Flow　dynamics　in　bubbling　and　turbulent　fluidized　beds　containing　both　Geldart-A　and　B　particles　were　investigated　in　this　research.　The　numerical　model　was　validated　against　experimental　data,　with　a　6.16%　average　deviation.　Results　show　that　binary　mixture　segregation　is　enhanced　as　superficial　gas　velocity　decreases.　A　larger　flotsam　packing　ratio　promotes　homogeneous　flotsam　distribution;　Second,　bed　density　decreases　with　increasing　bed　height　or　superficial　gas　velocity.　As　the　flotsam　packing　ratio　decreases　from　81.10　to　10.70%,　bed　density　reaches　the　maximum　at　41.50%,　indicating　the　most　severe　volume　contraction;　Third,　when　the　flotsam　packing　ratio　decreases,　the　local　mixing　index＇s　variances　between　upper　and　lower　sections　in　dense　phase　first　increases,　then　decreases,　with　stronger　radial　fluctuation　detected;　Fourth,　as　superficial　gas　velocity　or　flotsam　packing　ratio　increases,　the　full　mixing　height　ratio　improves;　Finally,　multivariate　correlations　for　dense　phase　bed　expansion　are　established,　yielding　a　3.94%　average　error.　©　2022　Elsevier　B.V.