The influences of pressure and temperature on laminar flame propagations of n-butanol, iso-octane and their blends

On one hand, n-butanol as a potential alternative bio-fuel is accepted more and more attention presently in the fields of both scientific research and commercial market; on the other hand, some n-butanol's (or its mixtures blended with conventional fossil fuels) combustion properties, especially the flame propagation characteristic, are still unknown widely or profoundly, especially under the ICE (internal combustion engine) operating conditions. Within these conditions, pressure and temperature are two critical factors affecting the flame's propagation characteristic. Driven by these facts, in this study, we investigated the laminar flame characteristics of n-butanol, iso-octane and their blends by simulations. First, the experimental data on n-butanol's laminar burning velocity were collected, and the development of n-butanol's chemical kinetic mechanisms was reviewed. Then, the mechanisms used in this study can be chosen, and the numerical results can be validated by experimental data. Based on this, we extended the condition range, which is limited in experimental measurements, to that of realistic applications by numerical method; besides, correlations including the influences of pressure and temperature are developed and extended to consider the mixture fuel blended between n-butanol and iso-octane (which represents the gasoline in SL, laminar burning velocity), this is useful to use the alcohol fuels for SI (spark-ignition) engines in an even better fashion; furthermore, their correlated parameters were resolved carefully through a wide range of data. From results, our correlations are sufficient in accuracy to describe the effects mentioned above. Within each effect, for better understanding the apparent influence on SL, the effects of thermal, density ratio and chemical kinetic are discussed respectively. In addition, our correlations were compared to those in literature widely; these comparisons suggested that the inherent law of laminar flames of fuels still deserves more attentions and investigations. Our investigation is expected to make a step on the understanding of this field.