基于BKW状态方程的爆轰产物及参数的改进算法

为了降低爆轰产物及爆轰参数的求解难度,通过对质量守恒方程的基本可行解进行线性组合,得到了爆轰产物的平衡组成,并在此基础上进一步获得了爆轰参数。其主要实现方法为:由最小自由能原理对基本可行解进行筛选,然后根据最大放热原则确定初始解,并在最小自由能原则的引导下,由初始解和基本可行解的线性组合获得爆轰产物的平衡组成,以上操作步骤均由自编程序完成。应用支持向量机(SVM)线性模型对BKW状态方程参数进行了调整,并详细介绍了其主要步骤。使用此方法预测了PETN、CL-20和含铝炸药的爆轰产物及爆轰参数,经参数调整后,发现预测结果与实验值吻合良好;通过与单质炸药爆轰实验数据对比,发现调整BKW状态方程参数时,应当尽可能使用爆轰产物中气体含量相近的含能材料对SVM模型进行训练;若预测含铝炸药,应当使用铝氧比接近待测炸药的样品来训练SVM模型。     

Predicting the Detonation Velocity of CHNO Explosives by a Simple Method

A simplified method is shown, based on a semi‐empirical procedure, to estimate the detonation velocities of CHNO explosives at various loading densities. It is assumed that the product composition consists almost of CO, CO₂, H₂O and N₂ for oxygen‐rich explosives. In addition solid carbon and H₂ are also counted for an oxygen‐lean explosive. The approximate detonation temperature, as a second needed parameter, can be calculated from the total heat capacity of the detonation products and the heat of formation of the explosive by PM3 procedure. The detonation velocities of some well‐known CHNO explosives, calculated by the simple procedure, fit well with measured detonation velocities and the results from the well‐established BKW‐EOS computer code.     

Partial Reparametrization of the BKW Equation of State for DNAN‐Based Melt‐Cast Explosives

DNAN‐based melt‐cast explosives are a type of new, insensitive munitions (IM) explosives. Quickly determining munitions’ explosive properties is extremely important during the formulation design stage. The aim of this study was to partially reparameterize BKW‐EOS (only β and κ were reparameterized on the basis of the parameters (α , β , κ , and θ ) of classical BKW‐RDX set and BKW‐TNT set) to more accurately predict the properties of DNAN‐based melt‐cast explosives. A new set of parameters β and κ was obtained (β =0.19, κ =9.81) according to measured detonation velocity and detonation pressure for ideal DNAN‐based melt‐cast formulations (DNAN/RDX and DNAN/HMX). For non‐ideal DNAN‐based melt‐cast formulations (DNAN/RDX/Al and DNAN/HMX/Al), aluminum oxidation degree was first determined according to the measured detonation heat; then, another new set of parameters β and κ was obtained in the same way as the ideal formulations (β =0.24, κ =8.5). The predicted detonation properties with BKW reparametrization for DNAN‐based melt‐cast explosives agreed with the measured data.     

工业炸药的爆轰性能研究

用有机玻璃法测定了岩石膨化、煤矿膨化、铵梯以及乳化炸药的爆速和爆压，同时用VLWR爆轰程序对岩11石膨化硝铵和铵梯炸药的爆轰参数及C—J产物的平衡组成进行了计算。结果表明，工业炸药具有低爆速和低爆压的非理想爆轰特征，而理论计算值和实验值比较接近，获得了较好的结果。     

含铝炸药圆筒试验及爆轰产物JWL状态方程研究

为分析含铝炸药在强约束条件下的爆轰性能,对含铝炸药进行了50mm圆筒试验。使用了电探讨测量炸药爆速,用高速相机记录圆筒膨胀过程,使要用了计算机图像技术对高速摄影照片进行分析处理,通过对圆筒试验二维爆轰数值模拟,标定了含铝炸药爆轰产物JWL状态方程参数。     

VLW爆轰产物状态方程的发展及应用

以国际公认理论完美的维里(VIRIAL)状态方程为基础,建立了VLW炸药爆轰产物状态方程,简述了VLW炸药爆轰产物状态方程的形成背景,呈现了VLW方程的推导过程;应用VLW方程计算了军用高能炸药、民用工业炸药、凝聚相炸药、气相燃料空气炸药的爆轰性能参数,以及火箭推进燃烧性能参数,推导了爆轰产物的热力学函数(内能、熵、化学位等)。结果表明,应用VLW方程计算的参数结果准确合理;成功解决了高温下(T*>20)高级维里系数计算难题,准确表达了爆轰条件下的维里方程属性。     

发展马丁-侯方程作为水的专用方程

发展了适用于极性物质水的MH方程。由线性最小二乘法拟合单相区和汽液共存区的PVT及相平衡数据 ,得到方程常数 ,并用统计方法检验了方程的有效性。计算结果表明 ,饱和蒸汽压和摩尔体积误差一般小于0 .6。单相区体积和压力平均误差分别为 0 .3 %和 2 .5 %。与Bender方程相比 ,新方程准确度更高     

Predicting Detonation Performance of CHNOFCl and Aluminized Explosives

A new “hand‐calculated” method is introduced for prediction of detonation pressure of explosive and mixture of explosives with general formula CHNOFClAl. Suitable decomposition paths are used to estimate heat of detonation and detonation pressure. These decomposition paths are based on the distribution of oxygen atoms between carbon and hydrogen atoms as well as the degree of oxidation of aluminum. For CHNOFCl explosives, it is shown that the predicted detonation pressures with the new method are more reliable with respect to one of the best available empirical methods for loading densities greater than or equal 0.8 g cm⁻³. Since aluminized explosives have non‐ideal behavior, the new method does not require using full or partial oxidation of aluminum, which is usually required by a computer code. The predicted results of the new model also provide more reliable results than outputs of complex computer code with the BKWS equation of state.     

Calculation of Detonation Properties of Gaseous Explosives Using Generalized Reduced Gradient Nonlinear Optimization

In this paper, a study on the development of a numerical modeling of the detonation of C H N O‐based gaseous explosives is presented. In accordance with the numerical model, a FORTRAN computer code named GasPX has been developed to compute both the detonation point and the detonation properties on the basis of Chapman–Jouguet (C‐J) theory. The determination of the detonation properties in GasPX is performed in chemical equilibrium and steady‐state conditions. GasPX has two improvements over other thermodynamic equilibrium codes, which predict steady‐state detonation properties of gaseous explosives. First, GasPX employs a nonlinear optimization code based on Generalized Reduced Gradient (GRG) algorithm to compute the equilibrium composition of the detonation products. This optimization code provides a higher level of robustness of the solutions and global optimum determination efficiency. Second, GasPX can calculate the solid carbon formation in the products for gaseous explosives with high carbon content. Detonation properties such as detonation pressure, detonation temperature, detonation energy, mole fractions of species at the detonation point, etc. have been calculated by GasPX for many gaseous explosives. The comparison between the results from this study and those of CEA code by NASA and the experimental studies in the literature are in good agreement.     

A New General Equation of State

A new general equation of state is presented, which can be used to express not only common cubic equations of state, but also quartic equations of state and so on. Main advantage of the new equation over the previous general equations is that it is in simple form, and is easy to manipulate mathematically.     

Tao-Mason状态方程扩展用于重正烷烃(英文)

In our previous paper we extended the Tao and Mason equation of state (TM EOS) to refrigerant fluids, using the speed of sound data. This is a continuation for evaluating TM EOS in predicting PVT properties of heavy n-alkanes. Liquid density of long-chain n-alkane systems from C 9 to C 20 have been calculated using an analytical equation of state based on the statistical-mechanical perturbation theory. The second virial coefficients of these n-alkanes are scarce and there is no accurate potential energy function for their theoretical calculation. In this work the second virial coefficients are calculated using a corresponding state correlation based on surface tension and liquid density at the freezing point. The deviation of calculated densities of these alkanes is within 0.5% from experimental data. The densities of n-alkanes obtained from the TM EOS are compared with those calculated from Ihm-Song-Mason equation of state and the corresponding-states liquid densities (COSTALD). Our results are in favor of the preference of the TM EOS over other two equations of state.     

Theoretical Study on Thermodynamic and Detonation Properties of Polynitrocubanes

We investigated the heat of formation (Δ_fH) of polynitrocubanes using density functional theory B3LYP and HF methods with 6‐31G*, 6‐311+G**, and cc‐pVDZ basis sets. The results indicate that Δ_fH firstly decreases (nitro number m=0–2) and then increases (m=4–8) with each additional nitro group being introduced to the cubane skeleton. Δ_fH of octanitrocubane is predicted to be 808.08 kJ mol⁻¹ at the B3LYP/6‐311+G** level. The Gibbs free energy of formation (Δ_fG) increases by about 40–60 kJ mol⁻¹ with each nitro group being added to the cubane when the substituent number is fewer than 4, then Δ_fG increases by about 100–110 kJ mol⁻¹ with each additional group being attached to the cubic skeleton. Both the detonation velocity and the pressure for polynitrocubanes increase as the number of substituents increases. Detonation velocity and pressure of octanitrocubane are substantially larger than the famous widely used explosive cyclotetramethylenetetranitramine (HMX).     

乳化剂对乳化炸药爆炸性能影响的研究

为了探究乳化剂对乳化炸药爆炸性能的影响,分别选取了三种不同的乳化剂制备乳化炸药,采用测时仪法和铅柱压缩法测试了各乳化炸药的爆速和猛度,结果发现,不同乳化剂制备的乳化炸药爆炸性能存在差异。单一的乳化剂不能达到最好的乳化效果,复合乳化剂能改善这一情况,一定程度上提高乳化炸药的爆炸性能。     

Extension of Tao-Mason Equation of State to Heavy n-Alkanes

In our previous paper we extended the Tao and Mason equation of state (TM EOS) to refrigerant fluids, using the speed of sound data. This is a continuation for evaluating TM EOS in predicting PVT prope...     

Substituent Effects on Thermodynamic and Detonation Properties of Polynitrobenzenes

Density functional theory (DFT) calculations were performed for a series of polynitrobenzene derivatives. Some nitrobenzenes with amino groups attached were also investigated as a benchmark or as a precursor. Heats of formation (HOF) were evaluated. The isodesmic reactions used for the prediction of HOFs are of permutation type in terms of the substituents. The HOFs increase non‐additively with increasing number of nitro groups. The attachment of the amino groups to polynitrobenzenes dramatically decreases the HOF. The HOF of hexanitrobenzene (HNB) is 344.05 kJ mol⁻¹ at the B3LYP/6‐311+G** level. This value is much larger than that of the widely used 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB), which engenders HNB a large chemical energy of detonation. The strengths of the group interactions were analyzed according to the disproportionation energy. The nearest‐neighbor interactions in polynitrobenzenes are in the range of 27.20–55.90 kJ mol⁻¹. The energy barrier for the internal rotation of nitro group in nitrobenzene is 24.6 kJ mol⁻¹. However, the energy barrier for the internal rotation of 2‐position nitro group of 1,2,3‐trinitrobenzene is as large as 216.3 kJ mol⁻¹. The chemical energies of detonation for polynitrobenzenes with three or more nitro groups are over 6000 J g⁻¹. Pentanitroaniline and HNB have good performances in terms of detonation velocity and pressure.     

Study of Plastic Explosives based on Attractive Cyclic Nitramines,Part II. Detonation Characteristics of Explosives with Polyfluorinated Binders

A series of plastic bonded explosives (PBXs) based on Viton A and Fluorel binders were prepared using four nitramines, namely RDX (1,3,5‐trinitro‐1,3,5‐triazinane), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane), BCHMX (cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole), and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane). The detonation velocities, D, were determined. Detonation parameters were also calculated by means of modified Kamlet & Jacobs method, CHEETAH and EXPLO5 codes. In accordance with our expectations BCHMX based PBXs performed better than RDX based ones. The Urizar coefficient for Fuorel binder was also calculated.     

利用PR状态方程计算临界终点

In the design of chemical processes, such as catalytic cracking of bitumen and heavy oil, the knowledge of phase behavior at the critical endpoint is essential. Based on the PR equation of state, the algorithm developed by Heidemann and Khalil for calculating critical properties was used to compute critical points. An algorithm for determining the equilibrium phase of the critical point using the tangent plane criterion was developed, and was used to calculate the critical endpoints of different mixtures, including non-polar, polar and associating systems. The critical endpoint, representing the type of the phase behavior, was employed to fit the interaction parameter of mixtures in critical state at high pressure. Lines of critical endpoints for ternary mixtures were also determined with the algorithm.     

微扰理论状态方程的发展现状

本文对近年来应用微扰理论和积分方程理论发展的半经验分子热力学状态方及其在非电解质和电解质溶液热力学性质及相平衡计算中的应用作了简要综述。     

立方型+缔合状态方程模拟离子液体的pVT性质和汽液平衡(英文)

Combining Peng-Robinson (PR) equation of state (EoS) with an association model derived from shield-sticky method (SSM) by Liu et al., a new cubic-plus-association (CPA) EoS is proposed to describe the ther-modynamic properties of pure ionic liquids (ILs) and their mixtures. The new molecular parameters for 25 ILs are obtained by fitting the experimental density data over a wide temperature and pressure range, and the overall aver-age deviation is 0.22%. The model parameter b for homologous ILs shows a good linear relationship with their mo-lecular mass, so the number of model parameters is reduced effectively. Using one temperature-independent binary adjustable parameter kij, satisfactory correlations of vapor-liquid equilibria (VLE) for binary mixtures of ILs + non-associating solvents and + associating solvents are obtained with the overall average deviation of vapor pressure 2.91% and 7.01%, respectively. In addition, VLE results for ILs + non-associating mixtures from CPA, lattice-fluid (LF) and square-well chain fluids with variable range (SWCF-VR) EoSs are compared.     

The Role of Aluminum in the Detonation and Post‐Detonation Expansion of Selected Cast HMX‐Based Explosives

In order to improve understanding of how aluminum contributes in non‐ideal explosive mixtures, cast‐cured formulations have been analyzed in a series of cylinder tests and plate‐pushing experiments. This study describes the contribution of 15 % aluminum (median size of 3.2 μm) vs. lithium fluoride (an inert substitute for aluminum; <5 μm) in cast‐cured HMX formulations in different temporal regimes. Small cylinder tests were performed to analyze the detonation and wall velocities (1–20 μs) for these formulations. Near‐field blast effects of 58 mm diameter spherical charges were measured at 152 mm and 254 mm using steel plate acceleration. Pressure measurements at 1.52 m gave information about free‐field pressure at several milliseconds. While the observed detonation velocities for all formulations were within uncertainty, significantly higher cylinder wall velocities, plate velocities, and pressures were observed for the aluminum formulations at ≥2 μs. Additionally, hydrocode calculations were performed to determine how non‐ideal behavior affected the plate test results. Collectively, this work gives a clearer picture of how aluminum contributes to detonation on timescales from 1 μs to about 2 ms, and how the post‐detonation energy release contributes to wall velocities and blast effects. The experiments indicate that significant aluminum reactions occur after the CJ plane, and continue to contribute to expansion at late times.