IR Spectroscopic Study of the Organic Component of Ultrafine Diamond Produced by Detonation Synthesis

IR spectra of ultrafine diamonds produced by different teams of researchers are studied. The effects of heating and radiation on the properties of ultrafine diamonds are studied. Quantitative assumptions on the kinetics of formation of ultrafine diamonds are made from analysis of IR spectra.     

Synthesis and Properties of Hydrogen‐Free Detonation Diamond

Detonation‐prepared nanocrystalline diamond powders usually contain hydrogen. Herein, the synthesis of practically hydrogen‐free nanodiamond particles by detonation of benzotrifuroxan (BTF) and their comprehensive characterization by elemental analysis, X‐ray diffraction, electron microscopy, DSC/TGA, and BTE specific‐surface determination is described. The effects of the porosity of BTF and of various neutral or carbonic admixtures to the explosive on the reaction thermodynamics as well as the yield and properties of the product were explored theoretically and experimentally. Hydrogen contamination of nanodiamond was investigated using solid‐state NMR spectroscopy and possible sources of hydrogen explored. Admixing hygroscopic solids to the explosive introduced 0.1 to 0.6 % of hydrogen, as did purification in acidic (rather than neutral) media.     

Using the tracer method to study detonation processes

The tracer method was used to study the synthesis of nanodiamonds during detonation of composite explosives. Alloys of TNT with RDX, HMX, PETN, and benzotrifuroxan were studied. It was shown that, in all cases, most nanodiamonds were formed from TNT carbon. It was concluded that during the chemical reaction in the detonation wave propagating in heterogeneous explosives, equilibrium parameters were not established. In homogeneous TNT/PETN mixtures, individual components react with each other to form common products. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 6, pp. 92–98, November–December, 2008.     

Detonation properties of the synthesis gas

Investigated parameters of combustion and detonation of mixtures of the synthesis gas with oxygen and air are presented. The ratios between carbon oxide and hydrogen and between the fuels and oxidizer are varied within wide ranges. The critical energy of detonation initiation is determined. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 6, pp. 90–96, November–December, 2007.     

Thrust Performance of an Ideal Pulse Detonation Engine

Quasisteady and twodimensional unsteady formulations of the problem on the operation cycle of a pulse detonation engine are derived. A formula for the specific impulse is obtained, and the thrust performance of the engine is calculated. It is found that the thrust performance of this engine for flight Mach numbers M [0; 3.6] and compression ratios p ₂/p ₁ [1; 80] are always higher than those of the ramjet and onespool turbojet. As the compression ratio increases, the advantage of the pulse detonation engine becomes less noticeable.     

铝含量对RDX基含铝炸药爆压和爆速的影响

利用锰铜压力传感器和测时仪测量了不同铝含量的RDX基含铝炸药的爆压和爆速。拟合出爆压、爆速与铝含量的关系式,分析了铝含量对RDX基含铝炸药爆压、爆速的影响因素。结果表明,随着铝含量的增加,RDX基含铝炸药的爆压和爆速呈线性减小。计算了铝粉的质量分数在0~40%时所对应的PC-J=A(x)0ρD2中的A(x)值,拟合出A(x)值与铝含量的关系式,得到RDX基含铝炸药爆压与爆速之间的关系式。     

多元混合燃料分散爆轰研究

在多元混合燃料分散爆轰设计基础上进行了相关实验研究,燃料在分散与爆轰的协调作用下完成了动态混合的多相爆轰过程;其爆炸场的状态不同于高能炸药爆炸后的单调衰减,有一个由衰减到增强的成长过程;通过燃料在不同爆炸气体中爆轰的对比实验表明,燃料在爆轰与分散的同时,环境中的氧参与反应,相对于燃料自身完成的爆轰,具有“超释能”效果。     

Isotope studies of detonation mechanisms of TNT,RDX, and HMX

An analysis is performed of experimental data from isotopic tracer studies of the detonation mechanism and formation of the diamond phase of carbon in the detonation products of TNT, RDX, HMX, and their mixtures. Dependences of the relative yield and phase composition of carbon in the detonation products of components of composite explosives on the particle sizes of the explosives are given. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 5, pp. 96–103, September–October, 2007.     

Synthesis of ultrafine diamonds from alloys of TNT with polycyclic nitramines

The synthesis of ultrafine diamonds from alloys of TNT with new polycyclic nitramines was studied experimentally. The use of nitramines with an oxygen balance smaller than that of RDX increases the yield of ultrafine diamonds. An increase in the particle size of the sensitizer in the TNT alloys was shown to result in a higher yield of diamonds. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 4, pp. 131–134, July–August, 2006.     

共轭爆轰模型及其数值解

按照CJ和ZND模型．在所有可能的终点状态中CJ面爆轰产物的熵最低．而且系统永远达不到热力学平衡态．不符合热力学基本定律。为克服这些缺点,取热力学平衡态作为爆轰过程终点,建立了一种新的共轭爆轰模型。在共轭爆轰模型中．阵面激发化学反应释放出的能量。使得爆轰产物粒子朝不同的方向运动。每一对分别向前和向后运动的粒子被称为共轭对。共轭对在做爆炸中产生并在膨胀中湮没。将此过程与爆轰波传播相关联．建立了共轭爆轰模型。它从守恒定律和热力学定律导出．没有类似于cJ似设之类的附加条件。共轭爆轰模型方程组封闭且有唯一解。对于理想气体,由该模型得出的爆轰参数与CJ-ZND模型相近。     

Use of Gas Detonation in a Controlled Frequency Mode (Review)

Research problems arising in the development of various devices with the use of detonation in a controlled frequency mode (pulsed detonation) are considered. The frequency of cycles can be varied by independent initiation of detonation by a controlled system of ignition. Problems of detonation initiation concerning the frequency mode are considered: direct initiation, deflagration-to-detonation transition, and transition of a detonation wave formed in a narrow channel into a wide channel. The possibility of using thermochemical conversion in devices with pulsed detonation is considered. Examples of practical applications of devices with pulsed detonation are given (pulsed detonation engine, using pulsed detonation for drilling and crushing of rocks, and removal of metal cord from rubber in worn tires).     

改性铵油炸药连续爆速实验研究

采用连续速度探针研究改性铵油炸药在不同起爆条件下爆速和爆轰成长的连续变化.在起爆条件分别为雷管/160g起爆药柱、雷管/160g起爆药柱/有机玻璃隔板和仅采用雷管时,改性铵油炸药在稳定爆轰阶段的稳定爆速分别为4569m/s、4496m/、4559m/s,爆轰成长距离分别为3.5、7.3和20cm,爆轰成长时间分别为0.01、0.025和0.06ms.结果表明,在相同的装药约束条件下,起爆能量越大,改性铵油炸药爆轰成长时间和爆轰成长距离越短,即越容易发展为稳定爆轰.     

Continuous Spin Detonation in Annular Combustors

An acetylene-oxygen mixture is burned in two annular chambers 100 mm in diameter in the spin detonation regime with supercritical and subcritical differences of oxygen pressure in the annular slot. By varying the flow rates of components of the mixture, width of the slot for oxidizer injection, point of fuel injection, and initial ambient pressure, the regions of existence and the structure of transverse detonation waves are studied, and the limits of existence of continuous detonation in terms of pressure in the chamber are determined. The losses of the total pressure in the flow in oxygen-injection slots and in fuel-injector orifices are estimated.__________Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 4, pp. 99–109, July–August, 2005.     

Model Detonation of Solid Explosives by the Homogeneous Mechanism

A twophase detonation model of solid porous explosives, which takes into account the compression of solidstate particles and the presence of a solid component in detonation products, is developed. The homogeneous detonation mechanism based on the Arrheniustype reaction is studied. Detonation is initiated by the region of highpressure and hightemperature gases modeling the detonator explosion. A numerical experiment confirms that there exists an initiationpressure limit below which no homogeneous mechanism of detonation is active. The detonation wave has the leading front in which the explosive is precompacted and the gas in the porous volume is compressed up to a pressure of 100 GPa without any significant change in particle density. Then the gas compresses the particles themselves up to the pressure and temperature of the thermal explosion. As a result, the leading front is followed (after a certain delay) by a narrow reaction zone where detonation products are formed with a further increase in pressure.     

Effect of Modification of Tetryl Detonation Nanodiamonds on Combustion of Model Paste-Like Propellants

Combustion, Explosion, and Shock Waves - Detonation nanodiamonds (DND) represent a unique material combining the properties of a rather passive diamond core with an active carbon shell. The effect...     

Synthesis of TiO<Subscript>2</Subscript> nanoparticles from sprayed droplets of titanium tetrachloride by the gas-phase detonation method

Nanostructured polycrystalline titanium dioxides are produced by gas-phase detonation and pyrohydrolysis. Titanium tetrachloride (TiCl₄) is used as a precursor in the gas phase, and a premixed gas (O₂ and H₂) is used as a source of energy. The product is a mixture of TiO₂ crystals in the rutile phase (80%) and anatase phase (20%). __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 5, pp. 112–116, September–October, 2008.     

Autoignition Parameters and Detonation Critical Diameter of Hexanitromannite

The dependence of the ignition delay of hexanitromannite on the initial temperature was determined experimentally. The detonation critical diameter of cast hexanitromannite and its solutions in nitroglycol and nitroglycerine were measured.     

Investigation of Diamond Synthesis from a Mixture of an Explosive with a Carbon Additive Using a Tracer Technique

The synthesis of detonation diamonds from a mixture of RDX labeled by C¹⁴ isotope with soot was studied experimentally. It was shown that a considerable portion of the diamonds (24.7 ± 3.4)% are formed from the carbon of RDX molecules. The degree of conversion of the carbon atoms of soot to the diamond phase is (16.0 ± 1.6)%. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 117–118, September–October, 2005.     

Detonation Velocity of Emulsion Explosives Containing Cenospheres

The detonation velocity of an emulsion explosive containing hollow alumosilicate microspheres (cenospheres) as the sensitizer is measured. The size of the microspheres is 50–250 μm. The relations between the detonation velocity and the charge density and diameter are compared for emulsion explosives containing cenospheres or glass microballoons as the sensitizer. It is shown that for a 55 mm diameter charge, the maximum detonation velocity of the composition with cenospheres of size 70–100 μm is 5.5–5.6 km/sec, as well as for 3M glass microballoons. The critical diameter for the emulsion explosive with cenosphere is 1.5–2 times larger than that for the emulsion explosive with glass microballoons and is 35–40 mm. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 119–127, September–October, 2005.     

铝粉-空气混合物的燃烧转爆轰过程

利用自行设计的长29.6 m、内径199 mm配有40套喷粉扬尘装置的大型水平爆轰管,研究了细片状铝粉-空气混合物在40 J弱点火条件下火焰从发生到加速、最后实现爆轰转捩的全过程,探讨了铝粉浓度和点火延迟时间对爆轰参数的影响.结果表明,铝粉-空气混合物燃烧转爆轰(DDT)过程可分为慢速反应压缩阶段和快速反应冲击阶段.当点火延迟时间为370 ms,铝粉质量浓度为300 g/m~3时,在管道中距离点火位置83倍长径比处峰值超压为9.8 MPa,爆速为1 670 m/s,发生了DDT过程.在铝粉-空气混合物自持爆轰波的传播过程中,由于呈现螺旋爆轰波结构,爆速和峰值超压随着传播距离振荡.