Characteristics of Detonation Propagating in Silane-Nitrous Oxide-Nitrogen Mixtures.

The present study investigated for the first time the characteristic length scale and chemical dynamics of steady and quasi-steady detonation waves propagating in silane-nitrous oxide-nitrogen mixtures, which are widely used in the semi-conductor industry and can be a promising additive for propulsion application. The conditions investigated cover the following ranges: equivalence ratio $\phi $ ϕ = 0.5–5; initial pressure ${P_1}$ P 1 = 10–1000 kPa; nitrogen mole fraction ${X_{{{\rm{N}}_2}}}$ X N 2 = 0–0.8; initial temperature ${T_1}$ T 1 = 300 K. The energy released by the formation of SiO(s) and SiO₂(s) was taken into account whereas the phase change from gas to liquid/solid was neglected. It was found that detonation in these silane-based mixtures is characterized by unusually large Mach numbers which result in up to 128.5 times pressure jump across the leading shock, and few micrometer-long induction zone length. For steady planar waves, the shortest induction distances were identified in the range $\phi $ ϕ = 2–4, while for curved detonations, the most resilient wave to curvature-induced losses was identified at $\phi $ ϕ around 1.5 for undiluted mixtures. Such phenomena are the results of the enhanced formation of SiO(s) under fuel-rich conditions, which also contributes to stabilizing the detonation wave, though the mixture should still be classified as unstable, according to traditional stability parameters. Detailed thermo-chemical analyses were performed to investigate the chemical dynamics. The study of the heat release per reaction shows the dominant contributions of R65: H+N₂O=N₂+OH, R207: SiH₄(+M)=H₂+SiH₂(+M), R377: N₂O+SiH₂=H₂SiO+N₂, R379: N₂O+Si=N₂+SiO, and R400: 2SiO = 2SiO(s). The dominant reactions for heat release are not modified by the curvature-induced loss according to sensitivity analyses. [ABSTRACT FROM AUTHOR]