A new paper published in the journal Fuel presents an investigation of a micro-diffusion burner and proposes a characteristic parameter (diffusion number N_dif) to evaluate the degree of dispersion of one larger nozzle.

The study examines flame stability, temperature, OH radicals, and pollutant emissions at three different N_dif values. The results demonstrated that as the nozzle diameter decreased and the number of nozzles increased, the N_dif gradually decreased, accompanied by an increase in the diffusivity and mixing degree of fuel and air. Additionally, the combustion characteristics of the micro-mixing flame exhibited greater similarities to those of premixed flame.

At N_dif = 0.083, the flame exhibited a uniform temperature field and OH radical distribution. At Φ = 0.87, the NO_x emission reached its maximum. When Φ is less than 0.67, the NO_x emission is less than 10mg/Nm³. As N_dif decreases, the combustion characteristics of the micro-mixing flame tend to be similar to those of the planar premixed flame.

The results of this study may provide valuable guidance in the assessment of the degree of air-fuel mixing at the nozzle outlet and serve as a criterion for future micro-mixing flame research.