Numerical simulation of flow, combustion and NO emission of a fuel-staged industrial gas burner

Three dimensional numerical simulations were performed to optimize the geometrical parameters of a fuel-staged low NOx gas burner. The effect of the primary gas injection angle (α), the staged gas injection angle (β) and position of the staged gun (H) on flame size and NO emission was analyzed based on the contours of temperature, stoichiometric mixture fraction, rate of thermal NO and the global NO emission. The predicted results were validated with the experimental measurements of the full scale burner (1.4 MW) at different excess air factors. The results indicate that H is the most important factors affecting the NO emission, followed by β and α respectively. The chemical flame heights increase with the increase of β and the decrease of H but the effect of α is negligible. Finally, α = 70°, β = 30° and H = 36 mm are recommended as the optimized results.