Investigating gas-solid flow hydrodynamics in spouted beds with a draft tube using XCT: The role of tube types, gas velocity, and diameter

This study explores the gas-solid flow hydrodynamics in spouted beds with various types of draft tubes using Xray computed tomography (XCT). We investigate the effects of different draft tube types (non-porous, porous, and open-sided), gas velocities, and tube diameters on the spouting behavior. XCT allows for the noninvasive, three-dimensional reconstruction of time-average voidage distribution within the spouted beds. Our findings indicate that draft tube types and diameters significantly influence the minimum spouting velocity, voidage distribution, and particle flow patterns. Porous and open-sided tubes demonstrate unique gas-solid flow characteristics, such as improved particle circulation and enhanced radial mixing, compared to non-porous tubes. This study provides critical insights into the mechanisms of spouting jet stability and the optimization of draft tube designs for industrial applications.