3-D model of solid and gas phase flow in the duct bend behind the mill gas classifier at the fan mill

Abstract

This paper shows the computer simulation of two-phase flow of the mill gases, the solid particles of monodisperse coal dust and the transport fluid. Numeric simulation was performed with the software pack Fluent 6.3.26, application of the internal method DPM (Discrete Phase Models) which is based on the Lagrange approach. The standard k-ε model was used for gas phase turbulence modeling.The simulation was done for smooth, rectangular 90 o bend of inclined mill gas duct, located behind the classifier, for fan mill N 80.75 in block 1 of the thermal power plant "Kostolac A" (Serbia), with the aim of determining the pulverized coal distribution on duct cross section before entering the jet burner. Obtained results show the transport fluid velocity, the pulverized coal velocity and the particle trajectories within the flow channel. The simulation covers the flow of monodisperse particles with diameters ds = 50 μm, ds = 100 μm, ds = 600 μm and ds = 1000 μm, and their mixture. The results of this work were verified against experimental results available in the literature. Mill gas classifier in the TPP "Kostolac A" was reconstructed based on the analysis of numerical results.