Recently, researchers in the Netherlands accidentally discovered spontaneous combustion of hydrogen and oxygen mixtures in nanosized bubbles. Of even greater interest, they discovered that combustion did not take place in microsized bubbles; it happened only when the size was below a critical value of about 200 nm. So the question is this: what is the uniqueness about chemical reactions that take place in nanoscale environment? Could it be due to the mean-free path effect, non-equilibrium fluid transport, and/or increasingly important gas/wall interactions at nanoscale? Motivated by these, this paper investigated hydrogen/oxygen combustion characteristics in confined nanoscale channels using Reactive Molecular Dynamics (RMD) simulations. ReaxFF reactive force field developed by Duin et al. was used for gas-phase interactions. For inert walls, L-J potentials were used for gas-wall interactions; and for reactive walls, ReaxFF reactive force field was used for gas-wall interactions. Nano-channels of various heights were considered. RMD simulations were performed to determine the effect of the Knudsen number and the gas-wall interaction strength on the combustion characteristics such as reaction rate, energy barrier and the ignition delay time. The results show that larger Knudsen numbers and gas-wall interaction strength are in favor of earlier reaction initiation, lower energy barrier and higher overall reaction rate. Radical quenching was also studied primitively for hydrogen/oxygen combustion in SiO_2 channels.
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