Abstract: After 30 years of development, the discrete element method (DEM) has developed to be a kind of numerical method of particle systems widely used in process engineering. In particular, the CFD-DEM coupling method has been widely used in the researches of fluidization. The DEM models are reviewed firstly, including the basic principles of DEM model, the particle shape model, the contact force model, the non-contact force model, and the fluid force model. Then the CFD-DEM coupling methods and the applications to fluidization are introduced, including the applications in fluidized bed, pneumatic conveying, and some other fields of process engineering. Finally, the future development of DEM and CFD-DEM coupling methods are presented, hoping to promote the development of DEM and its applications in process engineering.

Key words: discrete element method, computational fluid dynamics, fluidized bed, fluidization, pneumatic conveying

摘要： 经过三十余年的发展，离散单元法（discrete element method，DEM）已经发展成为一种广泛应用于过程工程领域中颗粒体系研究的数值方法，特别是将DEM与计算流体力学（computational fluid dynamics，CFD）相结合形成的CFD-DEM耦合方法，已经在流态化研究领域得到广泛应用。首先对DEM模型进行了综述，包括DEM模型的基本原理、颗粒形状模型、接触力模型、非接触力模型、流体作用力模型等；然后对CFD-DEM耦合方法及其在流态化领域的一些主要应用进行了介绍，包括在流化床、气力输送以及过程工程领域里的一些其他应用。最后对DEM模型以及CFD-DEM耦合方法的发展趋势进行了预测，希望能促进DEM方法的发展，并推动其在过程工程领域中的应用。

关键词: 离散单元法, 计算流体力学, 流化床, 流态化, 气力输送