基于有限元的电站锅炉直流燃烧器热力特性研究

Finite element analysis based thermal characteristic research on direct flow burner in utility boilers

以直流煤粉锅炉燃烧器为研究对象,一次风喷口为单元,利用ANSYS有限元分析软件,依据直流煤粉燃烧器的实际工况确定热分析边界条件,建立了燃烧器一次风喷口温度有限元热分析模型。通过分析一次风喷口的温度水平和温度变化梯度,得到在燃烧器正常运行工况下一次风喷口在不同方向上的温度分布,以及在燃烧器正常运行、停运及无周界风3种工况下一次风喷口正对炉膛侧横截面上拐角点温度的变化趋势。结果表明,直流煤粉燃烧器的最高温度集中分布于喷口方形出口的4角附近,这与燃烧器容易发生烧坏、结焦、热变形的部位相符。

Taking a direct flow burner as the research object,the primary air nozzle as the unit,the ANSYS software was applied to establish a finite element thermal analysis model for temperature at primary air nozzle of the burner with the boundary condition determined according to the burner's actual working condition.Through investigation on the temperature level and temperature variation gradient at the primary air nozzle,the temperature distribution in different directions of the primary air nozzle under normal working condition was obtained.Moreover,the variation tendencies of temperature at corner point on cross section of the furnace where directly against the primary air nozzle(under three conditions:normal operation,stop state and without surrounding air condition)were also obtained.The results showed that,the highest temperature of the direct flow burner concentrated in four corners of the square exit of the primary air nozzle,which agreed with the locations where the burnout,slagging and thermal deformation easily occurred.