Large eddy simulation of syngas combustion in a trapped vortex combustor

Trapped vortex combustors (TVCs) are well-suited for hydrogen-rich fuels as they stabilize combustion at high flow velocities. This study investigates syngas combustion in a third-generation TVC, focusing on the effect of H 2 /CO ratio (25/75 to 95/5) on combustion efficiency, vortex dynamics, temperature distribution, and emissions. The large eddy simulation (LES) approach coupled with the partially-stirred reactor model is employed to model turbulence-chemistry interactions. A reduced chemical kinetic mechanism for syngas, with 24 reactions and 13 species, governs combustion kinetics. Results reveal the 75 % H 2 /25 % CO blend achieves the highest combustion efficiency (94.7 % mass-based, 97.2 % energy-based) due to enhanced vortex stability and mixing within the cavity, while higher CO fractions degrade mixing and combustion efficiency. Emissions of NO, CO, and CO 2 rise monotonically with higher CO content in the fuel. An air inlet configuration study shows that offsetting fuel and air inlets boosts efficiency by 26 % by promoting counter-rotating vortices.