Gunpowder combustion energy generator simulation verification method

Abstract

The invention discloses a gunpowder combustion energy generator simulation verification method, and relates to the field of gunpowder combustion energy MHD power generation simulation verification, and the method comprises the steps: constructing a gunpowder combustion energy MHD power generation channel structure model according to a gunpowder combustion bullet launching process; based on the gunpowder combustion energy MHD power generation channel structure model, utilizing a Navier-Stokes equation and a secondary development Fluent MHD module to perform simulation on a multi-field coupled 3D numerical value in a gunpowder combustion energy power generator, and determining a high-power pulse power supply; according to the high-power pulse power supply, a high-power pulse power supply simulation principle prototype suitable for high-energy weapon power supply is prepared; and performing simulation verification on the high-power pulse power supply simulation principle prototype by combining the gunpowder combustion energy MHD power generation channel structure model. According to the invention, simulation verification can be performed on the gunpowder combustion energy generator.

Description

Technical Field

[0001] This application relates to the field of simulation verification of gunpowder combustion energy MHD power generation, and particularly to a method for simulating and verifying a gunpowder combustion energy generator. Background Art

[0002] Since the gunpowder combustion energy MHD (Magnetohydrodynamics) power generation technology originates from the conventional projectile launch process, only through the ignition test of gunpowder combustion energy (reflected as gunpowder force) in the firing range can the magnitude of the shock wave pressure at corresponding positions such as in the bore and muzzle brake be obtained. Furthermore, the power generation channel of the muzzle brake can be effectively designed to determine whether it can still meet the requirements of gunpowder combustion energy MHD power generation. Therefore, how to simulate and verify the gunpowder combustion energy generator is an urgent matter to be solved currently. Summary of the Invention

[0003] The purpose of this application is to provide a method for simulating and verifying a gunpowder combustion energy generator, which can simulate and verify the gunpowder combustion energy generator.

[0004] To achieve the above purpose, this application provides the following solutions:

[0005] In a first aspect, this application provides a method for simulating and verifying a gunpowder combustion energy generator, including:

[0006] Construct a structural model of the gunpowder combustion energy MHD power generation channel according to the process of gunpowder combustion and projectile launch;

[0007] Based on the structural model of the gunpowder combustion energy MHD power generation channel, use the Navier-Stokes equation and the secondary development FluentMHD module to perform 3D numerical simulation and simulation of multi-field coupling inside the gunpowder combustion energy generator to determine the high-power pulse power supply;

[0008] Prepare a high-power pulse power supply simulation prototype suitable for high-energy weapon power supply according to the high-power pulse power supply;

[0009] Combine the structural model of the gunpowder combustion energy MHD power generation channel to perform simulation verification on the high-power pulse power supply simulation prototype.

[0010] According to the specific embodiments provided by this application, the following technical effects are disclosed: This application provides a method for simulating and verifying a gunpowder combustion energy generator, constructs a structural model of the gunpowder combustion energy MHD power generation channel, and based on the Navier-Stokes equation and the secondary development FluentMHD module, determines the high-power pulse power supply to prepare a high-power pulse power supply simulation prototype, which can be used as a gunpowder combustion energy generator, thereby realizing the simulation verification of the gunpowder combustion energy generator. Description of the Drawings

[0011] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for use in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0012] Figure 1 It is the curve graph of the gas conductivity varying with temperature provided by the present application;

[0013] Figure 2 It is the flow chart of the simulation verification method for the gunpowder combustion energy generator provided by the present application;

[0014] Figure 3 It is the schematic diagram of the structure model of the gunpowder combustion energy MHD power generation channel provided by the present application;

[0015] Figure 4 It is the schematic flow diagram of the research plan for the gunpowder combustion energy MHD power generation technology provided by the present application. Detailed implementation manners

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the present application.

[0017] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0018] Generally, the gas temperature of gunpowder combustion can reach 3000K, which can cause partial gunpowder gas in the gun barrel to undergo high-temperature ionization, generating a plasma of high-speed moving gunpowder gas with low conductivity. When it passes through the muzzle magnetic brake power generation channel, theoretically, gunpowder combustion energy plasma MHD can be achieved. The prerequisite is that the gunpowder gas from the barrel to the power generation channel of the brake must be conductive, and the higher the conductivity, the higher the power generation efficiency.

[0019] Therefore, the present application proposes to add easily ionizable alkali metal seeds, such as K 2 CO 3 or ionization seeds such as potassium salts, to increase the density and conductivity of the gunpowder gas plasma in the barrel and improve the power generation efficiency of gunpowder combustion energy MHD power generation.

[0020] Due to the low ionization potential of alkali metal seeds, adding easily ionizable alkali metal seeds to the propellant makes the propellant gas contain various particles. The seeds are in a state close to complete ionization, and the working medium gas is in a state of weak ionization. All kinds of particles are in continuous thermal motion. The plasma contains three components: atoms, ions, and electrons, which can achieve an increase in the electrical conductivity of the gas.

[0021] Macroscopically, the entire propellant gas plasma is electrically neutral, that is, the total positive charge carried by the particles in the plasma is equal to the total negative charge carried by the particles, namely:

[0022]

[0023] In the formula, n e is the electron number density, is the number density of the primary ionization ions of the i-component.

[0024] Particles of different components should also satisfy the partial pressure law and the pressure equation principle. Then, the number density of various particles caused by electron collisions can be described by the Saha equation:

[0025]

[0026] In the formula, n i is the number density of atoms of the i-component, g i and are the statistical weights of the ground states of the neutral atoms and the ground states of the ions of the i-component respectively. m e is the mass of the electron, k is the Boltzmann constant, h is the Planck constant, T e is the electron temperature, ε i is the ionization potential of the i-component, with the unit of eV.

[0027] Here, the plasma conductivity and the Hall parameter can be expressed in the standard form:

[0028] σ = e 2 n e / m e v en

[0029] β = eB / m e v en

[0030] v en is the average collision frequency of electrons with other particles. C e is the average thermal velocity in the case of the Maxwell distribution of electrons, which can be expressed as:

[0031]

[0032] The collision cross-section of electrons with different components can be expressed as:

[0033]

[0034] where ε 0 is the vacuum permittivity and e is the electron charge.

[0035] From this, the relationship between the plasma conductivity and temperature can be simulated, as Figure 1 shown.

[0036] Conductivity is an important parameter for the electrical conductivity characteristics of gases. Figure 1 In [reference], when the gas temperature is low, due to the low electron density content in the combustion products, the electrical conductivity of the gas is also relatively small. As the temperature rises, the electron density in the combustion products increases, resulting in a gradual increase in the electrical conductivity of the gas. When the temperature range is between 2500 - 3500K, the conductivity is approximately proportional to the gas temperature. When the gas temperature reaches the maximum value of 3500K, its conductivity is 516 S / m, and this value can be further used to describe the plasma conductivity state at the tail of the metal projectile after gunpowder combustion.

[0037] Based on the above content, the embodiments of the present application provide a simulation verification method for a gunpowder energy MHD generator. This method is executed by a computer device, specifically, it can be executed alone by a computer device such as a terminal or a server, or jointly executed by a terminal and a server. In the embodiments of the present application, as Figure 2 shown, this method includes the following steps.

[0038] S1: According to the process of gunpowder combustion and projectile launch, construct a structural model of the gunpowder energy MHD power generation channel.

[0039] S2: Based on the structural model of the gunpowder energy MHD power generation channel, use the Navier - Stokes equation and the secondary - developed Fluent MHD module to perform 3D numerical simulation and simulation of multi - field coupling inside the gunpowder energy generator to determine the high - power pulse power supply.

[0040] S3: According to the high - power pulse power supply, prepare a simulation prototype of the high - power pulse power supply suitable for high - energy weapon power supply.

[0041] S4: Combine the structural model of the gunpowder energy MHD power generation channel to perform simulation verification on the simulation prototype of the high - power pulse power supply.

[0042] In an exemplary embodiment, S1 can be replaced by the following steps.

[0043] Combined with the characteristics of the propellant charge, the aerodynamic characteristics of the projectile, and the structural characteristics of the gun barrel, the microstructures of the relevant elements of the power generation channel are jointly constructed, and the finite element method is used to analyze the in-bore velocity and pressure distribution, and the structural model of the MHD power generation channel of the propellant combustion energy is simulated and calculated, as Figure 3 shown, including propellant 1, cartridge case 2, gun barrel 3, propellant gas or plasma 4, projectile 5, electrode 6, magnet 7, power generation channel 8, and load 9; the relevant elements include the charge structure, projectile, and gun barrel.

[0044] In an exemplary embodiment, S2 can be replaced by the following steps.

[0045] S21: Based on the continuity equation, Navier-Stokes equation, and Maxwell equations of the original generator, add the control equation of the MHD generator of the propellant combustion energy and the electromagnetic field equations of the generalized Ohm's law to construct the control model of the MHD generator of the propellant combustion energy;

[0046] S22: Based on the control model of the MHD generator of the propellant combustion energy, re-develop the Fluent MHD module, perform 3D numerical simulation of the multi-field coupling inside the MHD generator of the propellant combustion energy, obtain the distributions of the velocity field, pressure field, electric field, and magnetic field in the power generation channel at different times, and determine the high-power pulsed power supply.

[0047] In an exemplary embodiment, before S21, it further includes: using and to construct the continuity equation of the original generator; where t is time; v g is the gas velocity; v l is the velocity of the magnetohydrodynamic of the metal projectile; ρ g is the air density; ρ l is the density of the magnetohydrodynamic of the high-speed metal projectile; is the gradient of the electromagnetic field.

[0048] Furthermore, according to the high-dimensional complex system theory, explore the control equation of the magnetohydrodynamic generator in the high-dimensional complex power generation environment, that is, based on the continuity equation, Navier-Stokes equation, and Maxwell equations of the original generator, add the propellant combustion energy control equation and the electromagnetic field equation of the generalized Ohm's law to create the control model of the MHD generator of the propellant combustion energy.

[0049] Continuity equation:

[0050]

[0051] In the formula, t is time, v g and v l are the gas velocity and the velocity of the magnetohydrodynamic of the metal projectile respectively, ρ g and ρl They are the air density, the density of the high-speed metal projectile magnetohydrodynamics, and the density ρ of the control volume in the VOF model. m = α 1 ρ g +(1 - α 1 )ρ l , where α 1 is the volume fraction of the air phase. When α 1 = 1, the control volume is completely occupied by air. When α 1 = 0, the control volume is completely occupied by the high-speed metal projectile magnetohydrodynamics. When 0 < α 1 < 1, the interface of the two-phase substances is in this unit.

[0052] Momentum equation:

[0053]

[0054] In the formula, P is the total pressure, and F is the viscous force and electromagnetic force.

[0055] Energy equation:

[0056]

[0057] In the formula, Q is the sum of the work done by the viscous force, the Joule heat diffusion energy, and the heat conduction energy. T g , T l are the gas temperature and the temperature of the high-speed metal projectile magnetohydrodynamics respectively. C α is the gas-liquid heat transfer coefficient, J is the current density, B is the magnetic induction intensity, and σ is the conductivity.

[0058] ε g = (v 2 / 2 + P / ρ + h)

[0059]

[0060] Therefore, when the turbulence model is Reliable k-ε, the engine control equations are as follows:

[0061]

[0062] In the formula, G k is the turbulent kinetic energy generated by the laminar velocity gradient, G b is the turbulent kinetic energy generated by buoyancy, Y M represents the influence of the compressible turbulent pulsation expansion on the total dissipation rate, and S k and S ε are user-defined quantities.

[0063] In an exemplary embodiment, before S21, it further includes: Considering the magnetic body retarder power generation channel, the Navier-Stokes equation with an electromagnetic force source term added is:

[0064]

[0065] Among them, the electromagnetic field equations of the generalized Ohm's law added are:

[0066]

[0067] Among them, t is time; is the fluid velocity (m / s), p is the pressure (Pa), is the current density vector (A / m 2 ), is the stress tensor, is the magnetic induction intensity (T), E→ is the electric field intensity (V / m), is the electric displacement vector (Wb / m), is the scalar potential (V), ρ is the fluid density (kg / m 3 ), v is the kinematic viscosity (m 2 / s), μ 0 is the vacuum permeability (H / m), σ is the conductivity (S / m); is the stress tensor between the i-fluid and the j-fluid; u i is the velocity of the i-fluid; x j is the j-fluid in the x-direction; x i is the i-fluid in the x-direction; u j is the velocity of the j-fluid.

[0068] In an exemplary embodiment, before S21, it further includes: Using and to construct the Maxwell equations; among them, n is the remaining particles in the gunpowder gas; n n is the nth remaining particle; Q e-n is the electric charge amount between the electron and the particle.

[0069] In an exemplary embodiment, before S21, it further includes: Defining a scalar potential and a potential vector; based on the scalar potential and the potential vector, a control model of the gunpowder combustion energy MHD generator is constructed using the Coulomb gauge.

[0070] In an exemplary embodiment, defining a scalar potential and a potential vector specifically includes:

[0071] Using to define the potential vector; among them, is the potential vector; is the electric displacement vector.

[0072] Based on the said potential vector, use to define a scalar potential; where is the scalar potential.

[0073] In an exemplary embodiment, based on the said scalar potential and potential vector, a control model of a gunpowder combustion energy MHD generator is constructed using the Coulomb gauge, specifically including: using and to construct the control equation of the gunpowder combustion energy MHD generator.

[0074] Studying the gunpowder combustion energy MHD power generation technology and method, strictly speaking, includes two power generation systems. One is to study the direct magnetic pulse generator that uses the gunpowder combustion energy to drive a metal projectile, and the other is the gunpowder gas plasma MHD generator whose gunpowder combustion energy can be highly ionized at high temperature. Both occur simultaneously in the process of using gunpowder combustion energy to launch a projectile. Therefore, it is temporarily defined as the gunpowder combustion energy MHD power generation technology. And the projectiles involved in this technology are all projectiles without explosives, such as a large number of bullets, armor-piercing projectiles fired by artillery, training sand projectiles, etc.

[0075] This application intends to use the silencer or muzzle brake, barrel, and metal projectiles without explosives of a certain type of gun or artillery as the research carriers, and explain the technology and method of generating a combustion energy MHD high-power pulse power supply from three aspects: theoretical analysis and calculation, numerical simulation and simulation, and principle test verification. The specific research plan is as Figure 4 shown.

[0076] From Figure 4 the research plan, the structure of the proposed gunpowder combustion energy MHD generator seems simple, but the entire power generation process is carried out in an extremely complex extreme power generation channel environment formed by the gunpowder combustion energy drive, with high pressure, high temperature, high speed, etc. Its complexity and research difficulties are mainly reflected in:

[0077] Step 1, theoretical analysis and solution of gunpowder combustion energy MHD power generation: First, based on the ammunition launch process and MHD principle, simulate the typical gun and artillery launch states through AUTODYN simulation and gunpowder charge design for launching. From the perspective of the resource utilization of gunpowder energy, based on the unsteady aftereffect period theory and combined with multi-field coupling finite element numerical simulation, simulate various high-temperature and high-pressure flow fields and plasma states in the chamber and muzzle during gunpowder combustion, study the use of high-speed metal projectiles and plasma as MHD power generation working fluids, and design and generate high-T magnet silencer power generation channel structure models with different shapes and materials based on this simulation data, that is, the main structure of the generator.

[0078] Moreover, since the working medium for power generation in gunpowder combustion energy MHD is different from the single-phase liquid metal working medium for MHD power generation, it is formed by the metal projectiles and plasma driven by the combustion energy of the launched gunpowder. Due to its parameter characteristics such as velocity, conductivity, and electron density, it varies with different materials, shapes, and ionization seeds of the cartridge charge, and is also affected by the ablation and flow field of high-temperature and high-pressure gunpowder gases, all of which affect the research on power generation performance. Therefore, it is necessary to comprehensively study by combining numerical simulations such as multi-field coupling and decoupling.

[0079] Step 2: Numerically simulate and simulate the power generation channel, and develop a special high-power pulse power supply: Based on the power generation channel structure model established in Step 1, considering that the gunpowder combustion energy MHD power generation channel is a fusion body integrating multiple powers and multi-field coupling, with both the shock wave power generated by gunpowder combustion, gunpowder gas power, plasma fluid power, magnetohydrodynamic power, etc., there are multi-field couplings such as temperature field, pressure field, velocity field, electric field, and magnetic field in the power generation channel. Currently, there is no analysis and calculation of the distribution of various fields, and further development and research are needed. For this reason, this application uses the incompressible fluid Navier-Stokes equation and the secondary development Fluent MHD module to realize the 3D numerical simulation and simulation of the multi-field coupling inside the gunpowder combustion energy generator, laying a scientific basis for the development of a special high-power pulse power supply;

[0080] Step 3: Principle test verification and power generation performance simulation of gunpowder combustion energy MHD: Although the main body of the gunpowder combustion energy MHD generator can be theoretically constructed in Step 2, from the perspective of the formation and acquisition path of the working medium for power generation in gunpowder combustion energy MHD, neither the high-speed metal projectiles nor the gunpowder gas plasma can be obtained in the laboratory. In particular, the gunpowder combustion plasma is different from the nuclear fusion plasma, with characteristics such as high pressure, transient state, and low ionization degree, which brings great difficulties to the principle test verification of power generation. Moreover, for the design of magnets, electrodes, etc. in the power generation channel, the applicability for mufflers or muzzlebrakes on the barrel needs to be comprehensively and collaboratively considered, bringing difficulties to the design in terms of small volume, high strength, and light weight.

[0081] For this reason, this application comprehensively considers the aerodynamic characteristics and safety of the generator main body, collaboratively designs the mufflers or muzzlebrakes of guns and artillery to use high-T materials and corresponding structures, and then designs the gunpowder charge type, formula, structure, etc. to be coordinated and matched with the generator, constructs the gunpowder combustion energy MHD power generation system and the model prototype, and then combines the MHD model simulation and the ultra-high specific power pulse technology to carry out the principle simulation experiment verification research and develop the simulation prototype of the high-power pulse power supply suitable for high-energy weapon power supply.

[0082] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0083] In this article, specific examples are used to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A method for simulating and verifying a gunpowder combustion generator, characterized in that: include: According to the process of firing projectiles with gunpowder combustion, the structural model of the MHD power generation channel of gunpowder combustion energy is constructed; Based on the gunpowder-fueled MHD power generation channel structure model, the Navier-Stokes equation and the secondary development FluentMHD module are used to perform 3D numerical simulation of the multi-field coupling inside the gunpowder-fueled generator to determine the high-power pulse power supply; According to the high-power pulse power supply, a high-power pulse power supply simulation principle prototype suitable for powering high-energy weapons is prepared; The high-power pulse power supply simulation principle prototype is simulated and verified in combination with the gunpowder combustion MHD power generation channel structure model.

2. The method for simulating and verifying a gunpowder combustion generator according to claim 1, characterized in that: According to the process of gunpowder combustion and projectile launching, the structural model of the gunpowder combustion MHD power generation channel is constructed, which includes: The microstructure of the relevant elements of the power generation channel are jointly constructed by coordinating the gunpowder charge characteristics, the aerodynamic characteristics of the projectile and the barrel structure. The finite element method is used to analyze the velocity and pressure distribution in the bore, and the structural model of the gunpowder combustion MHD power generation channel is simulated and calculated. The relevant elements include the charge structure, the projectile and the barrel.

3. The method for simulating and verifying a gunpowder combustion generator according to claim 1, characterized in that: Based on the gunpowder-fueled MHD power generation channel structure model, the Navier-Stokes equation and the secondary development Fluent MHD module are used to perform a 3D numerical simulation of the multi-field coupling inside the gunpowder-fueled generator to determine the high-power pulse power supply, including: Based on the original generator continuity equation, Navier-Stokes equation and Maxwell equations, the control equation of the gunpowder-fueled MHD generator and the electromagnetic field equations of the generalized Ohm's law are added to construct the gunpowder-fueled MHD generator control model. Based on the gunpowder-fired MHD generator control model, the Fluent MHD module was secondary developed to perform 3D numerical simulation of multi-field coupling inside the gunpowder-fired generator, obtain the distribution of velocity field, pressure field, electric field and magnetic field in the power generation channel at different times, and determine the high-power pulse power supply.

4. The method for simulating and verifying a gunpowder combustion generator according to claim 3, characterized in that: Based on the original generator continuity equation, Navier-Stokes equation and Maxwell equations, the control equation of the gunpowder-fueled MHD generator and the electromagnetic field equations of the generalized Ohm's law are added to construct the gunpowder-fueled MHD generator control model, which previously also included: use and Construct the continuity equation of the original generator; where t is time; v g is the gas velocity; v l is the velocity of the metal projectile magnetic fluid; ρ g is the air density; ρ l is the density of the magnetic fluid of the high-speed metal projectile; ▽ is the gradient of the electromagnetic field.

5. The method for simulating and verifying a gunpowder combustion generator according to claim 4, characterized in that: Based on the original generator continuity equation, Navier-Stokes equation and Maxwell equations, the control equation of the gunpowder-fueled MHD generator and the electromagnetic field equations of the generalized Ohm's law are added to construct the gunpowder-fueled MHD generator control model, which previously also included: use and Construct the Navier-Stokes equations; where t is time; is the fluid velocity; ρ is the fluid density; is the stress tensor; is the current density vector; is the magnetic induction intensity; is the stress tensor between fluid i and fluid j; u i is the fluid velocity; x j is the j fluid in the x direction; x i is the fluid i in the x direction; u j is the fluid velocity j.

6. The method for simulating and verifying a gunpowder combustion generator according to claim 5, characterized in that: The electromagnetic field equations of the generalized Ohm's law are: in, is the electric field strength; μ0 is the magnetic permeability of vacuum; σ is the electrical conductivity.

7. The method for simulating and verifying a gunpowder combustion generator according to claim 6, characterized in that: Based on the original generator continuity equation, Navier-Stokes equation and Maxwell equations, the control equation of the gunpowder-fueled MHD generator and the electromagnetic field equations of the generalized Ohm's law are added to construct the gunpowder-fueled MHD generator control model, which previously also included: use and Construct Maxwell's equations; where v en is the average collision frequency between electrons and the remaining particles in the gunpowder gas; C e is the average thermal velocity of the electrons under the Maxwell distribution; n is the remaining particles in the gunpowder gas; n n is the nth remaining particle; Q e-n is the charge between the electron and the particle; k is the Boltzmann constant; m e is the mass of the electron; T e is the electron temperature; e is the electron charge.

8. The method for simulating and verifying a gunpowder combustion generator according to claim 7, characterized in that: Based on the original generator continuity equation, Navier-Stokes equation and Maxwell equations, the control equation of the gunpowder-fueled MHD generator and the electromagnetic field equations of the generalized Ohm's law are added to construct the gunpowder-fueled MHD generator control model, which previously also included: Define scalar potential and potential vector; Based on the scalar potential and potential vector, the Coulomb specification is used to build a control model of the gunpowder-fueled MHD generator.

9. The method for simulating and verifying a gunpowder combustion generator according to claim 8, characterized in that: Define scalar potential and potential vector, including: use Define the potential vector; where, is the potential vector; is the electric displacement vector; Based on the potential vector, using Define a scalar potential; where, is a scalar potential.

10. The method for simulating and verifying a gunpowder combustion generator according to claim 9, characterized in that: Based on the scalar potential and potential vector, the Coulomb specification is used to construct a control model of the gunpowder combustion MHD generator, which specifically includes: use and Construct the control equations of the gunpowder-fueled MHD generator.

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