关键词: 流化床, 气泡, 摆动工况, 图像分析, 压力分析

Abstract: In the marine environment, it is necessary to additionally consider the influence law of the swing movement of the bed with the floating platform on the gas-solid flow. From the previous research, there has been a basic understanding of the phenomena such as uneven gas-solid fluidization, gas-solid phase aggregation and separation in the rolling fluidized bed, but there is still a lack of in-depth understanding of the movement and aggregation characteristics of bubbles. The bubble motion characteristics of two-dimensional rolling bed made of transparent plexiglass and Geldart B spherical glass beads are studied in detail based on image analysis and pressure analysis. Through the analysis of the image method, the research results on the spatio-temporal dynamic characteristics of the bubble rising process in the rolling fluidized bed show that when the bed is in the inclined attitude, the bubble rising and aggregation phenomenon is similar to the conventional inclined bed, and the bubble aggregation direction to the wall changes dynamically with the change of the bed attitude. The "hot zone diagram" method is used to analyze the bubble aggregation characteristics in the swing process. It is found that the conversion of bubble aggregation direction obviously "lags behind" the conversion of bed attitude at higher apparent gas velocity. The analysis reason is that the influence of Coriolis force on particles becomes greater at higher gas velocity, which makes particles tend to aggregate in the opposite direction of swing direction, resulting in the delay of gas phase conversion. The analysis results of bubble time averaged characteristics by pressure method show that the swing bed attitude is always "inclined ? vertical" dynamic change, the distribution of bubbles in the bed, the average size of bubbles, and the frequency of bubble generation and rupture are between inclined bed and vertical bed. The influence of operating conditions on the bubble characteristics of rolling bed is studied. The increase of operating gas velocity increases the average bubble size and bubble generation and rupture frequency. The increase of oscillation amplitude increases the frequency of bubble formation and rupture, and has little effect on the average bubble size. The influence of rolling period on both is not obvious.

Key words: Fluidized bed, bubbles, Rolling condition, Image analysis, Stress analysis