Study on Factors Affecting Shape Characteristics of Spherically Propagating i-C₈H₁₈/O₂/N₂ Turbulent Flames Using Constant Volume Vessel

Abstract

Combustion enhancement is necessary for the improvement of thermal efficiency of spark ignition engines operated under lean and high EGR rate conditions. It is important to understand the interaction of turbulence and flame in order to enhance the combustion by the turbulence. The flame front area is considered to be one of the most dominant factor for turbulent burning velocity. The shape of turbulent flame can be characterized by fractal characteristics and the flame front area can be estimated using fractal characteristics. In this study, turbulent iso-octane/O₂/N₂ flames were investigated under N₂ diluted conditions and elevated pressure conditions using a constant volume vessel. The shape characteristics of spherically propagating premixed turbulent iso-octane/O₂/N₂ flames were evaluated by fractal analysis. Influences of turbulent properties and flame properties on fractal characteristics, such as fractal dimension and inner-cutoff scale were investigated.