Effect of premixing of fuel gas and air on NOx formation

Abstract The relation between air ratio fluctuations and NO x formation was investigated in a combustor with a multiport burner. By use of a laser absorption method to measure the fuel methane concentration, the air ratio fluctuations were evaluated under two mixing conditions: complete and incomplete mixing. From the measured fluctuations of the air ratio, the probability density distribution of the air ratio was obtained to quantify the degree of fluctuation. Using the model proposed by Heywood et al. , the effect of the air ratio fluctuations on NO x formation was investigated by numerical simulation. The simulation results using the measured probability density distribution of the air ratio accurately predicted the effect of the fluctuations on NO x formation.