Effects of flow rate and equivalence ratio on syngas flames in a multi-nozzle micromix model combustor

In this paper, the flame structural parameters, OH* distribution characteristics, and dynamic behavior of the global heat release rate of a novel multi-nozzle micromix model combustor are experimentally investigated. The experiments were conducted at atmospheric pressure, high air temperature (691 K), equivalence ratio of 0.1-1.2, and air velocity of 30-80 m/s. The results demonstrate that the combustor has a wide operation window of stable combustion. The flame height is weakly related to air velocity and varies with equivalence ratio from 4D to 19D (D = 10 mm). The peak position of axial OH* intensity at the same flow rate keeps unchanged at various equivalence ratios, and the peak position of axial OH* increases in the range of 1.5D similar to 2.3D with increasing air velocity. The global heat release fluctuation of the flame becomes larger as the equivalence ratio decreases, which shows unsteady combustion behavior.