| The explosion effects of thermobaric explosives, especially the parameters of the blast wave in a confined space, are studied both experimentally and numerically.The propagation and reflection of blast wave generated by thermobaric explosives in unconfined space are studied, and the relationships between overpressure, duration time and specific impulse with scale distances are obtained in virtue of explosion similar law and shell modified energy. The effects of the thermobaric explosives detonated in a room are tested. It is found that the loads formed by the detonation can be divided into two steps. The first one is generated before the shock reflection, the value of which can be estimated by the experiential formula obtained in unconfined space. Another one is formed after the reflection, and the data can be tested. The results show that the duration time is 40-100 times longer than the overpressure time of the incident shock wave. What's more, the whole impulse is 10-20 times as high as the incident impulse. Furthermore, because of the shock reflection from the ground, walls and the interactions between them, 7-11 peaks are found in each p(t) curve.Numerical simulations are accomplished for the propagation and reflection of thermobaric explosives in confined and unconfined space by using two-dimensional axisymmetric models. The parameters of state formulation of thermobaric explosives are verified by unconfined space model calculation. The results show that the overpressure is declined little faster and lower than the overpressure tested by experiments in near field, while the specific impulse is consistent with the experimental results. Another two two-dimensional axisymmetric models are used to simulate the propagation and reflection of blast wave in confined space along length and width directions, respectively. The calculation results indicate that the parameters of the first reflected wave are nearly the same as the experimental results.
|
PDF Full Text Request