Laminar burning characteristics of premixed methane-dissociated methanol-air mixtures under lean burn conditions

The influence of dissociated methanol addition on methane was studied in a constant volume chamber. The initial conditions were 0.1 MPa, 0.3 MPa, 0.5 MPa and 343 K, 393 K, and 443 K. The dissociated methanol fractions were from 20% to 80%, and the equivalence ratio varied from 0.8 to 1.4. The laminar burning velocities of methane-dissociated methanol-air mixtures were measured through the spherically expanding flame method using a Schlieren photography system. The influence of dissociated methanol addition on the laminar burning velocities were discussed. The relationship between the laminar burning velocity and equivalence ratio at 343 K and 0.3 MPa, and the relationship between the laminar burning velocity and the dissociated methanol fraction at the equivalence ratio of 0.8 under different initial conditions were fitted through a three-order polynomial function. Furthermore, the flame instabilities of methane-dissociated methanol-air mixtures were discussed. These results provide important theoretical references to lean burn natural gas engines with methane-dissociated methanol blended fuels under lean burn conditions.