循环流化床气固两相流颗粒分布的数值模拟

Numerical Simulation on Solids Fraction Distribution in Straw Burned Circulating Fluidized Beds

对于秸杆燃烧循环流化床锅炉,需要有足够高的悬浮段并且悬浮段有一定的颗粒数量浓度以保证易悬浮的秸杆能够在提升管内充分燃烧。因此,了解惰性物料在提升管内的颗粒数量浓度分布随级配的变化规律对秸杆燃烧循环流化床的设计有指导意义。文中根据实际冷态循环流化床的尺寸和实验参数,采用蒙特卡罗方法对提升管内气固两相流进行了数值模拟,通过改变石英砂颗粒的级配并进行相应计算分析,揭示了提升管内石英砂的颗粒浓度分布随级配的变化特性。结果表明,通过改变级配可以改变提升管内颗粒数量浓度分布,但不能改变密相区高度。

To make the suspended straws burn completely in the riser of circulating fluidized beds, lean phase zone should be high and suitable enough in straw burned circulating fluidized bed boilers. The influence of solids fraction distribution of inert materials in riser on original scale of various diameter particles was studied, which is significant to design straw burning circulating fluidized beds. Based on the actual size and experiment parameters of cold position circulating fluidized bed, the gas-solid two-phase flows in the riser was simulated. The effect of original scale of various diameter particles on solids fraction distribution in the riser was revealed through simulation and analysis. The results indicate that original scale of various diameter particles rationally contributes to the solids fraction distribution, and with changing the original scale of various diameter particles, solids fraction distribution can be changed but height of dense phase zone can＇t be changed.