Numerical Simulation of Flow and Combustion Process in the Tangentially Fired Furnace of a 200 MW Pulverized Coal Boiler
Fan Xianzhen¹,Guo Liejin¹,Gao Hui¹,Nie Jianping²
(1.State Key Laboratory of Multiphase Flow,Xi'an Jiaotong University,Xi'an 710049,China;2.Thermal Power Research Institute of State Power Corporation of China)

Abstract: Using a CFD software FLUENT, an Eulerian/Lagrangian approach was employed to investigate numerically the flow field, heat transfer and combustion process in a tangentially fired furnace of 200 MW pulverized coal boiler. Three different cases were simulated. To reduce the influence of the numerical pseudodiffusion on the computational results, a measure was taken to improve the grid system so that fluids enter the control unit in the direction of perpendicular to the unit's border, not 45 degrees to the border. The simulation results show that temperature drops with the increase of furnace height, and the highest temperature appears in the area of the burners; from bottom to top, the intensity of swirl firstly strengthens and then weakens in the furnace, but residual swirl still exists at the exit of furnace; the distributions of CO, O₂ and CO₂ concentration are strongly related to the temperature field, that is, the high temperature area cor-responds to the high CO and low O₂ and CO₂ concentration area. The distributions of the velocity, temperature and the particles' trajectories in the furnace were also obtained and analyzed.
Keywords: pulverized coal;tangentially fired boiler;numerical simulation;numerical pseudo-diffusion;concentration field of gas composition;particle trajectory