Method and system for efficiently predicting and calculating detonation performance parameters of thermobaric explosive

Abstract

The invention belongs to the technical field of explosion mechanics, and particularly discloses an efficient prediction and calculation method and system for detonation performance parameters of thermobaric explosives. Comprising the following steps: constructing an aluminum-containing explosive basic parameter system, and assuming the percentage of aluminum powder participating in a secondary reaction; performing preliminary prediction on detonation pressure, detonation temperature and detonation velocity of the aluminum-containing explosive to form a reference input parameter set of an explosive detonation reaction stage; constructing a thermodynamic equilibrium model, calculating the chemical component distribution of a secondary reaction product, and calculating the pressure of a gaseous product in combination with an improved BKW state equation; and establishing a dual convergence criterion and a nested iteration mechanism, dynamically feeding back and adjusting the reactivity of the aluminum powder participating in the secondary reaction in the iteration process until the dual criterion simultaneously meets the precision requirement, outputting the detonation pressure, the detonation temperature, the detonation velocity and the detonation heat in the CJ equilibrium state and balancing the amount of substance of each component, and solving to obtain the parameters required by the JWL state equation suitable for the aluminum-containing explosive. According to the invention, rapid convergence and high-precision matching of detonation parameter calculation are realized.

Description

Technical Field

[0001] This invention belongs to the field of quantum chemistry technology, and more specifically, relates to an efficient method and system for predicting and calculating the detonation performance parameters of thermobaric explosives. Background Technology

[0002] In recent years, with the improvement of computer hardware performance and the development of numerical algorithms, numerical simulation has become an important tool for evaluating the explosive performance of aluminum-containing explosives. Traditional methods for obtaining detonation parameters of aluminum-containing explosives (such as detonation pressure, detonation velocity, and detonation heat) rely on multiple complex experiments, including detonation velocity tests, detonation pressure tests, detonation heat tests, and cylindrical tests. These methods suffer from significant safety risks, high costs, operational difficulties, and limited test data. At the same time, existing models such as JWL-Miller have limited generalization ability because key parameters need to be derived from cylindrical tests, making it difficult to accurately describe the dynamic impact of secondary reactions of aluminum powder on the detonation process.

[0003] From a thermodynamic perspective, the detonation of aluminum-containing explosives is essentially a dynamic equilibrium process between the oxidation reaction of aluminum powder and the expansion of detonation products. Its final state follows chemical equilibrium laws, reflecting the stable state with the lowest energy. However, traditional simplified models based on the CJ assumption struggle to accurately characterize the energy and mass transfer laws of non-ideal detonations. Furthermore, existing numerical methods combined with thermodynamic calculations suffer from significant errors in the coupled calculation of energy release and pressure wave propagation because the JWL equation of state does not consider the dynamic influence of the aluminum powder reactivity λ on the product composition distribution. Additionally, traditional nested iterative algorithms are inefficient and cannot meet the needs of rapid optimization in engineering. Therefore, developing a highly efficient iterative algorithm based on thermodynamic equilibrium correction and dual convergence criteria, utilizing a dynamic feedback mechanism involving aluminum powder participation in the secondary reactivity λ and a prediction-correction hybrid framework, enables rapid and accurate prediction of detonation parameters for aluminum-containing explosives. This has significant theoretical and practical value for reducing experimental costs, optimizing explosive formulations, and expanding their engineering applications.

[0004] Chinese patent CN113593650B discloses a method for calculating detonation parameters of mixed explosives. This invention describes the phase changes of the gaseous and condensed phases of the detonation products using the BKW equation of state and the Cowan equation of state, respectively. It combines the principle of minimizing chemical equilibrium free energy, CJ detonation theory, and Hugoniot relations to achieve numerical calculations of parameters such as detonation velocity and detonation pressure. However, it does not consider the actual reactivity of difficult-to-react components such as solid aluminum powder, and relying solely on the chemical equilibrium assumption may lead to significant calculation errors. Furthermore, it lacks a predictive mechanism and relies entirely on numerical iteration, resulting in long calculation times and limited convergence. Summary of the Invention

[0005] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides an efficient method and system for predicting and calculating the detonation performance parameters of thermobaric explosives. It addresses the problems in existing technologies, such as "existing experimental testing methods require numerous detonation tests, leading to long development cycles and high costs," "traditional methods over-rely on chemical equilibrium assumptions, failing to consider the actual reactivity and non-equilibrium effects of reacting components like solid aluminum powder, resulting in high deviation rates between theoretical and measured values," and "existing technologies rely entirely on numerical iterations, lacking an advance prediction mechanism." By introducing the dynamic participation of solid aluminum powder in the reactivity model and an advance prediction mechanism, a hybrid algorithm framework with adaptive convergence capability is constructed. This significantly reduces the number of numerical calculation iterations while maintaining computational accuracy, thereby significantly improving the efficiency and accuracy of predicting detonation parameters for aluminum-containing explosives.

[0006] To achieve the above objectives, according to one aspect of the present invention, an efficient method for predicting and calculating the detonation performance parameters of thermobaric explosives is proposed, comprising the following steps:

[0007] Step 1: Construct a basic parameter system for aluminum-containing explosives and assume the percentage of aluminum powder participating in the secondary reaction;

[0008] Step 2: Make preliminary predictions on the detonation pressure, detonation temperature, and detonation velocity of aluminum-containing explosives to form a set of benchmark input parameters for the detonation reaction stage of the explosives;

[0009] Step 3: Using the preliminary predicted values ​​of detonation pressure, detonation temperature, and detonation velocity as the initial values ​​for the explosive detonation reaction, construct a thermodynamic equilibrium model, calculate the chemical composition distribution of the secondary reaction products, and combine the improved BKW equation of state to calculate the pressure of the gaseous products.

[0010] Step 4: Construct the first convergence criterion based on the difference between the initially predicted explosion pressure and the gaseous product pressure. If the difference is less than the threshold, proceed to step 5; otherwise, return to step 3 and adjust the initial values ​​of explosion pressure and explosion temperature.

[0011] Step 5: Construct an energy conservation criterion as the second convergence criterion. If the second convergence criterion is satisfied, output the explosion pressure, explosion temperature, explosion velocity, explosion heat, and the amount of each component in the equilibrium state of CJ. Otherwise, return to step 1, re-assume the percentage of aluminum powder participating in the secondary reaction, and solve for the parameters required for the JWL equation of state applicable to aluminum explosives.

[0012] As a further preferred embodiment, in step one, the basic parameter system of the aluminum-containing explosive includes the aluminum-containing explosive components, the mass m of the aluminum-containing explosive, the density ρ of the aluminum-containing explosive, the volume V of the aluminum-containing explosive, and the initial environmental pressure P0.

[0013] As a further preferred option, in step two, the following calculation model is used for detonation velocity prediction:

[0014] D = D max -KρTMD η

[0015] D max =∑ε i D i

[0016] K = (1-η)∑K i ε i +K min η

[0017]

[0018] In the formula, ε i D represents the volume fraction of the formulation components. i V is the characteristic detonation velocity of component i. i Let ρ be the volume of component i. TMD Let K be the theoretical density of the mixed explosive, K be the characteristic slope of the explosive, and η be the porosity of the explosive.

[0019] Preferably, the explosion temperature is predicted using the Castells heat capacity method:

[0020]

[0021] In the formula, For the average constant-volume heat capacity, n i Let i be the number of moles of the i-th component. Let Q be the isochoric heat capacity of the i-th component, where A and B are constants, T1 is the explosion temperature, and Q is the temperature at which the i-th component is formed. V This refers to the heat of combustion at constant volume released during the combustion process.

[0022] As a further preferred embodiment, in step three, the step of using the initially predicted detonation pressure, detonation temperature, and detonation velocity values ​​as the initial values ​​for the explosive detonation reaction to construct a thermodynamic equilibrium model includes:

[0023] Based on the Gibbs minimum free energy principle in chemical thermodynamics, chemical equilibrium calculations are performed on the detonation product system to determine the detailed composition of the detonation products under the final equilibrium state.

[0024] As a further preferred method, the molar Gibbs free energy of the gaseous components in the detonation products is calculated based on the following thermodynamic equilibrium model:

[0025]

[0026] Where G represents the Gibbs free energy; n i The value represents the molar amount of the i-th explosion product; k represents the total number of gaseous products; the subscripts g and s represent gaseous products and condensed phase products, respectively; l represents the total number of chemical elements in the system; b k It is the molar amount of the kth component in the explosion products; a ika is the number of atoms of the k-th element in the i-th product. jk P1 represents the number of atoms of the k-th chemical element in the j-th condensed phase product molecule, P1 represents the explosion pressure, T1 represents the explosion temperature, and μ represents the explosion temperature. i Let μ be the chemical potential of the i-th explosion product at explosion pressure P1 and explosion temperature T1. gi Let μ be the chemical potential of the i-th gaseous product at equilibrium. sj Let x be the chemical potential of the j-th condensed phase product at equilibrium. gi Let x be the mole fraction of the i-th component in the gaseous product. sj Let b be the mole fraction of the j-th component in the condensed phase product. k Let be the total atomic molar mass of the k-th chemical element in the explosive system.

[0027] As a further preferred embodiment, in step three, the calculation of the gaseous product pressure using the modified BKW equation of state includes:

[0028] The residual capacity correction and exponential correction terms of the product components are introduced into the BKW equation of state to construct an improved BKW equation of state.

[0029] Preferably, the improved BKW equation of state includes:

[0030]

[0031]

[0032] ρ g =ρ0·(γ+1) / γ

[0033]

[0034] m g =∑n gi M gi

[0035] V g =m g / ρ g

[0036] Where p represents pressure, V g Let x be the molar gas volume, R be the gas constant, and α, β, κ, and θ be adjustable parameters. i and k i ρ represents the mole fraction and residual volume of each product component i, respectively; g γ is the density of the gaseous products; γ is the adiabatic index; m g n is the total mass of the gaseous products; gi M is the amount of substance of gaseous component i; gi Let n be the relative molecular mass of gaseous component i. iLet represent the molar amount of the i-th explosion product, ρ0 be the initial density of the aluminum explosive, D be the detonation velocity, and P2 be the pressure of the gaseous product calculated by the improved BKW equation of state.

[0037] As a further preferred embodiment, the first convergence criterion includes:

[0038] P2-P1<ε1

[0039] The second convergence criterion includes:

[0040] E-E0-0.5(p2-p0)(v0+v)<ε2

[0041] In the formula, P2 is the pressure of the gaseous products calculated by the improved BKW equation of state, P1 is the preliminary predicted explosion pressure, ε1 is the first convergence criterion threshold, E is the total energy of the equilibrium products, E0 is the total energy of the explosive, v is the volume of the equilibrium component gas, p0 is the initial ambient atmospheric pressure, v0 is the initial volume of the explosive, and ε2 is the second convergence criterion threshold.

[0042] As a further preferred embodiment, in step five, the JWL equation applicable to aluminum-containing explosives includes:

[0043]

[0044] In the formula, P2 is the pressure of the gaseous products calculated by the improved BKW equation of state, V is the specific volume, E is the heat of explosion, A, B, R1, R2, and ω are material constants, ρ0 is the initial density of the aluminum explosive, and D is the detonation velocity.

[0045] As a further preferred option, in step five, based on the degree of aluminum powder participation in the secondary reaction, the amount of aluminum powder that did not participate in the secondary reaction is calculated. It is assumed that the aluminum powder that did not participate in the secondary reaction undergoes complete aerobic combustion, and an aluminum particle combustion model is used for calculation:

[0046]

[0047] In the formula, E Al The energy for the oxygenation combustion of aluminum powder, t Al v represents the combustion time of aluminum powder particles. Al X is the afterburning energy release rate, where a and n are constants. eff ρ is the concentration of the oxidant in the air, p is the air pressure, T0 is the initial temperature, and d is the particle size of the aluminum particles.

[0048] According to another aspect of the present invention, a high-efficiency prediction and calculation system for the detonation performance parameters of thermobaric explosives is also provided. This system is used to implement the method of any of the above embodiments or combinations thereof, including:

[0049] The first main control module is used to construct the basic parameter system of aluminum-containing explosives and assume the percentage of aluminum powder participating in the secondary reaction;

[0050] The second main control module is used to make preliminary predictions on the detonation pressure, detonation temperature and detonation velocity of aluminum-containing explosives, and to form a set of reference input parameters for the detonation reaction stage of the explosives.

[0051] The third main control module is used to take the preliminary predicted values ​​of detonation pressure, detonation temperature, and detonation velocity as the initial values ​​of the explosive detonation reaction, construct a thermodynamic equilibrium model, calculate the chemical composition distribution of the secondary reaction products, and calculate the pressure of gaseous products by combining the improved BKW equation of state.

[0052] The dual convergence criterion module is used to construct the first convergence criterion based on the difference between the initially predicted explosion pressure and the gaseous product pressure, and to use the energy conservation criterion as the second convergence criterion. The initial values ​​of explosion pressure and explosion temperature are adjusted until the first convergence criterion is met, and then the second convergence criterion is judged. The percentage of aluminum powder assumed to participate in the secondary reaction is adjusted until the second convergence criterion is met.

[0053] The fourth main control module is used to output the explosion pressure, explosion temperature, explosion velocity, explosion heat and the amount of each component in the equilibrium state of CJ, and finally solves for the parameters required for the JWL equation of state applicable to aluminum explosives.

[0054] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0055] 1. This invention achieves rapid convergence and high-precision matching of detonation parameter calculation by constructing a closed-loop technical route of "basic parameter setting - detonation parameter prediction - dynamic balance correction - dual criterion iteration - parameter output", which significantly improves the calculation efficiency and applicability. It provides an efficient tool with both theoretical rigor and engineering practicality for the optimization of aluminum-containing explosive formulations, and can effectively reduce the cost of detonation parameter testing and shorten the research and development cycle.

[0056] 2. This invention constructs a dynamic reaction participation model for aluminum powder and adjusts the reaction participation degree λ of aluminum powder in real time during the iteration process, which significantly reduces the deviation rate between theoretical and measured values ​​and significantly improves the calculation accuracy. It solves the problem in the prior art that relies on the chemical equilibrium assumption and ignores the degree to which solid aluminum powder actually participates in the secondary reaction.

[0057] 3. This invention establishes a process of "basic parameter setting → detonation parameter prediction → dynamic equilibrium correction". First, it quickly predicts detonation pressure, detonation velocity and detonation temperature based on empirical formulas, and then corrects them through the Gibbs minimum free energy principle and the BKW equation of state. Compared with traditional methods that rely on numerical iteration, the calculation time is greatly reduced.

[0058] 4. This invention is not only applicable to the calculation of detonation parameters of aluminum-containing explosives, but can also be used to calculate the detonation parameters of elemental or mixed explosives containing elements such as C, H, O, N, Cl, F, S, Na, K, Al, and Mg, making it highly adaptable. Attached Figure Description

[0059] Figure 1 This is a flowchart of an efficient prediction and calculation method for the detonation performance parameters of thermobaric explosives involved in an embodiment of the present invention;

[0060] Figure 2 This is a comparison chart of the shock wave time history curves of aluminum-containing explosives of type RDX / Al / WAX=55% / 30% / 15% in the embodiments of the present invention;

[0061] Figure 3 This is a comparison chart of the shock wave time history curves of aluminum-containing explosives of type RDX / LiF / WAX=55% / 30% / 15% in the embodiments of the present invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0063] like Figure 1As shown in this embodiment, the efficient prediction and calculation method for the detonation performance parameters of thermobaric explosives first completes the construction of the basic parameter system and reaction condition assumptions of aluminum-containing explosives: inputting core basic data such as the composition, density, mass, and initial environmental pressure of the aluminum-containing explosives, and assuming the percentage λ of aluminum powder participating in the secondary reaction, laying the initial condition foundation for subsequent calculations; secondly, based on existing formula theoretical models and the preset degree of aluminum powder participation in the secondary reaction λ, preliminary predictions are made of the detonation pressure P1, detonation temperature T1, and detonation velocity D of the aluminum-containing explosives, forming a set of benchmark input parameters for the detonation reaction stage of the explosives; thirdly, a thermodynamic equilibrium correction model is constructed to accurately calculate the products, using the preliminary predicted values ​​(P1, T1, D) as the reaction benchmark conditions, and a thermodynamic equilibrium model is constructed based on the Gibbs minimum free energy principle, systematically... The chemical composition distribution of the secondary reaction products is calculated, and then an improved BKW equation of state combined with equilibrium component data is used to accurately calculate the pressure P2 of the gaseous products. Next, a dual convergence criterion and a nested iterative mechanism are established: a pressure difference threshold criterion (|P2-P1|<δ) and an energy conservation criterion (E-E0-0.5(p-p0)(v0+v)<ε). The convergence of the two criteria is driven synchronously by a nested iterative algorithm. During the iteration process, the reactivity λ of aluminum powder participating in the secondary reaction is dynamically adjusted until both criteria simultaneously meet the accuracy requirements. Finally, when the iteration converges, the explosion pressure P1, explosion temperature T1, explosion velocity D, explosion heat E, and the amount of each component in equilibrium under the CJ equilibrium state are output synchronously. Finally, the JWL equation parameters applicable to aluminum-containing explosives are obtained by solving the equation. This invention achieves rapid convergence and high-precision matching of detonation parameter calculation through a closed-loop technical route of "basic parameter setting - detonation parameter prediction - dynamic balance correction - dual criterion iteration - parameter output", which significantly improves the calculation efficiency and applicability. It provides an efficient tool for optimizing aluminum-containing explosive formulations that combines theoretical rigor with engineering practicality, and can effectively reduce the cost of detonation parameter testing and shorten the research and development cycle.

[0064] More specifically, the method includes the following calculation steps:

[0065] (1) Complete the construction of the basic parameter system and reaction condition assumptions for aluminum-containing explosives: Input the core basic data such as the components, density, mass, and initial environmental pressure of the aluminum-containing explosives. Optional inputs include the amount of each component of the aluminum-containing explosives, the amount of substance of elements such as C, H, O, N, and Al, the mass m of the aluminum-containing explosives, the density ρ of the aluminum-containing explosives, the volume V of the aluminum-containing explosives, and the initial environmental pressure P0.

[0066] Alternatively, the calculation method may also include:

[0067] (2) Assume the percentage of aluminum powder participating in the secondary reaction, λ, to lay the initial condition foundation for subsequent calculations. Alternatively, assume the percentage of aluminum powder participating in the secondary reaction, λ, and recalculate the amount of each element participating in the reaction.

[0068] Alternatively, the calculation method may also include:

[0069] (3) Based on the existing formula theoretical model and the preset degree of secondary reaction of aluminum powder, the explosion pressure P1, explosion temperature T1 and explosion velocity D of aluminum explosive are initially predicted to form a set of benchmark input parameters for the detonation reaction stage of explosive.

[0070] In this step, the detonation pressure P1, detonation velocity D, and detonation temperature T1 are predicted based on the composition of the aluminum-containing explosive.

[0071] For explosive C a H b N c O d Al e The explosion pressure prediction uses the formula from the literature "Determination of performance of non-ideal aluminized explosives":

[0072]

[0073] The accuracy verification of the explosion pressure P prediction formula is shown in the table below:

[0074] Table 1. Accuracy Verification of Explosion Pressure Prediction Formula

[0075]

[0076] The detonation velocity D prediction formula uses the following detonation velocity calculation method:

[0077] D = D max -Kρ TMD η

[0078] D max =∑ε i D i

[0079] K = (1-η)∑K i ε i +K min η

[0080]

[0081] Where: ε i D represents the volume fraction of the formulation components. i V represents the characteristic detonation velocity of component i; i ρ is the volume of component i. TMD η is the theoretical density of the mixed explosive; K is the characteristic slope of the explosive; η is the porosity of the explosive; and D is the detonation velocity, which is the same as D1.

[0082] The characteristic detonation velocities and characteristic slopes of some components are shown in the table below:

[0083] Table 2. Characteristic detonation velocities and characteristic slopes of some components.

[0084]

[0085] The accuracy verification of the detonation velocity D prediction formula is shown in the table below:

[0086] Table 3. Accuracy Verification of Detonation Velocity Prediction Formula

[0087]

[0088] The formula for predicting explosion temperature uses the Castells heat capacity method:

[0089]

[0090] For diatomic molecules (such as N2, O2, CO, etc.): For water vapor: For triatomic molecules (such as CO2, HCN, etc.):

[0091] For tetraatomic molecules (such as NH3): For pentaatomic molecules (such as CH4): For carbon:

[0092] Alternatively, the calculation method may also include:

[0093] (4) Taking the aforementioned preliminary predictions of detonation pressure P1, detonation velocity D, and detonation temperature T1 as the standard initial conditions for the explosive detonation reaction, chemical equilibrium calculations are performed on the detonation product system based on the Gibbs minimum free energy principle in chemical thermodynamics to determine the detailed composition of the detonation products under the final equilibrium state. In this calculation process, the molar Gibbs free energy of the gaseous components in the detonation products is calculated according to the following standard thermodynamic expression:

[0094]

[0095] Where G represents the Gibbs free energy; ni represents the molar amount of the i-th explosion product; k represents the total number of gaseous products; the subscripts g and s represent gaseous products and condensed phase products, respectively; l represents the total number of chemical elements in the system; b k It is the molar amount of the kth component in the explosion products; a ik It is the number of atoms of the k-th element in the i-th product.

[0096] Alternatively, the calculation method may also include:

[0097] (5) Based on the secondary reaction equilibrium components obtained in the preceding steps, the Becker-Kistiakowsky-Wilson (BKW) equation of state is used to calculate the pressure of the detonation products. This equation, by introducing residual capacity correction and exponential correction terms for the product components, significantly improves the accuracy of detonation pressure calculation under high pressure conditions, and is particularly suitable for high-density detonation simulation of condensed explosives. The BKW equation of state is in the form of:

[0098]

[0099] ρ g =ρ0·(γ+1) / γ

[0100]

[0101] m g =∑n gi M gi

[0102] V g =m g / ρ g

[0103] Where: p represents pressure, V g Let be the molar gas volume, and R be the gas constant. α, β, κ, and θ are all adjustable parameters, and x... i and k i ρ represents the mole fraction and residual volume of each product component i, respectively; g γ is the density of the gaseous products; γ is the adiabatic index; m g n is the total mass of the gaseous products; gi M is the amount of substance of gaseous component i; gi Let be the relative molecular mass of gaseous component i;

[0104] Assume the products of the secondary reaction are C(s), H2, O2, CO, CO2, H2O, Al, Al2O3(l), N2, CH4, NH3, NO, NO2, N, and O.

[0105] The parameters for the BKW equation for aluminum-containing explosives are selected as follows:

[0106] Table 4 BKW Equation of State Parameters

[0107]

[0108] Table 5 Residual Capacity Values ​​of Gaseous Products

[0109]

[0110] Alternatively, the calculation method may also include:

[0111] (6) Compare the equilibrium product pressure P2 obtained based on the BKW equation of state with the initial predicted pressure P1 to determine whether the following conditions are met:

[0112] P2-P1<ε

[0113] If the above pressure criteria are not met, adjust the explosion pressure P1 and explosion temperature T2, and perform iterative calculations again.

[0114] If the above pressure criterion is met, then an energy conservation check is performed, and the energy conservation equation is in the form of:

[0115] E-E0-0.5(p2-p0)(v0+v)<ε

[0116] If the above energy conservation condition is not met, then return to adjust the percentage of aluminum powder participating in the secondary reaction λ, and recalculate iteratively.

[0117] If both the energy conservation criterion and the pressure criterion are satisfied, then the outputs are explosion pressure P2, explosion velocity D, explosion temperature T2, explosion heat E, and specific volume V.

[0118] Alternatively, the calculation method may also include:

[0119] (7) Based on the detonation pressure P2, detonation velocity D, detonation temperature T2, detonation heat E, and specific volume V of the aluminum-containing explosive obtained in the preceding steps, the expansion-driven work process of the detonation products is described using the Jones-Wilkins-Lee (JWL) equation of state. The JWL equation of state is as follows:

[0120]

[0121] In the formula: P2 is the detonation product pressure, V is the specific volume, E is the heat of detonation, A, B, R1, R2, and ω are material constants, and D is the detonation velocity, which is the same as D1.

[0122] Alternatively, the calculation method may also include:

[0123] (8) Based on the above JWL state equation, the parameters of the JWL state equation are obtained by solving, which are used to describe the expansion-driven work process of the detonation products.

[0124] Based on the degree of Al powder participation in the secondary reaction, the solution for Al powder not participating in the secondary reaction can be obtained. Assuming that the Al powder not participating in the secondary reaction undergoes complete aerobic combustion, an aluminum particle combustion model is used for calculation:

[0125]

[0126] In the formula: E Al The energy for the aerobic combustion of aluminum powder; t Al The combustion time of aluminum powder particles; v AlThe afterburning energy release rate; a: 0.00735; n: 1.8; X eff : Concentration of oxidant in air: 0.2; p: air pressure; T0: initial temperature; d: aluminum particle size.

[0127] Comparison of prediction results of this invention:

[0128] Table 6. Predicted detonation parameters for different explosive formulations.

[0129]

[0130] In engineering, the predicted shock wave overpressure time history curves for aluminum-containing explosives with RDX / Al / WAX = 55% / 30% / 15% are compared to, for example... Figure 2 As shown.

[0131] In engineering, the predicted shock wave overpressure time history curves for aluminum-containing explosives with RDX / LiF / WAX = 55% / 30% / 15% are compared to, for example... Figure 3 As shown in the figure. Through comparative analysis, the shock wave overpressure time history curves at each measuring point obtained by numerical simulation and experimental measurement are in good agreement. The relative errors between the calculated results of the maximum overpressure peak value and impulse of the shock wave and the experimental results are all within 10%, indicating that the detonation parameter prediction of this invention is reasonable.

[0132] According to another aspect of the present invention, a high-efficiency prediction and calculation system for the detonation performance parameters of thermobaric explosives is also provided. This system is used to implement the method of any of the above embodiments or combinations thereof, including:

[0133] The first main control module is used to construct the basic parameter system of aluminum-containing explosives and assume the percentage of aluminum powder participating in the secondary reaction;

[0134] The second main control module is used to make preliminary predictions on the detonation pressure, detonation temperature and detonation velocity of aluminum-containing explosives, and to form a set of reference input parameters for the detonation reaction stage of the explosives.

[0135] The third main control module is used to take the preliminary predicted values ​​of detonation pressure, detonation temperature, and detonation velocity as the initial values ​​of the explosive detonation reaction, construct a thermodynamic equilibrium model, calculate the chemical composition distribution of the secondary reaction products, and calculate the pressure of gaseous products by combining the improved BKW equation of state.

[0136] The dual convergence criterion module is used to construct the first convergence criterion based on the difference between the initially predicted explosion pressure and the gaseous product pressure, and to use the energy conservation criterion as the second convergence criterion. The initial values ​​of explosion pressure and explosion temperature are adjusted until the first convergence criterion is met, and then the second convergence criterion is judged. The percentage of aluminum powder assumed to participate in the secondary reaction is adjusted until the second convergence criterion is met.

[0137] The fourth main control module is used to output the explosion pressure, explosion temperature, explosion velocity, explosion heat and the amount of each component in the equilibrium state of CJ, and finally solves for the parameters required for the JWL equation of state applicable to aluminum explosives.

[0138] More specifically, the execution steps of each module correspond one-to-one with the methods in the above embodiments, and will not be repeated here.

[0139] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for efficient prediction and calculation of detonation performance parameters of thermobaric explosives, characterized in that, Includes the following steps: Step 1: Construct a basic parameter system for aluminum-containing explosives and assume the percentage of aluminum powder participating in the secondary reaction; Step 2: Make preliminary predictions on the detonation pressure, detonation temperature, and detonation velocity of aluminum-containing explosives to form a set of benchmark input parameters for the detonation reaction stage of the explosives; Step 3: Using the preliminary predicted values ​​of detonation pressure, detonation temperature, and detonation velocity as the initial values ​​for the explosive detonation reaction, construct a thermodynamic equilibrium model, calculate the chemical composition distribution of the secondary reaction products, and combine the improved BKW equation of state to calculate the pressure of the gaseous products. Step 4: Construct the first convergence criterion based on the difference between the initially predicted explosion pressure and the gaseous product pressure. If the difference is less than the threshold, proceed to step 5; otherwise, return to step 3 and adjust the initial values ​​of explosion pressure and explosion temperature. Step 5: Construct an energy conservation criterion as the second convergence criterion. If the second convergence criterion is satisfied, output the explosion pressure, explosion temperature, explosion velocity, explosion heat, and the amount of each component in the equilibrium state of CJ. Otherwise, return to step 1, re-assume the percentage of aluminum powder participating in the secondary reaction, and solve for the parameters required for the JWL equation of state applicable to aluminum explosives.

2. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to claim 1, characterized in that, In step one, the basic parameter system of the aluminum explosive includes the aluminum explosive components, the aluminum explosive mass m, the aluminum explosive density ρ, the aluminum explosive volume V, and the initial environmental pressure P0.

3. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to claim 1 or 2, characterized in that, In step two, the following calculation model is used to predict the detonation velocity: D=D max -Kr TMD or D max =∑ε i D i K=(1-η)∑K i e i +K min or In the formula, ε i D represents the volume fraction of the formulation components. i V is the characteristic detonation velocity of component i. i Let ρ be the volume of component i. TMD Let K be the theoretical density of the mixed explosive, K be the characteristic slope of the explosive, and η be the porosity of the explosive. Preferably, the explosion temperature is predicted using the Castells heat capacity method: In the formula, For the average constant-volume heat capacity, n i Let i be the number of moles of the i-th component. Let Q be the isochoric heat capacity of the i-th component, where A and B are constants, T1 is the explosion temperature, and Q is the temperature at which the i-th component is formed. V This refers to the heat of combustion at constant volume released during the combustion process.

4. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to any one of claims 1-3, characterized in that, Step three, which involves using the initially predicted detonation pressure, detonation temperature, and detonation velocity values ​​as the initial values ​​for the explosive detonation reaction to construct a thermodynamic equilibrium model, includes: Based on the Gibbs minimum free energy principle in chemical thermodynamics, chemical equilibrium calculations are performed on the detonation product system to determine the detailed composition of the detonation products under the final equilibrium state.

5. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to claim 4, characterized in that, The molar Gibbs free energy of the gaseous components in the detonation products is calculated based on the following thermodynamic equilibrium model: Where G represents the Gibbs free energy; n i The molar amount of the i-th explosion product; k represents the total number of gaseous products; the subscripts g and s represent gaseous products and condensed phase products, respectively; l represents the total number of chemical elements in the system; b k It is the molar amount of the kth component in the explosion products; a ik a is the number of atoms of the k-th element in the i-th product. jk P1 represents the number of atoms of the k-th chemical element in the j-th condensed phase product molecule, P1 represents the explosion pressure, T1 represents the explosion temperature, and μ represents the explosion temperature. i Let μ be the chemical potential of the i-th explosion product at explosion pressure P1 and explosion temperature T1. gi Let μ be the chemical potential of the i-th gaseous product at equilibrium. sj Let x be the chemical potential of the j-th condensed phase product at equilibrium. gi Let x be the mole fraction of the i-th component in the gaseous product. sj Let b be the mole fraction of the j-th component in the condensed phase product. k Let be the total atomic molar mass of the k-th chemical element in the explosive system.

6. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to any one of claims 1-5, characterized in that, In step three, the calculation of the gaseous product pressure using the improved BKW equation of state includes: The residual capacity correction and exponential correction terms of the product components are introduced into the BKW equation of state to construct an improved BKW equation of state. Preferably, the improved BKW equation of state includes: r g =ρ0·(γ+1) / γ m g =∑n gi M gi V g =m g / r g Where p represents pressure, V g Let x be the molar gas volume, R be the gas constant, and α, β, κ, and θ be adjustable parameters. i and k i ρ represents the mole fraction and residual volume of each product component i, respectively; g γ is the density of the gaseous products; γ is the adiabatic index; m g n is the total mass of the gaseous products; gi M is the amount of substance of gaseous component i; gi Let n be the relative molecular mass of gaseous component i. i Let represent the molar amount of the i-th explosion product, ρ0 be the initial density of the aluminum explosive, D be the detonation velocity, and P2 be the pressure of the gaseous product calculated by the improved BKW equation of state.

7. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to any one of claims 1-6, characterized in that, The first convergence criterion includes: P2-P1<ε1 The second convergence criterion includes: E-E0-0.5(p2-p0)(v0+v)<ε2 In the formula, P2 is the pressure of the gaseous products calculated by the improved BKW equation of state, P1 is the preliminary predicted explosion pressure, ε1 is the first convergence criterion threshold, E is the total energy of the equilibrium products, E0 is the total energy of the explosive, v is the volume of the equilibrium component gas, p0 is the initial ambient atmospheric pressure, v0 is the initial volume of the explosive, and ε2 is the second convergence criterion threshold.

8. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to any one of claims 1-7, characterized in that, In step five, the JWL equation applicable to aluminum-containing explosives includes: In the formula, P2 is the pressure of the gaseous products calculated by the improved BKW equation of state, V is the specific volume, E is the heat of explosion, A, B, R1, R2, and ω are material constants, ρ0 is the initial density of the aluminum explosive, and D is the detonation velocity.

9. The efficient prediction and calculation method for detonation performance parameters of thermobaric explosives according to any one of claims 1-8, characterized in that, In step five, based on the degree of aluminum powder participation in the secondary reaction, the amount of aluminum powder that did not participate in the secondary reaction is calculated. It is assumed that the aluminum powder that did not participate in the secondary reaction undergoes complete aerobic combustion, and an aluminum particle combustion model is used for the calculation. In the formula, E Al The energy for the oxygenation combustion of aluminum powder, t Al v represents the combustion time of aluminum powder particles. Al X is the afterburning energy release rate, where a and n are constants. eff ρ is the concentration of the oxidant in the air, p is the air pressure, T0 is the initial temperature, and d is the particle size of the aluminum particles.

10. A high-efficiency prediction and calculation system for the detonation performance parameters of thermobaric explosives, characterized in that, include: The first main control module is used to construct the basic parameter system of aluminum-containing explosives and assume the percentage of aluminum powder participating in the secondary reaction; The second main control module is used to make preliminary predictions on the detonation pressure, detonation temperature and detonation velocity of aluminum-containing explosives, and to form a set of reference input parameters for the detonation reaction stage of the explosives. The third main control module is used to take the preliminary predicted values ​​of detonation pressure, detonation temperature, and detonation velocity as the initial values ​​of the explosive detonation reaction, construct a thermodynamic equilibrium model, calculate the chemical composition distribution of the secondary reaction products, and calculate the pressure of gaseous products by combining the improved BKW equation of state. The dual convergence criterion module is used to construct the first convergence criterion based on the difference between the initially predicted explosion pressure and the gaseous product pressure, and to use the energy conservation criterion as the second convergence criterion. The initial values ​​of explosion pressure and explosion temperature are adjusted until the first convergence criterion is met, and then the second convergence criterion is judged. The percentage of aluminum powder assumed to participate in the secondary reaction is adjusted until the second convergence criterion is met. The fourth main control module is used to output the explosion pressure, explosion temperature, explosion velocity, explosion heat and the amount of each component in the equilibrium state of CJ, and finally solves the parameters required for the JWL equation of state applicable to aluminum explosives.

Images