Numerical simulation of the formation of nitric oxides in the combustion of coal-dust fuel

Abstract

A mathematical model and a method of calculating two-phase flows and heat and mass transfer in industrial combustion chambers operating on coal-dust fuels are given. The numerical model of coal-dust combustion in a high-temperature turbulent flow is based on three-dimensional steady-state equations of mechanics of heterogeneous media and describes the processes of yield and combustion of fuel volatiles, afterburning of the coke residue, radiative heat transfer in the combustion chamber, and the effect of the disperse phase on the turbulent structure of the carrier medium. To predict the concentration of nitric oxides inside a combustion chamber, an effective numerical model of NO formation during jet burning of coal dust, which is based on the Mitchell-Tarbell kinetic scheme, is proposed. The results obtained in the use of the proposed complex numerical model are in good agreement with experimental data for industrial combustion chambers. The degree of detail ensured by the calculations allows one to make effective decisions to organize coal-dust burning with a decreased yield of hazardous nitric oxides.