The interactions of a spherical flame with an incident shock wave and its reflected shock wave in a confined space were investigated using the three-dimensional reactive Navier-Stokes equations, with emphasis placed o...The interactions of a spherical flame with an incident shock wave and its reflected shock wave in a confined space were investigated using the three-dimensional reactive Navier-Stokes equations, with emphasis placed on the effect of chemical reactivity of mixture on the flame distortion and detonation initiation after the passage of the reflected shock wave. It is shown that the spatio-temporal characteristics of detonation initiation depend highly on the chemi- cal reactivity of the mixture. When the chemical reactivity enhances, the flame can be severely distorted to form a reactive shock bifurcation structure with detonations initiating at different three-dimensional spatial locations. Moreover, the detonation initiation would occur earlier in a mixture of more enhanced reactivity. The results reveal that the detona- tions arise from hot spots in the unburned region which are initiated by the shock-detonation-transition mechanism.展开更多
The linear,directly proportional,equations between the Arrhenius parameters(E_α,and log A)of the thermal decomposition and the crystal lattice free space per molecule,△V,of 22 nitramines are described.It is shown th...The linear,directly proportional,equations between the Arrhenius parameters(E_α,and log A)of the thermal decomposition and the crystal lattice free space per molecule,△V,of 22 nitramines are described.It is shown that,because of a significant limitation by the molecular structural characteristics of such compounds,they are divided into a number of partial relationships.These partial relationships divide the nitramines into a group of substances relating to dimethyl nitramine and a sub-group related to e-HNIW.These directly proportional equations mean that an increase in the△Vvalues is related to an increase in the thermal stability of the corresponding nitramines.A comparison with similar published dependencies for the impact and friction sensitivities,on the one hand,and with the relationship between the E_a values and the sum of the negative and positive extremes of molecular surface electrostatic potentials,on the other,confirms the well-known fact that intermolecular interaction in the nitramines studied plays a decisive role in the thermal reactivity of such compounds.The crystal lattice free space manifests itself here perhaps only in the solid state thermal decomposition of RDX,HMX and DINGU.This study again confirms a level of disorder in the distribution of the forces in the crystal lattice of the"common"quality of e-HNIW,compared with its"reduced sensitivity(RS)"or pure analogues.展开更多
基金supported by the National Natural Science Foundation of China (10972107)Open Fund of State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology (KFJJ12-4Y)Jiangsu Innovation Program for Graduate Education (CXLX11 0271)
文摘The interactions of a spherical flame with an incident shock wave and its reflected shock wave in a confined space were investigated using the three-dimensional reactive Navier-Stokes equations, with emphasis placed on the effect of chemical reactivity of mixture on the flame distortion and detonation initiation after the passage of the reflected shock wave. It is shown that the spatio-temporal characteristics of detonation initiation depend highly on the chemi- cal reactivity of the mixture. When the chemical reactivity enhances, the flame can be severely distorted to form a reactive shock bifurcation structure with detonations initiating at different three-dimensional spatial locations. Moreover, the detonation initiation would occur earlier in a mixture of more enhanced reactivity. The results reveal that the detona- tions arise from hot spots in the unburned region which are initiated by the shock-detonation-transition mechanism.
基金support from the Students Grant Projects No.SGSFCHT_2016002 of the Faculty of Chemical Technology at the University of Pardubicefinancial support came from the Chinese State Administration of Foreign Experts Affairs
文摘The linear,directly proportional,equations between the Arrhenius parameters(E_α,and log A)of the thermal decomposition and the crystal lattice free space per molecule,△V,of 22 nitramines are described.It is shown that,because of a significant limitation by the molecular structural characteristics of such compounds,they are divided into a number of partial relationships.These partial relationships divide the nitramines into a group of substances relating to dimethyl nitramine and a sub-group related to e-HNIW.These directly proportional equations mean that an increase in the△Vvalues is related to an increase in the thermal stability of the corresponding nitramines.A comparison with similar published dependencies for the impact and friction sensitivities,on the one hand,and with the relationship between the E_a values and the sum of the negative and positive extremes of molecular surface electrostatic potentials,on the other,confirms the well-known fact that intermolecular interaction in the nitramines studied plays a decisive role in the thermal reactivity of such compounds.The crystal lattice free space manifests itself here perhaps only in the solid state thermal decomposition of RDX,HMX and DINGU.This study again confirms a level of disorder in the distribution of the forces in the crystal lattice of the"common"quality of e-HNIW,compared with its"reduced sensitivity(RS)"or pure analogues.
