A V-shaped laminar stratified flame was investigated by numerical simulation. The primitive variable method, in which the fully elliptic governing equations were solved with detailed chemistry and complex thermal and transport properties, was used. The results indicate that in addition to the primary premixed flame, the stratified charge in a combustor causes the formation of a diffusion flame. The diffusion flame is located between the primary premixed flame branches. The fuel is fully decomposed and converted to some intermediate species, like CO and H2, in the primary premixed flame branches. Due to the shortage of oxygen, the formed CO and H2 in the fuel rich region of the premixed flame branch is further transported to the downstream until they meet the oxygen from the fuel lean region. This leads to the formation of the diffusion flame. There is an interaction between the diffusion flame and the primary premixed flame branches. The interaction intensifies the burning speed of the primary premixed flame. Both the heat transfer and the diffusion of hydrogen and some radicals cause the interaction. With the increase of the stratified charge region, the diffusion flame zone is enlarged and the interaction is enhanced.
Effect of Stratified Charge Compression Ignition on Emission and Power Output- A Review
