Effects of ozone on n-heptane low temperature chemistry and premixed cool flames

Ozone (O-3) has been shown to accelerate low and high temperature chemistry and is a promising strategy to effectively enhance and control combustion and ignition processes, such as for engines. There has, however, been a lack of experimental investigation of O-3 enhancement effects on low temperature chemistry and premixed cool flames. This study undertook a detailed experimental and numerical assessment of O-3 enhancement effects on ignition behavior, propagation speeds, flame temperatures, and CH2O production of n-heptane cool flames as functions of O-3 addition. Zero-dimensional simulations were used to gain insights into the effects of O-3 on two-stage ignition behavior and gradual suppression of NTC phenomena. Propagation speeds of O-3-enhanced cool flames were experimentally determined using a flame lift-offtechnique, and one-dimensional simulations utilizing several full and reduced mechanisms were performed for comparison. Enhancement by O-3 versus enhancement by preheating were experimentally compared and analyzed to evaluate relative effectiveness of these enhancement strategies. Finally, downstream temperature measurements and formaldehyde planar laser-induced fluorescence imaging (CH2O PLIF) were performed at different O-3 enhancement levels to further elucidate O-3 impacts, and numerical simulations were performed to support experimental insights. Results of this study reveal O-3 impacts on low temperature kinetics and resulting impacts on low temperature ignition and cool flames. (C) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

The study investigated the effects of ozone enhancement on n-heptane cool flames through experimental and numerical assessments. The results showed that ozone impacts low temperature kinetics and affects low temperature ignition and cool flames.