. Find the minimum value of the power supply voltage.

[0046] For an electromagnetic orbiter system with known magnetic flux density, armature length, armature mass, and total loop resistance, its power supply voltage has a minimum value.

[0047] (1) According to Ohm's law and Newton's second law for closed circuits, the equation of motion of the projectile is given. Substituting the initial values, we obtain the expression for the relationship between the projectile's velocity v and the power supply voltage E, magnetic induction intensity B, and acceleration time t in this system: Then, based on the above relationship v(t), we can obtain the expression for the required track length.

[0048] (2) Rewrite the expression for the velocity v of the projectile as the expression for E. Analyzing the graph of the expression, we find that the function of E with respect to B has a local minimum.

[0049] (3) After learning of the existence of a minimum voltage in step (2), the minimum voltage value is obtained through mathematical calculations such as differentiation. When the projectile velocity v, length L, mass m, total circuit resistance R, and time t are constant, the expression is differentiated with respect to the magnetic induction intensity and the derivative is set to zero to obtain... make Treat this expression as a function f(q) = e q When -2q-1 is zero, the zeros of f(q) can be obtained by plotting the function graph using MATLAB, and the corresponding magnetic flux density value at that point can also be determined. Therefore, the minimum value of the power supply voltage can be solved.

[0050] 3. Basic formulas for designing a small electromagnetic rail launcher system

[0051] The expression for acceleration time t can be derived from the expression for magnetic flux density when the power supply voltage is at its minimum value. Let k = 1 - e -q The expression for the track length in step 2(1) is simplified using the two equations described in step 2(3) to: Substituting q, we get Similarly, the muzzle velocity v c The expression is simplified to

[0052] Based on minimum voltage, acceleration time t, and muzzle velocity v c The direct relationship between the orbital length d and the orbital length d is derived. This formula and The basic formulas for designing small electromagnetic rail launcher systems.

[0053] 4. Two specific modes for designing a small electromagnetic rail launcher system

[0054] Using the basic formulas, we obtain two specific modes of the electromagnetic rail launcher system: a launch mode with a set magnetic induction intensity and a launch mode with a set exit velocity.

[0055] The emission mode is set to be for each magnetic induction intensity B. m Given the track length d, t and v are calculated sequentially using the basic formulas of a small electromagnetic track launcher system. c and E m value.

[0056] The firing mode is set to a muzzle velocity of v. c Given the track length d, t and B are calculated sequentially using the basic formulas of a small electromagnetic track launcher system. m and E m value.

[0057] 5. Verify that the effect of friction on the work done by the projectile is negligible.

[0058] pass To calculate the kinetic energy gained by the projectile upon exiting the barrel, substitute the relevant parameters of the small arms pistol's firing system into the expression for the work done by friction, |W|. f After |=μmgd, the calculated value is much smaller than the kinetic energy gained by the projectile when it leaves the barrel, proving that the influence of friction can be ignored in the derivation process of specific implementation method 2.

[0059] 6. Verify that the effect of air resistance on the work done by the projectile is negligible.

[0060] The formula for air resistance is The air drag coefficient C D Given the air density ρ, the expression for the work done by air resistance can be written as follows: Will Substitute, let get Substituting the relevant parameters of the firing system of the small arms pistol, the calculated work done by air resistance is much smaller than that obtained by... The calculated kinetic energy demonstrates that, for light weapon pistols, the effect of air resistance during the derivation process is negligible.

[0061] 7. Design Methods for Small Electromagnetic Rail Launcher Systems

[0062] Based on the principles of setting the launch mode of magnetic induction intensity and setting the launch mode of muzzle velocity as described in step 4, select the weapon assembly, substitute the specific required parameters of the light weapon into the formula, and obtain the specific configuration parameters of the small electromagnetic rail launcher, thereby completing the configuration method of setting the small electromagnetic rail launcher system.

[0063] Specific implementation examples:

[0064] For a small arms pistol, given a specific applied magnetic field strength, and considering the air gap of the electromagnet, the track length of the electromagnetic rail launcher system, and the material, mass, and dimensions of the projectile, the formula for calculating mass and resistance is m = ρ. m V=πρ m LD 2 / 4, R b =ρ b L / S=4ρ b L / (πD 2 This allows us to calculate the total circuit resistance, minimum orbital acceleration time, and applied magnetic field strength, thus revealing that only a very small external power supply voltage E is required. m =14.4507V, with an acceleration time of t=0.8195ms on a 0.1m track, the projectile velocity can reach the muzzle velocity v of a pistol. c =202.6877m / s, which gives the configuration method of a small electromagnetic railgun launcher system.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent changes or substitutions made by those skilled in the art within the technical scope disclosed in the present invention based on the technical solution steps and concepts of the present invention should be covered within the scope of protection of the present invention.

[0066] In summary, the dynamic efficiency of the electromagnetic railgun system designed according to this invention is significantly improved compared to both traditional and novel railguns, by 42.13% and 38.05%, respectively. After calculating the maximum current of the guide rail in the small electromagnetic railgun system using the above method, a comparison with the "small" power supply system successfully developed by the Institute of Electrical Engineering, Chinese Academy of Sciences in 2020 revealed that this achievement can meet the power supply requirements of the electromagnetic railgun system designed according to this invention. This indicates that current research in this area can be interconnected, increasing the likelihood of small electromagnetic railguns being put into practical production applications. The current linear density calculated according to this invention is far lower than the maximum current linear density that current guide rails can withstand, meaning it will not cause rail ablation, improving the service life of the electromagnetic railgun system and reducing the performance requirements of the guide rail and armature to a certain extent, resulting in good economic and social benefits.

Claims

1. A design method for a small electromagnetic rail launcher system, characterized in that, Includes the following steps: (1) System structure composition: The entire electromagnetic track launcher system includes a power supply (2), wires (4), rails (6), armature (5), and electromagnet (7). The positive terminal of the DC power supply is at the bottom and the negative terminal is at the top. The electromagnet (7) provides a uniform magnetic field. When the switch is closed, the power supply is connected. The current passes through the wires, rails, and armature to form a closed loop. When there is current in the armature, under the action of the uniform magnetic field, the armature accelerates between the two fixed rails. (2) Find the minimum value of the power supply voltage. For a given magnetic flux density B, armature length L, armature mass m, and total circuit resistance R, the power supply voltage E of the electromagnetic orbiter system has a minimum value: ①According to Ohm's law and Newton's second law for closed circuits, the equation of motion of the projectile is... Substituting the initial values, we obtain the expression relating the projectile's velocity v to the power supply voltage E, magnetic induction intensity B, and acceleration time t: Then, based on the above relationship v(t), we can obtain the expression for the required track length. ② Rewrite the expression for the velocity v of the projectile as an expression for E. Analyzing the graph of the expression, we find that the function of E with respect to B has a local minimum. ③ After learning in step ② that the power supply voltage has a minimum value, the minimum value of the power supply voltage is obtained by differentiation. When the projectile velocity v, length L, mass m, total circuit resistance R, and time t are constant, the expression for the power supply voltage is differentiated with respect to the magnetic induction intensity and the derivative is set to zero to obtain... make We obtain the function f(q) = e q The value of -2q-1 is zero. The zeros of f(q) can be obtained by plotting the function graph using MATLAB, and the corresponding magnetic flux density value is also determined. Therefore, the minimum value of the power supply voltage can be solved. (3) Formula for designing a small electromagnetic rail launcher system The expression for acceleration time t can be derived from the expression for magnetic flux density when the power supply voltage is at its minimum value. Let k = 1 - e -q The expression for the track length in step (2)① is simplified to: Substituting q, we get Similarly, the muzzle velocity v c The expression is simplified to Based on minimum voltage, acceleration time t, and muzzle velocity v c The direct relationship between the orbital length d and the orbital length d is derived. This formula and Formulas for designing small electromagnetic rail launcher systems.

2. The design method of the small electromagnetic rail launcher system according to claim 1, characterized in that, Substituting the relevant parameters of the small arms pistol firing system into the expression for the work done by friction |W f After |=μmgd, the calculated value is much smaller than that based on the projectile's muzzle velocity, from The calculated kinetic energy value was derived in step (2) without considering the influence of friction.

3. The design method of the small electromagnetic rail launcher system according to claim 1, characterized in that, The formula for air resistance is The air drag coefficient C D Given the air density ρ, the expression for the work done by air resistance is written as: Will Substitute, let get Substituting the relevant parameters of the small arms pistol firing system, the calculated work done by air resistance is much smaller than that obtained by... The calculated kinetic energy was derived in step (2) without considering the influence of air resistance.

4. The design method of the small electromagnetic rail launcher system according to claim 1, characterized in that, Using the formulas for the electromagnetic railgun system, two specific modes of the electromagnetic railgun system are derived: a launch mode with set magnetic induction intensity and a launch mode with set muzzle velocity. The emission mode is set to be for each magnetic induction intensity B. m Given the track length d, t and v are calculated sequentially using the formulas for a small electromagnetic track launcher system. c and E m value; The firing mode is set to a muzzle velocity of v. c Given the track length d, t and B are calculated sequentially using the formulas for a small electromagnetic track launcher system. m and E m value.

5. The design method of the small electromagnetic rail launcher system according to claim 4, characterized in that, The principles of setting the firing mode based on magnetic induction intensity and the firing mode based on muzzle velocity are established. The weapon assembly is selected, and the specific parameters required for the light weapon are substituted into the formula for designing the small electromagnetic rail launcher system to obtain the specific configuration parameters of the small electromagnetic rail launcher, thereby completing the configuration method for setting the small electromagnetic rail launcher system.

6. The design method of the small electromagnetic rail launcher system according to claim 3, characterized in that, Taking a pistol as an example of a light weapon, the projectile's muzzle velocity is used as the target. The mass and resistance of the aluminum projectile are calculated using formulas, and the total resistance of the entire circuit is estimated accordingly. Using the given magnetic induction intensity and air gap width provided by the electromagnet, as well as the track length, the acceleration time and projectile velocity are obtained. Substituting these values ​​into the minimum power supply voltage calculation formula derived in the design steps, the projectile reaches the target muzzle velocity after acceleration on a certain length of acceleration track under a given magnetic induction intensity. This demonstrates that the configuration of a small electromagnetic rail launcher system is indeed practically feasible.

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