Mathematical modeling of polydispersed (gas-solid particles) flow with light (ash) and heavy (corundum) particles is presented to analyze manifold process occurring in circulating fluidized beds (CFB). This study covers the process of turbulent mixing of particle and particle-particle collision, particle-surface collision and pertains the gravitation and viscous drag and lift forces. The 2D RANS (Reynolds Averaged Navier-Stokes) equations are used for numerical modeling of uprising polydispersed turbulent flow with implemented k-Lh model of closure. The flow domain is a round pipe with diameter of 30 mm and height of 100 calibers (pipe diameters). The flow (mean velocity up to 10 m/s) carries two fractions of ash particles (material density of 1020 kg/m3 and sizes of 0.25 and 0.4 mm) and corundum particles (material density of 4000 kg/m3 and size 0.4 mm). Two mass loadings – 5 and 10 kg/kg – were considered.
The results are presented in the form of distribution of axial and radial velocity components of gaseous and solid phases, particle mass concentration and kinetic turbulent energy along the flow height at steady-state flow cross-sections.
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