摘要：利用基于连续介质的计算流体力学方法 (CFD) 和离散单元法 (DEM) 耦合在一起, 建立CFD-DEM耦合方法对粗颗粒流态化过程进行模拟, 对气固两相流中的颗粒速度分布函数进行相应的统计分析, 并用麦克斯韦分布、指数分布、双峰分布和t分布等对模拟数据进行回归, 探讨非均匀气固两相流中合理的速度分布特征。模拟结果表明:麦克斯韦分布不适用于非平衡气固系统中颗粒速度分布函数的描述, t分布或指数分布可以较好地拟合非重力方向的速度分布函数, 而双峰分布则能较好地拟合重力方向的颗粒速度分布函数。

关键词：气固两相流；颗粒速度分布；动理论；流态化

Abstract：The computational fluid dynamics method (CFD) based on continuum model and the discrete element method (DEM) were coupled together to establish a CFD-DEM method which was used to simulate the coarse particle fluidization process in this study. The method of statistical analysis was applied to study the particle velocity distribution function, and the Maxwellian distribution, exponential distribution, bimodal distribution and t-distribution were used to regress the simulated data to explore the reasonable velocity distribution characteristics in the non-uniform gas-solid two-phase flow. It is shown that Maxwell distribution cannot be used to describe the particle velocity distribution in the non-equilibrium gas-solid flow; t distribution or exponential distribution can fit the velocity distribution in the non-gravitational direction well; while bimodal distribution offers a best fitting with the simulation data in the gravitational direction.

Keywords：gas-solid flow；particle velocity distribution；kinetic theory；fluidization