Study on combustion performances of partially premixed flame in a micro-combustor with cavity

Combustion characteristics of a partially premixed flame in a micro-combustor with a wall cavity were studied numerically under various conditions (primary air coefficient, α = 0.35, 0.5, and 0.65). The results show that the cavity has a significant effect on flame structure, establishing a typical double-flame structure (namely, a trapped-vortex flame and a main flame). The cavity effectively extends the operating range at a higher α . Although the trapped-vortex flame is relatively weak, it plays a crucial role in sustaining main flame through heat transfer. Specifically, the trapped vortex flame is dominated by the nature of the mixed gas flowing into the cavity, and assisted by the preheating effect. And the main flame is dominated by flow field and assisted by heat transfer. Research shows that with the increase of V in , reaction zone area, temperature, and heat release rate (HRR) of both the trapped-vortex flame and the main flame are increased simultaneously. And as α increases, reaction zone area, temperature, and HRR of the trapped-vortex flame increase significantly, while those of the main flame decrease. According to the field synergy principle, a higher V in does not necessarily lead to a better preheating effect of the fresh mixture.