循环流化床锅炉膜式水冷壁管与鳍片上的温度分布

Temperature Distributions in A Finned Water Wall Tube of A Circulating Fluidized Bed Boiler

研究了循环流化床锅炉膜式水冷壁管的传热 ,并通过采用二维传热分析方法 ,讨论了带有竖直鳍片和横向鳍片的水冷壁管上温度与热流分布。探讨了炉膛侧传热系数、水冷壁管水侧传热系数、水温、床温、水冷壁管材的导热率以及竖直鳍片长度和管壁厚度对水冷壁管各位置热流分布的影响。研究发现 :水冷壁管热流的分布在竖直鳍片端部最高 ,然后逐渐下降 ,但在横向鳍处的根部又会上升。为了验证传热分析的真实性 ,在 1台 6MWth循环流化床锅炉膜式水冷壁管的横截面内安置了 0 .8mm的热电偶 ,测量了水管横截面上的一些点的温度。实际测量值与预测值符合得相当好。图 1 6表 1参 1

Heat transfer improvement in a water wall tube with fins is investigated in a circulating fluidized bed(CFB). The distributions of temperature in the metal wall and that of heat flux around the outer wall of a tube with a longitudinal and lateral fins are examined by a two dimensional heat conduction analysis. Effects of bed to wall heat transfer coefficient, water to tube inside heat transfer coefficient, bed temperature, water temperature and thermal conductivity of the tube material on the heat flux around the water tube are discussed. The present work also examined the influence of the length of longitudinal fin and the water tube thickness. Heat flux was highest at the tip of the longitudinal fin. It dropped, but increased again near the root of lateral fin. To verify the reliability of the heat conduction analysis, temperature at some discrete points within wall cross section of the tube was measured. 0.8mm thermocouples were buried within the tube cross section in a 6MWth CFB demonstration boiler. Measurements agree well with the predicted results. Figs16, table1 and refs10.