Numerical studies of a 2D trapped vortex combustor

Numerical investigations are performed on a 2D Trapped Vortex Combustor to study the flow structure, temperature distribution and flame behavior under reacting conditions for two cases: (i) slot injection case and (ii) hole injection case. The cavity aspect ratio and momentum flux ratio (MFR) are maintained at 1.2 and 1.56 respectively. For both cases, reactions were initiated during the post-vortex formation i.e. after the formation of stable vortex. However the primary vortex in the cavity domain got disrupted during reaction, giving rise to the formation of a secondary vortex. For slot injection case, the fuel concentration is found more at the interface of primary and secondary air jets indicating inferior mixing. On the other hand, the hole-injection configuration resulted in better species transport within the cavity. It was observed that the flow is highly three dimensional in nature for the hole injection case whereas for slot injection case, the gradients across the transverse direction appears to be negligible. The flame is found to be anchored inside the cavity for the hole injection case, thereby shielding it from the mainstream flow. Hence the hole injection case is found superior than the slot injection case in all aspects.