基于CFD的秸秆颗粒流化特性模拟

在秸秆流化床锅炉中，秸秆颗粒的流化特性对燃烧效率、床料聚团及积灰等有重要的影响。采用计算流体力学软件FLUENT对秸秆颗粒在流化床内的流动情况进行数值模拟，并分析颗粒直径对最小流化速度、颗粒速度场和平均体积分数的影响。结果表明，颗粒最小流化速度与颗粒直径呈现近似线性的关系；达到流化状态后，流化床的床层压降不会随颗粒直径的改变而改变；随着颗粒直径的增加，床层高度减小，床内固相的体积分数增加，气泡直径增大，气泡破裂时引起的床层表面波动增大。分析结果能够为秸秆流化床锅炉的优化设计和运行提供指导。 

Numerical Simulation on Fluidization Characteristics of Straw Particles in Fluidized Bed Based on CFD

In straw fluidized bed boiler，fluidization characteristics of straw particles have important effects on combustion efficiency，agglomerating behaviors and fouling.ANSYS FLUENT was used for simulation of flow of straw particles in fluidized bed，and effects of particle diameter on minimum fluidization velocity，particle velocity field and average volume fraction were analyzed.Results indicated that minimum fluidization velocity had a linear relationship with particle diameter. After reached fluidization state，bed′s pressure drop did not change with particle diameter.With increase of particle diameter，bed height of fluidized bed decreased and volume fraction of solid phase increased，also bubble diameter increased，and surface fluctuation caused by bubble burst increased.Simulation results could provide guidance for optimal design and operation of straw fluidized bed boiler.