Computational fluid dynamics technique as a tool for description of the phenomena occurring in pulverized coal combustion systems

The paper presents the overall frame, principal steps, and some results of a numerical model of a power boiler furnace that uses pulverized coal, with tangential disposition of the burners. This model demonstrates the application potential of the computational fluid dynamics (CFD) technique and of the computational thermal analysis. Complex three-dimensional furnace geometry, two-phase turbulent flow, coal combustion, and heat transfer have been examined. Two numerical modelling approaches were employed in the investigation, both based on the Euler-Lagrangean two-phase flow concept and on the gas-phase semi-empirical k-epsilon turbulence model. The first approach is based on a specially developed comprehensive model of processes in a pulverized coal furnace. In the second case, a commercial CFD code is used to create a three-dimensional furnace model. Some distinctive results concerning the performance of the boiler that was examined are presented graphically. On the basis of a comparison between the simulation predictions and available site measurements, a conclusion can be drawn that these two numerical codes provide realistic insight into furnace processes. Qualitative agreement indicates that the calculations are reasonable and validates the submodels employed