Strength of Commercial Explosives

Strength is determined for mixtures of Amatol (79/21 AN/TNT) with various additives and mixtures of ammonium nitrate and aluminum of various compositions. The results obtained and literature data are used to obtain a formula for calculating the relative strength of commercial explosives containing two parameters — explosion heat and volume of explosion products. The strength of mixtures of ammonium nitrate and aluminum (under powerful initiation leading to overcompressed detonation) exceeds the strength of the reference explosive (Amatol) when the aluminum content is 10—40%. In this case, maximum strength is observed for a mixture containing 30% aluminum. The experimental results and calculations using the proposed formula are in satisfactory agreement.     

Shock‐Wave Initiation of Detonation of Double‐Base Propellants

In the known experimental system active charge–target–HE charge to be tested, critical pressures of shock waves initiating detonation of doublebase propellant charges are determined. TNT charges of various density were used as active HE, and copper plates 5 mm thick were used as targets. The pressure of the shock wave acting on the propellant versus the TNT density was constructed; this dependence being known the critical pressure can be readily determined with only the density of the active charge available. It was found that doublebase propellants are close to liquid HE in terms of sensitivity to shock waves; the critical pressure is 6.0–9.0 GPa for a charge diameter of 40 mm and decreases with increasing diameter. By an example of the NDT2 propellant, it is shown that the use of factorypacked propellants in line charges may lead to failure in transfer of detonation from one propellant charge to another.     

Energy release of mixed explosives during propagation of a nonideal detonation under conditions similar to the operation conditions of a blasthole charge

Detonation experiments were performed in a specially developed explosive device simulating a blasthole using charges of fine-grained and coarse-grained (granular) 30/70 TNT/ammonium nitrate mixtures of identical density 0.89 g/cm³ in steel shells with an inner diameter of 28 mm and a wall thickness of 3 mm at detonation velocities of 4.13 and 2.13 km/sec, respectively. Despite significant differences in detonation velocity (pressure), identical expansion of the charge shells was observed. On the other hand, numerical simulations of detonation propagation in the explosive device with the corresponding velocities ignoring the possibility of energy release behind the shock front show that the expansion of the charge shell is always greater in the case of a high-velocity regime. It is concluded that under the conditions simulating detonation propagation and the work of explosion products in a blasthole, effective additional energy release occurs behind the low-velocity (nonideal) detonation front. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 111–120, July–August, 2007.     

Discoveries in Detonation of Molecular Condensed Explosives in the 20th Century

A number of experimental results that could not be satisfactorily explained within the framework of the Grib—Zel'dovich—Neumann—Döring detonation theory are reviewed, namely, the oscillating detonation of some liquid high explosives (HE), the weak dependence of the time of detonation transformation of heterogeneous charges on their structure (particle size, liquid or solid state, etc.) with a strong dependence of the critical diameter of detonation on the structure, and the extremely weak dependence of the detonation rate of liquid HE on the charge diameter with a significant value of the critical diameter of detonation. These studies yielded the following results: 1) for each heterogeneous HE, a typical shock–wave pressure p ^* and a typical initial density ₀ ^* were found, such that, for their low values, HE transformation follows the mechanism of hot points (depends on the charge structure), and for high values of these parameters, HE transformation obeys the homogeneous mechanism (does not depend on the charge structure); 2) two new theoretical notions were discovered and used in the detonation theory: the phenomenon of breakdown of the chemical reaction in the shock–wave front by rarefaction waves and the notion of a shock jump, which reflects the specific character of action of shock waves on complex multiatomic molecules of condensed HE. It was also shown that the discovery of the parameters p ^* and ₀ ^* and the breakdown and shock jump phenomena allowed one to confirm experimentally the explanations of the above observations, which are incompatible with the Grib—Zel'dovich—Neumann—Döring detonation theory, to propose the structure of the front of detonation waves both in homogeneous (stable and oscillating) and heterogeneous HE whose basic property is HE transformation (partial or complete depending on the HE power and initial density) already in the shock–wave front, and to proposed principally new ideas on the nature of the critical diameter of detonation of homogeneous and heterogeneous HE.     

Critical detonation diameter of industrial explosive charges: Effect of the casing

The critical detonation diameter of industrial explosive charges is analyzed as a function of their state characteristics (composition, density, and structure) and the presence of a casing. The main reason for the increase in the critical diameter with increasing density of ammonium nitrate explosive charges is the reduction in the energy release rate in the chemical reaction zone of the detonation wave. The effect of the particle size of the components and the amount of the sensitizing component on the critical diameter of powdered and granular explosives fits into the concept of explosive combustion. An analytical formula for the critical detonation diameter of emulsion explosives is obtained which correctly describes experimental data. A possible mechanism of the effect of metal casings on the critical detonation diameter is considered for porous explosives whose detonation velocity is lower than the sound velocity in the casing.     

Detonation properties of ammonium nitrate

A published equation for determining the detonation parameters of mixed explosive compositions is used to compute the detonation characteristics. When this equation was used to analyze the detonation parameters of 6ZhV ammonite, the detonation characteristics of the TNT and ammonite in this composition were taken from published data and the parameters of the ammonium nitrate were determined from the equation for the mixture. The results of large-scale experiments on a mixture of no more than 3% TNT with ammonium nitrate are presented. The detonation velocity of ammonium nitrate is found to be 5 km/sec. The equation for the mixture is used to determine the pressure and adiabatic exponent of the explosion products of ammonium nitrate when the size of the explosion exceeds the limiting diameter. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 2, pp. 102–104, March–April 1999     

岩石膨化硝铵炸药的爆破威力研究

研究了岩石膨化硝铵的爆炸性能和爆破威力，在分析岩石爆破机理的基础上，通过与铵梯炸药，铵梯油炸药的爆破性能比较，并根据其自身的爆速高，重量威力大而体积威力稍小的特点，提出进一步提高该炸药爆破威力的技术途径。     

Detonation Products as a Function of Initiation Strength,ambient gas and binder systems of explosives charges

The way of initiating an insensitive high explosive can influence the start of a detonation reaction remarkably. In order to study the extent of this influence, different boosters and different booster structures for the initiation of explosive mixtures containing TNT and nitroguanidine (NQ) have been used. The experiments have been conducted in a 1.5 m³ containment from which the detonation products could be taken and analyzed. In those cases where we only used a 10 g RDX booster together with a detonation cap no. 8, we had not a complete detonation reaction by initiating cylindrical charges of TNT/NQ and TNT/AN. This means that unreacted TNT was analyzed in the solid residue, mainly consisting of carbon soot. On the other hand, we had a complete detonation using an additional booster of about 18 g detonation sheet, placed on the front side of the cylindrical explosive, having the same diameter as the explosive charge. Another part of the investigations deals with the determination of the influence of different argon pressures on the composition of the detonation gas and the solid residue. Between vacuum and one bar argon a strong change not only of the gas but also of the soot residue was measured. A stronger influence on the products was found using a confinement with glass tubes. The investigation of Al-containing charges exhibited a very different behavior compared with charges without Al. No more influence of vaccum or of different ambient gas pressure could be observed. By investigation of two composite explosive charges (PBX) containing binder systems of different energies and different oxygen balances, a great influence on the reaction of Al was found. The PBX charges with the better O₂-balance containing the energetic GAP-binder reacted nearly completely with the Al, opposite to the charge containing the polyisobutylene (PIB) binder system.     

The formation of smooth spalls in steel during the interaction of glancing detonation waves

A study is made of the formation of smooth spalls in steel specimens when their surfaces are blasted by explosive charges via a glancing detonation wave. When a steel specimen is blasted with an explosive, behind the front of glancing shock waves of compression two glancing shock waves of rarefaction, propagating toward each other, form, the interaction of which produces in the steel a smooth spall in the form of a dihedral angle. It is shown that a variation of the composition of the explosive (TNT, plastic explosive, TG 50/50 alloy) of a given thickness changes the distance from the vertex of the dihedral angle to the surface at which the charge was placed.VNIIÉF, Arzamas-16 607200. Translated from Fizika Goreniya i Vzryva, Vol. 30, No. 4, pp. 138–140, July–August, 1994.     

Analysis of Post Detonation Products of Different Explosive Charges

High explosive charges containing TNT, Comp. B, PBXN-106, TNT/TATB and the aluminium containing charges TNT/AN/Al, Comp. B/Al and a PBX high explosive with polyurethane binder, RDX, AP and Al have been initiated in a containment of 1.5 m³ in argon atmosphere. The gaseous and solid products were analyzed by mass spectrometry and other techniques. From the reaction products, the completeness of the Al reaction under different conditions was evaluated. The heat of detonation was calculated from the heat of formation of the products and the components of the explosive charges. The method described is suitable for studying the reaction behavior of components in composite explosives, especially of less sensitive high explosives.     

Comparative brisant characteristics of some classes of industrial emulsion explosives

The four types of mixtures consisting of the two bases (aqueous solutions of ammonium nitrate and ammonium dinitroamide) and the two additions (hollow glass microballoons and gunpowder) are considered in this work. On the base of thermodynamic computations of an ideal detonation and accompanying processes (shock and rarefaction waves) there were obtained not only the dependences of detonation parameters on addition quantities to mixtures, but the pressure versus particle velocity diagrams, too, which in comparison with Hugoniots relatively soft (water) and hard (aluminium) substances allowed to determine values of pressure in the shock waves being produced in surroundings nearby the end-wall and lateral surface of a charge. It is proposed to characterize the brisant effect of an explosive by a value of relative brisance which is calculated as percentage ratio of pressures of shock waves generated in surroundings under the same conditions by detonation products of the given explosive and the standard one. It is shown that the brisant effect of the new emulsion explosives is comparable and even can exceed that of TNT of maximal density. It is shown as well that the brisant ability of industrial emulsion explosives can be raised by 60 and more percents by replacing ammonium nitrate with ammonium dinitroamide and hollow glass microballoons with powders being obtained as a result of military industry conversion and utilization of munitions.     

Detonation Properties and Electrical Conductivity of Explosive–Metal Additive Mixtures

Detonation properties of mixtures of condensed high explosives with metal additives are studied. A scheme of measurement of high electrical conductivity of detonation products ( > 10 ^–1 · cm^–1) with a time resolution of 10 nsec is developed. It is shown that the properties of detonation products depend significantly on the content of the additive in the HE and on dispersion and density of the mixture. The electrical conductivity of detonation products of the compositions examined reaches 5 · 10^{3 –1} · cm^–1, which is more than three orders higher than the electrical conductivity of the HE without the additive. Significant variation of electrical conductivity of detonation products over the conducting region thickness has been found. The main conductivity corresponds to a sector 1 mm long near the detonation front. The overdriven state of the detonation wave has a strong effect on electrical conductivity and conducting region thickness. It is assumed that the behavior of electrical conductivity with time is caused by successive processes of shock compression of the HE, excitation of the chemical reaction (including the reaction of the additive with detonation products), and expansion of detonation products. The measurement technique used is highly informative due to the possibility of studying detonation in various regimes.     

Critical diameter and spin effects in detonation of cast and liquid explosives

Results of experimental measurement of critical diameter d_cr, of cast charges of TNT/RDX, TNT/potassium picrate, TNT/PETN, and liquid solutions of dinitrotoluene in bisnitroxyethylnitramine are presented. The data obtained are compared with the results of previous investigations of spin detonation waves in the systems under consideration. For both TNT-based cast charges and liquid mixtures, the domains were registered on the dependence of critical diameter on content in which d_cr remained invariant. These areas coincide with the range of sensitizer content in the mixtures in which spin phenomena are observed. Experimental results corroborate a previous conclusion that spin waves favor spreading of the general detonation process in cast systems and prevent detonation of liquid explosives.Mendeleev Russian Institute of Chemical Engineering, 125190 Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 161–165, March–April, 1995.     

Influence of Ammonium Nitrate Prills' Properties on Detonation Velocity of ANFO

Prilled/granulated ammonium nitrate is commonly used as a fertilizer and a basic ingredient of industrial explosives, especially of ANFO. One of the most important factors that affect the explosive properties of ANFO is the porosity of the prills/granules. This paper describes an attempt to manufacture ammonium nitrate prills of determined porosity in order to investigate its influence on the ANFO detonation velocity. A method of manufacturing porous ammonium nitrate prills with a high‐level of oil absorption (up to 20% by volume) was developed. The relations between porosity and granulometric distribution of ammonium nitrate prills versus the detonation velocity of ANFO were examined. It has been proved that the detonation velocity of ANFO increases significantly with higher porosity and smaller size of ammonium nitrate prills/granules. The influence of ANFO oxygen balance (researched by changing the content of fuel oil in the mixture) on detonation velocity has been determined for two kinds of ammonium nitrate prills–one with a low and another one with a high level of porosity.     

高威力震源药柱的配方研究

在普通热塑型膨化硝铵震源药柱内装药组分的基础上,加入高能添加剂铝粉,通过内装药配方的优化设计和实际爆炸性能的测定,确定了高威力震源药柱内装炸药的配方为膨化硝铵67．3％、木粉1．O％、柴油0．3％、石蜡0．7％、梯恩梯25．O％、铝粉5．7％。试验表明,高威力震源药柱内装药爆炸性能优良,作功能力比普通热塑型膨化硝铵震源药柱内装药提高15％。将聚能效应用于震源药柱,使高威力震源药柱具有更好的勘探效果。     

The Concept of Chamber Design for Explosive Thermonuclear Fusion Energetics

The possibility of realizing the solution of mankind's energy problem by the explosive thermonuclear fusion method that was proposed by Academician A. D. Sakharov is assessed. The essence of the method consists of the use of the energy of low–power thermonuclear explosions performed cyclically in stationary explosion–proof chambers equipped with a means for selection and utilization of the thermal energy of the explosion. Here the basic problem is to design airtight chambers capable of withstanding multiple thermonuclear explosions whose power is equal to 10—25 ktons of TNT. The available data on this problem are examined. The concept of designingreliable explosion–proof chambers for the solution of the indicated problem is formulated.     

Verification of the Explosive Quality of TH‐5

This paper reports the characteristics of the explosive TH‐5, recycled (recovered) trinitrotoluene (TNT) with max. 5 wt‐% of hexogen (RDX). The explosive TH‐5 was obtained by delaboration of warheads and melting of explosive charges based on TNT and RDX and by separation (extraction) of high explosive components. The thermal characteristics of pure (virgin) TNT and RDX, and recycled explosive TH‐5 are determined by differential scanning calorimetry. The possibility of processing TH‐5 by pressing and casting is also examined. The comparative analysis of sensitivity of TH‐5 and TNT to friction is determined, as well as compressibility of explosives, and the detonation velocity of pressed and cast charges. Based on the analysis of experimental results, the defense standard requirements for the quality of TH‐5 are defined and possibility of practical application of explosive TH‐5 was estimated.     

军民两用乳化炸药的制备

为解决战争期间军用炸药短缺的问题,以民爆行业生产的乳化炸药为研究对象,通过添加乙二胺二硝酸盐(EDD)、钝化RDX等高能组分,增加其能量水平;通过高效乳化剂丙烯酰化Span 80及微乳化技术进一步提高乳化炸药的稳定性,形成高能乳化炸药。结果表明,当EDD和钝化RDX的质量分数均为10%时,乳化炸药的装药密度为1.57g/cm3,爆速为6 120m/s,威力(TNT当量)136%,爆热4 910kJ/kg。     

Initiation of detonation in hydrogen—Air mixture by explosion of a spherical TNT charge

Direct initiation of detonation by explosion of a TNT charge in a hydrogen—air mixture is considered. The critical mass of initiating charge is determined numerically using a finite-difference method based on the Godunov scheme, taking into account the real chemical kinetics of combustion of hydrogen in air and the real equation of state for gaseous detonation products of TNT. The applicability of the equation of state of a perfect gas to the detonation products of TNT is considered. The effective value of the exponent of Poisson's adiabat is determined.Moscow. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 91–95, March–April, 1995.     

Formation of diamond from the liquid phase of carbon

Results are presented for synthesis of the diamond phase of carbon during detonation of the high-temperature explosive benzotrifuroxan (BTF)-C₆N₆O₆. The detonation products of this nonhydrogenic explosive have a high temperature which initially falls in the region of thermodynamic stability of the liquid phase of carbon. A two-stage synthesis process is proposed: drops of liquid carbon with diameters 0.1–1.0 m are formed initially, and these drops subsequently crystallize into the diamond structure. The experimental results given here confirm this hypothesis.Novosibirsk. Chelyabinsk. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 4, pp. 131–134, July–August, 1993.