Effect of diluent content and H2/CO ratio on the laminar combustion characteristics of syngas.

A constant volume combustion chamber is employed to investigate the laminar burning characteristics of syngas. The effects of changes in diluent gas composition (CO 2 /N 2) and H 2 /CO ratio on the laminar burning velocity (S L) of syngas are decoupled and analyzed. The instability of laminar flames is analyzed using effective Lewis number, flame thickness, thermal expansion ratio, and linear stability theory. The results indicate that as the amount of diluent gas increases, thermal diffusion instability (TD) increases, while hydrodynamic instability (DL) gradually decreases. With a decrease in the H 2 /CO ratio, TD gradually decreases, and DL increases. When the diluent content is below 45%, the critical flame radius under N 2 dilution conditions exceeds that under CO 2 dilution conditions. Above 45%, the situation reverses. As the H 2 /CO ratio decreases, the critical flame radius gradually increases. When the H 2 content is high, the critical flame radius under N 2 dilution conditions is larger. • Comprehensive analysis of the impact of diluent content and H 2 /CO ratio. • Decoupling analyzes the dilution, thermal, and chemical effects of CO 2. • Decoupling analyzes the chemical and physical effects of changing the H 2 /CO ratio. • The spherical flame instability is analyzed with linear stability theory. • Analyzing the instability range of flames by incorporating critical radius. [ABSTRACT FROM AUTHOR]