Numerical analysis of the aerodynamics and combustion of a turbulent pulverized-coal burner jet

A mathematical model and a computing technique are proposed for the motion, heat transfer, and combustion in the initial region of a pulverized-coal jet injected through a burner into the furnace volume. In the simulation, the dispersed phase is divided into two kinds of particles: particles that enter the region being studied from the portion of the furnace volume that is external with respect to the selected zone and the burner-jet particles. The continual approach and the assumption of equilibrium with respect to the gas phase are used to describe the motion of particles of the first kind, and the Lagrangian approach taking into account the dynamic and thermal lag of particles is used to simulate the processes in the medium of particles of the second kind. The model also describes the evolution of volatile substances and burnup of the coke residue. The results obtained using this numerical model make it possible to analyze in detail the combustion of a pulverized coal-air jet in the area near the burner. The degree of detail achieved allows one to make effective decisions for organization of an optimal jet aerodynamics to reduce nitric-oxide formation.