CFD-DEM模拟气固两相在陶瓷膜内的流动特性

CFD-DEM simulating transport characteristic of gas-solid phases in ceramic filters

针对多孔陶瓷膜内复杂的气固两相流动体系,首先用颗粒随机堆积方法对多孔陶瓷几何结构进行了构建.随后采用计算流体力学(CFD)描述气相的流动传递行为;采用离散单元法(DEM)描述颗粒相运动轨迹.模拟结果揭示了滤饼层在膜表面的形成过程,以及压降和粉尘去除率随滤饼层和过滤速度的演变情况.此外,还考察了系统压降随粉尘颗粒恢复系数的变化情况,当恢复系数为0.3时,系统压降存在一个相对较高值.该方法可以为除尘过程中粉尘颗粒在微孔尺度中的传递过程提供精确描述.

The geometric structure of ceramic membrane was constructed by the random stacking method of particle. Then transport characteristic of gas-solid phases in ceramic filters was investigated, among that the transport behavior of gas phase and solid phase were described by the computational fluid dynamics(CFD) and discrete element method(DEM), respectively. The simulation results revealed that the formation of cake layer on the membrane surface and the evolution of pressure drop and rejection with cake layer were observed. In addition, influence of various inlet velocities on pressure drop of the system was investigated. When recovery coefficient was 0.3, system pressure drop presented a relatively high value. It can be concluded that this method could provide an accurate description of transmission process of dust particles in microporous scale during the process of dust removal.