A NUMERICAL STUDY ON CHARACTERISTICS OF SWIRL PREMIXED FLAME INTERACTION AFFECTING NO EMISSION IN A GAS TURBINE COMBUSTOR

Flame interaction between two neighboring burners in a gas turbine combustor is investigated numerically for pursuit of its effect on NOx emission from the burners. In a model chamber or liner, EV burners with double cone are installed. Two burners with the opposite rotating directions (L-R type burner) of air stream are adopted and the distance between them is variable from 74.2 mm to 222.6 mm by the step size of 37.1 mm and an additional distance of 171.3 mm is considered. Gaseous methane and air are adopted as fuel and oxidizer, respectively. From steady-state numerical analyses, flow, temperature, and NO concentration fields are calculated in all computational cases to find their correlation with NO formation. NO emission is evaluated at the exit of the model chamber with two burners as a function of burner distance. Swirl flows induced by EV burner are kept up to the liner exit, but with weaker swirl than that of the same rotating burners (L-L type burners). The case of shortest distance presents strong correlation between two flames while the other cases present weak correlation. In all cases of L-R type burners, NO emission is lower than that of L-L type burners, which results from change in swirl flow patterns. NO emission from L-R type burners with intermediate distances is greater than that from a single burner, but it is smaller than the latter with relatively shorter and longer burner distances.