Effect of CO2 on self-acceleration properties of syngas/air turbulent premixed flame at different equivalence ratios.

For studying the effect of carbon dioxide (CO 2) on the self-accelerating properties of syngas/air mixture's turbulent premixed flame, an experimental study was carried out on 90%H 2 /10%CO/air mixture at the turbulence intensity of 1.31 m/s. The effects of various equivalence ratios (0.6, 0.8 and 1.0) and carbon dioxide contents (10%, 20% and 30%) on the flame evolution and propagation speed were studied. The effects of the CO 2 contents and equivalence ratios on the self-acceleration properties in the flame propagation transition stage were evaluated. The effects of effective Lewis number and Zel'dovich number on the fractal excess and acceleration exponent were analyzed. The results showed that, as the CO 2 contents increased, the development process of the flame slowed down, and the rate of growth of the flame's radius and the turbulent premixed flame propagation speed decreased at the same radius. The fractal excess and acceleration exponent increased with the increasing CO 2 contents and decreased with the increasing equivalence ratio. Under different equivalence ratios and CO 2 contents, the syngas/air premixed flame acceleration exponent was less than 1.5 in the transition stage. • Effect of CO 2 content on the flame evolution and propagation speed was studied. • Effect of ϕ and CO 2 content on the self-acceleration properties were evaluated. • The self-acceleration properties in the transition stage were studied. • Effect of Le eff and Ze on the acceleration exponent was analyzed. [ABSTRACT FROM AUTHOR]