This study establishes a numerical deposition and removal model coupled with unsteady gas–solid turbulent flow to predict transport, impaction, sticking, and removal (or rebounding) characteristics of ash particles with high alkali metals based on Ansys Fluent software extended by user–defined functions. Dynamic mesh analytical strategy is employed to adjust the grid on the interface of flue gas and deposition layer to illustrate ash deposit growth characteristics. In this study, the effects of particle size, flow velocity, and inlet gas temperature on formation and distribution of ash deposits are studied. The results indicate that ash deposit distribution has significant particle size dependence. Larger particles tend to deposit on the windward side of first–row tubes, and account for the greatest share of total deposited mass. Smaller particles may deposit on the leeward side of the tube surfaces. Variation in impaction rates with time are influenced by the thermophoretic force and enlarged deposition area. With the increase in flow velocity, total deposited mass increases gradually. The influence of flow temperature on impacting rates is mainly embodied in the effect of flow temperature on thermophoretic force. However, the increase in inlet gas temperature has little effect on the sticking efficiency and ash deposit distribution. Nevertheless, the total deposited mass shows an increasing trend with inlet flue gas temperature.

这项研究基于Ansys Fluent软件（由用户定义的功能扩展），建立了一个数值沉积和清除模型，以及不稳定的气固两相湍流，以预测高碱金属灰分颗粒的迁移，撞击，粘附和清除（或反弹）特性。 。采用动态网格分析策略调整烟气与沉积层界面上的网格，以说明灰渣沉积物的生长特性。在这项研究中，研究了粒径，流速和入口气体温度对灰渣沉积物形成和分布的影响。结果表明，灰分沉积物分布具有显着的粒度依赖性。较大的颗粒倾向于沉积在第一行管的迎风侧，并且占总沉积质量的最大份额。较小的颗粒可能沉积在管表面的背风侧。撞击速度随时间的变化受热泳力和扩大的沉积面积影响。随着流速的增加，总沉积质量逐渐增加。流动温度对冲击速率的影响主要体现在流动温度对热泳力的影响。然而，进气温度的升高对粘着效率和灰分分布的影响很小。然而，总沉积质量显示出随进口烟气温度增加的趋势。流动温度对冲击速率的影响主要体现在流动温度对热泳力的影响。但是，进气温度的升高对粘着效率和灰烬沉积分布几乎没有影响。然而，总沉积质量显示出随进口烟气温度增加的趋势。流动温度对冲击速率的影响主要体现在流动温度对热泳力的影响。然而，进气温度的升高对粘着效率和灰分分布的影响很小。然而，总沉积质量显示出随进口烟气温度增加的趋势。