Abstract： The image binarization method was used to process the picture and the measurement of porosity was realized by Matlab programming. The effect of the porosity on the flow state in the spouted fluidized bed was analyzed from the micro perspective. The effects of particle size, nozzle number and superficial gas velocity on the porosity distribution were studied. The results showed that the dilute phase area at the bottom of the bed increased with the increase of the apparent gas velocity. Furthermore, the height of bed and porosity also increased. The minimum critical fluidization rate would increase with the increase of particle size, therefore, the particle size of the fluidized bed increased when it reached the fluidized state, and the porosity of the spouted zone decreased significantly. Under the same conditions, compared with the single nozzle, the double nozzle had a combined jet near the bottom of the bed, the height which the particles could reach significantly increased, and the dead zone on both sides of the bottom decreased. Based on the analysis of porosity, a new parameter, fluidization index was proposed, to characterize the fluidization state in a fluidized bed, and could visually represent the fluidization state of the particles in the fluidized bed.
Chen Cuiling,Ma Mengxiang,Yu Yang et al. Study on Porosity in Spouted Fluidized Bed Based on the Digital Image Analysis Method[J]. 化学反应工程与工艺, 2017, 33(4): 343-348.
