铝粉含量对梯铝炸药爆压和冲击波参数的影响

测试了以TNT为基不同含量含铝炸药的爆压和空中爆炸冲击波参数,通过分析铝粉对炸药爆压、空中爆炸参数和爆炸冲击波超压的影响,建立了爆压与铝氧比的关系曲线、5种TNT基含铝炸药的冲击波相似律方程和TNT/Al炸药的爆压与空中爆炸冲击波超压的关系式.结果表明,随着铝粉含量的增加,炸药的爆压呈指数衰减,近距离的冲击波超压也快速减小,但爆炸场温度和爆炸火球的直径及持续时间会增大.     

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.     

From Analysis of the Structure of Ultrafine Diamond to the Problem of Its Formation Kinetics

The formation kinetics of ultrafine diamond samples produced by detonation synthesis is inferred from infrared and ultraviolet absorption spectra.     

GI-920炸药爆轰波阵面的光纤探针测量

利用熔石英在冲击作用下的发光特性开发了一种测量冲击到达时间的光纤探针技术。当爆轰波阵面到达光纤探针端面时会产生一个瞬时光信号,经光纤传输到光电探测器,变换为电信号,再由示波器记录,通过判读就可以知道冲击波或飞片到达光纤探针的时刻。采用芯径0．3mm的石英光纤探针阵列对一点起爆的爆压为10GPa的GI-920炸药的爆轰波阵面进行了测量,测量到3条不同直径上的波形,并利用所测数据绘出爆轰波阵面的三维形状图。结果表明,随着测试半径增大,爆轰到达时间分散性明显增加,爆轰波阵面的倾角也增大。实验所得信号的上升时间均小于4ns,说明光纤探针技术为炸药爆轰时间参数的测量提供了一种新的高精度的测试手段。     

Transmission of Bubble Detonation through a Layer of an Inert Liquid

The possibility of detonation transmission through a water plug from one column of a chemically active bubbly medium to another is experimentally verified. The critical length of the liquid plug is determined. The experiments are performed in a shock tube with bubbles of a stoichiometric acetylene–oxygen mixture in water. The character of peakpressure decay after detonationwave departure from the bubbly medium to the liquid is established. It is shown that the pressure profile retains similarity as the compression wave propagates over a discrete gas–iquid medium.     

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.     

Theory of solid-state detonation

The Jouguet theory allows one to estimate the detonation velocity from the known shock adiabat of the product of a solid-state chemical reaction initiated by a shock wave. Using manganese and zinc chalcogenides as an example, it is shown that such estimates are close to experimental detonation velocities in these systems. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 2, pp. 108–110, March–April, 2007.     

B炸药爆轰波拐角传播的三维数值模拟

为研究B炸药起爆后爆轰波在拐角中的传播特性以及拐角爆轰低压流场现象,运用LS-DYNA3D程序对120°,90°,45°三种特定的拐角装药的爆轰波传播现象进行了数值模拟,观察了爆轰波通过拐角的传播过程,讨论了爆轰波波阵面通过拐角后爆速的变化情况.结果表明,爆轰波通过拐角后由于传播面积的变化而产生衰减-增长过程,装药拐角越大,爆轰波通过时越稳定;随着装药拐角的减小,拐角处的波阵面压力、爆速和传播能力都逐渐降低.     

Hugoniot adiabat of a quartz-aluminum mixture

The Hugoniot adiabats of mixtures of quartz with aluminum are calculated with and without allowance for the chemical interaction of the components behind the shock front. It is shown that the results of experiments at pressures above 25 GPa can be explained not only by the faster phase transition of quartz to stishovite in the mixture but also by the formation of aluminum and silicon oxides behind the shock front. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 2, pp. 111–113, March–April, 2007.     

大板实验中TATB基炸药爆轰波的传播特征

为研究点起爆条件下TATB基炸药爆轰波传播特征,用双灵敏度激光速度干涉仪(VISAR)对TATB基炸药进行了大板实验研究,并用DYNA2D程序对实验进行了模拟计算.结果表明,大板实验中TATB基炸药爆轰波传播过程中的压力剖面具有"二维结构",且爆轰波传播方向由轴线方向逐渐向半径方向转变.实测铜飞片自由面的速度与计算值相吻合.     

Numerical Study of Formation of a Detonation Wave in a Supersonic Flow over a Wedge by an H2-O2 Mixture with Nonequilibrium Excitation of Molecular Vibrations of Reagents

Specific features of formation of an oblique detonation wave in a supersonic hydrogen-oxygen mixture flow over a plane wedge are analyzed. Preliminary excitation of molecular vibrations of H₂ is shown to lead to a noticeable (severalfold) decrease in the induction-zone length and the distance at which the detonation wave is formed. These effects are manifested even if H₂ molecules are excited in a narrow region in the vicinity of the flow centerline. The reason for these effects is intensification of chain reactions in the H₂-O₂ (air) mixture owing to the presence of vibrationally excited hydrogen molecules in the flow. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 1, pp. 78–86, January–February, 2006.     

复合结构装药爆轰波爆速与曲率关系的数值模拟

为了研究复合结构中爆轰波传播速度和曲率的关系,利用通用有限元程序AUTODYN对钝感复合装药结构单点起爆的爆轰效应进行了数值模拟。分析说明了不同尺寸的装药结构爆速和曲率的对应变化情况,根据曲面爆轰波曲率和爆速的线性近似关系,描述了复合装药药柱的爆速与曲率的关系方程,并拟合得到了相关参数。     

Experimental Investigation and Numerical Simulation of an Expanding Multifront Detonation Wave

Results of experimental investigations of an expanding multifront detonation wave are presented. Two stages of spontaneous formation of new disturbances and transverse waves on the expanding detonationwave front are observed. The main mechanisms of reinitiation of detonation waves are discussed. Twodimensional numerical simulation of the dynamics of a multifront detonation wave in a linearly expanding channel is performed. The effect of spontaneous formation of new disturbances and new transverse waves is confirmed by computations, and the main mechanism of multiplication of transverse waves is the instability of detonationwavefront elements at the stage they cease to be in the overdriven state and are attenuated during expansion.     

Dynamic Compressibility of Carbamide at Low Pressures

The shock adiabats of pressed carbamide samples with a density of 1.29 g/cm³ and carbamide samples with a bulk density of 0.78 g/cm³ were studied at pressures of 1–14 GPa using an electromagnetic method. In the coordinates D and U, the shock adiabat of pressed carbamide is linear and the shock adiabat of carbamide of bulk density at a pressure of 2.4 GPa is represented as two linear segments: D = 2U at 0.6 < U <1.3 km/sec and D = 0.6 + 1.55U at 1.3 <U < 2.8 km/sec. The possibility of a phase transition in carbamide under shock compression is discussed.     

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).     

Triggering of Detonation upon Flame Interaction with an Expansion Wave

The transition of a deflagration wave into an abruptly expanding part of a plane channel, where a quasisteady supersonic underexpanded jet of an unburned gas is formed, is studied for a propane–oxygen mixture using schlieren pictures. Two explosioninitiation modes (weak and strong) are registered. In the first case, almost instantaneous onset of the detonation wave occurs when the flame front enters the expanding section; the initial velocity of this wave is approximately 1.5 times the Chapman–Jouguet detonation velocity (D_CJ) and then decreases to a value corresponding to selfsustaining detonation. In the second case, the front velocity gradually increases from 0.4D _CJ to 1.0D _CJ. It is established that the starting pulse triggering the transformation of turbulent combustion to explosion and detonation regimes is generated by interaction of the flame front with expansion waves, which are elements of the structure of the initial section of the jet.     

Dependence of the Shape of a Detonation Wave Front on the Detonation Wave Velocity upon Detonation of a Cylindrical Charge

The transition of a system of partial differential equations which describe the stationary flow behind the shock–wave front of a detonation complex upon detonation of a cylindrical charge to a system of ordinary differential equations is performed by means of the series expansion in terms of the radial variable. The necessary equations for determination of the derivatives of solutions with respect to the parameters and the initial conditions for them are formulated. Imposing the condition of continuous extendibility of the solutions leads to equations that allow one to determine the shape of a shock–wave front as a function of wave velocity.     

Behavior of the vorticity vector in a supersonic nonuniform swirl flow of a combustible gas behind a moving curvilinear shock or detonation wave

Expressions for components of the vorticity vector behind a curvilinear shock or detonation wave propagating in a supersonic nonuniform flow of a combustible gas are derived. Plane and axisymmetric gas flows are considered. The free stream in the general case is a vortex flow with a specified distribution of parameters. Formulas for the vorticity components in the plane of the flow for axisymmetric flows are found to have the same form as formulas for steady axisymmetric flows. As in the case of steady flows, the normal-to-wave component of vorticity is demonstrated to remain continuous across the discontinuity surface; in the case of axisymmetric flows, the ratio of the tangential component of vorticity aligned in the plane of the flow to density also remains continuous, though the quantities themselves become discontinuous. __________ Translated from Fizika Goreniya i Vzryva, Vol. 45, No. 2, pp. 68–75, March–April, 2008.     

Radiographic study of interaction of shock and detonation waves in a high explosive

Collisions of shock and detonation waves in an HMX-based high explosive are experimentally studied with the use of flash radiography. Based on X-ray patterns, specific features of the wave-interaction process are identified, and qualitative differences are found in detonation formation and evolution in an explosive precompressed by a weak shock wave and in an undisturbed explosive. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 3, pp. 132–138, May–June, 2007.