Effect of the vane angle for outer secondary air on the flow and combustion characteristics and NOx emissions of the low-NOx axial-swirl coal burner

摘要

We conducted a cold air experiment and numerical simulation to investigate flow and combustion characteristics and NOx emission of a low-NO x axial-swirl burner in a 600MWe bituminous coal-burning boiler. Comparison of single-phase numerical simulation results and measurements made by a probe with hot-film sensors shows that the numerical model is a reasonable description. By changing the vane angle for outer secondary air, we obtain different results for the recirculation zone, the divergence angle, the distance that the recirculation zone extends into the burner, the mass of the flue gas that returns to the burner, the temperature of the furnace, and the concentration of NOx emission. The best vane angle for the outer secondary air is determined to be 15°.