Assessing Reliability and Accuracy of IBM-DEM Coupling Method: Modelling SingleParticle Sedimentation

Numerous numerical techniques have been increasinglyused in the modelling the fluid-solid two-phase flows.Coupling between Immersed Boundary Method (IBM)and Discrete Element Method (DEM) is one of thepromising approaches in the field of modellingparticulate flows. This paper assesses the reliability andaccuracy of the IBM-DEM coupling technique as a fullyresolved method through modelling single particlesedimentation (SPS).At the first step, the ratio of the particle diameter to thegrid size (D/dx) was specified through comparing thesimulation results with the reliable analytical solution.The dynamic mesh refinement model was utilized torefine the grid close to the particle to a fraction of theuniform grid (dx). Also, the optimum coupling intervalbetween IBM and DEM models was determined basedon the experimental results of the SPS within Silicon oilat the Reynolds number of ۱.۵. Secondly, the propertemporal discretization scheme was determinedaccording to the experimental results (Re=۱.۵). Finally,the experimental results along with the analyticalsolution were utilized to validate the model at Reynoldsnumbers of ۴.۱, ۱۱.۶ and ۳۱.۹.It was confirmed that the particle settling can beaccurately modelled with the IBM-DEM technique whenthe ratio of D/dx is at least equal to ۴ while the grid closeto the particle were refined to a quarter of uniform grid.Also the wall effect on the particle motion is negligiblewhen the ratio of domain width to the particle diameter(W/D) is in the order of ۵. It was seen that the IBMDEMmethod is a reliable technique in the modelling ofall three stages of a single particle sedimentation. Acomparison between the experimental data and IBMDEMresults confirmed the accuracy of model in thesecond stage of sedimentation (steady speed).

کلیدواژه ها:

Immersed Boundary Method ، DiscreteElement Method ، Sedimentation