颗粒沉降问题的高解析度CFD-DEM-IBM流固耦合数值模拟方法
摘要
A CFD-DEM-IBM method with high resolution is proposed based on the immersed boundary method (IBM) to describe the sedimentation phenomenon accurately and to investigate the underlying influence mechanism between fluid and particles in dense fluid-particle systems. The fluid phase is analyzed by the computational fluid dynamics (CFD) while the discrete element method (DEM) is utilized to simulate the motion of individual particles. The IBM is introduced to tackle the moving boundaries of particles and the interaction forces between fluid and particles are considered by an extra body force added to the Navier-Stokes momentum equation. The strongly coupled fluid-solid system is then achieved through the successive iterative scheme where several iterations are required within each time step until the convergence conditions are exactly satisfied. Sedimentations of one, two and multiple particles are simulated, which reveal that the proposed method could obtain the accurate interaction forces among discrete particles and fluid along with the fully resolved fluid phase around the particles compared with the conventional unresolved CFD-DEM method. The agreement between present results and previous work demonstrates the accuracy and validity of the presented method, and the applicability together with the superiority of the CFD-DEM-IBM method is also proved when the dense particulate flows occur.