By using the Large Eddy Simulation(LES)method of Fluent software,three kinds of swirl unpremixed low-nox burners are numerically simulated,their temperature,velocity field and pollutant emission characteristics are analyzed,and the influence of burner structure on the interaction between vortex and flame is discussed.The results show that the inner swirl structure and swirl Venturi structure can effectively reduce the combustion temperature,and the maximum temperature reduction can reach 300 K.The NOx generation of ultra-low NOx burners is mainly concentrated in the middle and lower reaches of the furnace.Compared with conventional swirl structure,the NOx emission of swirl Venturi structure and swirl internal structure is reduced by 13.77%and 12.32%,respectively,and the lowest NOx emission of swirl internal structure is 11.9 mg·kg-1.At the outlet of the furnace,Soot emission of swirl built-in structure decreased by 5.56%compared with that of conventional structure to 20.4 mg·kg-1,while Soot emission of swirl Venturi structure increased by 18.06%,which showed a poor performance.
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