Imaging the Reactive Flow Structure in Shocked Nitromethane and Nitromethane with Additives

We used table-top laser driven flyer plates to generate planar shock waves in tiny cuvettes to produce detonations in liquid nitromethane (NM), and NM with sensitizing, desensitizing and inert additives. The detonations were probed by a combination of high-speed video and photon Doppler velocimetry (PDV). The thermal emission revealed cellular structures in the detonation front, whose size was dependent on the type of additive. Since there is a close relationship between these structures and the reaction zone, this technique may prove useful in determining how the reaction zone length is affected by additives. We considered the possibility that these structures arose from similar structures in the initiating shock using Al or steel lids on the entry face of the cuvettes with different roughnesses, which should introduce similar structures in the initiating shock, we showed that the structures we observe are a property of the reactive flow in NM itself.