含灰煤气火管式废热锅炉内流场数值分析

Numerical Analysis of Firetube Waste Heat Boiler with Ashes and Gases

采用Fluent数值模拟软件对立式火管式废热锅炉内气固两相流场进行了分析计算,利用k-ε湍流模型、对流传热模型和离散相模型分别研究了换热管内的流场、温度场和气固耦合过程中的颗粒运动轨迹的变化情况。研究发现：换热管内粉尘流速为7~9m/s,变化范围很小;下管板附近存在回流区,回流流速最大为3m/s,同时有颗粒富集;沿含灰煤气流动（轴向）方向温度变化很大,在横截面（径向）方向布管区内部温度稍低于布管区周边。

The Fluent software was employed to analyze and calculate gas-solid flow field within the vertical firetube waste heat boiler; making use of turbulence model k-ε,convection heat transfer model and discrete phase model respectively,both internal flow field and temperature field within the heat exchange tube and the change of particle trajectories in the gas-solid coupling process were investigated. The study result shows that,the variation range of particle trajectories in the heat exchange tube is small when the dust flow velocity stays at7 ~ 9 m / s; and the backflow zone near the down tube plate has a maximum flow velocity of 3m / s and particle enrichment; along the ash-gas（ axial） direction,the temperature change becomes bigger obviously,but in the cross section（ radial） direction where tubes stay,the internal temperature stays slightly lower than that around the tube-staying zone.