CFD modeling of non-premixed combustion of pulverized coal in a furnace

Coal continues to be one of the main sources of energy, even in the present scenario, for power generation and process industries. A 2D blast furnace (duct) with air as inlet (two inlets with different velocities at same temperature) has been considered for modeling of non-premixed combustion of coal particles being injected as the high-velocity stream with air being supplied from the top and bottom inlets. ANSYS Fluent CFD code (version 12) has been used for modeling. Considering the symmetric geometry, only one-half of the domain is considered. Validation and mesh independent study has been done for a group of coal particles (10 discrete particles with different diameters that follow Rosin-Rammler size distribution law) considering the total heat transfer rate as our main concern. Furthermore, results of the total heat transfer rate have been obtained for different bottom air inlet velocities. Dimensionless length versus parameters (such as static temperature, burnout, and mean mixture fraction) have been plotted by considering different sections along the height of the furnace for different bottom air velocities. Results show that as bottom air inlet velocity increases the peak temperature inside the furnace decreases, the furnace length occupied for burnout increases, the peak value of mean mixture fraction decreases, and the total heat transfer rate decreases and then increases. © 2017 by Begell House, Inc.