Experiment and CFD study on the hydrodynamics in novel internal-intensified spouted beds

Abstract

To overcome the limitations of traditional spouted beds, two novel internal-intensified spouted beds were proposed: swirl-nozzle anticlockwise-axial-swirler (SNAAS) and swirl-nozzle clockwise-axial-swirler (SNCAS) spouted beds. The hydrodynamics of the novel internal-intensified, conventional, and swirl-nozzle spouted beds (SBs) were experimentally and numerically investigated. Adding internal-intensified structures could reduce the minimum spouting velocity and accelerate particle fluidization. The gas radial velocity in novel spouted beds with ξ = 3 is the largest, which is the optimal height ratio. Compared with conventional and swirl-nozzle SBs, adding novel internal-intensified structures can effectively promote the radial velocity of gas and particle, reduce the flow-dead zone in the bed, obtaining larger gas turbulent kinetic energy. The flow field uniformity of gas and particle within beds in descending order as SNCAS SB > SNAAS SB > swirl-nozzle SB > conventional SB. The enhancement factor I of flow field uniformity in novel internal-intensified SBs is 2 to 3 times that in the swirl-nozzle SB. Mesh of (a) Conventional SB, (b) Swirl-nozzle SB and (c) Swirl-nozzle axial-swirler SB. • Internal-intensified spouted beds were proposed by introducing axial swirler and swirl nozzle. • The minimum spouting velocity can be reduced by novel internal-intensified structures. • Internal-intensified improves gas-solid contact throughout the spouted bed. • The enhancement factor I in novel internal-intensified SBs is 2 to 3 times that in the swirl-nozzle SB.