Detonation on a tabletop in nitromethane: effects of sensitizers and desensitizers*

We have developed a method to study shock to detonation process on a tabletop with high temporal and spatial resolution¹. Here we present effects of additives on nitromethane (NM) detonation studied with optical pyrometry, photon doppler velocimetry, and high-speed video photography. Addition of ethylenediamine (EDA, 1% by wt.) reduces the detonation threshold from 20 GPa to 14 GPa of input pressures, while addition of acetone (up to 30% by wt.) inhibits the reaction and detonation is not at all observed for up to 20 GPa input pressure. With the help of optical pyrometry and high-speed videos, thermal properties of emission from the above mixtures were probed. Detonation experiments often measure the detonation shock wave using an optical window contacted to the explosive. We measured NM detonation in 9 different window materials and found that polycrystalline materials such as LiF are somewhat better than glasses, and both are much better than polymers, reported in earlier works.

1. M. Bhowmick, E.J.Nissen, and D.D. Dlott, J. Appl. Phys 124, 075901 (2018).