Experimental study of turbulent syngas/methane/air flames at a sub-atmospheric condition

The aim of this work was determined turbulent burning velocities of air-syngas-methane flames at sub-atmospheric conditions using the angle method and Schlieren imaging. We analyzed a high hydrogen content syngas that can be obtained with a Conoco-Phillips coal gasification process. Equivalence ratios evaluated here correspond to lean combustion conditions: 0.8-1.0. Experiments were carried out at room temperature of 297 K and 849 mbar. The chemical-turbulence interaction was evaluated considering geometric parameters, laminar flame properties, and turbulence length scales. It was found that the turbulent burning velocity and the ratio between turbulent and laminar burning velocities increases with the turbulence intensity. Additionally, the addition of syngas to methane increases the laminar and turbulent burning velocity. (paper)