Chemical Reaction Rate Model And Theoretical Analysis Of Overdriven Detonation About Insensitive High Explosives

In this dissertation, the reaction rate of Insensitive High Explosives (IHE) in the process of shock initiation and the constitutive relationships of overdriven detonation products are mainly introduced. Firstly, we research the mechanism of IHE shock initiation, and series of chemical reaction rate models are present. Following, we take PBX-9502 (a representative kind of IHE) for example. Making use of the condition of steady detonation wave, and added by the experimental particle-velocity history in detonation zone, we come up with Lagrange analysis method in reaction zone of steady detonation. On the basis of the results of this method, a form of reaction rate in high pressure state has been calibrated. By added the reaction rate of hot spot in Kim's model, then we can obtain total reaction rate model which is made up of two parts respectively stand for low and high pressure state. Putting this total reaction rate model in CSIN program,observing the pressure and the particle-velocity on different Lagrange position, we can found that the calculations are in accord with the experimental dates and theoretical analysis very well.Equations of state (EOS) of overdriven detonation products are also discussed in our research. As there is a major difference between the data in modeling both the shock pressure on the Hugoniot and the sound speed by using the standard Jones-Wilkins-Lee (JWL) EOS and real experimental data, the standard JWL EOS is not fit for overdriven detonation above the CJ pressure. On the basis of P.K.Tang reporting the development of a modified JWL EOS to correct the deficiency found in the standard formulation, here we utilize Genetic Algorithms to modeling shock pressure on the Hugoniot and the sound speed data simultaneously, and three modified JWL state equations have been given for overdriven detonation. Finally these modified JWL state equations have been used directly to DYNA-2D procedure. Compared to the numerical simulations of the overdriven release experiments for the PBX-9502 using the standard JWL and our modified JWL, the major improvement is seen in a shorter time interval between the arrival of the detonation wave and the lead rarefaction wave as the result of the higher calculated sound speed in our EOS formulations than standard one.