Sensitization of two-dimensional detonations in nitromethane by glass microballoons

Abstract

Experimental results are reported on charge diameter effect and critical detonation diameter of nitromethane (NM) gelled by 4 wt.% of PMMA and sensitized by thin-walled (1 \(\mu\)m) monosize glass microballoons (GMB) of 47 \(\mu\)m or 102 \(\mu\)m size at a constant mass fraction of glass (1%) in the mixture. The dependence of the detonation velocity on the detonation shock-front total curvature at the explosive charge axis is presented for steel and PVC detonation tubes of various inner diameters. The predictive ability of the quasi-one-dimensional hydrodynamic model of detonation-reaction zone in GMB-sensitized NM is improved by a better description of the hot spot growth stage. Dependencies of detonation velocity in NM sensitized by different GMBs on the charge diameter are calculated using available data on NM regression rate at detonation pressures and a reasonable agreement with experimental data is obtained. The effect of the confinement on the charge diameter effect as well as the dependence of the normal detonation velocity on the total detonation shock front curvature at the charge axis is also predicted by the model. However, there are still some difficulties in reproducing the experimental linear correlation between the critical detonation diameter of GMB-sensitized nitromethane and its reciprocal specific surface area.