PREDICTION OF GAS-PARTICLE FLOWS AND GAS COMBUSTION IN A CYCLONE FURNACE

On the basis of the pure two-fluid model for turbulent reacting gas-particle flows with combusting pulverized coal particles, a new comprehensive model for pulverized coal combustion was developed by incorporating a modified k−ε−kp model, a general model of pulverized coal devolatilization and a general model of char combustion. Both gas-phase and particle-phase conservation equations are described in the Eulerian coordinates, and these equations are integrated in the computational cell to obtained finite-difference equations. As the first stage of numerical modeling of pulverized coal combustion in the cyclone furnace, three dimensional simulation of turbulent gas combustion and gas-particle flows have been made. Predicted results show that there is a near wall re-circulating zone at the bottom of the cyclone furnace, and the re-circulating zone enhances ignition and flame stabilization. Results of tangential velocity distribution of both gas phase and particle phase are similar to those of the Rankine vortex.