Considering the fact that the temperature distribution in furnace of a tangential fired pulverized coal boiler is difficult to be measured and monitored, two-stage numerical simulation method was put forward. First, m...Considering the fact that the temperature distribution in furnace of a tangential fired pulverized coal boiler is difficult to be measured and monitored, two-stage numerical simulation method was put forward. First, multi-field coupling simulation in typical work conditions was carried out off-line with the software CFX-4.3, and then the expression of temperature profile varying with operating parameter was obtained. According to real-time operating parameters, the temperature at arbitrary point of the furnace can be calculated by using this expression. Thus the temperature profile can be shown on-line and monitoring for combustion state in the furnace is realized. The simul-(ation) model was checked by the parameters measured in an operating boiler, (DG130-9.8/540.) The maximum of relative error is less than 12% and the absolute error is less than 120℃, which shows that the proposed two-stage simulation method is reliable and able to satisfy the requirement of industrial application.展开更多
Aiming at the optimization of the operation condition, a general numerical method for calculating pulverized coal combustion in a full scale furnace fired tangentially at four corners is adopted. “ k ε ” turbulence...Aiming at the optimization of the operation condition, a general numerical method for calculating pulverized coal combustion in a full scale furnace fired tangentially at four corners is adopted. “ k ε ” turbulence model is used for the gas phases and a stochastic approach based on the Lagrangian technique is used for particle phases. Two competing reactions model for the coal devolatilization and PDF (the probability density function) method for the combustion of the gas phases are employed. In the numerical simulations, assuming the air distribution of second port level is of pagoda, waist drum and uniform type. The results show that pagoda type air distribution is advantageous to ignition and smooth combustion of pulverized coal, and suitable to inferior coal combustion in practice. In the present furnace, the igniting distance at 1st and 3rd corner is longer than that at 2nd and 4th corner. The results from numerical calculations are in good agreement with those of observed in practice.展开更多
文摘Considering the fact that the temperature distribution in furnace of a tangential fired pulverized coal boiler is difficult to be measured and monitored, two-stage numerical simulation method was put forward. First, multi-field coupling simulation in typical work conditions was carried out off-line with the software CFX-4.3, and then the expression of temperature profile varying with operating parameter was obtained. According to real-time operating parameters, the temperature at arbitrary point of the furnace can be calculated by using this expression. Thus the temperature profile can be shown on-line and monitoring for combustion state in the furnace is realized. The simul-(ation) model was checked by the parameters measured in an operating boiler, (DG130-9.8/540.) The maximum of relative error is less than 12% and the absolute error is less than 120℃, which shows that the proposed two-stage simulation method is reliable and able to satisfy the requirement of industrial application.
文摘Aiming at the optimization of the operation condition, a general numerical method for calculating pulverized coal combustion in a full scale furnace fired tangentially at four corners is adopted. “ k ε ” turbulence model is used for the gas phases and a stochastic approach based on the Lagrangian technique is used for particle phases. Two competing reactions model for the coal devolatilization and PDF (the probability density function) method for the combustion of the gas phases are employed. In the numerical simulations, assuming the air distribution of second port level is of pagoda, waist drum and uniform type. The results show that pagoda type air distribution is advantageous to ignition and smooth combustion of pulverized coal, and suitable to inferior coal combustion in practice. In the present furnace, the igniting distance at 1st and 3rd corner is longer than that at 2nd and 4th corner. The results from numerical calculations are in good agreement with those of observed in practice.
