A model for the macrokinetics of chemical reactions in detonating heterogeneous explosives is proposed based on the assumption that not only point but also surface microcenters (hot surfaces) are formed under the action of an initiating shock wave. The occurrence of surface hotspots can be cause by a local rise in temperature near microcracks and on grain boundaries. The model is tested by measuring pressure profiles during detonation initiation in a TATB based explosive composition.At present, the hotspot mechanism of shock-wave initiation of detonation in heterogeneous condensed explosives is generally accepted. It assumes that the passage of a head shock wave through heterogeneities in an explosive leads to the formation of microscopic reaction centers -hotspots -and burnout of most of the explosive mass proceeds in spherical waves of layer-by-layer combustion which propagate from the hotspots [1].Specific energy release during combustion of the microcenters (ΔE) should increase with time in proportion to the relative mass of the material at the hotspots in an elementary volume of the reactive heterogeneous explosive mixture and explosion products (EPs). As usual (see, for example, [1]), the macrokinetics of heterogeneous reactions in a detonating explosive is considered with reference to volume elements whose sizes are small compared to the characteristic sizes of the sample in the experiment but much larger than the average distance between the microcenters.In the initial stage where the microcenters are not overlapped, ΔE ∼ (Dt) 3 [2], where D is the velocity of propagation of the combustion wave. The increase in pressure (Δp) due to energy release in the explosive also depends on time as Δp ∼ ΔE ∼ t 3 . However, in experiments with detonation initiation, a linear rather than cubic time dependence of the pressure is observed [3].
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