Investigation on dilution effect on laminar burning velocity of syngas premixed flames

To provide more insight into the laminar burning velocity reduction of diluted syngas premixed flames, the laminar burning velocities of diluted syngas premixed (H2/CO/N2/air and H2/CO/CO2/air) laminar spherical flames were systematically and thoroughly investigated experimentally via Schlieren technology. In the present investigation, the volume fraction of H2 was varied from 30% to 70%, the volume fraction of CO was varied from 30% to 70%, the volume fraction of CO2 was varied from 0% to 60%, and the equivalence ratio was varied from 0.7 to 1.0. In the present investigation, the effects of equivalence ratio, hydrogen fraction, and dilution fraction on the laminar burning velocities were studied. Compared to N2 dilution, the laminar burning velocity reduction with CO2 dilution was analysed through the thermal, transport, and chemical effects. In addition, the contributions of third-body and direction effects were also studied.