碰撞特性对喷动流化床动力学影响的实验研究
In this paper we experimentally study the effect of collision properties ofdifferent particle systems on the bed dynamics of a spout fluidized bed. Thisis done for different flow regimes: the spout-fluidization regime (case A), thejet-in-fluidized-bed regime (case B) and the spouting-with-aeration regime(case C). The considered particle systems comprise glass beads, -aluminaoxide and zeolite 4A particles, which are all classified as Geldart D. A nonintrusivemeasurement technique is used, viz. particle image velocimetry(PIV) to measure the particle flow field in a pseudo two-dimensional (2D)spout fluidized bed. Additionally, digital images are analyzed using a newlydeveloped digital image analysis (DIA) algorithm to evaluate the particlevolume fraction. It is demonstrated that the new proposed DIA algorithmprovides reliable information on the particle volume fraction distribution,showing that it is a powerful tool when combined with PIV. The added valueof DIA is confirmed by comparing the particle velocity fields and volumetricparticle fluxes. The effect of the collision properties for glass beads, -alumina oxide and zeolite 4A particles has been studied in three flow regimes,i.e. the intermediate/spout-fluidization regime (case A), the jet-in-fluidizedbedregime (case B) and the spouting-with-aeration regime (case C). For each flow regime, the particle volume fraction shows small differences betweenthe different particle systems. For the -alumina oxide and zeolite 4Aparticles, the spout channel is less stable for the cases A and C. The particlefluxes display also small differences between the particle systems for eachflow regime.