基于离散单元法的丝状颗粒传热数学模型

丝状颗粒作为一类长径比较大的非球形颗粒，其传热特性及相关技术广泛应用于工农业生产的诸多领域。但目前颗粒在运动过程中传热问题的研究还很不充分，特别是对于丝状颗粒，更是缺乏有效的数学模型进行描述。从颗粒传热机理出发，提出了一种基于离散单元法的丝状颗粒传热模型，模型中综合考虑了颗粒碰撞（接触）传热、颗粒的内部导热以及颗粒与气体间的对流换热。利用该模型，对固定床中堆积丝状颗粒的热量迁移过程进行了数值模拟，着重比较了各种传热方式对传热过程的影响。研究表明，对流换热对整体传热量的贡献较大。此外，还获得了不同工况下颗粒温度随时间的变化规律。

Model of heat transfer in filamentous granular materials based on discrete element method

Filamentous particle is a kind of non-spherical particles with large aspect ratio.It has been widely applied in industrial and agricultural processes.However, the heat transfer phenomenon about particles is not well understood, especially the filamentous particle.In this study, in order to describe the heat transfer process of filamentous particle, a new mathematical model based on the discrete element method was proposed through the analysis of heat transfer mechanisms.The impact heat transfer between particles, the internal heat conduction and the convection heat exchange between gas and particles were considered in this model, and then it was used to numerically study the heat transfer process of filamentous particles in a fixed bed.Comparing the mechanisms with each other, it showed that the convection heat exchange had greater contribution to the total heat transfer.In addition, the simulation results revealed some internal temperature rules in filamentous particles under different operating conditions.