Statistical and frequency analysis of the pressure fluctuation in a fluidized bed of non-spherical particles

• Published in: Particuology Vol. 16; no. 5; pp. 178 - 186
• Main Authors: He, Honghao, Lu, Xiaofeng, Shuang, Wei, Wang, Quanhai, Kang, Yinhu, Yan, Liyun, Ji, Xuanyu, Luo, Guangyu, Liu, Hai
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2014
• Subjects: Fluidized bed; Non-spherical particles; Pressure fluctuation; Transition velocity; 功率谱分析; 压力波动; 标准偏差; 气体速度; 流化床; 统计; 非球形颗粒; 频率分析; Pressure fluctuation; Transition velocity; Non-spherical particles; Fluidized bed
• ISSN: 1674-2001; 2210-4291
• DOI: 10.1016/j.partic.2014.02.004

In this paper, the pressure fluctuation in a fluidized bed was measured and processed via standard devia- tion and power spectrum analysis to investigate the dynamic behavior of the transition from the bubbling to turbulent regime. Two types （Geldart B and D） of non-spherical particles, screened from real bed materials, and their mixture were used as the bed materials. The experiments were conducted in a semi- industrial testing apparatus. The experimental results indicated that the fluidization characteristics of the non-spherical Geldart D particles differed from that of the spherical particles at gas velocities beyond the transition velocity Uo The standard deviation of the pressure fluctuation measured in the bed increased with the gas velocity, while that measured in the plenum remained constant. Compared to the coarse particles, the fine particles exerted a stronger influence on the dynamic behavior of the fluidized bed and promoted the fluidization regime transition from bubbling toward turbulent. The power spectrum of the pressure fluctuation was calculated using the auto-regressive （AR） model; the hydrodynamics of the flu- idized bed were characterized by the major frequency of the power spectrum of the pressure fluctuation. By combining the standard deviation analysis, a new method was proposed to determine the transition velocity Uk via the analysis of the change in the major frequency. The first major frequency was observed to vary within the range of 1.5 to 3 Hz.