FULL-SCALE CFD STUDY OF SWIRL NUMBER EFFECT ON PARTICLE AND FLOW BEHAVIOR IN INTERACTION WITH COMBUSTION DYNAMICS INSIDE COAL PULVERIZED BURNER

Abstract

The present paper reports a numerical investigation of an atmospheric pulverized coal combustor. The main goal is to study the effects of flow behavior and gas-particle interaction on combustion dynamics for various swirl numbers (SN). This will help in better understanding of the combustion properties inside a large-scale facility. The RANS and quick discretization scheme are combined during this numerical simulation. For turbulence, the realizable k-ε model is adopted. Turbulence and chemistry interaction are modeled using the finite rate/eddy dissipation model along with reduced global reaction mechanism. Four swirl numbers were investigated. The numerical results are validated with previous experimental data. Good agreement between both results is found for temperature distribution and species concentration along the center axis of the nozzle. Flow topology, temperature, particle trajectory, and species concentrations in several locations downstream the injection nozzle are presented and analyzed for the considered swirl numbers. Analysis of the flow velocity and the particle trajectory showed that the combustion behavior and flame shape were directly related to the particle trajectory inside the nozzle. The numerical results also outlined that the variation of swirl number has changed the particle trajectory and consequently the flame topology. Thus, the swirl number significantly influences the burner efficiency.